20080067 Ver 3_401 Application_20110211

WITHERS RAVENEL
ENGINEERS I PLANNERS 1 SURVEYORS
14'10 COMMONWEALTH DRIVE, SUITE 1o1
WILMINGTON, NORTH CAROLINA, 28403
[phone]
FAX [phone]
TO: NC Division of Water Quality - 4o'1 Wetlands Unit
512 N. Salisbury Street; 9`h Floor
Raleigh, NC 276o4
WE ARE SENDING YOU
? Shop Drawings
? Copy of Letter
® Attached
? Prints
? Change order
the following items:
? Specifications
COPIES DATE NO. DESCRIPTION
1 2/1/11 02100 .00 $570-oo Application Fee
5 2/1/11 02100 .00 Alston Pond PCN
2/1/11 02100349-00 Alston Pond Stormwater Management Report
1 2/1/11 02100 .00 CD with Electronic Co of PCN Information

THESE ARE TRANSMITTED as checked below:
® For approval ? Approved as submitted
? For your use ? Approved as noted
? As requested ? Returned for corrections
? For review and comment ?
? FOR BIDS DUE 20 ? PRINTS RETURNED AFTER LOAN TO US
REMARKS:
Signature: I-cts U 3 2011
Date: il?7tANas In
COPY TO: File
? Resubmit
? Submit
? Return
- copies for approval
copies for distribution
corrected prints
SIGNED: Troy Beasley
if enclosures are not as noted, kindly notify us at once.

DATE 2/2/11 JOB NO. 02100349-00
ATTENTION Mr. Ian McMillan
PHONE# [phone]
RE: Alston Pond Subdivision PCN Submittal

? -o u

? Under separate cover via _
? Plans ? Samples
? Diskette ?
WITHERS &RAV E N E L
ENGINEERS I PLANNERS I SURVEYORS
February 1, 2011
US Army Corps of Engineers
Attn: Mr. James Latsinger
1333 Heritage Trade Drive, Suite 105
Wake Forest, NC 27857
NC-Division of Water Quality
Attn: Mr. Ian McMillan
1650 Mail Service Center
Raleigh, NC 27699-1650
Re: Alston Pond Subdivision
Request for 404/401 Certification and Buffer Compliance
W&R Project Number- 03100349.00
Previous Corps AID #2oo8-oo68o
Previous DWQ#: o8-oo67
Dear Mr. Latsinger and Mr. McMillan:
On behalf of North Broad Street, LLC, we are requesting authorization from the USACE to use
NWP 29 for the construction of a residential subdivision. We are also requesting 401
Certification and Buffer Compliance from the NC-DWQ for impacts to streams, wetlands and
riparian buffers. The proposed project was previously issued NWPs 3 & 29 by the USACE (AID
#2oo8-oo68o) and a 401 WQC and Buffer Compliance (DWQ Project #o8-oo67) by NC-DWQ.
Due to the downturn of the economy, the project was never constructed and the NWPs 3 & 29
and the 401 WQC and Buffer Authorization issued for the project expired on June 13, 2010.
The applicant wishes to move forward with the project at this time, and due to revisions to
the site plan, the proposed impacts have changed.
The subject property is approximately 148 acres in size and is located on the east and west
side of HWy 55, south of the intersection of Old Adams Road and Hwy 55 in Fuquay-Varina,
Wake County, North Carolina at Latitude: 35.6262765°N and Longitude: 78.8132158°W. The
site contains unnamed tributaries to Basal Creek and is located in the Neuse River Basin.
The Water Quality Classification for these features is: B; NSW, the Cataloging Unit for this
site is: 030202o1, and the Stream Index number is: 27-43-15-3•
Project History
The Alston Pond Subdivision was previously issued NWPs 3 & 29 for 147 if of permanent
stream impacts and o.o6 acres of permanent wetland impacts and 49 if of temporary stream
impacts by the Corps of Engineers (AID# 2oo8-oo68o). NC-DWQ issued a 401 WQC for 147 if
of permanent stream impacts, 49 if of temporary stream impacts and o.o6 acres of
permanent wetland impact and Buffer Authorization for 10,848 sq ft of buffer impacts
associated with the Alston Pond Subdivision. Due to the downturn of the economy, the
project was never constructed and the NWPs 3 & 29 and the 401 WQC and Buffer
iii MacKenan Drive I Cary, NC 275111 tel.: [phone] I fax: [phone]oo8 I www.withersravenet.com
1410 Commonwealth Drive I Suite lol Wilmington, NC 28403 1 tel: [phone] I fax: [phone]
416 D Gallimore Dairy Road Greensboro, NC 27409 1 tel: [phone] I fax: [phone]oo8
N.C. Engineering Board No. C-0832
WITHERS RAVENEL
ENGINEERS I PLANNERS I SURVEYORS
Authorization issued for the project expired on June 13, 2010.
Due to the extensive cost of rehabilitating the existing dam to meet Dam Safety
requirements, the applicant has decided to breach the dam and permanently drain the pond.
A pipe will be installed within the base of the dam to will allow unimpeded now of water to
the existing stream below the dam and the open cut in the dam will be backfilled. Until a
stream channel establishes itself within the pond bed and new stream/buffer location is
determined and approved by DWQ, the pond is still buffered, as exhibited in the enclosed
site plans.
During the previous permitting process, numerous meetings and correspondence with the
USACE and NC-DWQ occurred to determine how the impacts from the proposed Hilltop
Needmore Road would be permitted. Specifically, the proposed four-lane thoroughfare is
part of Fuquay-Varina's future development plans and bisects the site and will stub at the
property line that is adjacent to a stream and beaver impoundment. Through the review
process with the USACE, NC-DWQ and the Town of Fuquay-Varina, the alignment of Hilltop
Needmore Road was realigned to minimize future impacts and is now at the current location
shown on the attached site plans. It was decided that the proposed subdivision could not
support the need for a four-lane road at that time. Therefore, North Broad Street, LLC would
apply for the stream crossing for Hilltop Needmore Road in association with the Alston Pond
Subdivision and the Town of Fuquay-Varina would need to apply for future impacts
associated with the extension of Hilltop Needmore Road. Please reference the previous
permit application for a compilation of all correspondence associated with the Hilltop
Needmore Road issue.
The USACE issued a final JD for the onsite wetlands on June 13, 2008.
NC-DWQ issued a Buffer Determination Letter for the subject property on March 20, 2007.
Proposed Impacts
The proposed impacts have changed from the original permitted impacts due to revisions to
the site plan.
Wetland/Stream Impacts
The proposed permanent impacts consist of 147 linear feet of perennial/important stream
channel for a road crossing (Impact #3), 0.03 acres of wetland impacts for installation of an
energy dissipater below a culvert (Impact #8) and fill from backslopes to stabilize site fill
(Impacts #9 & 12). The proposed temporary impacts consist of 27 if of impact to an
intermittent stream for a sewer crossing (Impact # 15) and 0.014 acres of wetland impact from
a sewer crossing (Impact #12).
iii MacKenan Drive I Cary, NC 275-1-11 tel.: [phone] I fax: [phone] I www.withersravenet.com
1410 Commonwealth Drive Suite lot I Wilmington, NC 28403 I tel: [phone] I fax: [phone]
416 D Gallimore Dairy Road I Greensboro, NC 27409 I tel: [phone] I fax: [phone]
N.C. Engineering Board No. C-0832
WITHERS RAVENEL
ENGINEERS I PLANNERS I SURVEYORS
Buffer Impacts
The proposed project will result in 13,550 sq ft of permanent impacts to Zone 1 and 19,501 sq
ft of permanent impacts to Zone 2.
Impact # 1 & 2 will result from a road crossing. The total buffer impacts are less than 1/3 acre
for this crossing and will not require mitigation.
Impact #4 will result from construction of a bypass channel. Bypass channels are an
allowable activity following nitrogen treatment and mitigation is not required for this impact.
Impact #5 will result in impacts from grading for the backslopes of the BMP and installation
of the bypass channel. The disturbed area within Zone 2 will be vegetated with grass once
grading is complete. Grading and revegetation within Zone 2 is an exempt activity and will
not require mitigation. As previously bypass channels are an allowable activity and do not
require mitigation.
Impact #6 & 7 will result from construction of a road. Since the total buffer impacts for this
crossing are less than 1/3 acre, no mitigation is required.
Impact #1o will result in buffer impacts as a result of grading of the backslopes from site fill.
The disturbed area within Zone 2 will be vegetated with grass once grading is complete.
Grading and revegetation within Zone 2 is an exempt activity and mitigation is not required
for this impact.
Impact #13, 14 & 16 will result from installation of the sewer line and construction of a
greenway trail. The proposed sewer easement will be 20' wide. A 10' greenway trail will be
constructed within the sewer easement and will be utilized as the maintenance corridor.
Sewer lines that disturb less than 40 if and have a permanent maintenance corridor of 10 if or
less are an exempt activity and mitigation is not required forthis impact.
Impact #17 will result from grading within Zone 2 for construction of the adjacent BMP. The
disturbed area within Zone 2 will be vegetated with grass once grading is complete. Grading
and revegetation within Zone 2 is an exempt activity and mitigation is not required for this
impact.
Impact #18 & 19 will occur from construction of a bypass channel. Bypass channels are an
allowable activity following nitrogen treatment and mitigation is not required forthis impact.
Impact #20 will result from grading within Zone 2 for construction of the adjacent BMP. The
disturbed area within Zone 2 will be vegetated with grass once grading is complete. Grading
and revegetation within Zone 2 is an exempt activity and mitigation is not required for this
impact.
iii MacKenan Drive I Cary, NC 275-1-11 tel.: [phone] I fax: [phone] I www.withersravenet.com
1410 Commonwealth Drive Suite lot I Wilmington, NC 28403 I tel: [phone] I fax: [phone]
416 D Gallimore Dairy Road I Greensboro, NC 27409 I tel: [phone] I fax: [phone]
N.C. Engineering Board No. C-0832
WITHERS RAVENEL
ENGINEERS I PLANNERS I SURVEYORS
Future Plans
The Alston Pond Subdivision is a single and complete project with no additional phases
proposed at this time. However, there is a thoroughfare that bisects the site. The proposed
alignment was designed such that it terminates at a point that will minimize future impacts.
The Town of Fuquay will be responsible for permitting any future impacts needed to complete
this road. The culverts at this crossing may need to be extended to accommodate future
traffic volumes. If the road should need to be widened, the Town of Fuquay Varina will be the
applicant for additional impacts.
Avoidance and Minimization
Prior to site plan development, the applicant requested that a detailed wetland delineation
be conducted so that impacts to wetlands and `waters' could be minimized. A stream
channel bi-sects the property, and in order to access high ground, impacts were
unavoidable. Impacts were minimized by crossing the channel at a nearly perpendicular
angle, through the use of extensive headwalls at the crossing (Sheet A). A headwall was
also utilized to avoid additional wetland impacts from the northern road (Sheet B).
Backslopes to stabilize lot fill were designed at a 2:1 slope to minimize wetland impacts as
well. The greenway trail was designed to utilized elevated pedestrian bridges at wetland
and stream crossings to furtherminimize wetland impacts.
The project was also designed to avoid and minimize buffer impacts by crossing streams at
almost perpendicular angles.
Stormwater Management Plan
The proposed Stormwater Management Plan consists of 4 proposed BMP's (wet detention
ponds), which provide detention of the 1-year and 1o-year storms to below pre-development
levels. The BMP's are designed in accordance with the latest Stormwater Best Management
Practices Manual. Level Spreaders are provided at all water quality outlet pipes from the
proposed BMP's. High flow bypass pipes are channeled directly to a stream channel. At
BMP's not located adjacent to Riparian Buffers, stormwater is discharged at non-erosive
velocities through at least 30' of natural wetlands or a vegetated filter strip. The Stormwater
Management Plan and supporting information has been provided as an Appendix.
Mitigation
Wetland and Stream Mitigation
Because permanent impacts to streams are less than 150 linear feet and wetland impacts are
less than o.1 acres, mitigation is not proposed for this project.
iii MacKenan Drive I Cary, NC 275-1-11 tel.: [phone] I fax: [phone] I www.withersravenet.com
1410 Commonwealth Drive I Suite lot I Wilmington, NC 28403 I tel: [phone] I fax: [phone]
416 D Gallimore Dairy Road I Greensboro, NC 27409 I tel: [phone] I fax: [phone]
N.C. Engineering Board No. C-0832
WITHERS RAVENEL
ENGINEERS I PLANNERS I SURVEYORS
Buffer Mitigation
Because all proposed buffer impacts are either exempt or allowable uses, the applicant is
not proposing buffer mitigation.
Please feel free to contact me if you have any questions or require additional information to
complete your review of the application.
Sincerely,
Troy Beasley
Environmental Scientist
WITHERS & RAVENEL, INC.
Attachments -
1) PCN Form
2) Agent Authorization
3) USGS Quadrangle Map
4) Wake County Soil Survey Map
5) Previously Issued NWPs 3 & 29
6) Previously Issued 401 WQC and Buffer Authorization
7) NC-DWQ Buffer Approval Letter
8) StormwaterMangementPlan Information
9) BMP Supplement Forms (DWQ PCN Only)
1o) BMP 0&M Agreements (DWQ PCN Only)
11) Impact Plans
iii MacKenan Drive I Cary, NC 275-1-11 tel.: [phone] I fax: [phone]oo8 I www.withersravenet.com
1410 Commonwealth Drive Suite lot I Wilmington, NC 28403 I tel: [phone] I fax: [phone]
416 D Gallimore Dairy Road I Greensboro, NC 27409 I tel: [phone] I fax: [phone]oo8
N.C. Engineering Board No. C-0832
o??o'Fyw?a rF9Q?
oNii? -c
Office Use Only:
Corps action ID no.
DWQ project no.
Form Version 1.3 Dec 10 2008
Pre-Construction Notification (PCN) Form
A. Applicant Information
1. Processing
1 a. Type(s) of approval sought from the
Corps:
®Section 404 Permit El Section 10 Permit
1 b. Specify Nationwide Permit (NWP) number: NWP 29 or General Permit (GP) number:
1 c. Has the NWP or GP number been verified by the Corps? ® Yes ? No
1 d. Type(s) of approval sought from the DWQ (check all that apply):
® 401 Water Quality Certification - Regular ? Non-404 Jurisdictional General Permit
? 401 Water Quality Certification - Express ® Riparian Buffer Authorization
1 e. Is this notification solely for the record
because written approval is not required? For the record only for DWQ 401
Certification:
? Yes ® No For the record only for Corps Permit:

? Yes ® No
1f. Is payment into a mitigation bank or in-lieu fee program proposed for mitigation
of impacts? If so, attach the acceptance letter from mitigation bank or in-lieu
fee program. ? Yes ® No
1 g. Is the project located in any of NC's twenty coastal counties. If yes, answer 1 In
below. ? Yes ® No
1 h. Is the project located within a NC DCM Area of Environmental Concern (AEC)? ? Yes ® No
2. Project Information
2a. Name of project: Alston Pond Subdivision
2b. County: Wake
2c. Nearest municipality / town: Fuquay-Varina
2d. Subdivision name:
2e. NCDOT only, T.I.P. or state
project no:
3. Owner Information
3a. Name(s) on Recorded Deed: North Broad Street, LLC
3b. Deed Book and Page No. DB: 12671; DP:0810
3c. Responsible Party (for LLC if
applicable): Tim Smith
3d. Street address: 201 Weston Parkway, Suite 203
3e. City, state, zip: Cary, NC 27513
3f. Telephone no.: 919-481-3000
3g. Fax no.:
3h. Email address: [e-mail]
Page I of 13
PCN Form - Version 1.3 December 10, 2008 Version
4. Applicant Information (if different from owner)
4a. Applicant is: ? Agent ? Other, specify:
4b. Name:
4c. Business name
(if applicable):
4d. Street address:
4e. City, state, zip:
4f. Telephone no.:
4g. Fax no.:
4h. Email address:
5. Agent/Consultant Information (if applicable)
5a. Name: Troy Beasley
5b. Business name
(if applicable): Withers and Ravenel
5c. Street address: 1410 Commonwealth Drive, Suite 101
5d. City, state, zip: Wilmington, NC 28403
5e. Telephone no.: 910-256-9277
5f. Fax no.: 910-256-2584
5g. Email address: [e-mail]
Page 2 of 13
PCN Form - Version 1.3 December 10, 2008 Version
B. Project Information and Prior Project History
1. Property Identification
1 a. Property identification no. (tax PIN or parcel ID): PIN#s 0658523920; 0658317536
1 b. Site coordinates (in decimal degrees): Latitude: 35.6262765 Longitude: - 78.8132158
(DD.DDDDDD) (-DD.DDDDDD)
1 c. Property size: ±148 acres
2. Surface Waters
2a. Name of nearest body of water (stream, river, etc.) to Basal Creek
proposed project:
2b. Water Quality Classification of nearest receiving water: B;NSW (Stream Index #27-43-15-3
2c. River basin: Neuse River Basin
3. Project Description
3a. Describe the existing conditions on the site and the general land use in the vicinity of the project at the time of this
application:
The site is approximately 75% forested and 25% agricultural fields. A small residential community is located to the north,
NC Hwy 55 is located to the west and Basal Creek borders the property to the east.
3b. List the total estimated acreage of all existing wetlands on the property:
±9.62 acres
3c. List the total estimated linear feet of all existing streams (intermittent and perennial) on the property:
±4,579 If
3d. Explain the purpose of the proposed project:
The purpose of the proposed project is to construct a residential subdivision.
3e. Describe the overall project in detail, including the type of equipment to be used:
The overall project includes the construction of a residential community. Large grading equipment will be used to install
the infrastructure (i.e. roads, sewer, BMPs) and prepare the site for construction of the residential homes and apartments.
4. Jurisdictional Determinations
4a. Have jurisdictional wetland or stream determinations by the
Corps or State been requested or obtained for this property /
®Yes ? No ? Unknown
project (including all prior phases) in the past?
Comments:
4b. If the Corps made the jurisdictional determination, what type
? Preliminary ®Final
of determination was made?
4c. If yes, who delineated the jurisdictional areas? Agency/Consultant Company: Withers and Ravenel
Name (if known): Todd Preuninger Other:
4d. If yes, list the dates of the Corps jurisdictional determinations or State determinations and attach documentation.
Corps JD - 6/13/2008 (AID#200800680)
DWQ Buffer Determination - March 20, 2007 (Project # NBRRO 07-028)
5. Project History
5a. Have permits or certifications been requested or obtained for ® Yes ? No ? Unknown
this project (including all prior phases) in the past?
5b. If yes, explain in detail according to "help file" instructions.
NWP 3 & 29 - issued 6/13/2008 - AID# 200800680
401 WQC and Buffer Authorization - issued 8/26/2008 - DWQ Project # 08-0067. Ver. 2
Page 3 of 13
PCN Form - Version 1.3 December 10, 2008 Version
6. Future Project Plans
6a. Is this a phased project? ® Yes ? No
6b. If yes, explain.
The subdivision will be constructed in Phases. However, the impacts for the entire project are being permitted as a single
project.
Page 4 of 13
PCN Form - Version 1.3 December 10, 2008 Version
C. Proposed Impacts Inventory
1. Impacts Summary
1 a. Which sections were completed below for your project (check all that apply):
® Wetlands ® Streams - tributaries ® Buffers
? Open Waters ? Pond Construction
2. Wetland Impacts
If there are wetland impacts proposed on the site, then complete this question for each wetland area impacted.
2a. 2b. 2c. 2d. 2e. 2f.
Wetland impact Type of jurisdiction
number - Permanent Type of impact Type of wetland Forested (Corps - 404, 10 Area of impact
(P) or Temporary (T) (if known) DWQ - non-404, other) (acres)
Impact 8 ® P ? T Permanent / Fill Headwater Forest ® Yes
? No ® Corps
® DWQ 0.005 ac
Impact 9 ® P ? T Permanent / Fill Headwater Forest ® Yes
? No ® Corps
® DWQ 0.011 ac

Impact 11 ? PET Sewer
Construction
Headwater Forest ® Yes
? No ® Corps
® DWQ
0.014 ac
Impact 12 ® P ? T Permanent / Fill Headwater Forest ® Yes
? No ® Corps
® DWQ 0.003 ac
2g. Total wetland impacts 0.033 ac
2h. Comments: Impacts to wetlands will occur from rehabilitation of an existing dam to meet dam safety requirements.
3. Stream Impacts
If there are perennial or intermittent stream impacts (including temporary impacts) proposed on the site, then complete this
question for all stream sites impacted.
3a. 3b. 3c. 3d. 3e. 3f. 3g.
Stream impact Type of impact Stream name Perennial Type of jurisdiction Average Impact
number -Permanent (PER) or (Corps - 404, 10 stream length
(P) or Temporary (T) intermittent DWQ - non-404, width (linear
(INT)? other) (feet) feet)

Impact 2 ®P F-1 T
Fill /Culvert
UT to Basal
Creek
PER
®
? INT ®
Corps
® DWQ
5'
147 If
Impact 15 ? P ® T Sewer Crossing UT to Basal
Creek ? PER
® INT ® Corps
® DWQ 3' 27 If
3h. Total stream and tributary impacts 150 If
3i. Comments:
4. Open Water Impacts
If there are proposed impacts to lakes, ponds, estuaries, tributaries, sounds, the Atlantic Ocean, or any other open water of
the U.S. then individually list all open water impacts below.
4a. 4b. 4c. 4d. 4e.
Open water impact Name of
number - Permanent waterbody Type of impact Waterbody type Area of impact (acres)
(P) or Temporary (T) (if applicable)
01 ?P?T
02 ?P?T
03 ?P?T
04 ?P?T
4f. Total open water impacts
4g. Comments:
Page 5 of 13
PCN Form - Version 1.3 December 10, 2008 Version
5. Pond or Lake Construction
If pond or lake construction proposed, then complete the chart below.
5a.

Pond ID 5b.

Proposed use or purpose of 5c.
Wetland Impacts (acres) 5d.
Stream Impacts (feet) 5e.
Upland
(acres)
number pond
Flooded
Filled
Excavated
Flooded
Filled
Excavated
Flooded
P1
P2
K Total
5g. Comments:
5h. Is a dam high hazard permit required?
? Yes ? No If yes, permit ID no:
5i. Expected pond surface area (acres):
5j. Size of pond watershed (acres):
5k. Method of construction:
Page 6 of 13
PCN Form - Version 1.3 December 10, 2008 Version
6. Buffer Impacts (for DWQ)
If project will impact a protected riparian buffer, then complete the chart below. If yes, then individually list all buffer impacts
below. If any impacts require mitigation, then you MUST fill out Section D of this form.
6a.
® Neuse ? Tar-Pamlico ? Other:
Project is in which protected basin? ? Catawba ? Randleman
6b. 6c. 6d. 6e. 6f. 6g.
Buffer impact number
- Permanent (P) or Reason for Buffer Zone 1 impact Zone 2 impact
Temporary (T) impact Stream name mitigation (square feet) (square feet)
required?
Impact 1 ® P ? T Road
Crossing UT to Basal Creek ? Yes
® No N/A 5,338 sq ft
Impact 2 ® P ? T CoRoad ss ng UT to Basal Creek ®Neos 9,045 sq ft N/A
Impact 4 ® P ? T ChBypass annel UT to Basal Creek ®Neos 456 sq ft N/A
Grading and ? Yes
Impact 5 ® P ? T outfall UT To Basal Creek ® No N/A 1,191 sq ft
structure
Impact 6 ® P ? T Road
Crossing UT To Basal Creek ? Yes
® No N/A 3,707 sq ft
Impact 7 ® P ? T CoRoad ss ng UT To Basal Creek ®Neos 2,503 sq ft N/A
Impact 10 ® PEI T Grading UT To Basal Creek ®Neos N/A 4,665 sq ft
Impact 13 ® P ? T ConsSewer t ruction UT To Basal Creek ®Neos N/A 426 sq ft
Impact 14 ® P ? T ConsSewer t ruction UT To Basal Creek ®Neos 1,485 sq ft N/A
Impact 16 ® P ? T ConsSewer t ruction UT To Basal Creek ®Neos N/A 668 sq ft
Impact 17 ® P ? T Grading UT To Basal Creek ®Neos N/A 668 sq ft
Impact 18 ® P ? T ChBypass annel UT To Basal Creek ®Neos N/A 285 sq ft
Impact 19 ® PEI T ChBypass annel UT To Basal Creek ®Neos 61 sq ft N/A
Impact 20 ® P ? T Grading UT To Basal Creek ®Neos N/A 2,553 sq ft
6h. Total buffer impacts 13,550 sq ft 19,501 sq ft
6i. Comments: Because buffer impacts are less than 1/3 of an acre at each road crossing and grading within zone 2, sewer
lines less than 40 If and stormwater conveyances are considered an allowable uses, the applicant is not proposing buffer
mitigation.
D. Impact Justification and Mitigation
1. Avoidance and Minimization
1 a. Specifically describe measures taken to avoid or minimize the proposed impacts in designing project.
Prior to site plan development, the applicant requested that a detailed wetland delineation be conducted so that impacts to
wetlands and `waters' could be minimized. A stream channel bi-sects the property, and in order to access high ground,
impacts were unavoidable. Impacts were minimized by crossing the channel at a nearly perpendicular angle, through the use
of extensive headwalls at the crossing (Sheet A). A headwall was also utilized to avoid additional wetland impacts from the
northern road (Sheet B). Backslopes to stabilize lot fill were designed at a 2:1 slope to minimize wetland impacts as well. The
greenway trail was designed to utilized elevated pedestrian bridges at wetland and stream crossings to further minimize
wetland impacts.
Page 7 of 13
PCN Form - Version 1.3 December 10, 2008 Version
1 b. Specifically describe measures taken to avoid or minimize the proposed impacts through construction techniques.
Head walls will be used to stabilize fill at all road crossings and pedestrian bridges will be used for greenway crossings. Also,
silt fencing will be installed around all disturbed areas to prevent sediment from escaping the site and entering downstream
waters and wetlands.
2. Compensatory Mitigation for Impacts to Waters of the U.S. or Waters of the State
2a. Does the project require Compensatory Mitigation for
impacts to Waters of the U.S. or Waters of the State? ? Yes ® No
2b. If yes, mitigation is required by (check all that apply): ? DWQ ? Corps

2c. If yes, which mitigation option will be used for this project? ? Mitigation bank
? Payment to in-lieu fee program
? Permittee Responsible Mitigation
3. Complete if Using a Mitigation Bank
3a. Name of Mitigation Bank:
3b. Credits Purchased (attach receipt and letter) Type Quantity
3c. Comments:
4. Complete if Making a Payment to In-lieu Fee Program
4a. Approval letter from in-lieu fee program is attached. ? Yes
4b. Stream mitigation requested: linear feet
4c. If using stream mitigation, stream temperature: ? warm ? cool ?cold
4d. Buffer mitigation requested (DWQ only): square feet
4e. Riparian wetland mitigation requested: acres
4f. Non-riparian wetland mitigation requested: acres
4g. Coastal (tidal) wetland mitigation requested: acres
4h. Comments:
5. Complete if Using a Permittee Responsible Mitigation Plan
5a. If using a permittee responsible mitigation plan, provide a description of the proposed mitigation plan.
Page 8of13
PCN Form - Version 1.3 December 10, 2008 Version
6. Buffer Mitigation (State Regulated Riparian Buffer Rules) - required by DWQ
6a. Will the project result in an impact within a protected riparian buffer that requires ? Yes ® No
buffer mitigation?
6b. If yes, then identify the square feet of impact to each zone of the riparian buffer that requires mitigation. Calculate the
amount of mitigation required.
6c. 6d. 6e.
Zone Reason for impact Total impact Multiplier Required mitigation
(square feet) (square feet)
Zone 1 3 (2 for Catawba)
Zone 2 1.5
6f. Total buffer mitigation required:
6g. If buffer mitigation is required, discuss what type of mitigation is proposed (e.g., payment to private mitigation bank,
permittee responsible riparian buffer restoration, payment into an approved in-lieu fee fund).
6h. Comments: Because buffer impacts are less than 1/3 of an acres at each road crossing and stormwater conveyances are
considered an allowable activity following nitrogen treatment, the buffer impacts do not require mitigation.
Page 9 of 13
PCN Form - Version 1.3 December 10, 2008 Version
E. Stormwater Management and Diffuse Flow Plan (required by DWQ)
1. Diffuse Flow Plan
1 a . Does the project include or is it adjacent to protected riparian buffers identified ® Yes ? No
within one of the NC Riparian Buffer Protection Rules?
1 b . If yes, then is a diffuse flow plan included? If no, explain why.
® Yes ? No
Comments:
2. Stormwater Management Plan
2a . What is the overall percent imperviousness of this project? 31 %
2b . Does this project require a Stormwater Management Plan? ® Yes ? No
2c. If this project DOES NOT require a Stormwater Management Plan, explain why:
2d . If this project DOES require a Stormwater Management Plan, then provide a brief, narrative description of the plan:
The Stormwater Plan consists of 4 proposed BMP's (wet detention ponds), which provide detention of the 1-year and 10-
year storms to below pre-development levels. The BMP's are designed in accordance with the latest Stormwater Best
Management Practices Manual. Level Spreaders are provided at all water quality outlet pipes from the proposed BMP's.
High flow bypass pipes are channeled directly to a stream channel. At BMP's not located adjacent to Riparian Buffers,
stormwater is discharged at non-erosive velocities through at least 30' of natural wetlands or a vegetated filter strip. The
Stormwater Management plan has been provided as an Appendix.
? Certified Local Government
2e . Who will be responsible for the review of the Stormwater Management Plan? ? DWQ Stormwater Program
® DWQ 401 Unit
3. Certified Local Government Stormwater Review
3a. In which local government's jurisdiction is this project?
? Phase II
3b . Which of the following locally-implemented stormwater management programs ? NSW
? USMP
apply (check all that apply): ? Water Supply Watershed
? Other:
3c. Has the approved Stormwater Management Plan with proof of approval been ? Yes ? No
attached?
4. DWQ Stormwater Program Review
? Coastal counties
? HQW
4a . Which of the following state-implemented stormwater management programs apply ? ORW
(check all that apply): ® Session Law 2006-246
? Other:
4b . Has the approved Stormwater Management Plan with proof of approval been
attached? ? Yes ® No
5. DWQ 401 Unit Stormwater Review
5a . Does the Stormwater Management Plan meet the appropriate requirements? ® Yes ? No
Page 10 of 13
PCN Form - Version 1.3 December 10, 2008 Version
5b. Have all of the 401 Unit submittal requirements been met? ® Yes ? No
F. Supplementary Information
1. Environmental Documentation (DWQ Requirement)
1 a. Does the project involve an expenditure of public (federal/state/local) funds or the ? Yes ® No
use of public (federal/state) land?
1 b. If you answered "yes" to the above, does the project require preparation of an
environmental document pursuant to the requirements of the National or State ? Yes ? No
(North Carolina) Environmental Policy Act (NEPA/SEPA)?
1 c. If you answered "yes" to the above, has the document review been finalized by the
State Clearing House? (If so, attach a copy of the NEPA or SEPA final approval
? Yes ? No
letter.)
Comments:
2. Violations (DWQ Requirement)
2a. Is the site in violation of DWQ Wetland Rules (15A NCAC 2H .0500), Isolated
Wetland Rules (15A NCAC 2H .1300), DWQ Surface Water or Wetland Standards, ? Yes ® No
or Riparian Buffer Rules (15A NCAC 2B .0200)?
2b. Is this an after-the-fact permit application? ? Yes ® No
2c. If you answered "yes" to one or both of the above questions, provide an explanation of the violation(s):
3. Cumulative Impacts (DWQ Requirement)
3a. Will this project (based on past and reasonably anticipated future impacts) result in ? Yes ® No
additional development, which could impact nearby downstream water quality?
3b. If you answered "yes" to the above, submit a qualitative or quantitative cumulative impact analysis in accordance with the
most recent DWQ policy. If you answered "no," provide a short narrative description.
This is a single and complete project with no additional phases proposed at this time.
4. Sewage Disposal (DWQ Requirement)
4a. Clearly detail the ultimate treatment methods and disposition (non-discharge or discha rge) of wastewater generated from
the proposed project, or available capacity of the subject facility.
Page 11 of 13
PCN Form - Version 1.3 December 10, 2008 Version
5. Endangered Species and Designated Critical Habitat (Corps Requirement)
5a . Will this project occur in or near an area with federally protected species or ? Yes ® No
habitat?
5b . Have you checked with the USFWS concerning Endangered Species Act ? Yes ® No
impacts?
E] Raleigh
5c. If yes, indicate the USFWS Field Office you have contacted.
? Asheville
5d . What data sources did you use to determine whether your site would impact Endangered Species or Designated Critical
Habitat?
W&R reviewed the NC OneMap Viewer GIS website, located at http://www.nconemap.net/Default.aspx?tabid=286, to
identify if any potential occurrence of endangered species on or near the proposed project. The review of the GIS
database did not identify any recent occurrences of endangered species or critical habitat on the subject property or
within 0.5 miles of the project. The previous issuance of NWPs 3 & 29 documents that the proposed project will not
impact endangered species or critical habitat.
It should also be noted that this project was previously permitted, which documents that the project will not result in
impacts to Endangered Species or Critical Habitat.
6. Essential Fish Habitat (Corps Requirement)
6a . Will this project occur in or near an area designated as essential fish habitat? ? Yes ® No
6b . What data sources did you use to determine whether your site would impact Essential Fish Habitat?
There are no waters designated as EFH in Wake County.
7. Historic or Prehistoric Cultural Resources (Corps Requirement)
7a . Will this project occur in or near an area that the state, federal or tribal
governments have designated as having historic or cultural preservation ? Yes ® No
status (e.g., National Historic Trust designation or properties significant in
North Carolina history and archaeology)?
7b . What data sources did you use to determine whether your site would impact historic or archeological resources?
There are no historic structures located on the project site.
8. Flood Zone Designation (Corps Requirement)
8a. Will this project occur in a FEMA-designated 100-year floodplain? ? Yes ® No
8b . If yes, explain how project meets FEMA requirements:
8c. What source(s) did you use to make the floodplain determination? FEMA FIRM Panel 0658J
Tro
Beasle
y
y
Withers and Ravenel 2/1 /11

Applicant/Agent's Printed Name Applicant/Agent's Signature
' Date
(Agent
s signature is valid only if an authorization letter from the applicant
is provided.)
Page 12 of 13
PCN Form - Version 1.3 December 10, 2008 Version
AGENT AUTHORIZATION
WITHERS &`RAVENEL
ENGiNEERS I PLANNERS I SURVEYORS
AUTHORITY FOR APPOINTMENT OF AGENT
The undersigned owner(s) North Broad Street, LLC do(es) hereby appoint Trov Beasley /
Withers & Ravenel. Inc, as his, her, or It's agent for the purpose of petitioning the appropriate
local, state and federal environmental regulatory agencies (US Army Corps of Engineers, NC
Division of Water Quality. NC Division of Coastal Management. eta) for. a) review and approval
of the jurisdictional boundaries of onsite jurisdictional areas (wetlands, surface water, etc.)
and/or: b) preparation and submittal of appropriate environmental permit application$/requests for
the Alston Pond Subdivision,
The owner does hereby authorize that sold agent has the authority to de the following acts on
behalf of the owner:
(1) To submit appropriate requests/applications and the required supplemental
materials:
(2) To attend meetings to give representation on behalf of the Client.
(3) To authorize access to subject property for the purpose of environmental
review by appropriate regulatory agencies.
This authorization shall continue in effect until completion of the contracted task or termination by
the property owner.

Agents Name, Address & Telephone:
Date.
Signatu vP Owner(s):
(Name - Print) (Title)
III ,
(S n
Mailing Address f
rlk(m 1v C- --2i-In
City State Zip
111 MacKenan Drive I Cary, NC 275111 tel.; 919,469.33401 fax: 919,467-60081 www.withefsrevanel.com I License No, C-0832
1410 Commonwealth 1]rive 1 Suite 1011 Wilmington, NC 284031 tel; 910.256.92771 fax: 910.256,2584
416 D Gallimore Dairy Road I Greensboro, NC 274091 tel: [phone] fax: [phone]
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Fu E. Wake Courh North Carolina
PREVIOUSLY ISSUED
NWP 3 & 29
L fr
U.S. ARMY CORPS OF ENGINEERS
WILMINGTON DISTRICT
Action ID. 200800680 County: Wake
USGS Quad: Apex
GENERAL PERMIT (REGIONAL AND NATIONWIDE) VERIFICATION
ref CE/V
Property Owner / Authorized Agent: North Broad Street, LLC r®
Address: Attn: Jeffrey Smerko oy 18 ?pdo
14600 Weston Par",ay it?)ng
Cary, NC' 1°t'Ell't r?-,
Telephone No.: 919-678-8800
Size and location of property (water body, road name/number, town, etc.): The Alston Pond site is approximately 148
acres of land located northeast of Broad Street 0.5 miles northwest of the intersection of Broad Street and Wade
Nash U, in Fuqu`iy-Varina, Wake County, North Carolina.
Description of projects area and activity: This authorization is for the permanent impact of .06 acres of wetlands and
the temporary impact of 49 linear feet (lf) of stream channel, clue to construction associated with a damn
....l...l.:l:?..t..... k.1.7;4;nnoll.f fh;e norrnit antharhtie q tho Tinrrnaneat ininact of 147 if of streani channel due to the
The
ith the annlication and d
on May 28, 2008 and in accordance with the permit conditions stated below.
Applicable Law: ® Section 404 (Clean Water Act, 33 USC 1344)
? Section 10 (Rivers and Harbors Act, 33 USC 403)
Authorization: Regional General Permit Number:
Nationwide Permit Number: 29
Your work is authorized by the above referenced permit provided it is accomplished in strict accordance with the attached
conditions and your submitted plans. Any violation of the attached conditions or deviation from your submitted plans may subject the
permittee to a stop work order, a restoration order and/or appropriate legal action.
This verification will remain valid until the expiration date identified below unless the nationwide authorization is modified,
suspended or revoked. If, prior to the expiration date identified below, the nationwide permit authorization is reissued and/or
modified, this verification will remain valid until the expiration date identified below, provided it complies with all requirements of
the modified nationwide permit. If the nationwide permit authorization expires or is suspended, revoked, or is modified, such that the
activity would no longer comply with the terms and conditions of the nationwide permit, activities which have commenced. (i.e., are
under construction) or are under contract to commence in reliance upon the nationwide permit, will remain authorized provided the
activity is completed within twelve months of the date of the nationwide permit's expiration, modification Or revocation, uzzless
discretionary authority has been exercised on a case-by-case basis to modify, suspend or revoke the authorization.
Activities subject to Section 404 (as indicated above) may also require an individual Section 401 Water Quality Certification. You
should contact the NC Division of Water Quality (telephone [phone]) to determine Section 401 requirements.
For activities occurring within the twenty coastal counties subject to regulation under the Coastal Area Management Act (CAMA),
prior to beginning work you must contact the N.C. Division of Coastal Management.
This Department of the Army verification does not relieve the permittee of the responsibility to obtain any other required Federal,
State or local approvals/permits.
If there are any questions regarding this verification, any of the conditions of the Permit, or the Corps of Engineers regulatory
program, please contact Jamie Shern.
Permit Condition: A pre-construction inspection of the project site must be performed by the Army Corps of Engineers,
Wilmington District (USACE), prior to beginning work within jurisdictional waters. The applicant must contact the USACE to
establish a suitable date and time to conduct the pre-construction inspection. The applicant, and construction contractor who will be
installing the culvert/road crossing, must be present during the pre-construction inspection. Also, the exact footprint of the proposed
fill must be demarcated for the pre-construction meeting. Geographic coordinates (latitude and longitude), for the project endpoints
(upstream and downstream locations) must be provided before or on the pre-construction inspection date. The coordinates roust be
provided in North American Datum 1983(NII D83), decimal degree format.
Page 1 of 2
The applicant must notify the USACE, in writing, no later than 30 days after completion of work within jurisdictional waters. The
notification must be sent to the appropriate project r anager in the Raleigh Regulatory Field Office, U.S. Army Corps of Engineers,
3331 Heritage Trade Drive, Suite 105, Wake Forest, Vc ? Iz Carolina 27'87.
Corps Regulatory Official
Expiration Date of Verification: 6/13/2010
Date: 06/13/2008
The Wilmington District is committed to providing the highest level of support to the public. To help us ensure we continue to do so,
please complete the Customer Satisfaction Survey located at our website at hqp://regulatoKy.usacesurvey.com/ to complete the survey
online.
Page 2 of 2
Determination of Jurisdiction:
? Based on preliminary information, there appear to be waters of the US including wetlands within the above described project area.
This preliminary determination is not an appealable action under the Regulatory Program Administrative Appeal Process
(Reference 33 CFR Part 331).
? There are Navigable Waters of the United States within the above described project area subject to the permit requirements of
Section 10 of the Divers and Harbors Act and Section 404 of the Clean Water Act. Unless there is a change in the law or our
published regulations, this determination may be relied upon for a period not to exceed five years from the date of this
notification.
® There are waters of the U5 and/or wetlands within the above described project area subject to the permit requirements of Section
404 of the Clean Water Act (CWI+A)(33 USC § 1344). Unless there is a change in the law or our published regulations, this
determination may be relied upon for a period not to exceed five years from the date of this notification.
? The jurisdictional areas within the above described project area have been identified under a previous action. Please reference
jurisdictional determination issued . Action ID
Basis of Jurisdictional Determination: Wetlands were detc? nthied tts n? the Corps 1987 delineation manual. Streams were
identified utilizing ot-dinat`y high water marl. as ideittilied in the fwld.
Appeals Information (This information applies only to approved jurisdictional determinations.)
Attached to this verification is an approved jurisdictional determination. If you are not in agreement with that approved jurisdictional
determination, you can make an administrative appeal under 33 CFR 331. Enclosed you will find a Non Iication of Appeal Process
(NAP) fact sheet and request for appeal (RFA) form. If you request to appeal this determination you trust submit a completed RFA
form to the following address:
District Engineer, Wilmington Regulatory Division
Attn: Jean Manuele, Field Office Chief,
Raleigh Regulatory Field Office
3331 Heritage Trade Drive, Suite 105
Wake Forest, North Carolina 27587
In order for an 11.FA to be accepted by the Corps, the Corps must determine that it is complete, that it meets the criteria for appeal
under 33 CFR part 331.5, and that it has been received by the District Office within 60 days of the date of the NAP. Should you
decide to submit an RFA form, it must be received at the above address by 8/12/2008.
**It is not necessary to submit an A form to the District Office if you do not object to the determination in this correspondence.**
Corps Regulatory Official: ^
Date 06/13/2008 Expiration Date 06/13/2013
SURVEY PLATS, FIELD SKETCH, WETLAND DELINEATION FORMS, PROJECT PLANS, ETC., MUST BE
ATTACHED TO THE FILE COPY OF THIS FORM, IF REQUIRED OR AVAILABLE.
Copy Furnished:
Withers & Ravenel
Attn: Todd Preuninger
111 MacKenan Drive
Cary, NC 27511
Page 3 of 2
PREVIOUSLY ISSUED
401 WQC & BUFFER AUTHORIZATION
?F W A rFR J f? Michael F. Easley, Governor
William G. Ross Jr., Secretary
North Carolina Department of Environment and Natural Resources
p Coleen H. Sullins, Director
Division of water Quality
August 26, 2008 'Pc
C'
D'ect # 08-0067, Ver. 2
Wake County
Mr. Jeffrey Smerko th?rs 1008
North Broad Street, LLC
14600 Weston Parkway RdL
Cary, NC 27513 P??of
Subject Property: Alston Pond/North Broad Street
Utto Basal Creek [030403, 27-43-15-3, B, NSW]
Approval of 401 Water Quality Certification and Authorization Certificate per the Neuse River
Buffer Protection Rules (15A NCAC 2B.0233) with Additional Conditions
Dear Mr. Smerko:
You have our approval, in accordance with the attached conditions and those .listed below, to place fill
within or otherwise impact 0.06 acres.of 404/wetland, 196 linear feet of perennial stream (147 linear feet
permanent impact and 49 linear feet temporary impact), and 10,848 square feet of Zone 1 Neuse River
basin protected riparian buffers-and 8;543 square feet of Zone 2 Neuse River basin protected riparian
buffers, as described in-your revised application dated July 21, 2008, and received by the Division of
Water Quality (DWQ)-6mJuly 21, 2008, to construct the proposed residential demplppment -at the site.
After reviewing your application, we have decided that the impacts are covered by General Water Quality
Certification Number(s) 3687 and 3705 (GC3687) and (GC3705).r The Certification(s) allows you to use
Nationwide Permit(s) NW3 and NW29, respectively, when issued by the US Army Corps of Engineers
(USACE). In addition, you should obtain or otherwise comply with any other required federal, state or
local permits before you go ahead with your project including (but not limited to) Erosion and Sediment
Control, and Non-discharge regulations. Also, this approval to proceed with your proposed impacts
or to conduct impacts to waters as depicted in your application shall expire upon expiration of the
404 or CAMA Permit.
This approval is for the purpose and design that you described in your application. If you change your
project, you must notify us and you may be required to send us a new application. If the property is sold,
the new owner must be given a copy of this Certification and approval letter and is thereby responsible for
complying with all conditions. If total fills for this project (now or in the future) exceed one acre of
wetland or 150 linear feet of stream, compensatory mitigation may be required as described in 15A
NCAC 2H .0506 (h). This approval requires you to follow the conditions listed in the attached
certification and any additional conditions listed below.
The Additional Conditions of the Certification are:
1. Impacts Approved
The following impacts are hereby approved as long as all of the other specific'and general
conditions of this Certification (or Isolated Wetland Permit) are met. No other impacts are
approved including incideptal impacts:
None Carolina
401 Oversight/Express Review Permitting Unit tura!!y
1650 Mail Service Center, Raleigh, North Carolina 27699-1650
2321 Crabtree Boulevard, Suite 250, Raleigh, North Carolina 27604
Phone: [phone] FAX [phone] / Intemet: htty:/lh2o.enr.state.nc.us/ncwetlands
An Equal Opportunity/Affirmative Action Employer - 50% Recycled/] 0% Post Consumer Paper
North Broad Street, LLC
Page 2 of 5
August 26, 2008
Type of Impact Amount Approved Units Plan Location or Reference
404/Wetland 0.06 (acres) PCN page 4 of 9
Stream - perennial 196 [(linear feet) 147 linear feet permanent
impact and 49 linear feet temporary impact] PCN page 4 of 9
Buffers Zone 1 10,848 (square ft. PCN page 7 of 9
Buffers Zone 2 8,453 (square tt. PCN page 7 of 9
2. No Waste, Spoil, Solids, or Fill of Any Kind
No waste, spoil, solids, or fill of any kind shall occur in wetlands, waters, or riparian areas beyond
the footprint of the impacts depicted in the Pre-Construction Notification. All construction
activities, including the design, installation, operation, and maintenance of sediment and erosion
control Best Management Practices, shall be performed so that no violations of state water quality
standards, statutes, or rules occur.
3. Erosion and sediment control practices must be in full compliance with all specifications governing
the proper design, installation and operation and maintenance of such Best Management Practices in
order to protect surface waters standards:
a. The erosion and sediment control measures for the project must be designed, installed,
operated, and maintained in accordance with the most recent version of the North Carolina
Sediment and Erosion Control Planning and Design Manual.
-b,. The design, installation, operation, and maintenance of the sediment and erosion control
measures must be such that they equal, or exceed, the requirements specified in the most
recent version of the North Carolina Sediment and Erosion Control Manual. The devices
shall be maintained on all construction sites, borrow sites, and waste pile (spoil) projects,
including contractor-owned or leased borrow pits associated with the project.
C.- , 'Sufficient materials required for stabilization and/or repair of erosion control measures and
stormwater routing and treatment shall be on site at all times.
4. Sediment and Erosion Contr6l-Mpasures
Sediment and erosion control measures shall not be placed in wetlands. or waters without prior
approval from the Division. if placement of sediment and erosion control devices in wetlands and
waters is unavoidable, design and placement of temporary erosion control measures shall not be
conducted in a manner that may result in dis-equilibrium of wetlands or stream beds or banks,
adjacent to or upstream and down stream of the above structures. All sediment and erosion control
devices shall be removed and the natural grade restored within two (2) months of the date that the
Division of Land Resources or locally delegated program has released the project;
5. Culvert Installation
All work in or adjacent to stream waters shall be conducted in a dry work area. Approved BMP
measures from the most current version of NCDOT Construction and Maintenance Activities manual
(httl2-'//www.nedot.org/doh/opei-ations/BMP manual/download/BMP Manual.pdf)
such as sandbags, rock berths, cofferdams and other diversion structures shall be used to prevent
excavation in flowing water.
Culverts required for this project shall be installed in such a manner that the original stream
profiles are not altered. Existing stream dimensions (including the cross section dimensions,
pattern, and longitudinal profile) must be maintained above and below locations of each culvert.
Culverts shall be designed and installed to allow for aquatic life movement as well as to prevent
North Broad Street, LLU
Page 3 of 5
August 26, 2008
head cutting of the streams. If any of the existing pipes are or become perched, the appropriate
stream grade shall be re-established or, if the pipes installed in a perched manner, the pipes shall
be removed and re-installed correctly.
Culvert(s) shall not be installed in such a manner that will cause aggradation or erosion of the
stream up or down stream of the culvert(s). Existing stream dimensions (including the cross section
dimensions, pattern and longitudinal profile) shall be maintained above and below locations of each
culvert.
Placement of culverts and other structures in waters, streams, and wetlands must be placed below
the elevation of the streambed by one foot for all culverts with a diameter greater than 48 inches,
and 20 percent of the culvert diameter for culverts having a diameter less than 48 inches, to allow
low flow passage of water and aquatic life. Design and placement of culverts and other structures
including temporary erosion control measures shall not be conducted in a manner that may result
in dis-equilibrium of wetlands or streambeds or banks, adjacent to or upstream and down stream
of the above structures. The applicant is required to provide evidence that the equilibrium shall be
maintained if requested in writing by DWQ.
The establishment of native, woody vegetation and other soft stream bank stabilization techniques
must be used where practicable instead of rip rap or other bank hardening methods. If rip-rap is
necessary, it shall not be placed in the stream bed, unless specifically approved by the Division of
Water Quality.
Installation of culverts in wetlands must ensure continuity of water movement and be designed to
adequately accommodate high water or flood conditions.
Upon completion of the project, the Applicant shall complete and return the enclosed "Certificate
of Completion" form to notify NCDWQ when all work included in the §401 Certification has
been completed. The responsible party shall complete the attached form and return it to the
401/Wetlands Unit of the NC Division of Water Quality upon completion of the project. Please
send photographs upstream and downstream of each culvert site to document correct installation
along with the Certificate of Completion form.
6. Diffuse Flow (DWQ Reviewed Plans)
All stormwater shall be directed as diffuse flow at non-erosive velocities through the protected
stream buffers and will not re-concentrate before discharging into the stream as identified within
15A NCAC 213.0233 (5)
In an effort to comply with the diffuse flow provision of the Buffer Rule (15A NCAC 02B
.0233(5)), you have provided the DWQ with level spreader designs received by the DWQ on July
16, 2008. The DWQ believes that if implemented, as per these plans, diffuse flow will be
achieved. However, if diffuse flow as per 15A NCAC 02B ,0233(5) is not achieved, then the
DWQ shall be notified and corrective actions to restore diffuse flow shall be taken if necessary to
impede the formation of erosion gullies. At no time shall stormwater from the proposed
development be piped directly through the buffer without prior DWQ written authorization.
The structural stormwater practices as approved by this Office as well as drainage patterns must
be maintained in perpetuity. No changes to the structural stormwater practices shall be made
without written authorization from the Division of Water Quality. Stormwater easements shall be
recorded for a distance of at least 10 feet on each side of all stormwater conveyances on all lots
containing these structures including future access for maintenance. The stormwater easements
North Broad Street, LLC
Page 4 of 5
August 26, 2008
shall allow for the ability to maintain the structures, perform corrective actions as described
above and shall provide protection of the structures from potential alternations by future property
owners.
An Operation & Maintenance (O&M) agreement signed by the current landowner must be
approved by the DWQ. This O&M agreement must transfer with the sale of the land or transfer
of responsibility for the stormwater facilities and the DWQ must be notified of every transfer.
7. Stormwater Management Plan (SMP) Approval Required
Before the impacts specified in this Certification may occur, the applicant must meet all of the
provisions set forth in the document Stormwater Management Plan (SMP) Requirements for
Applicants other than the North Carolina Department of Transportation, available at:
http://h2o,enr.state.ne.us/newetlands/documents/SMPRequirementsforApplicantsotherthanNCDO
T.pdf. The required SMP documentation must be submitted within 60 days of the issuance of the
401 Water Quality Certification to the DWQ (401 Oversight and Express Permitting Unit, 2321
Crabtree Blvd., Suite 250, Raleigh, NC, 27604).
SMP approval and implementation procedures shall be as follows:
• The SMP must be approved in writing by either the 401 Oversight/Express Unit or, if the project
is subject to another state stormwater program, a copy of the approval letter and approved SMP
must be submitted before any impacts authorized in this certification occur. If a development is
phased, then the SMP for each future phase must approved by the 401 Oversight/Express Unit or,
if the project is subject to another state stormwater program, a copy of the approval letter and
approved SMP must be submitted before any impacts associated with that phase may occur.
• The approved SMP must be constructed and operational before any permanent building or other
structure is occupied at the site. If a development is phased, then the approved SMP for each
future phase must be constructed and operational before any permanent building or other
structure associated with that phase is occupied.
• The approved SMP as well as drainage patterns must be maintained in perpetuity.
• The SMP may not be modified without prior written authorization from the SMP approval
authority. If the SMP falls under another state stormwater program, then a copy of the approval
letter and the modified SMP must be submitted to the 401 Oversight/Express Unit prior to the
commencement of the modifications.
8. Protective Fencing
The outside buffer, wetland or water boundary and along the construction corridor within these
boundaries approved under this authorization shall be clearly marked with orange warning fencing
(or similar high visibility material) for the areas that have been approved to infringe within the
buffer, wetland or water prior to any land disturbing activities;
9. Certificate of Completion
Upon completion of all work approved within the 401 Water Quality Certification or applicable
Buffer Rules, and any subsequent modifications, the applicant is required to return the attached
certificate of completion to the 401 Oversight/Express Review Permitting Unit, North Carolina
Division of Water Quality, 1650 Mail Service Center, Raleigh, NC, 27699-1650.
Violations of any condition herein set forth may result in revocation of this Certification and may result in
criminal and/or civil penalties. The authorization to proceed with your proposed impacts or to conduct
North Broad Street, LLL
Page 5 of 5
August 26, 2008
impacts to waters as depicted in your application and as authorized by this Certification, shall expire upon
expiration of the 404 or CAMA Permit.
If you do not accept any of the conditions of this Certification (associated with the approved wetland or
stream impacts), you may ask for an adjudicatory hearing. You must act within 60 days of the date that
you receive this letter. To ask for a hearing, send a written petition, which conforms to Chapter 150B of
the North Carolina General Statutes to the Office of Administrative Hearings, 6714 Mail Service Center,
Raleigh, N.C. 27699-6714. This certification and its conditions are final and binding unless you ask for a
hearing.
Any disputes over determinations regarding this Authorization Certificate (associated with the approved
buffer impacts) shall be referred in writing to the Director for a decision. The Director's decision is
subject to review as provided in Articles 3 and 4 of G.S. 150B.
This letter completes the review of the Division of Water Quality under Section 401 of the Clean Water
Act and the Neuse riparian buffer protection rule as described within 15A NCAC 2B .0233. If you have
any questions, please telephone Cyndi Karoly or Ian McMillan at 919-733.1786.
Since ly,
i
H. Sullins
CHSlijm
Enclosures: GC3687 and GC3705
Certificate of Completion
cc: USACE Raleigh Regulatory Field Office
Lauren Witherspoon, DWQ Raleigh Regional Office
DLR Raleigh Regional Office
File Copy
Central Files
Todd Preuninger, Withers & RaveneI, 111 MacKenan Drive, Cary, NC 27511
Filename: 080067 Ver2AIstonPondNorthBroadStreet(Wake)401 _NBR
NC-DWQ BUFFER APPROVAL LETTER
O? WAT§R Michael F. Easley, Governor
Q William G. Ross Jr., Secretary
0 North Carolina Department of Environment and Natural Resources
r Alan W. Klimek, P.E. Director
Division of Water Quality
ii E
March 20, 2007
MAR Z I L00f
Mr. Todd Preuninger
Withers & Ravenel
111 MacKenan Drive
Cary, NC 27511
ffi ?ke!"5 ::? azVF
e
NBRRO 07-028
Wake County
BASIN:
Neuse River X Tar-Pamlico
(15A NCAC 2B .0233) (15A NCAC 213.0259)
Complaint NOV Buffer Determination X
Incident # ADneal Call
Project Name: Adams Fuquay Tract
Location/Directions: located north of the intersection of SR 1398 and NC 55, south of the Town of Holly Springs
Subject Stream: Basal Creek and UT's to Basal Creek
Date of Determination: 3/9/07
Feature(s) Not Subject Subject Start @ Stop@ Stream
Form Pts. Soil
Survey USGS
Topo
A X (not contested) Throughout
property X X
B X (not contested) Throughout
property X X
C X (not on maps)
D X (not on maps)
E X Flag E1 (origin)
and Flag E
(outfall of pond) X X
F X X
G X X
H X X
I X X
J X Fla J X
Note: A portion of feature A is a beaver impoundment. A 50-ft buffer should extend from the mean high
water in this impounded area.
Explanation: The feature(s) listed above has or have been located on the Soil Survey of Wake County, North
Carolina or the most recent copy of the USGS Topographic map at a 1:24,000 scale. Each feature that is checked
"Not Subject" has been determined not to be a stream or is not present on the property. Features that are checked
"Subject" have been located on the property and possess characteristics that qualify it to be a stream. There may be No°rthCarolina
Naturally
North Carolina Division of Water Quality Raleigh Regional Office Surface Water Protection
Internet: h2o.enr.state.nc.us 1628 Mail Service Center Raleigh, NC 27699-1628
Phone [phone] Customer Service
FAX [phone]
An Equal Opportunity/Affirmative Action Employer- 50% Recycledl10% Post Consumer Paper
Adams Fuquay Tract
Wake County
3/20/2007
Page 2 of 2
other streams located on your property that do not show up on the maps referenced above but, still may be
considered jurisdictional according to the US Army Corps of Engineers and/or to the Division of Water Quality.
This on-site determination shall expire five (5) years from the date of this letter. Landowners or affected
parties that dispute a determination made by the DWQ or Delegated Local Authority that a surface water
exists and that it is subject to the buffer rule may request a determination by the Director. A request for a
determination by the Director shall be referred to the Director in writing c/o Cyndi Karoly, DWQ
Wetlands/401 Unit, 2321 Crabtree Blvd., Raleigh, NC 27604-2260. Individuals that dispute a determination
by the DWQ or Delegated Local Authority that "exempts" a surface water from the buffer rule may ask for
an ad judicatory hearing. You must act within 60 days of the date that you receive this letter. Applicants are
hereby notified that the 60-day statutory appeal time does not start until the affected party (including
downstream and adjacent landowners) is notified of this decision. DWQ recommends that the applicant
conduct this notification in order to be certain that third party appeals are made in a timely manner. To ask
for a hearing, send a written petition, which conforms to Chapter 150B of the North Carolina General
Statutes to the Office of Administrative Hearings, 6714 Mail Service Center, Raleigh, N.C. 27699-6714. This
determination is final and binding unless you ask for a hearing within 60 days.
The (owner/future owners) should notify the Division of Water Quality (including any other Local, State, and
Federal Agencies) of this decision concerning any future correspondences regarding the subject property
(stated above). This project may require a Section 404/401 Permit for the proposed activity. Any inquiries
should be directed to the Division of Water Quality (Central Office) at (919)-733-1786, and the US Army
Corp of Engineers (Raleigh Regulatory Field Office) at (919)-876-8441.
Respectfully, ,
Lauren Cobb
Environmental Specialist III
CC: Wetlands/Stormwater Branch, 2321 Crabtree Blvd, Suite 250, Raleigh, NC 27604
RRO/SWP File Copy
Central Files
NorrhCarolina
Aahtrally
North Carolina Division of Water Quality Raleigh Regional Office Surface Water Protection
Intemet: h2o.enr.state.nc.us 1628 Mail Service Center Raleigh, NC 27699-1628
Phone [phone] Customer Service
FAX [phone]
An Equal Opportunity/Affirmative Action Employer - 50% Recycled/10% Post Consumer Paper
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Project Name: Alston Pond
City/State: Fuquay-Varina
Table 1.1 Surface Area to Drainage Area Ratio for Permanent Pool Sizing for 85% Pollutant
Removal Fff c ivrnct• in the Piedmont
% Impervious
Cover Permanent Pool Depth (feet)
3.0 4.0 5.0 6.0 7.0 8.0 9.0
10 0.59 0.49 0.43 0.35 0.31 0.29 0.26
20 0.97 0.79 0.70 0.59 0.51 0.46 0.44
30 1.34 1.08 0.97 0.83 0.70 0.64 0.62
40 1.73 1.43 1.25 1.05 0.90 0.82 0.77
50 2.06 1.73 1.50 1.30 1.09 1.00 0.92
60 2.40 2.03 1.71 1.51 1.29 1.18 1.10
70 2.88 2.40 2.07 1.79 1.54 1.35 1.26
80 3.36 2.78 2.38 2.10 1.86 1.60 1.42
90 3.74 3.10 2.66 2.34 2.11 1.83 1.67
Source: NCDENR/DWQ Stormwater Best Management Practices, pg. 10-9, July 2007
STORMWATER BMP 1 - STORMWATER WET POND

Land Use Area
(ac) % IA Imp. Area
(ac)
Impervious 15.62 100 15.62
Open Space 16.88 0 0.00

Totals 32.50 15.62
Total % Impervious Surface Area = 48.1 %
Surface Area of Permanent Pool:
Assumed depth = 3 feet
SA/DA ratio = 2.00 % From Table 1.1
Minimum pond surface area (SA) _ (DA * SA/DA ratio)/100
SA = 0.649 acres
28258 sq. ft.
Normal pool elevation = feet
Surface area provided = 0.871 acres
37920 sq. ft.
1-Inch Runoff Volume Calculation
Using the runoff volume calculations in the "Simple Method" as described by Schueler (1987)
Rv = 0.05 + 0.009(1) where, Rv = Runoff coefficient, in./in.
I = Percent impervious
RV = 0.48 in./in.
Total runoff volume from 1-inch precipitation:
Runoff volume, S = (Design rainfall) (Rv) (Drainage Area)
S = 1.307 acre-ft
56929 cu. ft.
Temporary Pool Elevation = 343.8
Water quality pool elevation= 342.00 feet
Storage volume provided = 1.687 acre-ft
73486 cu. ft.
Orifice Calculator
Q =Cd*A*(2gh)^(1/2)
Variables
WQ Volume:
Head:
Draw down time:
Orifice Area =
1.307 Acre-ft
1.80 ft
48 hrs
0.0721235 sq. ft
Orifice Diameter: 3.6364262 in
USE 4 INCH DIAMETER ORIFICE
A 0.34906585 4
Q 2.25495459
56929.29 cf
0.9 ft
172800 s
10.38578 sq. in
Constants
9
cd =
32.2 ft/sz
0.6
Project Name: Alston Pond
City/State: Fuquay-Varina
Table 1.1 Surface Area to Drainage Area Ratio for Permanent Pool Sizing for 85% Pollutant
Removal Efficiency in the Piedmont
% Impervious
Cover
3.0
4.0 re1,,,a,Ic
5.0 „i , UUN .., FL
6.0 IN ..,. l
7.0
8.0
9.0
10 0.59 0.49 0.43 0.35 0.31 0.29 0.26
20 0.97 0.79 0.70 0.59 0.51 0.46 0.44
30 1.34 1.08 0.97 0.83 0.70
0.64
0.62
40 _
1.73 1.43 1.25 1.05 0.90 0.82 0.77
50 2.06 1.73 1.50 1.30 1.09 1.00 0.92
60 2.40 2.03 1.71 1.51 1.29 1.18 1.10
70 2.88 2.40 2.07 1.79 1.54 1.35 1.26
80 3.36 2.78 2.38 2.10 1.86 1.60 1.42
90 3.74 3.10 2.66 2.34 2.11 1.83 1.67
Source: NCDENR/D WQ Stormwater Best Manageme nt Practices, pg. 10-9, July 2007
STORMWATER BMP 2 - STORMWATER WET POND

Land Use
Impervious Area
(ac)
18.75 % IA

100 Imp. Area
(ac)
18.75
Open Space 17.75 0 0.00

Totals 36.50 18.75
Total % Impervious Surface Area = 51.4 %
Surface Area of Permanent Pool:
Assumed depth = 4 feet
SA/DA ratio = 1.77 % From Table 1.1
Minimum pond surface area (SA) = (DA * SA/DA ratio)/100
SA = 0.646 acres
28159 sq. ft.
Normal pool elevation = 4.0 feet
Surface area provided = 0.577 acres
25150 sq. ft.
31.5
1-Inch Runoff Volume Calculation
Using the runoff volume calculations in the "Simple Method" as described by Schueler (1987)
Rv = 0.05 + 0.009(1) where, Rv _ Runoff coefficient, in./in.
I = Percent impervious
Rv = 0.51 inAn.
Total runoff volume from 1-inch precipitation:
Runoff volume, S = (Design rainfall) (Rv) (Drainage Area)
S = 1.558 acre-ft
67881 cu. ft.
Temporary Pool Elevation = 367.4
Water quality pool elevation= 365.00 feet
Storage volume provided = 1.936 acre-ft
84332 cu. ft.
Orifice Calculator
Q =Cd*A*(2gh)"(1/2)
Variables
WQ Volume:
Head:
aw down time:
1.558 Acre-ft
2.40 ft
120 hrs
Orifice Area= 0.0297906 sq. ft
Orifice Diametf 2.3370948 in
USE 2 INCH DIAMETER ORIFICE
A 0.1154099 2
Q 0.86088047
67881 cf
1.2 ft
432000 s
4.289851 sq. in
Constants
9=
cd =
32.2 ft/s2
0.6
Project Name: Alston Pond
City/State: Fuquay-Varina
Table 1.1 Surface Area to Drainage Area Ratio for Permanent Pool Sizing for 85% Pollutant
RPmnval Fffirienrv in the Piedmont
% Impervious
Cover Permanent Pool Depth (feet)
3.0 4.0 5.0 6.0 7.0 8.0 9.0
10 0.59 0.49 0.43 0.35 0.31 0.29 0.26
20 0.97 0.79 0.70 0.59 0.51 0.46 0.44
30 1.34 1.08 0.97 0.83 0.70 0.64 0.62
40 1.73 1.43 1.25 1.05 0.90 0.82 0.77
50 2.06 1.73 1.50 1.30 1.09 1.00 0.92
60 2.40 2.03 1.71 1.51 1.29 1.18 1.10
70 2.88 2.40 2.07 1.79 1.54 1.35 1.26
80 3.36 2.78 2.38 2.10 1.86 1.60 1.42
90 3.74 3.10 2.66 2.34 2.11 1.83 1.67
Source: NCDENR/DWQ Stormwater Best Management Practices, pg. 10-9, July 2007
STORMWATER BMP 3 - STORMWATER WET POND

Land Use Area
(ac) % IA Imp. Area
(ac)
Impervious 6.24 100 6.24
Open Space 9.76 0 0.00

Totals 16.00 6.24
Total % Impervious Surface Area = 39.0 %
Surface Area of Permanent Pool:
Assumed depth = 3 feet
SA/DA ratio = 1.69 % From Table 1.1
Minimum pond surface area (SA) _ (DA * SA/DA ratio)/100
SA = 0.271 acres
11786 sq. ft.
Normal pool elevation = 4.0 feet
Surface area provided = 0.255 acres
11111 sq. ft.
1-Inch Runoff Volume Calculation
Using the runoff volume calculations in the "Simple Method" as described by Schueler (1987)
Rv = 0.05 + 0.009(1) where, Rv = Runoff coefficient, in./in.
I = Percent impervious
Rv = 0.40 in./in.
Total runoff volume from 1-inch precipitation:
Runoff volume, S = (Design rainfall) (Rv) (Drainage Area)
S = 0.535 acre-ft
23290 cu. ft.
Temporary Pool Elevation = 382.8
Water quality pool elevation= 381.00 feet
Storage volume provided = 0.638 acre-ft
27791 cu. ft.
Orifice Calculator
Q =Cd*A*(2gh)^(l/2)
Variables
WQ Volume:
Head:
aw dawn time:
0.535 Acre-ft
1.80 ft
48 hrs
Orifice Area = 0.0295061 sq. ft
Orifice Diameti 2.3259072 in
USE 2 INCH DIAMETER ORIFICE
A 0.08726646 2
Q 0.56373865
23290.08 cf
0.9 ft
17280.0 s
4.248878 sq. in
Constants
9_
Cd =
32.2 ft/s2
0.6
Project Name: Alston Pond
City/State: Fuquay-Varina
Table 1.1 Surface Area to Drainage Area Ratio for Permanent Pool Sizing for 85% Pollutant
Removal Efficiency in the Piedmont
% Impervious Permane nt Pool Dept h (feet)
Cover 3.0 4.0 5.0 6.0 7.0 8.0 9.0
10 0.59 0.49 0.43 0.35 0.31 0.29 0.26
20 0.97 0.79 0.70 0.59 0.51 0.46 0.44
30 1.34 1.08 0.97 0.83 0.70 0.64 0.62
40 1.73 1.43 1.25 1.05 0.90 0.82 0.77
50 2.06 1.73 1.50 1.30 1.09 1.00 0.92
60 2.40 2.03 1.71 1.51 1.29 1.18 1.10
70 2.88 2.40 2.07 1.79 1.54 1.35 1.26
80 3.36 2.78 2.38 2.10 1.86 1.60 1.42
90 3.74 3.10 2.66 2.34 2.11 1.83 1.67
Source: NCDENR/DWQ Stormwater Best Management Practices, pg. iu-`J, duly Luui
STORMWATER BMP 4 - STORMWATER WET POND

Land Use Area
(ac) % IA Imp. Area
(ac)
Impervious 2.6 100 2.60
02en Space 3.4 0 0.00

Totals 6.00 2.60
Total % Impervious Surface Area = 43.3 %
Surface Area of Permanent Pool:
Assumed depth = 3 feet
SA/DA ratio = 1.84 % From Table 1.1
Minimum pond surface area (SA) _ (DA * SA/DA ratio)/100
SA = 0.110 acres
4809 sq. ft.
Normal pool elevation = 344.0 feet
Surface area provided = 0.142 acres
6197 sq. ft.
1-Inch Runoff Volume Calculation
Using the runoff volume calculations in the "Simple Method" as described by Schueler (1987)
Rv = 0.05 + 0.009(1) where, Rv = Runoff coefficient, in./in.
I = Percent impervious
Rv = 0.44 in./in.
Total runoff volume from 1-inch precipitation:
Runoff volume, S = (Design rainfall) (Rv) (Drainage Area)
S = 0.220 acre-ft
9583 cu. ft.
Temporary Pool Elevation = 344.5
Water quality pool elevation= 343.00 feet
Storage volume provided = 0.227 acre-ft
9888 cu. ft.
Orifice Calculator
Q =CdW(2gh)^(1/2)
Variables
WQ Volume:
Head:
aw down time:
0.220 Acre-ft
1.50 ft
48 hrs
Orifice Area= 0.0132997 sq. ft
Orifice Diameb 1.5615557 in
USE 2 INCH DIAMETER ORIFICE
A 0.08726646 2
Q 0.51462062
9583.2 cf
0.75 ft
172800 s
1.915157 sq. in
Constants
9=
cd =
32.2 ft/S2
0.6
BMP SUPLMENT FORMS
Permit N
A N.
NCDENR
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
WET DETENTION BASIN SUPPLEMENT
This form must be filled out, printed and submitted.
The Required Items Checklist (Part lll) must be printed, filled out and submitted along with all of the required information.
(to be provided by DWQ)
V AFT .-
€. PROJECT INFORMATION
_
Project name Alston Pond
Contact person Alwyn V. Smith III, P.E.
Phone number 919) 469-3340
Date 22-Dec-10
Drainage area number 1
II. DESIGN INFORMATION
Site Characteristics
Drainage area 1,415,700 ftz
Impervious area, post-development 680,407 fe
% impervious 48.06 %
Design rainfall depth 1.0 in
Storage Volume: Non-SA Waters
Minimum volume required
Volume provided
Storage Volume: SA Waters
1.5" runoff volume
Pre-development 1-yr, 24-hr runoff
Post-development 1-yr, 24-hr runoff
Minimum volume required
Volume provided
Peak Flow Calculations
Is the pre/post control of the 1yr 24hr storm peak flow required?
1-yr, 24-hr rainfall depth
Rational C, pre-development
Rational C, post-development
Rainfall intensity: 1-yr, 24-hr storm
Pre-development 1-yr, 24-hr peak flow
Post-development 1-yr, 24-hr peak flow
Pre/Post 1-yr, 24-hr peak flow control
Elevations
Temporary pool elevation
Permanent pool elevation
SHWT elevation (approx. at the perm. pool elevation)
Top of 1Oft vegetated shelf elevation
Bottom of 1 Oft vegetated shelf elevation
Sediment cleanout, top elevation (bottom of pond)
Sediment cleanout, bottom elevation
Sediment storage provided
Is there additional volume stored above the state-required temp. pool?
Elevation of the top of the additional volume
56,930 ft3 OK
73,486 ft3 OK, volume provided is equal to or in excess of volume required.
ft3
ft3
ft3
ft3
ft3
y (Y or N)
3.0 in
(unitless)
(unitless)
0.13 in/hr OK
15.61 ft3/sec
11.47 ft3/sec
-4.14 ft3/sec
343.80 fmsl
342.00 fmsl
fmsl
342.50 fmsl
341.50 fmsl
338.00 fmsl
337.00 fmsl
1.00 ft
n (Y or N)
fmsl
Form SW401-Wet Detention Basin-Rev 8-9117109 Parts I & 11 Design Summary, Page 1 of 2
Permit No.
(to be provided by DWQ)
II. DESIGN INIF M_ATION _
Surface Areas
Area, temporary pool 45,229 fe
Area REQUIRED, permanent pool 28,314 ff
SAIDA ratio 2.00 (unitless)
Area PROVIDED, permanent pool, A?mjw, 34,308 ft` OK
Area, bottom of 1 Oft vegetated shelf, 4.1 ahen 28,442 ft1
Area, sediment cleanout, top elevation (bottom of pond), &t-d 21,265 ft`
Volumes
Volume, temporary pool 73,486 ft3 OK
Volume, permanent pool, \?,,_, 104,707 ft3
Volume, forebay (sum of forebays if more than one forebay) _ ft3
Forebay % of permanent pool volume %
SAIDA Table Data
Design TSS removal 85 %
Coastal SAIDA Table Used? n (Y or N)
Mountain/Piedmont SA/DA Table Used? y (Y or N)
SAIDA ratio 2.00 (unitless)
Average depth (used in SAIDA table):
Calculation option 1 used? (See Figure 10-2b) n (Y or N)
Volume, permanent pool, \?.
_pod 104,707 W
Area provided, permanent pool, Awm,?j 34,308 ft`
Average depth calculated ft Need 3 ft min.
Average depth used in SAIDA, 4, (Round to nearest 0.5ft) ft
Calculation option 2 used? (See Figure 10-2b) y (Y or N)
Area provided, permanent pool, 'P? _pwj 34,308 fe
Area, bottom of 1 Oft vegetated shelf, A01 shell 28,442 ft'
Area, sediment cleanout, top elevation (bottom of pond), &I-pd 21,265 ft3
"Depth" (distance b/w bottom of 1 Oft shelf and top of sediment) 3.50 ft
Average depth calculated 3.50 ft OK
Average depth used in SAIDA, 4, (Round to nearest 0.5ft) 3.0 ft Insufficient. Check calculation.
Drawdown Calculations
Drawdown through orifice? y (Y or N)
Diameter of orifice (if circular) 4.00 in
Area of orifice (if-non-circular) in2
Coefficient of discharge (CD) 0.60 (unitless)
Driving head (FL) 1.80 ft
Drawdown through weir? n (Y or N)
Weir type 0.3 (unitless)
Coefficient of discharge (C4) 0.51 (unitless)
Length of weir (L) ft
Driving head (H) ft
Pre-development 1-yr, 24-hr peak flow 15.61 ft3lsec
Post-development 1-yr, 24-hr peak flow 11.47 ft3lsec
Storage volume discharge rate (through discharge orifice or weir) 0.54 ft3lsec
Storage volume drawdown time 2.00 days OK, draws down in 2-5 days.
Addkional Information
Vegetated side slopes 3 :1 OK
Vegetated shelf slope 10 :1 OK
Vegetated shelf width 10.0 ft OK
Length of flowpath to width ratio 4 :1 OK
Length to width ratio 4.0 :1 OK
Trash rack for overflow & orifice? y (Y or N) OK
Freeboard provided 0.8 ft Insufficient freeboard, minimum of 1-ft required
Vegetated filter provided? n (Y or N) Insufficient Vegetated filter required.
Recorded drainage easement provided? y (Y or N) OK
Capures all runoff at ultimate build-out? y (Y or N) OK
Drain mechanism for maintenance or emergencies is: Pump required
Form SW401-Wet Detention Basin-Rev B-9/17/09 Parts I & 11 Design Summary, Page 2 of 2
Permit No
AN"A'
NCDENR
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
WET DETENTION BASIN SUPPLEMENT
This form must be filled out, printed and submitted.
The Required Items Checklist (Part 111) must be printed, filled out and submitted along with all of the required information.
(to be provided by DWQ)
c ;,2 A I,,
r
LID U -, G 19_
I. PROJECT: INFORMATION
Project name Alston Pond
Contact person Alwyn V. Smith III, P.E.
Phone number 919) 469-3340
Date
Drainage area number
11. DESIGN INFORMATION
Site Characteristics
Drainage area 1,589,940 ft2
Impervious area, post-development 816,750 ft2
% impervious 51.37 %
Design rainfall depth 1.0 in
Storage Volume: Non-SA Waters
Minimum volume required 67,881 ft3 OK
Volume provided 84,332 ft3 OK, volume provided is equal to or in excess of volume required.
Storage Volume: SA Waters
1.5" runoff volume
Pre-development 1-yr, 24-hr runoff
Post-development 1-yr, 24-hr runoff
Minimum volume required
Volume provided
Peak Flow Calculations
Is the pre/post control of the 1yr 24hr storm peak flow required?
1-yr, 24-hr rainfall depth
Rational C, pre-development
Rational C, post-development
Rainfall intensity: 1-yr, 24-hr storm
Pre-development 1-yr, 24-hr peak flow
Post-development 1-yr, 24-hr peak flow
Pre/Post 1-yr, 24-hr peak flow control
Elevations
Temporary pool elevation
Permanent pool elevation
SHWT elevation (approx. at the perm, pool elevation)
Top of 1 Oft vegetated shelf elevation
Bottom of 1 Oft vegetated shelf elevation
Sediment cleanout, top elevation (bottom of pond)
Sediment cleanout, bottom elevation
Sediment storage provided
Is there additional volume stored above the state-required temp. pool?
Elevation of the top of the additional volume
10
ft3
ft3
ft3
ft3
ft3
y (Y or N)
3.0 in
0.30 (unitless)
0.51 (unitless)
0.13 in/hr OK
15.61 ft3/sec
11.47 ft3/sec
4.14 ft3/sec
367.40 fmsl
365.00 fmsl
fmsl
365.50 fmsl
364.50 fmsl
360.00 fmsl
359.00 fmsl
1.00 ft
n (Y or N)
fmsl
Form SW401-Wet Detention Basin-Rev B-9/17/09 Parts I & 11 Design Summary, Page 1 of 2
Permit No.
(to be provided by DWQ)
II, DESIGN INFORMATION _
Surface Areas
Area, temporary pool 39,090 ff
Area REQUIRED, permanent pool 28,142 fl2
SAIDA ratio 1.77 (unitless)
Area PROVIDED, permanent pool, Pp°,
Area, bottom of 1 Oft vegetated shelf,
Area, sediment cleanout, top elevation (bottom of pond), &I.d
Volumes
Volume, temporary pool
Volume, permanent pool, \?,,,_pw
Volume, forebay (sum of forebays if more than one forebay)
Forebay % of permanent pool volume
SAIDA Table Data
Design TSS removal
Coastal SAIDA Table Used?
Mountain/Piedmont SAIDA Table Used?
SAIDA ratio
Average depth (used in SAIDA table):
Calculation option 1 used? (See Figure 10-2b)
Volume, permanent pool, V,,,_pw
Area provided, permanent pool,
Average depth calculated
Average depth used in SAIDA, 4, (Round to nearest 0.5ft)
Calculation option 2 used? (See Figure 10-2b)
Area provided, permanent pool, /e?_pw
Area, bottom of 1Oft vegetated shelf, !fit a,1l
Area, sediment cleanout, top elevation (bottom of pond), JL-P d
"Depth" (distance blw bottom of IN shelf and top of sediment)
Average depth calculated
Average depth used in SAIDA, cL, (Round to nearest 0.5ft)
Drawdown Calculations
Drawdown through orifice?
Diameter of orifice (if circular)
Area of orifice (if-non-circular)
Coefficient of discharge (Cq)
Driving head (Ft)
Drawdown through weir?
Weir type
Coefficient of discharge (C.)
Length of weir (L)
Driving head (H)
Pre-development 1-yr, 24-hr peak flow
Post-development 1-yr, 24-hr peak flow
Storage volume discharge rate (through discharge orifice or weir)
Storage volume drawdown time
Additional Information
Vegetated side slopes
Vegetated shelf slope
Vegetated shelf width
Length of flowpath to width ratio
Length to width ratio
Trash rack for overflow & orifice?
Freeboard provided
Vegetated filter provided?
Recorded drainage easement provided?
Capures all runoff at ultimate build-out?
Drain mechanism for maintenance or emergencies is
28,282 ft? OK
23,027 if
13,943 if
84,332 ft3 OK
94,500 ft3
ft3
85 %
n (Y or N)
y (Y or N)
1.77 (unitless)
n (Y or N)
94,500 fe
28,282 W
ft
ft
y (Y or N)
28,282 ff
23,027 ft`
.13,943 ff
4.50 ft
4.10 ft
4.0 ft
y (Y or N)
4.00 in
in2
0.60 (unitless)
2.40 ft
n (Y or N)
(unitless)
(unitiess)
ft
ft
15.61 ft3/sec
11.47 ft3/sec
0.63 ft3/sec
2.00 days
3 :1
10 :1
10.0 ft
3 :1
3.0 :1
y (Y or N)
0.8 ft
n (Y or N)
y (Y or N)
y (Y or N)
Gate valve
Need 3 ft min.
OK
OK
OK, draws down in 2-5 days.
OK
OK
OK
OK
OK
OK
Insufficient freeboard, minimum of 1-ft required
Insufficient. Vegetated filter required.
OK
OK
Form SW401-Wet Detention Basin-Rev 9-9/1 7109 Parts I. & 11 Design Summary, Page 2 of 2
Permit No
NCDENR
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
WET DETENTION BASIN SUPPLEMENT
This form must be filled out, printed and submitted.
The Required Items Checklist (Part III) must be printed, filled out and submitted along with all of the required information.
(to be provided by DWQ)
ry
? e
of fl?i.?.F ?..Jti
I. PROJECT INFORMATION
Project name Alston Pond
Contact person Alwyn V. Smith III, P.E.
Phone number 919) 469-3340
Date 22-Dec-10
Drainage area number 3
II, DESIGN INFORMATION
Site Characteristics
Drainage area 696,960 fe
Impervious area, post-development 271,814 ftz
% impervious 39.00%
Design rainfall depth 1.0 in
Storage Volume: Non-SA Waters
Minimum volume required
Volume provided
Storage Volume: SA Waters
1.5" runoff volume
Pre-development 1-yr, 24-hr runoff
Post-development 1-yr, 24-hr runoff
Minimum volume required
Volume provided
Peak Flow Calculations
Is the pre/post control of the lyr 24hr storm peak flow required?
1-yr, 24-hr rainfall depth
Rational C, pre-development
Rational C, post-development
Rainfall intensity: 1-yr, 24-hr storm
Pre-development 1-yr, 24-hr peak flow
Post-development 1-yr, 24-hr peak flow
Pre/Post 1-yr, 24-hr peak flow control
Elevations
Temporary pool elevation
Permanent pool elevation
SHWT elevation (approx. at the perm. pool elevation)
Top of 1 Oft vegetated shelf elevation
Bottom of 1Oft vegetated shelf elevation
Sediment cleanout, top elevation (bottom of pond)
Sediment cleanout, bottom elevation
Sediment storage provided
Is there additional volume stored above the state-required temp. pool?
Elevation of the top of the additional volume
23,290 ft3 OK
27,791 ft3 OK, volume provided is equal to or in excess of volume required,
ft3
ft3
ft3
ft3
ft3
y (Y or N)
3.0 in
0.30 (unitless)
0.51 (unitless)
0.13 in/hr OK
15.61 ft3/sec
11.47 ft3/sec
-4.14 ft3/sec
382.80 fmsl
381.00 fmsl
fmsl
381.50 fmsl
380.50 fmsl
377.00 fmsl
376.00 fmsl
1.00 ft
(Y or N)
fmsl
Form SW401-Wet Detention Basin-Rev 8-9/17109 Parts I & 11 Design Summary, Page 1 of 2
Permit No
(to be provided by D WQ)
11. DESIGN INFORMATION -
Surface Areas
Area, temporary pool 17,329 f?
Area REQUIRED, permanent pool 11,779 ft'
SAIDA ratio 1.69 (unitless)
Area PROVIDED, permanent pool, PI 12,414 ft OK
Area, bottom of 1 Oft vegetated shelf, 4o, „ 9,710 ft
Area, sediment cleanout, top elevation (bottom of pond), &,_?nd 5,979 ft
Volumes
Volume, temporary pool 27,791 ft3 OK
Volume, permanent pool, V,.,,d 33,021 ft3
Volume, forebay (sum of forebays if more than one forebay) ft3
Forebay % of permanent pool volume %
SAIDA Table Data
Design TSS removal 85 %
Coastal SAIDA Table Used? n (Y or N)
Mountain/Piedmont SAIDA Table Used? y (Y or N)
SAW ratio 1.69 (unitless)
Average depth (used in SAIDA table):
Calculation option 1 used? (See Figure 10-2b) n (Y or N)
Volume, permanent pool, V,,,,_p.i 33,021 ft'
Area provided, permanent pool, 4._pod 12,414 W
Average depth calculated ft Need 3 ft min.
Average depth used in SAIDA, qv, (Round to nearest 0.5ft) ft
Calculation option 2 used? (See Figure 10-2b) y (Y or N)
Area provided, permanent pool, P,,. j., 12,414 ft`
Area, bottom of 1 Oft vegetated shelf, Aa shelf 9,710 ft
Area, sediment cleanout, top elevation (bottom of pond), &lyq,d 5,979 ff
"Depth" (distance blw bottom of IN shelf and top of sediment) 3.50 ft
Average depth calculated 3.30 ft OK
Average depth used in SAIDA, q, (Round to nearest 0.5ft) 3.0 ft Insufficient. Check calculation.
Drawdown Calculations
Drawdown through orifice? y (Y or N)
Diameter of orifice (if circular) 2.00 in
Area of orifice (if-non-circular) in2
Coefficient of discharge (C)) 0.60 (unitless)
Driving head (Ft) 1.80 ft
Drawdown through weir? n (Y or N)
Weir type (unitless)
Coefficient of discharge (CN) (unitless)
Length of weir (L) ft
Driving head (H) ft
Pre-development 1-yr, 24-hr peak flow 15.61 ft3/sec
Post-development 1-yr, 24-hr peak flow 11.47 ft3/sec
Storage volume discharge rate (through discharge orifice or weir) 0.14 ft lsec
Storage volume drawdown time 2.00 days OK, draws down in 2-5 days.
Additional Information
Vegetated side slopes 3 :1 OK
Vegetated shelf slope 10 :1 OK
Vegetated shelf width 10.0 ft OK
Length of flowpath to width ratio 4 :1 OK
Length to width ratio 5.0 :1 OK
Trash rack for overflow & orifice? y (Y or N) OK
Freeboard provided 0.5 ft Insufficient freeboard, minimum of 1-ft required
Vegetated filter provided? n (Y or N) Insufficient. Vegetated filter required.
Recorded drainage easement provided? y (Y or N) OK
Capures all runoff at ultimate build-out? y (Y or N) OK
Drain mechanism for maintenance or emergencies is: gate valve
Form SW401-Wet Detention Basin-Rev-8-9/17/09 Parts I & 11 Design Summary, Page 2 of 2
Permit No
NCQENR
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
WET DETENTION BASIN SUPPLEMENT
This form must be filled out, printed and submitted.
The Required Items Checklist (Part HI) must be printed, filled out and submitted along with all of the required information.
(to be provided by DWQ)
0 61
?UJ C )6!
I. PROJECT INFORMATION
Project name Alslon Pond
Contact person Alwyn V. Smith III, P.E.
Phone number 919) 469-3340
Date 22-Dec-10
Drainage area number 4
14, DESIGN INFORMATION
Site Characteristics
Drainage area 261,360 fe
Impervious area, post-development 113,256 fe
% impervious 43.33 %
Design rainfall depth 1.0 in
Storage Volume: Non-SA Waters
Minimum volume required
Volume provided
Storage Volume: SA Waters
1.5" runoff volume
Pre-development 1-yr, 24-hr runoff
Post-development 1-yr, 24-hr runoff
Minimum volume required
Volume provided
Peak Flow Calculations
Is the pre/post control of the lyr 24hr storm peak flow required?
1-yr, 24-hr rainfall depth
Rational C, pre-development
Rational C, post-development
Rainfall intensity: 1-yr, 24-hr storm
Pre-development 1-yr, 24-hr peak flow
Post-development 1-yr, 24-hr peak flow
Pre/Post 1-yr, 24-hr peak flow control
Elevations
Temporary pool elevation
Permanent pool elevation
SHWT elevation (approx. at the perm. pool elevation)
Top of 1 Oft vegetated shelf elevation
Bottom of 1Oft vegetated shelf elevation
Sediment cleanout, top elevation (bottom of pond)
Sediment cleanout, bottom elevation
Sediment storage provided
Is there additional volume stored above the state-required temp pool?
Elevation of the top of the additional volume
9,584 ft3 OK
9,888 ft3 OK, volume provided is equal to or in excess of volume required.
ft3
ft3
ft3
ft3
ft3
y (Y or N)
3.0 in
0.30 (unitless)
0.51 (unitless)
0.13 Whir OK
15.61 ft3/sec
11.47 ft3lsec
A.14 ft3/sec
343.00 fmsl
344.50 fmsl
Imsl
343.50 fmsl
342.50 fmsl
339.00 fmsl
338.00 fmsl
1.00 ft
(Y or N)
fmsl
Form SW401-Wet Detention Basin-Rev B-9/17/09 Parts 1811 Design Summary, Page 1 of 2
Permit No
(to be provided by D WQ)
111. DESIGN' INFORMATION
Surface Areas
Area, temporary pool 7,756 ft?
Area REQUIRED, permanent pool 4,809 fe
SAIDA ratio 1.84 (unitless)
Area PROVIDED, permanent pool, ?__,.I 4,897 ft' OK
Area, bottom of 10ft vegetated shelf, A,,, ,heIl 3,346 ft`
Area, sediment cleanout, top elevation (bottom of pond), Qol_ood 1,418 ft`
Volumes
Volume, temporary pool 9,888 ft3 OK
Volume, permanent pool, 10,290 ft3
Volume, forebay (sum of forebays if more than one forebay) ft3
Forebay % of permanent pool volume %
SAIDA Table Data
Design TSS removal 85 %
Coastal SAIDA Table Used? n (Y or N)
Mountain/Piedmont SAIDA Table Used? y (Y or N)
SAIDA ratio 1.84 (unitless)
Average depth (used in SAIDA table):
Calculation option 1 used? (See Figure 10-2b) n (Y or N)
Volume, permanent pool, V?m_pcd 10,290 ft'
Area provided, permanent pool, A?,,,,_pw 4,897 ft
Average depth calculated ft Need 3 ft min.
Average depth used in SAIDA, 4, (Round to nearest 0.5ft) ft
Calculation option 2 used? (See Figure 10-2b) y (Y or N)
Area provided, permanent pool, P,,,,,_pd 4,897 ftL
Area, bottom of 1 Oft vegetated shelf, At ,,ejl 3,346 ft`
Area, sediment cleanout, top elevation (bottom of pond), Q„_p d 1,418 fl2
"Depth" (distance b/w bottom of 1 Oft shelf and top of sediment) 3.50 ft
Average depth calculated 3A0 ft OK
Average depth used in SAIDA, 4, (Round to nearest 0.5ft) 3.0 ft OK
Drawdown Calculations
Drawdown through orifice?
Diameter of orifice (if circular)
Area of orifice (if-non-circular)
Coefficient of discharge (CD)
Driving head (F6)
Drawdown through weir?
Weir type
Coefficient of discharge (C„)
Length of weir (L)
Driving head (H)
Pre-development 1-yr, 24-hr peak flow
Post-development 1-yr, 24-hr peak flow
Storage volume discharge rate (through discharge orifice or weir)
Storage volume drawdown time
Additional Information
Vegetated side slopes
Vegetated shelf slope
Vegetated shelf width
Length of flowpath to width ratio
Length to width ratio
Trash rack for overflow & orifice?
Freeboard provided
Vegetated filter provided?
Recorded drainage easement provided?
Capures all runoff at ultimate build-out?
Drain mechanism for maintenance or emergencies is:
y (Y or N)
2.00 in
inz
0.60 (unitless)
1.50 ft
(Y or N)
(unitless)
(unitless)
ft
?ft
15.61 ft3lsec
11.47 ft3lsec
0.13 ft3lsec
2.00 days
OK, draws down in 2-5 days.
3 :1 OK
10 :1 OK
10.0 ft OK
3 :1 OK
3.0 :1 OK
YT (Y or N) OK
0.5 ft Insufficient freeboard, minimum of 1-ft required
n (Y or N) Insufficient Vegetated filter required-
y (Y or N) OK
y (Y or N) OK
pump required
Form SW401-Wet Detention Basin-Rev 8-9117/09 Parts I. & 11 Design Summary, Page 2 of 2

A 7-PA (}'r ifFA;itrra
..
NCDENR ^?
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
LEVEL SPREADER - VEGE TATED FILTER STRIP (LS-VFS) SUPPLEMENT
This form must be completely filled out, printed, initialed, and submitted.
1. PROJECT INFORMATION
Project name Alston Pond
Contact name Troy Beasley
Phone number 919-469-3340
Date January 25, 2011
Drainage area number BMP #2
H. DESIGN INFORMATION
The purpose of the LS-VFS Buffer Rule: Diffuse Flow
Stormwater enters LS-VFS from A BMP
Type of VFS Protected riparian buffer (slope < 5%)
Explanation of any "Other" responses above
If Stormwater Enters the LS-VFS from the Drainage Area
Drainage area ftZ Do not complete this section of the form.
Impervious surface area ftz Do not complete this section of the form.
Percent impervious % Do not complete this section of the form.
Rational C coefficient Do not complete this section of the form.
Peak flow from the 1 in/hr storm cfs Do not complete this section of the form.
Time of concentration min Do not complete this section of the form.
Rainfall intensity, 10-yr storm in/hr Do not complete this section of the form.
Peak flow from the 10-yr storm cfs Do not complete this section of the fo+m.
Design storm Pick one:
Maximum amount of flow directed to the LS-VFS cfs Do not complete this section of the form.
Is a flow bypass system going to be used? (Y or N) Do not complete this section of the form.
Explanation of any "Other" responses above
If Stormwater Enters the LS-VFS from a BMP
Type of BMP Wet detention pond
Peak discharge from the BMP during the design storm 0.86 cfs
Peak discharge from the BMP during the 10-year storm 0.86 cfs
Maximum capacity of a 100-foot long LS-VFS 2 cfs
Peak flow directed to the LS-VFS 0.86 cfs
Is a flow bypass system going to be used? y (Y or N)
Explanation of any "Other" responses above
LS-VFS Design
Forebay surface area sq ft
Depth of forebay at stormwater entry point in
Depth of forebay at stormwater exit point in
Feet of level lip needed per cfs 50 fvcfs
Computed minimum length of the level lip needed ft
Length of level lip provided ft
Form SW401 - LS-VFS - 29Nov2010 - Rev 8 page 1 of 3
Width of VFS
Elevation at downslope base of level lip
Elevation at the end of the VFS that is farthest from the LS
Slope (from level lip to the end of the VFS)
Are any draws present in the VFS?
Is there a collector swale at the end of the VFS?
Bypass System Design (if applicable)
Is a bypass system provided?
Is there an engineered flow splitting device?
Dimensions of the channel (see diagram below):
M
B
W
y (flow depth for 10-year storm)
freeboard (during the 10-year storm)
Peak velocity in the channel during the 10-yr storm
Channel lining material
Does the bypass discharge through a wetland?
Does the channel enter the stream at an angle?
Explanation of any "Other" responses above
,
ft
fmsl
fmsl
(Y or N)
(Y or N)
Y (Y or N)
Y (Y or N) Please provide plan details of flow splitter 8, supporting calcs
2.00 ft
4.00 ft
12.00 ft
0-85 ft
1.15 ft
3,84 ft/sec
Pick one: &9 W G41An1Ar_-[-
N (Y or N)
Y (Y or N)
W
N
# L 1
EDIT Please indicate the page or plan sheet numbers where the supporting documentation can be found. An incomplete submittal package will result in
a request for additional information. This will delay final review and approval of the project. Initial in the space provided to indicate the following
design requirements have been met. If the applicant has designated an agent, the agent may initial below. If a requirement has not been met, attach
justification.
Requried Item:
1. Plans (1" - 50' or larger) of the entire site showing:
- Design at ultimate build-out,
Off-site drainage (if applicable),
Delineated drainage basins (include Rational C coefficient per basin),
Forebay (if applicable),
High flow bypass system,
Maintenance access,
Proposed drainage easement and public right of way (ROW), and
Boundaries of drainage easement.
Initials Page or plan sheet number and any notes:
del -S.? ZZ-2`2 -Z
600 t-OTP('t_ 15 00 s?tr Z 3
Form SW401 - LS-VFS - 29Nov2010 - Rev.8 page 2 of 3
2- Plan details (1' = 30' or larger) for the level spreader showing:
Forebay (if applicable),
High flow bypass system,
One foot topo lines between the level lip and lop of stream dank,
Proposed drainage easement, and
Design at ultimate build-gift.
3. Section view of (lie level spreader (3' = 20' or larger) showing:
- Underdrain system (if applicable),
Level lip,
Upslope channel, and
Downs Iope filler fabric.
4. Plan details of the flow splitling device and supporting calculations (if applicable),
5. A construction sequence Ihal shows haw the level spreader will be protected from
sediment until the entire drainage area is stabilized.
6. It a non-engineered VFS is being used, then provide a photograph of the VFS showing
that no draws are present.
7- The supporting calculations.
8. A copy of the signed and notarized operation and maintenance (O&M) agreement.
?t
ZY
I -
I

r Psz0"14 rk I i e_QrI Pc (--r-
PR6V 1?b
Form SW401 - LS-VF5 -29Nov2olo - Rev.8 page 3 of 3
BMP #2 HIGH FLOW BYPASS
Project Description
Friction Method
Solve For
Input Data
Roughness Coefficient
Channel Slope
Left Side Slope
Right Side Slope
Bottom Width
Discharge
Results
Normal Depth
Flow Area
Wetted Perimeter
Top Width
Critical Depth
Critical Slope
Velocity
Velocity Head
Specific Energy
Froude Number
Flow Type
GVF Input Data
Downstream Depth
Length
Number Of Steps
GVF Output Data
Upstream Depth
Profile Description
Profile Headloss
Downstream Velocity
Upstream Velocity
Normal Depth
Critical Depth
Channel Slope
Critical Slope
1/28/20119:05:13 AM
Manning Formula
Normal Depth
Subcritical
0.069
006000 ft/ft
2.00 ft/ft (H:V)
2.00 ft/ft (H:V)
4.00 ft
18.60 Wis
0.85 ft
4.85 ft2
7.80 ft
7.40 ft
0.77 f[
0.08793 ft/ft
3.84 ft/s
0.23 ft
1.08 ft
0.84
0.00 ft
0.00 ft
0
0.00 ft
0.00 ft
Infinity ft/s
Infinity ft/s
0.85 ft
0.77 ft
0.06000 ft/ft
0.08793 ft/ft
Bentley Systems, Inc. Haestad Methods Solution Center Bentley FlowMaster [08.01.071.00]
27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA [phone] Page 1 of 1
HCDEMR

STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
LEVEL SPREADER - VEGETATED FILTER STRIP (LS-VFS) SUPPLEMENT
This form must be completely filled out, printed, initialed, and submitted.
#. PROJECT INFORMATION
Project name Alston Pond
Contact name Troy Beasley
Phone number 919.469-3340
Date January 25, 2011
Drainage area number BMP #4
The purpose of the LS-VFS
Stormwater enters LS-VFS from
Type of VFS
Explanation of any "Other" responses above
If Stormwater Enters the LS-VFS from the Drainage Area
Drainage area
Impervious surface area
Percent impervious
Rational C coefficient
Peak flow from the 1 in/hr storm
Time of concentration
Rainfall intensity, 10-yr storm
Peak flow from the 10-yr storm
Design storm
Maximum amount of flow directed to the LS-VFS
Is a flow bypass system going to be used?
Explanation of any "Other" responses above
If Stormwater Enters the LS-VFS from a BMP
Type of BMP
Peak discharge from the BMP during the design storm
Peak discharge from the BMP during the 10-year storm
Maximum capacity of a 100-foot long LS-VFS
Peak flow directed to the LS-VFS
Is a flow bypass system going to be used?
Explanation of any "Other" responses above
LS-VFS Design
Forebay surface area
Depth of forebay at stormwater entry point
Depth of forebay at stormwater exit point
Feet of level lip needed per cfs
Computed minimum length of the level lip needed
Length of level lip provided
Buffer Rule: Diffuse Flow
A BMP
Engineered filter strip (graded & sodded, slope < 8%)

ft z Do not complete this section of the form.
ft z Do not complete this section of the form-
% Do not complete this section of the form.
Do not complete this section of the form,
cfs Do not complete this section of the form,
min Do not complete this section of the form,
in/hr De not complete this section of the form.
cfs Do not complete this section of the form.
Pick one:
cfs Do not complete this section of the form.
(Y or N) Do not complete this section of the form.

Wet detentio n pond
0.5 cfs
0.5 cfs
10 cfs
0.5 cfs
y (Y or N)

sq ft
in
in
10 fucfs
ft
ft
Form SW401 - LS-VFS - 29Nov2010 - Rev.8 page 1 of 3
Width of VFS
Elevation at downslope base of level lip
Elevation at the end of the VFS that is farthest from the LS
Slope (from level lip to the end of the VFS)
Are any draws present in the VFS?
Is there a collector swale at the end of the VFS?
Bypass System Design (if applicable)
Is a bypass system provided?
Is there an engineered flow splitting device?
Dimensions of the channel (see diagram below):
M
B
W
y (flow depth for 10-year storm)
freeboard (during the 10-year storm)
Peak velocity in the channel during the 10-yr storm
Channel lining material
Does the bypass discharge through a wetland?
Does the channel enter the stream at an angle?
Explanation of any "Other" responses above
ft
fmsl
fmsl
(Y or N)
(Y or N)
Y (Y or N)
Y (Y or N)
2.00 ft
4.00 ft
12.00 ft
0.62 ft
1.38 ft
4.57 ft/sec
Pick one:
Please provide plan details of flow splitter & supporting calcs.
N (Y or N)
N (Y or N) Redesign channel so that it enters the stream at an angle
Channel enters along wetland edge as stated in the above cell
W

EDIT Please indicate the page or plan sheet numbers where the supporting documentation can be found. An incomplete submittal package will result in
a request for additional information. This will delay final review and approval of the project. Initial in the space provided to indicate the following
design requirements have been met. If the applicant has designated an agent, the agent may initial below. If a requirement has not been met, attach
justification.
Requried Item:
1. Plans (1" - 50' or larger) of the entire site showing:
- Design at ultimate build-out,
- Off-site drainage (if applicable),
- Delineated drainage basins (include Rational C coefficient per basin),
- Forebay (if applicable),
- High flow bypass system,
- Maintenance access,
- Proposed drainage easement and public right of way (ROW), and
- Boundaries of drainage easement.
Initials Page or plan sheet number and any notes:
C)o
Form SW401 - LS-VFS - 29Nov2010 - Rev.8 page 2 of 3
2. Plan details (1" = 30' or larger) for the level spreader showing:
- Forebay (if applicable),
- High flow bypass-system,
- One foot topo lines between the level lip and top of stream bank,
- Proposed drainage easement, and
- Design at ultimate build-out.
3. Section view of the level spreader (1" = 20' or larger) showing:
- Underdrain system (if applicable),
- Level lip,
- Upslope channel, and
- Downslope filter fabric,
4. Plan details of the flow splitting device and supporting calculations (if applicable).
5. A construction sequence thatshows how the level spreader will be protected from
sediment until the entire drainage area is stabilized.
6. If a non-engineered VFS is being used, then provide a photograph of the VFS showing
that no draws are present.
7. The supporting calculations.
8. A copy of the signed and notarized operation and maintenance (O&M) agreement
e L -C'
. ZY
Mt_ 4
y1'1 ?•? ? ? t
I
QRaV'd? +? SWr^ 2ir Pof?'
PROV1?r<D
Form SW401 - LS-VFS - 29Nov2010 - Rev.8 page 3 of 3
BMP #4 HIGH FLOW BYPASS
Project Description
Friction Method Manning Formula
Solve For Normal Depth
Input Data
Roughness Coefficient 0.069
Channel Slope 0.12000 ft/ft
Left Side Slope 2.00 ft/ft (H:V)
Right Side Slope 2.00 ft/ft (H:V)
Bottom Width 4.00 ft
Discharge 14.83 ft'/s
Results
Normal Depth 0.62 ft
Flow Area 3.25 ftZ
Wetted Perimeter 6.77 ft
Top Width 6.48 ft
Critical Depth 0.67 ft
Critical Slope 0.09088 ft/ft
Velocity 4.57 ft/s
Velocity Head 0.32 ft
Specific Energy 0.94 ft
Froude Number 1.14
Flow Type Supercritical
GVF Input Data
Downstream Depth 0.00 ft
Length 0.00 ft
Number Of Steps 0
GVF Output=Data
Upstream Depth 0.00 ft
Profile Description
Profile Headloss 0.00 ft
Downstream Velocity Infinity ft/s
Upstream Velocity Infinity ft/s
Normal Depth 0.62 ft
Critical Depth 0.67 ft
Channel Slope 0.12000 ft/ft
Critical Slope 0.09088 ft/ft
Bentley Systems, Inc. Haestad Methods Solution Center Bentley FlowMaster (08.01.071.00]
1/28120119:15:56 AM 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA [phone] Page 1 of 1
BMP O&M AGREEMENTS
Permit Number:
(to be provided by DWQ)
Drainage Area Number: AIVP-?t I
Wet Detention Basin Operation and Maintenance Agreement
I will keep a maintenance record on this BMP. This maintenance record will be kept in a
log in a known set location. Any deficient BMP elements noted in the inspection will be
corrected, repaired or replaced immediately. These deficiencies can affect the integrity
of structures, safety of the public, and the removal efficiency of the BMP.
The wet detention basin system is defined as the wet detention basin,
pretreatment including forebays and the vegetated filter if one is provided.
This system (check one):
? does © does not incorporate a vegetated filter at the outlet.
This system (check one):
? does © does not incorporate pretreatment other than a forebay.
Important maintenance procedures:
- Immediately after the wet detention basin is established, the plants on the
vegetated shelf and perimeter of the basin should be watered twice weekly if
needed, until the plants become established (commonly six weeks).
- No portion of the wet detention pond should be fertilized after the first initial
fertilization that is required to establish the plants on the vegetated shelf.
- Stable groundcover should be maintained in the drainage area to reduce the
sediment load to the wet detention basin.
- If the basin must be drained for an emergency or to perform maintenance, the
flushing of sediment through the emergency drain should be minimized to the
maximum extent practical.
- Once a year, a dam safety expert should inspect the embankment.
After the wet detention pond is established, it should be inspected once a month and
within 24 hours after every storm event greater than 1.0 inches (or 1.5 inches if in a
Coastal County). Records of operation and maintenance should be kept in a known set
location and must be available upon request.
Inspection activities shall be performed as follows. Any problems that are found shall
be repaired immediately.
BMP element: Potential problem: How I will remediate the roblem:
The entire BMP Trash/ debris is resent. Remove the trash/ debris.
The perimeter of the wet Areas of bare soil and/or Regrade the soil if necessary to
detention basin erosive gullies have formed. remove the gully, and then plant a
ground cover and water until it is
established. Provide lime and a
one-time fertilizer application.
Vegetation is too short or too Maintain vegetation at a height of
long. approximately six inches.
Form SW401-Wet Detention Basin O&M-Rev.4 Page 1 of 4
Pen-nit Number:
(to be provided by DWQ)
Drainage Area Number: g!'2/-) ;d-/
BMP element: Potential problem: How I will remediate the problem:
The inlet device: pipe or The pipe is clogged. Unclog the pipe. Dispose of the
swale sediment off-site.
The pipe is cracked or Replace the pipe.
otherwise damaged.
Erosion is occurring in the Regrade the swale if necessary to
swale. smooth it over and provide erosion
control devices such as reinforced
turf matting or riprap to avoid
future problems with erosion.
The forebay Sediment has accumulated to Search for the source of the
a depth greater than the sediment and remedy the problem if
original design depth for possible. Remove the sediment and
sediment storage. dispose of it in a location where it
will not cause impacts to streams or
the BMP.
Erosion has occurred. Provide additional erosion
protection such as reinforced turf
matting or riprap if needed to
prevent future erosion problems.
Weeds are present. Remove the weeds, preferably by
hand. If pesticide is used, wipe it on
the plants rather than spraying.
The vegetated shelf Best professional practices Prune according to best professional
show that pruning is needed practices
to maintain optimal plant
health.
Plants are dead, diseased or Determine the source of the
dying. problem: soils, hydrology, disease,
etc. Remedy the problem and
replace plants. Provide a one-time
fertilizer application to establish the
ground cover if a soil test indicates
it is necessary.
Weeds are present. Remove the weeds, preferably by
hand. If pesticide is used, wipe it on
the plants rather than spraying.
The main treatment area Sediment has accumulated to Search for the source of the
a depth greater than the sediment and remedy the problem if
original design sediment possible. Remove the sediment and
storage depth. dispose of it in a location where it
will not cause impacts to streams or
the BMP.
Algal growth covers over Consult a professional to remove
50% of the area. and control the algal growth.
Cattails, phragmites or other Remove the plants by wiping them
invasive plants cover 50% of with pesticide (do not spray).
the basin surface.
Form SW401-Wet Detention Basin O&M-Rev.4 Page 2 of 4
Permit Number:
(to be proililerl by 1) JFQ)
Drainage Area Number: (
BMP element: Potential problem: How I will remediate the problem:
The embankment Shrubs have started to grow Remove shrubs immediately.
on the embankment.
Evidence of muskrat or Use traps to remove muskrats and
beaver activity is present. consult a professional to remove
beavers.
A tree has started to grow on Consult a dam safety specialist to
the embankment. remove the tree.
An annual inspection by an Make all needed repairs.
appropriate professional
shows that the embankment
needs repair. if applicable)

The outlet device
Clogging has occurred. _
Clean out the outlet device. Dispose
of the sediment off-site.
The outlet device is damaged Repair or replace the outlet device.
The receiving water Erosion or other signs of Contact the local NC Division of
damage have occurred at the Water Quality Regional Office, or
outlet. the 401 Oversight Unit at 919-733-
1786.
The measuring device used to determine the sediment elevation shall be such
that it will give an accurate depth reading and not readily penetrate into
accumulated sediments.
When the permanent pool depth reads t-l feet in the main pond, the
sediment shall be removed.
When the permanent pool depth reads I-? feet in the forebay, the sediment
shall be removed.
Sediment Removal
Bottom Elevat
BASIN DIAGRAM
ill in the blanks)
Q Permanent Pool Elevation L
33?f Pe manen Pool
- - - - - - - - - - - - - Volume Sediment Removal Elevation
-7 ft Min . j
`71 ?' --------------------------------------------
Sediment Bottom Elevation 7
Storage
FOREBAY MAIN POND
Volume
1-ft
Storage
Form SW401-Wet Detention Basin O&M-Rev.4 Page 3 of 4
Permit Number:
(to be provided by DWQ)
I acknowledge and agree by my signature below that I am responsible for the
performance of the maintenance procedures listed above. I agree to notify DWQ of any
problems with the system or prior to any changes to the system or responsible party.
Project name: 41-57-o&, Po il)
BMP drainage area number: -#:-
Print name: ?vLtA1 ?4wI-
Title: • _ ,r?-r`
Address: 2 U 1 C S %71n? ?Ale t'? ? i 2c?" r „A? y PVC 2? V 3
Phone: 97q E7 F??3dc?a ??
J
Date: ( / i--si -
Note: The legally responsible party should not be a homeowners association unless more than 50% of
the lots have been sold and a resident of the subdivision has been named the president.
a Notary Public for the State of
•7?, , CO«nty of do hereby certify that
c.wJ personally appeared before me this
clay ofT Cl t _? , and acknowledge the due execution of the
forgoing wet detention basin maintenance requirements. Witness my hand and official
seal,
iILI
SEAL

My commission expires - a I _-?L& 1 3
Form SW401-Wet Detention Basin O&M-Rev.4 Page 4 of 4
Permit Number:
(to be provided by DWQ)
Drainage Area Number: jow
Filter Strip, Restored Riparian Buffer and Level Spreader
Operation and Maintenance Agreement
I will keep a maintenance record on this BMP. This maintenance record will be kept in a
log in a known set location. Any deficient BMP elements noted in the inspection will be
corrected, repaired or replaced immediately. These deficiencies can affect the integrity
of structures, safety of the public, and the removal efficiency of the BMP.
Important maintenance procedures:
- Immediately after the filter strip is established, any newly planted vegetation
will be watered twice weekly if needed until the plants become established
(commonly six weeks).
- Once a year, the filter strip will be reseeded to maintain a dense growth of
vegetation
- Stable groundcover will be maintained in the drainage area to reduce the
sediment load to the vegetation.
- Two to three times a year, grass filter strips will be mowed and the clippings
harvested to promote the growth of thick vegetation with optimum pollutant
removal efficiency. Turf grass should not be cut shorter than 3 to 5 inches and
may be allowed to grow as tall as 12 inches depending on aesthetic requirements
(NIPC,1993). Forested filter strips do not require this type of maintenance.
- Once a year, the soil will be aerated if necessary.
- Once a year, soil pH will be tested and lime will be added if necessary.
After the filter strip is established, it will be inspected quarterly and within 24 hours
after every storm event greater than 1.0 inch (or 1.5 inches if in a Coastal County).
Records of operation and maintenance will be kept in a known set location and will be
available upon request.
Inspection activities shall be performed as follows. Any problems that are found shall
be repaired immediately.
BMP element: Potential problem: How I will remediate the problem:
The entire filter strip Trash/debris is present. Remove the trash/ debris.
system
The flow splitter device The flow splitter device is Unclog the conveyance and dispose
(if applicable) clogged. of an sediment off-site.
The flow splitter device is Make any necessary repairs or
damaged. replace if damage is too large for
repair.
Form SWU401-Level Spreader, Filter Strip, Restored Riparian Buffer O&M-Rev.3 Page 1 of 3
BMP element: Potential problem: How I will remediate the problem:
The swale and the level The swale is clogged with Remove the sediment and dispose
lip -sediment. of it off-site.
The level lip is cracked, Repair or replace lip.
settled, undercut, eroded or
otherwise damaged.
There is erosion around the Regrade the soil to create a berm
end of the level spreader that that is higher than the level lip, and
shows stormwater has then plant a ground cover and
bypassed it. water until it is established. Provide
lime and a one-time fertilizer
application.
Trees or shrubs have begun Remove them.
to grow on the swale or just
downslo e of the level lip.
The bypass channel Areas of bare soil and/or Regrade the soil if necessary to
erosive gullies have formed. remove the gully, and then
reestablish proper erosion control,
Turf reinforcement is Study the site to see if a larger
damaged or ripap is rolling bypass channel is needed (enlarge if
downhill. necessary). After this, reestablish
the erosion control material.
The filter strip Grass is too short or too long Maintain grass at a height of
if applicable). approximately three to six inches.
Areas of bare soil and/or Regrade the soil if necessary to
erosive gullies have formed. remove the gully, and then plant a
ground cover and water until it is
established. Provide lime and a
one-time fertilizer application.
Sediment is building up on Remove the sediment and
the filter strip. restabilize the soil with vegetation if
necessary. Provide lime and a one-
time fertilizer application.
Plants are desiccated. Provide additional irrigation and
fertilizer as needed.
Plants are dead, diseased or Determine the source of the
dying. problem: soils, hydrology, disease,
etc. Remedy the problem and
replace plants. Provide a one-time
fertilizer application.
Nuisance vegetation is Remove vegetation by hand if
choking out desirable species. possible. If pesticide is used, do not
allow it to get into the receiving
water.
The receiving water Erosion or other signs of Contact the NC Division of Water
damage have occurred at the Quality local Regional Office, or the
outlet. 401 Oversight Unit at 919-733-1786.
Form SWU401-Level Spreader, Filter Strip, Restored Riparian Buffer O&M-Rev. 3 Page 2 of 3
Permit Number:
(to be provided by DWQ)
I acknowledge and agree by my signature below that I am responsible for the
performance of the maintenance procedures listed above. I agree to notify DWQ of any
problems with the system or prior to any changes to the system or responsible party.
Project name: ALST0AJ A),?JQ
BMP drainage area number:_ _f_I. ' '
Print name:

Phone:
ssignakrrU-
Date: W

Note: The legally responsible party should not be a homeowners association unless more than 50% of
the lots have been sold and a resident of the subdivision has been named the president.
t _1 , a Notary Public for the State of
of do hereby certify that
personally appeared before me this ZJ_
dof , and acknowledge the due execution of the
forgoing Ater strip, riparian buffer, and/or level spreader maintenance requirements.
Witness my hand and official seal,

SEAL

My commission expires I -- ? 1- ?-_)b 0
Form SWU401-Level Spreader, Filter Strip, Restored Riparian Buffer O&M-Rev.3 Page 3 of 3
Title: 4?
y
Address: Z 4 L_l wGs r1? s,, , Z - c %-?o C.-V Y 'V C Z_ 7 S-
13
Permit Number:
(to be provided by DWQ)
Drainage Area Number: ?2
Wet Detention Basin Operation and Maintenance Agreement
I will keep a maintenance record on this BMP. This maintenance record will be kept in a
log in a known set location. Any deficient BMP elements noted in the inspection will be
corrected, repaired or replaced immediately. These deficiencies can affect the integrity
of structures, safety of the public, and the removal efficiency of the BMP.
The wet detention basin system is defined as the wet detention basin,
pretreatment including forebays and the vegetated filter if one is provided.
This system (check one):
K does ? does not
This system (check one):
? does X does not
incorporate a vegetated filter at the outlet.
incorporate pretreatment other than a forebay.
Important maintenance procedures:
- Immediately after the wet detention basin is established, the plants on the
vegetated shelf and perimeter of the basin should be watered twice weekly if
needed, until the plants become established (commonly six weeks).
- No portion of the wet detention pond should be fertilized after the first initial
fertilization that is required to establish the plants on the vegetated shelf.
- Stable groundcover should be maintained in the drainage area to reduce the
sediment load to the wet detention basin.
- If the basin must be drained for an emergency or to perform maintenance, the
flushing of sediment through the emergency drain should be minimized to the
maximum extent practical.
- Once a year, a dam safety expert should inspect the embankment.
After the wet detention pond is established, it should be inspected once a month and
within 24 hours after every storm event greater than 1.0 inches (or 1.5 inches if in a
Coastal County). Records of operation and maintenance should be kept in a known set
location and must be available upon request.
Inspection activities shall be performed as follows. Any problems that are fqund shall
be repaired immediately.
BMP element: Potential problem: How I will remediate the problem:
The entire BMP Trash/debris is resent. Remove the trash/ debris.
The perimeter of the wet Areas of bare soil and/or Regrade the soil if necessary to
detention basin erosive gullies have formed. remove the gully, and then plant a
ground cover and water until it is
established. Provide lime and a
one-time fertilizer application.
Vegetation is too short or too Maintain vegetation at a height of
long. a roximatel six inches.
Form SW401-Wet Detention Basin O&M-Rev.4 Page 1 of 4
Permit Number:
(to be prm,ielerl l) y DWQ)
Drainage Area Number: I I
BMP element: Potential problem: How I will rernediate the problem:
The inlet device: pipe or The pipe is clogged. Unclog the pipe. Dispose of the
swale
T sediment off-site.
The pipe is cracked or Replace the pipe.
otherwise damaged.
Erosion is occurring in the Regrade the swale if necessary to
swale. smooth it over and provide erosion
control devices such as reinforced
turf matting or riprap to avoid
future problems with erosion.
The forebay Sediment has accumulated to Search for the source of the
a depth greater than the sediment and remedy the problem if
original design depth for possible. Remove the sediment and
sediment storage. dispose of it in a location where it
will not cause impacts to streams or
the BMP.
Erosion has occurred. Provide additional erosion
protection such as reinforced turf
matting or riprap if needed to
prevent future erosion problems.
Weeds are present. Remove the weeds, preferably by
hand. If pesticide is used, wipe it on
the 121ants rather than spraying.
The vegetated shelf Best professional practices Prune according to best professional
show that pruning is needed practices
to maintain optimal plant
health.
Plants are dead, diseased or Determine the source of the
dying. problem: soils, hydrology, disease,
etc. Remedy the problem and
replace plants. Provide a one-time
fertilizer application to establish the
ground cover if a soil test indicates
it is necessary.
Weeds are present. Remove the weeds, preferably by
hand. If pesticide is used, wipe it on
the plants rather than spraying.
The main treatment area Sediment has accumulated to Search for the source of the
a depth greater than the sediment and remedy the problem if
original design sediment possible. Remove the sediment and
storage depth. dispose of it in a location where it
will not cause impacts to streams or
the BMP.
Algal growth covers over Consult a professional to remove
50% of the area. and control the algal growth.
Cattails, phragmites or other Remove the plants by wiping them
invasive plants cover 50% of with pesticide (do not spray).
the basin surface.
Form SW401-Wet Detention Basin O&M-Rev.4 Page 2 of 4
Permit Number:
(to be prnvideel ky DPYO)
Drainage Area Number: _13,-Tf10- 2-
BMP element: Potential problem: How I will remediate the problem:
The embankment Shrubs have started to grow Remove shrubs immediately.
on the embankment.
Evidence of muskrat or Use traps to remove muskrats and
beaver activity is present. consult a professional to remove
beavers.
A tree has started to grow on Consult a dam safety specialist to
the embankment. remove the tree.
An annual inspection by an Make all needed repairs.
appropriate professional
shows that the embankment
needs repair. if applicable)
The outlet device Clogging has occurred. Clean out the outlet device. Dispose I
of the sediment off-site.
The outlet device is damaged Repair or replace the outlet device.
The receiving water Erosion or other signs of Contact the local NC Division of
damage have occurred at the Water Quality Regional Office, or
outlet. the 401 Oversight Unit at 919-733-
1786.
The measuring device used to determine the sediment elevation shall be such
that it will give an accurate depth reading and not readily penetrate into
accumulated sediments.
When the permanent pool depth reads `) feet in the main pond, the
sediment shall be removed.
When the permanent pool depth reads 5 feet in the forebay, the sediment
shall be removed.
BASIN DIAGRAM
fll in the blanks)
Sediment Removal
Bottom
0 Permanent Pool Elevation 36-5
>'C- l Pe ianen Pool
- - - - - - - - - - - - - - - - - - Volume Sediment Removal Elevation 360
Volume
? =? • ' `l
----
-ft Min.
------------------------------------
---- - -
Sediment Bottom Elevation `361 1-ft 4n.
Storage Sediment
Storage
FOREBAY MAIN POND
Form SW401-Wet Detention Basin O&M-Rev.4 Page 3 of 4
Permit Number:
(to be provided by DWQ)
I acknowledge and agree by my signature below that I am responsible for the
performance of the maintenance procedures listed above. I agree to notify DWQ of any
problems with the system or prior to any changes to the system or responsible party.
Project name: J L S 7-6/A/ POwD
BMP drainage area number: 41?yo #2
Print name: .Tt
• Title:
+, ?s •
Address: Zq ol Lti?C'?y N& a7?
Phone; `!? -? 3 coo
Sill
Date;
Note: The legally responsible party should not be a homeowners association unless more than 50% of
the lots have been sold and a resident of the subdivision has been named the president.
I, _?? .-.? "/2-1, ,._., r- , '. ) , a Notary Public for the State of
w-vk O'V County of ?'J - , do hereby certify that
personally appeared before me this Q_I_
ay of a1 , and acknowledge the due execution of the
forgoing wet detention basin maintenance requirements. Witness my hand and official
seal,
gyp 2
?I?,,? wwJJ
,Y""rltlNlf Ilill»ti??
SEAL ?y,14
My commission expires
Form SW401-Wet Detention Basin O&M-Rev.4
J
Page 4 of 4
Permit Number:
(to be provided by DWQ)
Drainage Area Number: 'eJ7'?_l .4?_ 3
Wet Detention Basin Operation and Maintenance Agreement
I will keep a maintenance record on this BMP. This maintenance record will be kept in a
log in a known set location. Any deficient BMP elements noted in the inspection will be
corrected, repaired or replaced immediately. These deficiencies can affect the integrity
of structures, safety of the public, and the removal efficiency of the BMP.
The wet detention basin system is defined as the wet detention basin,
pretreatment including forebays and the vegetated filter if one is provided.
This system (check one):
? does N does not
This system (check one):
? does [Rj does not
incorporate a vegetated filter at the outlet.
incorporate pretreatment other than a forebay.
Important maintenance procedures:
- Immediately after the wet detention basin is established, the plants on the
vegetated shelf and perimeter of the basin should be watered twice weekly if
needed, until the plants become established (commonly six weeks).
- No portion of the wet detention pond should be fertilized after the first initial
fertilization that is required to establish the plants on the vegetated shelf.
- Stable groundcover should be maintained in the drainage area to reduce the
sediment load to the wet detention basin.
- If the basin must be drained for an emergency or to perform maintenance, the
flushing of sediment through the emergency drain should be minimized to the
maximum extent practical.
- Once a year, a dam safety expert should inspect the embankment.
After the wet detention pond is established, it should be inspected once a month and
within 24 hours after every storm event greater than 1.0 inches (or 1.5 inches if in a
Coastal County). Records of operation and maintenance should be kept in a known set
location and must be available upon request.
Inspection activities shall be performed as follows. Any problems that are found shall
be repaired immediately.
BMP element: Potential problem: How I will remediate the problem.
The entire BMP Trash/debris is resent. Remove the trash/debris.
The perimeter of the wet Areas of bare soil and/or Regrade the soil if necessary to
detention basin erosive gullies have formed. remove the gully, and then plant a
ground cover and water until it is
established. Provide lime and a
one-time fertilizer application.
Vegetation is too short or too Maintain vegetation at a height of
long. a roximatel six inches.
Form SW401-Wet Detention Basin O&M-Rev.4 Page 1 of 4
Permit Number:
_
(to be provided by DWQ)
Drai nage Area Number: _411?
BMP element: Potential problem: How I will remediate the problem:
The inlet device: pipe or The pipe is clogged. Unclog the pipe. Dispose of the
swale sediment off-site.
The pipe is cracked or Replace the pipe.
otherwise damaged.
Erosion is occurring in the Regrade the swale if necessary to
swale. smooth it over and provide erosion
control devices such as reinforced
turf matting or riprap to avoid
future problems with erosion.
The forebay Sediment has accumulated to Search for the source of the
a depth greater than the sediment and remedy the problem if
original design depth for possible. Remove the sediment and
sediment storage. dispose of it in a location where it
will not cause impacts to streams or
the BMP.
Erosion has occurred. Provide additional erosion
protection such as reinforced turf
matting or riprap if needed to
prevent future erosion problems.
Weeds are present. Remove the weeds, preferably by
hand. If pesticide is used, wipe it on
the plants rather than s ra in .
The vegetated shelf Best professional practices Prune according to best professional
show that pruning is needed practices
to maintain optimal plant
health.
Plants are dead, diseased or Determine the source of the
dying. problem: soils, hydrology, disease,
etc. Remedy the problem and
replace plants. Provide a one-time
fertilizer application to establish the
ground cover if a soil test indicates
it is necessary.
Weeds are present. Remove the weeds, preferably by
hand. If pesticide is used, wipe it on
the plants rather than spraying.
The main treatment area Sediment has accumulated to Search for the source of the
a depth greater than the sediment and remedy the problem if
original design sediment possible. Remove the sediment and
storage depth. dispose of it in a location where it
will not cause impacts to streams or
the BMP.
Algal growth covers over Consult a professional to remove
50% of the area. and control the algal growth.
Cattails, phragmites or other Remove the plants by wiping them
invasive plants cover 50% of with pesticide (do not spray).
the basin surface.
Form SW401-Wet Detention Basin O&M-Rev.4 Page 2 of 4
Permit Number:
(to be p) -owded by UPVQ)
Drainage Area Number: S, ' '?-
BMP element: Potential problem: How I will remediate the problem:
The embankment Shrubs have started to grow Remove shrubs immediately.
on the embankment. _
Evidence of muskrat or Use traps to remove muskrats and
beaver activity is present. consult a professional to remove
beavers.
A tree has started to grow on Consult a dam safety specialist to
the embankment. remove the tree.
An annual inspection by an Make all needed repairs.
appropriate professional
shows that the embankment
needs repair. if a licable
The outlet device Clogging has occurred. Clean out the outlet device. Dispose
of the sediment off-site.
The outlet device is damaged Repair or replace the outlet device.
The receiving water Erosion or other signs of Contact the local NC Division of
damage have occurred at the Water Quality Regional Office, or
outlet. the 401 Oversight Unit at 919-733-
1786.
The measuring device used to determine the sediment elevation shall be such
that it will give an accurate depth reading and not readily penetrate into
accumulated sediments.
When the permanent pool depth reads feet in the main pond, the
sediment shall be removed.
When the permanent pool depth reads feet in the forebay, the sediment
shall be removed.
BASIN DIAGRAM
(fill in the blanks)
V Permanent Pool Elevation
Sediment Removal L . 377 YPe iane n Pool
- - - - - - - - - - - - Volume Sediment Removal Elevation '77 Volinne
BottomElevaiioi "j7(-, t Min. -------------------------?-----------ediment Bottom Elevation °? 7L 1-ft n
Storage Sedsnier
Storage
FOREBAY MAIN POND
Form SW401-Wet Detention Basin O&M-Rev.4 Page 3 of 4
Permit Number:
(to be provided by DWQ)
I acknowledge and agree by my signature below that I am responsible for the
performance of the maintenance procedures listed above. I agree to notify DWQ of any
problems with the system or prior to any changes to the system or responsible party.
?5!'Url:" %sJJr
Project name:
BMP drainage area number: I-qJ/T1/F #
Print name: j,//-
.Title: 6?P?.r?,?_
Address. 27goi W 657Akl Aeet,.? -l Svr m ? 3 c?Qy AIC 2 r13
iJel - tiff-30a
. J1,?Il
Date.

--?, 1-f1

Note: The legally responsible party should not be a homeowners association unless more than 50% of
the lots have been sold and a resident of the subdivision has been named the president.
I, V D-, s Q ? y a Notary Public for the State of
1 In ?_ C?8 f c ,`County of L-J , do hereby certify that
personally appeared before me this
da of C,,< Gr!I, and acknowledge the due execution of the
forgoii et detention basin maintenance requirements. Witness my hand and official
seal,

My commission expires 4-_ .0-01S.
Form SW401-Wet Detention Basin O&M-Rev.4 Page 4 of 4
Permit Number:_ _
(to be provided by DWQ)
Drainage Area Number:, L
Filter Strip, Restored Riparian Buffer and Level Spreader
Operation and Maintenance Agreement
I will keep a maintenance record on this BMP. This maintenance record will be kept in a
log in a known set location. Any deficient BMP elements noted in the inspection will be
corrected, repaired or replaced immediately. These deficiencies can affect the integrity
of structures, safety of the public, and the removal efficiency of the BMP.
Important maintenance procedures:
- Immediately after the filter strip is established, any newly planted vegetation
will be watered twice weekly if needed until the plants become established
(commonly six weeks).
- Once a year, the filter strip will be reseeded to maintain a dense growth of
vegetation
- Stable groundcover will be maintained in the drainage area to reduce the
sediment load to the vegetation.
- Two to three times a year, grass filter strips will be mowed and the clippings
harvested to promote the growth of thick vegetation with optimum pollutant
removal efficiency. Turf grass should not be cut shorter than 3 to 5 inches and
may be allowed to grow as tall as 12 inches depending on aesthetic requirements
(NIPC,1993). Forested filter strips do not require this type of maintenance.
- Once a year, the soil will be aerated if necessary.
- Once a year, soil pH will be tested and lime will be added if necessary.
After the filter strip is established, it will be inspected quarterly and within 24 hours
after every storm event greater than 1.0 inch (or 1.5 inches if in a Coastal County).
Records of operation and maintenance will be kept in a known set location and will be
available upon request.
Inspection activities shall be performed as follows. Any problems that are found shall
be repaired immediately.
BMP element: Potential problem: How I will remediate the problem:
The entire filter strip Trash/ debris is present. Remove the trash/ debris.
system
The flow splitter device The flow splitter device is Unclog the conveyance and dispose
(if applicable) -clogged. of an sediment off-site.
The flow splitter device is Make any necessary repairs or
damaged. replace if damage is too large for
repair.
Form SWU401-Level Spreader, Filter Strip, Restored Riparian Buffer O&M-Rev.3 Page 1 of 3
BMP element: Potential problem: How I will remediate the problem:
The swale and the level The swale is clogged with Remove the sediment and dispose
lip sediment. of it off-site.
The level lip is cracked, Repair or replace lip.
settled, undercut, eroded or
otherwise damaged.
There is erosion around the Regrade the soil to create a berm
end of the level spreader that that is higher than the level lip, and
shows stormwater has then plant a ground cover and
bypassed it. water until it is established. Provide
lime and a one-time fertilizer
application.
Trees or shrubs have begun Remove them.
to grow on the swale or just
downslo e of the level lip.
The bypass channel Areas of bare soil and/or Regrade the soil if necessary to
erosive gullies have formed. remove the gully, and then
reestablish proper erosion control.
Turf reinforcement is Study the site to see if a larger
damaged or ripap is rolling bypass channel is needed (enlarge if
downhill. necessary). After this, reestablish
the erosion control material.
The filter strip Grass is too short or too long Maintain grass at a height of
if a licable . approximately three to six inches.
Areas of bare soil and/or Regrade the soil if necessary to
erosive gullies have formed. remove the gully, and then plant a
ground cover and water until it is
established. Provide lime and a
one-time fertilizer application.
Sediment is building up on Remove the sediment and
the filter strip. restabilize the soil with vegetation if
necessary. Provide lime and a one-
time fertilizer application.
Plants are desiccated. Provide additional irrigation and
fertilizer as needed.
Plants are dead, diseased or Determine the source of the
dying. problem: soils, hydrology, disease,
etc. Remedy the problem and
replace plants. Provide a one-time
fertilizer application.
Nuisance vegetation is Remove vegetation by hand if
choking out desirable species. possible. If pesticide is used, do not
allow it to get into the receiving
water.
The receiving water Erosion or other signs of Contact the NC Division of Water
damage have occurred at the Quality local Regional Office, or the
outlet. 401 Oversight Unit at 919-733-1786.
Form SWU401-Level Spreader, Filter Strip, Restored Riparian Buffer O&M-Rev.3 Page 2 of 3
Permit Number:
(to be provided by DWQ)
I acknowledge and agree by my signature below that I am responsible for the
performance of the maintenance procedures listed above. I agree to notify DWQ of any
problems with the system or prior to any changes to the system or responsible party.
Project name: 41_STa&j /' wn
BMP drainage area number:
Print name: Tv L` A rJ
• Title:
240'1 W&',70
elI ? - y ?l - Sao V
Date: ? i-
< v %i€ 2a 3
Note: The legally responsible party should not be a homeowners association unless more than 50% of
the lots have been sold and a resident of the subdivision has been named the president.
I, a Notary Public for the State of
???- ounty of , do hereby certify that
G.., c personally appeared before me this
d• of and acknowledge the due execution of the
forgoing filter strip, riparian buffer, and/or level spreader maintenance requirements.
Witness my hand and official seal,
'r?Jff'fjPO ' k0'!y``>
.•+?TffTR7lS+•••-
SEAT, J l r?-
My commission expiresF ? - _x 1- -;*13
Form SWU401-Level Spreader, Filter Strip, Restored Riparian Buffer O&M-Rev.3 Page 3 of 3
Permit Number:
(to be provided by DWQ)
Drainage Area Number: /? p may
Wet Detention Basin Operation and Maintenance Agreement
I will keep a maintenance record on this BMP. This maintenance record will be kept in a
log in a known set location. Any deficient BMP elements noted in the inspection will be
corrected, repaired or replaced immediately. These deficiencies can affect the integrity
of structures, safety of the public, and the removal efficiency of the BMP.
The wet detention basin system is defined as the wet detention basin,
pretreatment including forebays and the vegetated filter if one is provided.
This system (check one):
0 does ? does not incorporate a vegetated filter at the outlet.
This system (check one):
? does ® does not incorporate pretreatment other than a forebay.
Important maintenance procedures:
- Immediately after the wet detention basin is established, the plants on the
vegetated shelf and perimeter of the basin should be watered twice weekly if
needed, until the plants become established (commonly six weeks).
- No portion of the wet detention pond should be fertilized after the first initial
fertilization that is required to establish the plants on the vegetated shelf.
- Stable groundcover should be maintained in the drainage area to reduce the
sediment load to the wet detention basin.
- If the basin must be drained for an emergency or to perform maintenance, the
flushing of sediment through the emergency drain should be minimized to the
maximum extent practical.
- Once a year, a dam safety expert should inspect the embankment.
After the wet detention pond is established, it should be inspected once a month and
within 24 hours after every storm event greater than 1.0 inches (or 1.5 inches if in a
Coastal County). Records of operation and maintenance should be kept in a known set
location and must be available upon request.
Inspection activities shall be performed as follows. Any problems that are found shall
be repaired immediately.
BMP element: Potential problem: How I will remediate the problem:
The entire BMP Trash/ debris is resent. Remove the trash/ debris.
The perimeter of the wet Areas of bare soil and/or Regrade the soil if necessary to
detention basin erosive gullies have formed. remove the gully, and then plant a
ground cover and water until it is
established. Provide lime and a
one-time fertilizer application.
Vegetation is too short or too Maintain vegetation at a height of
long. approximately six inches.
Form SW401-Wet Detention Basin O&M-Rev.4 Page 1 of 4
Permit Number: _
(to be provided by DWQ)
Drainage Area Number:
BMP element: Potential problem: How I will remediate the problem:
The inlet device: pipe or The pipe is clogged. Unclog the pipe. Dispose of the
swale sediment off-site.
The pipe is cracked or Replace the pipe.
otherwise damaged.
Erosion is occurring in the Regrade the swale if necessary to
swale. smooth it over and provide erosion
control devices such as reinforced
turf matting or riprap to avoid
future problems with erosion.
The forebay Sediment has accumulated to Search for the source of the
a depth greater than the sediment and remedy the problem if
original design depth for possible. Remove the sediment and
sediment storage. dispose of it in a location where it
will not cause impacts to streams or
the BMP.
Erosion has occurred. Provide additional erosion
protection such as reinforced turf
matting or riprap if needed to
prevent future erosion problems.
Weeds are present. Remove the weeds, preferably by
hand. If pesticide is used, wipe it on
the plants rather than s ra in .
The vegetated shelf Best professional practices Prune according to best professional
show that pruning is needed practices
to maintain optimal plant
health.
Plants are dead, diseased or Determine the source of the
dying. problem: soils, hydrology, disease,
etc. Remedy the problem and
replace plants. Provide a one-time
fertilizer application to establish the
ground cover if a soil test indicates
it is necessary.
Weeds are present. Remove the weeds, preferably by
hand. If pesticide is used, wipe it on
the plants rather than spraying.
The main treatment area Sediment has accumulated to Search for the source of the
a depth greater than the sediment and remedy the problem if
original design sediment possible. Remove the sediment and
storage depth. dispose of it in a location where it
will not cause impacts to streams or
the BMP.
Algal growth covers over Consult a professional to remove
50% of the area. and control the algal growth.
Cattails, phragmites or other Remove the plants by wiping them
invasive plants cover 50% of with pesticide (do not spray).
the basin surface.
Form SW401-Wet Detention Basin O&M-Rev.4 Page 2 of 4
Permit Number:
(to be proilided by D i,VQ)
Drainage Area Number:_ Y
BMP element: Potential problem: How I will remediate the problem:
The embankment Shrubs have started to grow Remove shrubs immediately.
on the embankment.

Evidence of muskrat or _
Use traps to remove muskrats and
beaver activity is present. consult a professional to remove
beavers.
A tree has started to grow on Consult a dam safety specialist to
the embankment. remove the tree.
An annual inspection by an Make all needed repairs.
appropriate professional
shows that the embankment
needs repair. fife_plicable)
The outlet device Clogging has occurred. Clean out the outlet device. Dispose
of the sediment off-site.
The outlet device is damaged Repair or replace the outlet device.
The receiving water Erosion or other signs of Contact the local NC Division of
damage have occurred at the Water Quality Regional Office, or
outlet. the 401 Oversight Unit at 919-733-
1786.
The measuring device used to determine the sediment elevation shall be such
that it will give an accurate depth reading and not readily penetrate into
accumulated sediments.
When the permanent pool depth reads feet in the main pond, the
sediment shall be removed.
When the permanent pool depth reads feet in the forebay, the sediment
shall be removed.
BASIN DIAGRAM
ill in the blanks)
Sediment Removal
Bottom
V Permanent Pool Elevation '3q 3
'
?q Pe ntanen Pool
L volume

f
----
Mi Sediment Removal Elevation
--------------------- Volume
-
t
n.
Sediment
Bottom Elevation '3:31f
1-ft n.
Storage Sediment
Storage
FOREBAY MAIN POND
Form SW401-Wet Detention Basin O&M-Rev.4 Page 3 of 4
Permit Number:
(to be provided by DWQ)
I acknowledge and agree by my signature below that I am responsible for the
performance of the maintenance procedures listed above. I agree to notify DWQ of any
problems with the system or prior to any changes to the system or responsible party.
Project name: ,/- ILS7z>
BMP drainage area number: f 3c' I /f
Print name: JUi. A-i - k4-t,1!s
• Title:
Address: Z-Elul WE57u 0 ;,?,QCCVAY s'v; r? ze3 6+p ,eve ? 7 -/,?
Phone: 1 qi - Jq 8 t
Date: ( f /--31 -1
Note: The legally responsible party should not be a homeowners association unless more than 50% of
the lots have been sold and a resident of the subdivision has been named the president.

County of
do hereby certify that
personally appeared before me this
da of _ , and acknowledge the die execution of the
forgoin wet detention basin maintenance requirements. Witness my hand and official
cPal
yyy?r4yHa??lue?yj?i
r ? ?J
N+rrlain?Y`? yyy
SEAL
My commission expires - - 13
a Notary Public for the State of
Form SW401-Wet Detention Basin O&M-Rev.4 Page 4 of 4
IMPACT MAPS

MATCH LINE
- _ - - ? as as m NN Ns NNc
=r-r,T
SHEET A
1 \
1TR !? r I ` .? ? r'
l + +
}}eR
tk t t
\14 1
t y
s
\
' / 1 R
..' ..` . ? ?.. ? ...... ?.. ++ a ++
--______________ a •RR
.._._._.. . ?. P /.

/ .? aooo.er: e. ? . `

+
+
?
O
'
x
+
++`+ SITE DATA TABLE
' \ ++ PIN: 0658523920
DEEDBOOK: 12671
+
' + DEED PAGE: 0810
DEED DATE: 712512007
TOTAL ACREAGE: 13749 ACRES
GRAPHIC SCALE
:00
1 inch - 200 k

S
E
T
IMPACT
# PERMANENT
PERENNIAL
STREAMIMPACT TEMPORARY
IMERMITTENT
STREAMIMPACT PERMANENT
ZONE 1 BUFFER
IMPACT PERMANENT
ZONE 2 BUFFER
IMPACT PERMANENT
WETLANDS
IMPACT TEMPORARY
WETLANDS
IMPACT
#1 5,338 SF (0123 AC)
#2 9,045 SF (0206 AC)
A #3 147 LF 567 SF(0013 AC)
#4 456 SF (0.010 AC)
#5 1,191 SF (0 027 AC)
#6 3,707 SF (0 B05 AC)
B #7 2,503 SF (D 057 AC)
#8 226 SF (0.005 AC)
C 19 494 SF (0.011 AC)
#10 4,665 SF(0107 AC)
#11 627 SF (0.014 AC)
D #12 133 SF(0003 AC)
#13 426 SF (0 010 AC)
914 1,485 SF (0 034 AC)
915 23 LF 7SF (0 001 ACI
#16 66B SF (0 015 AC)
E E!#I!7 660 SF (0 015 AC)
285 SF (0.007 AC)
#19 61 SF (0 001 AC)
F #20 2,553 SF (0.059 AC)
TOTALS 47 LF 567 SF(0013 AC) 23 LF 7SF(0001 AC) 13,550 SF(0311 AC) 19,501 SF (D 440 AC) 853 SF(0019 AC) 627SF(DOtq AC))
ALSTON POND WITHERB ? RAVENEL?
OVERALL SITE PLAN WITH IMPACTS III SEMI N-KRA I PLAN HERS R.U.V.T.J.
I
+ f.
Sf•iF-FT B ++' r?
Mal 7w WrIr
11 1 I II I 1 I ?1\\111!I?11\ \ rl\f *71+...\.\
1 4I \
?(q S qD
I RBT?ININGWALI
\
.%
r? T ? I Y
PRO OSED
+ f I j fJ ENGY
DISSIPATER
PR PQS?¢ y j 1 / r
?\ \ 1 ` 4 1 '"ry
RE?AININO WAIL
.?\
fl I /// .- k7 -7
PROPOSE IP-RAP
?F CHANNEL TO STREAM )
(HIGH FLO ?WPASS 4 1
FROM BMP1

IMPACT #1 IMPACT #2 IMPACT #3 IMPACT #4
PERMANENT ZONE 2 PERMANENTZONEI PERMANENT PERENNIAL PERMANENTZONEI
BUFFERIMPACT BUFFERIMPACT STREAMIMPACT BUFFERIMPACT
5,338 SF (0.123 AC) 9,045 SF (0.208 AC) 147 LF 456 SF (0.010 AC)
567 SF (0.013 AC)
r ? \ -C
r
r
r
a
r
t
ll? ? \

IMPACT #5
PERMANENTZONE2
BUFFERIMPACT
1,191 SF (0.027 AC)
SCALE: 1 inch = 40 ft.
ALSTON POND SHEET A WITHERS & RAVENEL
IMPACTS #1 - #5 ?ni"ets3 ' """Kxs l suev[rnks
!l'i `i?•?Y L'?.$L4A 1b'.1Kf l:('",lY K,ap C.. vii e
' - - PROPOSED 50 LF
,? r - -- --- 48" RCP
- 7=21

i
i

-
r
I ? f
f 1 r
r ?
P r r
r r / f J
r
PROPOSED
RETAINING WA
- w.
PROPQSFw0 ti
RETAININGIWALL', `
PROPOSEbENERG?DISSIPATER
?WETLANOS \
yy
1 I ?? ? \ '0 ti ` '
\ .
I O \ \
11, It, %V
IMPACT #6 IMPACT #7 IMPACT #8
PERMANENT ZONE 2 PERMANENT ZONE: 1 PERMANENT WETLANDS IMPACT
BUFFER IMPACT BUFFER IMPACT 226 SF (0.005 AC)
3,707 SF (0.085 AC) 2,503 SF (0.057 AC)
GRAPHIC SCALE
40 0
1 inch = 40 ft.
ALSTON POND
SHEET B
IMPACTS #6 - #8
WITHERS & RAVENEL
EKSIMEF0% I P1A11NE115 i SURVEYORS

1
- +- PROPOSED
_ - - ?+ \L I ENERGY
i DISSIPATER
Sil?s?
.." ? . - N'
/ ?
f O
EXI,*ING
\ I? WETLANDS
\
\

v
ti
\
r \
\ r[7
y

EXISTING POND
y? ? Jr
EXISTING POND

IMPACT #9 IMPACT #10
PERMANENT WETLANDS IMPACT PERMANENT ZONE 2
494SF (0.011 AC) BUFFER IMPACT
4,665 SF (0.107 AC)
s
S
ALSTON POND SHEET C
IMPACT #9 & #10
WAKE COUNiv Norrh C?rnlina
GRAPHIC SCALE
40 0
1 inch = 40 ft.
WITHERS &- RAVENEL
ENGINEERS 1 PLANNERS I SURVEYORS
irr/ ' l
r I t
?r ? r?f,r r•7 ? ?r ,_ i *?
IMPACT #11 \ •
TEMPORARY WETLANDS ?•w„/: / 'i
IMPACT / ! ?
627 SF (0.014 AC)
I ROPO. i?' / ? ?
GREEW Y ' / r +
£OGE OF - 20' SANITARY
f SEWER
POND EASEMENT
f'r 4? 'w f /' i ?' BOARDWALK
'd ?g(9?r err f - e i OVER
?7p f .. WETLANDS_
I 1 r ?
EDGE OF • I. { `?+? e' "?.- \
POND ?r ?.: ?/ rr? '? "•,? \
j'Y•, \ X51=?? \
10, !
x ? ? 1 r

IMPACT#12 GRAPHIC SCALE
PERMANENT WETLANDS IMPACT 40 1
133 SF (0.003 AC) I !I
1 inch = 40 ft.
ALSTON POND SHEET D WITHERS & RAVENEL
IMPACTS #11412 ENGINEERS I PLANNERS I SURVEYORS
FU UAV-VARINA WAKE COUNJY North Carolina - .. .. .,, .:;.,,,., ,.. .... ...
IMPACT #13 IMPACT #14 IMPACT #15
PERMANENT ZONE 2 PERMANENTZONE1 TEMPORARY INTERMITTENT
BUFFERIMPACT BUFFERIMPACT STREAMIMPACT
426 SF (0.010 AC) 1,485 SF (0.034 AC) 23 LF
47 SF (0.001 AC)
s
i , Yr •,. //mar ?r
' rf 1'
'y r rti i' PR I@SEI7 RIP-RAP
BOARUNALK -? ANWIEL TO ST
.'-OVER STREAIvt tHIGI FL91N k"S
(NO IMPACT) PROM BkI
r i %f
s
?'' .. r i i r ?` `'•: PROPQSEI]
VEUTAT
.i
7
41
/ r 5p ?? r
60, v
r
/ rr ,err }'/` t %?,.
r ?p .10000
q
140, / Jr
-? / 20' SANITARY
/ SEWER ? I / /
EASEMENT? y 1000* w , / .v 14, •Y
IMPACT #16 IMPACT #17 IMPACT #18 IMPACT #19
PERMANENT ZONE 2 PERMANENTZONE2 PERMANENTZONE2 PERMANENTZONE1
BUFFERIMPACT BUFFERIMPACT BUFFERIMPACT BUFFERIMPACT
668 SF (0.015 AC) 668 SF (0.015 AC) 285 SF (0.007 AC) 61 SF (0.001 AC)
GRAPHIC SCALE
40 ! s
1 inch = 40 ft.
ALSTON POND SHEET E WITHERS &- RAVENEL
IMPACTS #13 - #19 1N0INK AAS I PLAIV PIERS I SURVEYORS
it.DI..KT-V?KNIti.I WAKE COUMY tiny1? c „u°In?

'41 \1
\bc v y" eV
i`
IN

\ \
\
b y \ --- -.?-JOP OF BANK
TOP

WETLANDS
lie Q/

t
\ \ \ i
•
? ?i? PROPOSED.
? ? ? "
? ? . i i r - v+ y. ENERGY

,, =
\ s r

IMPACT #20
PERMANENT ZONE 2
BUFFERIMPACT
2,553 SF (0.059 AC)
GRAPHIC SCALE
40 0
1 inch = 40 ft.
SHEET F #20 I W?THER8 RAVENEL II
I ALSTON POND III IMPACT
ENGINEERS 1 PLANNERS I SURVEYORS
i
365 I i 365
PROPOSED
BOARDWALK 1
360 PROPOSED GRADE 360
EXISTING GRADE
i
_ i
EXISTING STREAM '
355 355
GREENWAY CROSSING AT IMPACT #15

345

i
340
I PROPOSED
BOARDWALKS

_ ?N/?' _ EXISTING GL

DE 345

40

GREENWAY CROSSING AT IMPACT #11
GRAPHIC SCALE
40 (1
1 inch = 40 ft.
ALSTON POND GREENWAY CROSSING DETAILS WITHERS & RAVENEL
ENGINEERS 1 PLANNERS I SURVEYORS
WAKF CHANTY Noah Carolina ... . .....-...,

385_,_ !! - -.1- -- -- - - - .. 385,
1 ? ' - ?
PROPOSED I u

-
! ?
GRADE V

380 - - !! L - . - - - 380
! I I
1 ? f ]
?
i r
375 -/? 375

i !
1 1 f
I ! EXISTING
_
370 GRADE
370

365 365

66"RC
CROSSNG
360 360
I 1
355 - - ] - 1 355
UPSTREAM

-
385
] i - I
385 I

_
PROPOSED {
GRADE
I !
I ! I i I
380 360 J
? I'
- I
i ! I 1
I I I
I
375 375

I r
I C !1 -t - ? ? /'
I '
370 !
_ cISrik6 -
f - -- - -3700
! r
'• /
OWE

?
_ 365
y
I
N.
360 _ , 1 360 _
_
- Or Re
- CROSS NG - - -

- 355 35,9
E DOWNSTREAM
8
i

s`
a NOT TO SCALE

CULVERT CROSS SECTION WITHERS &- RAVENEL

s ALSTON POND IMPACTS #1 - #3 ENGINEERS 1 PLANNERS I SURVEYORS
i Ill UAY-VARINA WAKE COUNIY N'odh Catalina -
MAIN BARRELL SECONDARY BARRELL
EXISTING PROPOSED EXISTING PROPOSED
GRADE INVERT GRADE INVERT
UPSTREAM 360.00 359.00 361.50 361.50
DOWNSTREAM 356.50 355.50 358.00 358.00
Project Name: Alston Pond
City/State: Fuquay-Varina
Table 1.1 Surface Area to Drainage Area Ratio for Permanent Pool Sizing for 85% Pollutant
Removal Fff c ivrnct• in the Piedmont
% Impervious
Cover Permanent Pool Depth (feet)
3.0 4.0 5.0 6.0 7.0 8.0 9.0
10 0.59 0.49 0.43 0.35 0.31 0.29 0.26
20 0.97 0.79 0.70 0.59 0.51 0.46 0.44
30 1.34 1.08 0.97 0.83 0.70 0.64 0.62
40 1.73 1.43 1.25 1.05 0.90 0.82 0.77
50 2.06 1.73 1.50 1.30 1.09 1.00 0.92
60 2.40 2.03 1.71 1.51 1.29 1.18 1.10
70 2.88 2.40 2.07 1.79 1.54 1.35 1.26
80 3.36 2.78 2.38 2.10 1.86 1.60 1.42
90 3.74 3.10 2.66 2.34 2.11 1.83 1.67
Source: NCDENR/DWQ Stormwater Best Management Practices, pg. 10-9, July 2007
STORMWATER BMP 1 - STORMWATER WET POND

Land Use Area
(ac) % IA Imp. Area
(ac)
Impervious 15.62 100 15.62
Open Space 16.88 0 0.00

Totals 32.50 15.62
Total % Impervious Surface Area = 48.1 %
Surface Area of Permanent Pool:
Assumed depth = 3 feet
SA/DA ratio = 2.00 % From Table 1.1
Minimum pond surface area (SA) _ (DA * SA/DA ratio)/100
SA = 0.649 acres
28258 sq. ft.
Normal pool elevation = feet
Surface area provided = 0.871 acres
37920 sq. ft.
1-Inch Runoff Volume Calculation
Using the runoff volume calculations in the "Simple Method" as described by Schueler (1987)
Rv = 0.05 + 0.009(1) where, Rv = Runoff coefficient, in./in.
I = Percent impervious
RV = 0.48 in./in.
Total runoff volume from 1-inch precipitation:
Runoff volume, S = (Design rainfall) (Rv) (Drainage Area)
S = 1.307 acre-ft
56929 cu. ft.
Temporary Pool Elevation = 343.8
Water quality pool elevation= 342.00 feet
Storage volume provided = 1.687 acre-ft
73486 cu. ft.
Orifice Calculator
Q =Cd*A*(2gh)^(1/2)
Variables
WQ Volume:
Head:
Draw down time:
Orifice Area =
1.307 Acre-ft
1.80 ft
48 hrs
0.0721235 sq. ft
Orifice Diameter: 3.6364262 in
USE 4 INCH DIAMETER ORIFICE
A 0.34906585 4
Q 2.25495459
56929.29 cf
0.9 ft
172800 s
10.38578 sq. in
Constants
9
cd =
32.2 ft/sz
0.6
Project Name: Alston Pond
City/State: Fuquay-Varina
Table 1.1 Surface Area to Drainage Area Ratio for Permanent Pool Sizing for 85% Pollutant
Removal Efficiency in the Piedmont
% Impervious
Cover
3.0
4.0 re1,,,a,Ic
5.0 „i , UUN .., FL
6.0 IN ..,. l
7.0
8.0
9.0
10 0.59 0.49 0.43 0.35 0.31 0.29 0.26
20 0.97 0.79 0.70 0.59 0.51 0.46 0.44
30 1.34 1.08 0.97 0.83 0.70
0.64
0.62
40 _
1.73 1.43 1.25 1.05 0.90 0.82 0.77
50 2.06 1.73 1.50 1.30 1.09 1.00 0.92
60 2.40 2.03 1.71 1.51 1.29 1.18 1.10
70 2.88 2.40 2.07 1.79 1.54 1.35 1.26
80 3.36 2.78 2.38 2.10 1.86 1.60 1.42
90 3.74 3.10 2.66 2.34 2.11 1.83 1.67
Source: NCDENR/D WQ Stormwater Best Manageme nt Practices, pg. 10-9, July 2007
STORMWATER BMP 2 - STORMWATER WET POND

Land Use
Impervious Area
(ac)
18.75 % IA

100 Imp. Area
(ac)
18.75
Open Space 17.75 0 0.00

Totals 36.50 18.75
Total % Impervious Surface Area = 51.4 %
Surface Area of Permanent Pool:
Assumed depth = 4 feet
SA/DA ratio = 1.77 % From Table 1.1
Minimum pond surface area (SA) = (DA * SA/DA ratio)/100
SA = 0.646 acres
28159 sq. ft.
Normal pool elevation = 4.0 feet
Surface area provided = 0.577 acres
25150 sq. ft.
31.5
1-Inch Runoff Volume Calculation
Using the runoff volume calculations in the "Simple Method" as described by Schueler (1987)
Rv = 0.05 + 0.009(1) where, Rv _ Runoff coefficient, in./in.
I = Percent impervious
Rv = 0.51 inAn.
Total runoff volume from 1-inch precipitation:
Runoff volume, S = (Design rainfall) (Rv) (Drainage Area)
S = 1.558 acre-ft
67881 cu. ft.
Temporary Pool Elevation = 367.4
Water quality pool elevation= 365.00 feet
Storage volume provided = 1.936 acre-ft
84332 cu. ft.
Orifice Calculator
Q =Cd*A*(2gh)"(1/2)
Variables
WQ Volume:
Head:
aw down time:
1.558 Acre-ft
2.40 ft
120 hrs
Orifice Area= 0.0297906 sq. ft
Orifice Diametf 2.3370948 in
USE 2 INCH DIAMETER ORIFICE
A 0.1154099 2
Q 0.86088047
67881 cf
1.2 ft
432000 s
4.289851 sq. in
Constants
9=
cd =
32.2 ft/s2
0.6
Project Name: Alston Pond
City/State: Fuquay-Varina
Table 1.1 Surface Area to Drainage Area Ratio for Permanent Pool Sizing for 85% Pollutant
RPmnval Fffirienrv in the Piedmont
% Impervious
Cover Permanent Pool Depth (feet)
3.0 4.0 5.0 6.0 7.0 8.0 9.0
10 0.59 0.49 0.43 0.35 0.31 0.29 0.26
20 0.97 0.79 0.70 0.59 0.51 0.46 0.44
30 1.34 1.08 0.97 0.83 0.70 0.64 0.62
40 1.73 1.43 1.25 1.05 0.90 0.82 0.77
50 2.06 1.73 1.50 1.30 1.09 1.00 0.92
60 2.40 2.03 1.71 1.51 1.29 1.18 1.10
70 2.88 2.40 2.07 1.79 1.54 1.35 1.26
80 3.36 2.78 2.38 2.10 1.86 1.60 1.42
90 3.74 3.10 2.66 2.34 2.11 1.83 1.67
Source: NCDENR/DWQ Stormwater Best Management Practices, pg. 10-9, July 2007
STORMWATER BMP 3 - STORMWATER WET POND

Land Use Area
(ac) % IA Imp. Area
(ac)
Impervious 6.24 100 6.24
Open Space 9.76 0 0.00

Totals 16.00 6.24
Total % Impervious Surface Area = 39.0 %
Surface Area of Permanent Pool:
Assumed depth = 3 feet
SA/DA ratio = 1.69 % From Table 1.1
Minimum pond surface area (SA) _ (DA * SA/DA ratio)/100
SA = 0.271 acres
11786 sq. ft.
Normal pool elevation = 4.0 feet
Surface area provided = 0.255 acres
11111 sq. ft.
1-Inch Runoff Volume Calculation
Using the runoff volume calculations in the "Simple Method" as described by Schueler (1987)
Rv = 0.05 + 0.009(1) where, Rv = Runoff coefficient, in./in.
I = Percent impervious
Rv = 0.40 in./in.
Total runoff volume from 1-inch precipitation:
Runoff volume, S = (Design rainfall) (Rv) (Drainage Area)
S = 0.535 acre-ft
23290 cu. ft.
Temporary Pool Elevation = 382.8
Water quality pool elevation= 381.00 feet
Storage volume provided = 0.638 acre-ft
27791 cu. ft.
Orifice Calculator
Q =Cd*A*(2gh)^(l/2)
Variables
WQ Volume:
Head:
aw dawn time:
0.535 Acre-ft
1.80 ft
48 hrs
Orifice Area = 0.0295061 sq. ft
Orifice Diameti 2.3259072 in
USE 2 INCH DIAMETER ORIFICE
A 0.08726646 2
Q 0.56373865
23290.08 cf
0.9 ft
17280.0 s
4.248878 sq. in
Constants
9_
Cd =
32.2 ft/s2
0.6
Project Name: Alston Pond
City/State: Fuquay-Varina
Table 1.1 Surface Area to Drainage Area Ratio for Permanent Pool Sizing for 85% Pollutant
Removal Efficiency in the Piedmont
% Impervious Permane nt Pool Dept h (feet)
Cover 3.0 4.0 5.0 6.0 7.0 8.0 9.0
10 0.59 0.49 0.43 0.35 0.31 0.29 0.26
20 0.97 0.79 0.70 0.59 0.51 0.46 0.44
30 1.34 1.08 0.97 0.83 0.70 0.64 0.62
40 1.73 1.43 1.25 1.05 0.90 0.82 0.77
50 2.06 1.73 1.50 1.30 1.09 1.00 0.92
60 2.40 2.03 1.71 1.51 1.29 1.18 1.10
70 2.88 2.40 2.07 1.79 1.54 1.35 1.26
80 3.36 2.78 2.38 2.10 1.86 1.60 1.42
90 3.74 3.10 2.66 2.34 2.11 1.83 1.67
Source: NCDENR/DWQ Stormwater Best Management Practices, pg. iu-`J, duly Luui
STORMWATER BMP 4 - STORMWATER WET POND

Land Use Area
(ac) % IA Imp. Area
(ac)
Impervious 2.6 100 2.60
02en Space 3.4 0 0.00

Totals 6.00 2.60
Total % Impervious Surface Area = 43.3 %
Surface Area of Permanent Pool:
Assumed depth = 3 feet
SA/DA ratio = 1.84 % From Table 1.1
Minimum pond surface area (SA) _ (DA * SA/DA ratio)/100
SA = 0.110 acres
4809 sq. ft.
Normal pool elevation = 344.0 feet
Surface area provided = 0.142 acres
6197 sq. ft.
1-Inch Runoff Volume Calculation
Using the runoff volume calculations in the "Simple Method" as described by Schueler (1987)
Rv = 0.05 + 0.009(1) where, Rv = Runoff coefficient, in./in.
I = Percent impervious
Rv = 0.44 in./in.
Total runoff volume from 1-inch precipitation:
Runoff volume, S = (Design rainfall) (Rv) (Drainage Area)
S = 0.220 acre-ft
9583 cu. ft.
Temporary Pool Elevation = 344.5
Water quality pool elevation= 343.00 feet
Storage volume provided = 0.227 acre-ft
9888 cu. ft.
Orifice Calculator
Q =CdW(2gh)^(1/2)
Variables
WQ Volume:
Head:
aw down time:
0.220 Acre-ft
1.50 ft
48 hrs
Orifice Area= 0.0132997 sq. ft
Orifice Diameb 1.5615557 in
USE 2 INCH DIAMETER ORIFICE
A 0.08726646 2
Q 0.51462062
9583.2 cf
0.75 ft
172800 s
1.915157 sq. in
Constants
9=
cd =
32.2 ft/S2
0.6
I 1 1 I I •1
I I I I I ? ?' I i
I I I I I 1
I I I 1 1 , i ?1 i
1 I '/
I 1 1 I 1 , °-'
/ 1
I I I I I 1 /
1 I I I I ( '?
I I I 1 1 r
4e4W 41#
10
_ .. ,
?" .. ?,i,r?RalC.rutrlara _ 230 231
L ?• Vii` ??
78 221 m ?? ???z --- ??_ - - --- ------ -• --- -- -??, i Syr-- ; I
232
233
dN$ 1 ?? ?? nf1 ?. ??.212
62 f,
10
411 44 - u
79 4koF tee
so
41 S, .-?a .?..
m? _
63
40
71 -? 1 z,e ?f- -- -- I l
80
AIWA#b??L2 '
2 23,
¦ i "?. ¦ 24IJ a
1 46 „ ??
r L s *`
17 -W
226 / 236V
211 242 5,
37 a
48
241
221 e
16
49
fir" 49 16 ? ?? BMP #3 217/ M
?I 240 67 71 218 46??1239 237 4 W
31 11
68
1: 81
21
34 14 ! ' t
70 -WNW
69 223
l?Rh, 4.
26 26'l
33
12' 1
v 'k ?,?
C7 262
. ; ; I, T - P
96 1? ; -:. al 15 •LI[l(? 121
' /? l?•'apr ?? 1 f
90
eu`ire'97 o?E 9 ?`?? BMP #4 ia1aP' ?I jl ?p ,
If' 1T 90 218
Ilk
Y 0
09
92
261
00-
1 217
28
1
f??
9
r ,e
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17 ?MI?N
s
26 0
/267 N
24 118 171 t?!
103 , 268N
?N
18, 4 4f#
'PEN
23 137
132 73 323
321
/ "I HEET 10
212 !
324
00 172 1,
2 4
®, /
J 20 211 3
71 -11 321
122 12" 4 /317 16
170 341 3 6
128 141 Z 141 19 209 116, 327 342 315
o
r\?_ 1
????? ??' , 1' ``.ti / • ?''?? 4 2n
339 43 127 _;A7 207 3- 278
192
313
14 ;;• .
16 f 344 s \k ff Y°
?? 2797,
112
341
194
V14 204 0 ;l 311
335 3.46 NEI
141 332
V1 r
ff 347 3110
309
134
12
282
309
'148 163
_ {.
333
212
301
e ` ' i mow' / vuti}i.
149
37
- --
??
a: r 'I -r --___..m .,`* 307 \+ i ` ¦ ¦ . ;Ay.
201
200
3`l43 369 301 286\
010
`? ?
31 287
288
x -
??/ 304
"s° 1?* e?
ti
/ p;/
89
?
.. .....376 ?* .
r------------ % 313
303
%
117 314
6 Of -, I'll
7 378 3 302 290
BMP #1
I - I I , 0 6 /4 29?
_0, 364
ti ¦?
c---------------
301
3 379 316
ti:sy'. ?.
1?? / .... a GRAPHIC SCALE
38111 41. .
-0 r 1, 294
300 0 150 300 600
382
361
291
N
s
3 319N
297
I A
1 296
1 inch 300 ft.
i BMP #2 ` Ip __ _ _ _ t_y? ?? _- ?_ . ,<• ;°8?°I
1 p t «"/, I \,•\ ° ,? .?.Q... 9 v ?..: _ - R?lr?-« ?' car' 1 7,
- - - - - - - - - - - - - - - - - - - - - - - - - - - -
ill ? ,4 t • b I •/• •?.? • .- . ? ) S 1 •"iv h ae?
No. Revision Dale B oa;- NU sale K NORO sn ,
D- By ZZZ ALSTON POND BMP DRAINAGE AREA MAP WITHERS RAVENEL
a--y N. ENGINEERS 1 PLANNERS I SURVIVORS
FU UAY-VARINA WAKE COUNTY North Carolina N.1hC-I-27511 m1 9194-3340 wl1M1esaven I- L
17 0?
r.,
.a
288 28
290 289 F
L 2 86 2&5
-- - - 291. 284 282 2$1
I ..?83
I
292
293
a ,.
95
100,
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FOREBAY,
J % ? ? RISER - \ ?
v
7-. S '0001?
i FOREBAY
10,
10,
ooo .01 011,
-N 500-YR FLOOD LINE
10, / \ 9 \ \ r 00-YR FLOOD LINE
r
1 i
ENERGY
DISSIPATER
WETLANDS V- V
?? - --?
GRAPHIC SCALE
k e
50 0 25 50 100
,'° ! fi_ k t k k k k k k 1 inch = 50 k.
o. v k k k D k k k k k k k k k k k V k k k 4
No. Revision Date B ,--, ? BMP EXHIBIT
° - ALSTON POND µq WITHERS ? RAVENEL ?
Gf
--d By M ioeN. BMP # I ENGINEERS I PLANNERS I SURVEY
711LAY-VARINA WAKE COUNTY North Carolina N.lhC-l-27s„ mL9194-33ao .w?h--l-!
77
\ ... 381
I
Q
\HITG
HOIN
ASS PIPE \ Z
RSER
ANN
REAM 382
11 \
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c ?
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QUALITY OUTLET FOREBAY
24
ENERGY ,',?` \ \
r
{ DISSIPATER °'
` LEVEL SPREADER / / l \
/ GRAPHIC SCALE
50 0 25 50 100
• 0
1 inch = 50 k.
No. Revision NJ o?..:, AS BMP EXHIBIT
D- By ALSTON POND µ WITHERS & RAVENEL 2
ae-dBy iii J.bN. BMP #2 ENGINEERS I PLANNERS I SURVIVORS
FU UAY-VARINA WAKE COUNTY North Carolina 111 -K- D- C- N.lhC-1-27s„ m1 9194-3340 www-M1rsmv-l- L
? • V
254
T OF BAN
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i
BAY W W
\ , \ \ FORE
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v`
?? ?? •? A W W W WETLANDS W
2
BMP#3
/ ? 2,`3U ? . ` •I GRAPHIC SCALE
t
A 50 0 25 50 100
ye ., `\ / / / / I I 1 inch = 50 k.
k?
0
I
/ l
? I I
4" DIP"WATER
W _ UALITY OIlTLET <
° w
41
HIGFWFL0Wv W
/ w BYPASSWPIPE W lk
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W STR w I
/ NEF DISSIPATER w w W W W W '-
??/?? LEVEL SPREADER w ` w w w S
? I
-41
VTGPTATED? TER / l Ww W
144, lk
BMP #4
No. Revision oa,e B o??:, waR F-As? BMP EXHIBIT
UZI-
°`.a°
ALSTON POND WITHERS RAVENEL 3
--d By joeN. BMP #3 AND BMP #4 ENGINEERS I PLANNERS I SURVIVORS
MR FU UAY-VARINA WAKE COUNTY North Carolina 111 M-- D- N N.lhC-l-3,t„ 11 9194-3340 www-M1rsmv-l- oc
Permit Number:
(to be provided by DWQ)
Drainage Area Number: AIVP-?t I
Wet Detention Basin Operation and Maintenance Agreement
I will keep a maintenance record on this BMP. This maintenance record will be kept in a
log in a known set location. Any deficient BMP elements noted in the inspection will be
corrected, repaired or replaced immediately. These deficiencies can affect the integrity
of structures, safety of the public, and the removal efficiency of the BMP.
The wet detention basin system is defined as the wet detention basin,
pretreatment including forebays and the vegetated filter if one is provided.
This system (check one):
? does © does not incorporate a vegetated filter at the outlet.
This system (check one):
? does © does not incorporate pretreatment other than a forebay.
Important maintenance procedures:
- Immediately after the wet detention basin is established, the plants on the
vegetated shelf and perimeter of the basin should be watered twice weekly if
needed, until the plants become established (commonly six weeks).
- No portion of the wet detention pond should be fertilized after the first initial
fertilization that is required to establish the plants on the vegetated shelf.
- Stable groundcover should be maintained in the drainage area to reduce the
sediment load to the wet detention basin.
- If the basin must be drained for an emergency or to perform maintenance, the
flushing of sediment through the emergency drain should be minimized to the
maximum extent practical.
- Once a year, a dam safety expert should inspect the embankment.
After the wet detention pond is established, it should be inspected once a month and
within 24 hours after every storm event greater than 1.0 inches (or 1.5 inches if in a
Coastal County). Records of operation and maintenance should be kept in a known set
location and must be available upon request.
Inspection activities shall be performed as follows. Any problems that are found shall
be repaired immediately.
BMP element: Potential problem: How I will remediate the roblem:
The entire BMP Trash/ debris is resent. Remove the trash/ debris.
The perimeter of the wet Areas of bare soil and/or Regrade the soil if necessary to
detention basin erosive gullies have formed. remove the gully, and then plant a
ground cover and water until it is
established. Provide lime and a
one-time fertilizer application.
Vegetation is too short or too Maintain vegetation at a height of
long. approximately six inches.
Form SW401-Wet Detention Basin O&M-Rev.4 Page 1 of 4
Pen-nit Number:
(to be provided by DWQ)
Drainage Area Number: g!'2/-) ;d-/
BMP element: Potential problem: How I will remediate the problem:
The inlet device: pipe or The pipe is clogged. Unclog the pipe. Dispose of the
swale sediment off-site.
The pipe is cracked or Replace the pipe.
otherwise damaged.
Erosion is occurring in the Regrade the swale if necessary to
swale. smooth it over and provide erosion
control devices such as reinforced
turf matting or riprap to avoid
future problems with erosion.
The forebay Sediment has accumulated to Search for the source of the
a depth greater than the sediment and remedy the problem if
original design depth for possible. Remove the sediment and
sediment storage. dispose of it in a location where it
will not cause impacts to streams or
the BMP.
Erosion has occurred. Provide additional erosion
protection such as reinforced turf
matting or riprap if needed to
prevent future erosion problems.
Weeds are present. Remove the weeds, preferably by
hand. If pesticide is used, wipe it on
the plants rather than spraying.
The vegetated shelf Best professional practices Prune according to best professional
show that pruning is needed practices
to maintain optimal plant
health.
Plants are dead, diseased or Determine the source of the
dying. problem: soils, hydrology, disease,
etc. Remedy the problem and
replace plants. Provide a one-time
fertilizer application to establish the
ground cover if a soil test indicates
it is necessary.
Weeds are present. Remove the weeds, preferably by
hand. If pesticide is used, wipe it on
the plants rather than spraying.
The main treatment area Sediment has accumulated to Search for the source of the
a depth greater than the sediment and remedy the problem if
original design sediment possible. Remove the sediment and
storage depth. dispose of it in a location where it
will not cause impacts to streams or
the BMP.
Algal growth covers over Consult a professional to remove
50% of the area. and control the algal growth.
Cattails, phragmites or other Remove the plants by wiping them
invasive plants cover 50% of with pesticide (do not spray).
the basin surface.
Form SW401-Wet Detention Basin O&M-Rev.4 Page 2 of 4
Permit Number:
(to be proililerl by 1) JFQ)
Drainage Area Number: (
BMP element: Potential problem: How I will remediate the problem:
The embankment Shrubs have started to grow Remove shrubs immediately.
on the embankment.
Evidence of muskrat or Use traps to remove muskrats and
beaver activity is present. consult a professional to remove
beavers.
A tree has started to grow on Consult a dam safety specialist to
the embankment. remove the tree.
An annual inspection by an Make all needed repairs.
appropriate professional
shows that the embankment
needs repair. if applicable)

The outlet device
Clogging has occurred. _
Clean out the outlet device. Dispose
of the sediment off-site.
The outlet device is damaged Repair or replace the outlet device.
The receiving water Erosion or other signs of Contact the local NC Division of
damage have occurred at the Water Quality Regional Office, or
outlet. the 401 Oversight Unit at 919-733-
1786.
The measuring device used to determine the sediment elevation shall be such
that it will give an accurate depth reading and not readily penetrate into
accumulated sediments.
When the permanent pool depth reads t-l feet in the main pond, the
sediment shall be removed.
When the permanent pool depth reads I-? feet in the forebay, the sediment
shall be removed.
Sediment Removal
Bottom Elevat
BASIN DIAGRAM
ill in the blanks)
Q Permanent Pool Elevation L
33?f Pe manen Pool
- - - - - - - - - - - - - Volume Sediment Removal Elevation
-7 ft Min . j
`71 ?' --------------------------------------------
Sediment Bottom Elevation 7
Storage
FOREBAY MAIN POND
Volume
1-ft
Storage
Form SW401-Wet Detention Basin O&M-Rev.4 Page 3 of 4
Permit Number:
(to be provided by DWQ)
I acknowledge and agree by my signature below that I am responsible for the
performance of the maintenance procedures listed above. I agree to notify DWQ of any
problems with the system or prior to any changes to the system or responsible party.
Project name: 41-57-o&, Po il)
BMP drainage area number: -#:-
Print name: ?vLtA1 ?4wI-
Title: • _ ,r?-r`
Address: 2 U 1 C S %71n? ?Ale t'? ? i 2c?" r „A? y PVC 2? V 3
Phone: 97q E7 F??3dc?a ??
J
Date: ( / i--si -
Note: The legally responsible party should not be a homeowners association unless more than 50% of
the lots have been sold and a resident of the subdivision has been named the president.
a Notary Public for the State of
•7?, , CO«nty of do hereby certify that
c.wJ personally appeared before me this
clay ofT Cl t _? , and acknowledge the due execution of the
forgoing wet detention basin maintenance requirements. Witness my hand and official
seal,
iILI
SEAL

My commission expires - a I _-?L& 1 3
Form SW401-Wet Detention Basin O&M-Rev.4 Page 4 of 4
Permit Number:
(to be provided by DWQ)
Drainage Area Number: jow
Filter Strip, Restored Riparian Buffer and Level Spreader
Operation and Maintenance Agreement
I will keep a maintenance record on this BMP. This maintenance record will be kept in a
log in a known set location. Any deficient BMP elements noted in the inspection will be
corrected, repaired or replaced immediately. These deficiencies can affect the integrity
of structures, safety of the public, and the removal efficiency of the BMP.
Important maintenance procedures:
- Immediately after the filter strip is established, any newly planted vegetation
will be watered twice weekly if needed until the plants become established
(commonly six weeks).
- Once a year, the filter strip will be reseeded to maintain a dense growth of
vegetation
- Stable groundcover will be maintained in the drainage area to reduce the
sediment load to the vegetation.
- Two to three times a year, grass filter strips will be mowed and the clippings
harvested to promote the growth of thick vegetation with optimum pollutant
removal efficiency. Turf grass should not be cut shorter than 3 to 5 inches and
may be allowed to grow as tall as 12 inches depending on aesthetic requirements
(NIPC,1993). Forested filter strips do not require this type of maintenance.
- Once a year, the soil will be aerated if necessary.
- Once a year, soil pH will be tested and lime will be added if necessary.
After the filter strip is established, it will be inspected quarterly and within 24 hours
after every storm event greater than 1.0 inch (or 1.5 inches if in a Coastal County).
Records of operation and maintenance will be kept in a known set location and will be
available upon request.
Inspection activities shall be performed as follows. Any problems that are found shall
be repaired immediately.
BMP element: Potential problem: How I will remediate the problem:
The entire filter strip Trash/debris is present. Remove the trash/ debris.
system
The flow splitter device The flow splitter device is Unclog the conveyance and dispose
(if applicable) clogged. of an sediment off-site.
The flow splitter device is Make any necessary repairs or
damaged. replace if damage is too large for
repair.
Form SWU401-Level Spreader, Filter Strip, Restored Riparian Buffer O&M-Rev.3 Page 1 of 3
BMP element: Potential problem: How I will remediate the problem:
The swale and the level The swale is clogged with Remove the sediment and dispose
lip -sediment. of it off-site.
The level lip is cracked, Repair or replace lip.
settled, undercut, eroded or
otherwise damaged.
There is erosion around the Regrade the soil to create a berm
end of the level spreader that that is higher than the level lip, and
shows stormwater has then plant a ground cover and
bypassed it. water until it is established. Provide
lime and a one-time fertilizer
application.
Trees or shrubs have begun Remove them.
to grow on the swale or just
downslo e of the level lip.
The bypass channel Areas of bare soil and/or Regrade the soil if necessary to
erosive gullies have formed. remove the gully, and then
reestablish proper erosion control,
Turf reinforcement is Study the site to see if a larger
damaged or ripap is rolling bypass channel is needed (enlarge if
downhill. necessary). After this, reestablish
the erosion control material.
The filter strip Grass is too short or too long Maintain grass at a height of
if applicable). approximately three to six inches.
Areas of bare soil and/or Regrade the soil if necessary to
erosive gullies have formed. remove the gully, and then plant a
ground cover and water until it is
established. Provide lime and a
one-time fertilizer application.
Sediment is building up on Remove the sediment and
the filter strip. restabilize the soil with vegetation if
necessary. Provide lime and a one-
time fertilizer application.
Plants are desiccated. Provide additional irrigation and
fertilizer as needed.
Plants are dead, diseased or Determine the source of the
dying. problem: soils, hydrology, disease,
etc. Remedy the problem and
replace plants. Provide a one-time
fertilizer application.
Nuisance vegetation is Remove vegetation by hand if
choking out desirable species. possible. If pesticide is used, do not
allow it to get into the receiving
water.
The receiving water Erosion or other signs of Contact the NC Division of Water
damage have occurred at the Quality local Regional Office, or the
outlet. 401 Oversight Unit at 919-733-1786.
Form SWU401-Level Spreader, Filter Strip, Restored Riparian Buffer O&M-Rev. 3 Page 2 of 3
Permit Number:
(to be provided by DWQ)
I acknowledge and agree by my signature below that I am responsible for the
performance of the maintenance procedures listed above. I agree to notify DWQ of any
problems with the system or prior to any changes to the system or responsible party.
Project name: ALST0AJ A),?JQ
BMP drainage area number:_ _f_I. ' '
Print name:

Phone:
ssignakrrU-
Date: W

Note: The legally responsible party should not be a homeowners association unless more than 50% of
the lots have been sold and a resident of the subdivision has been named the president.
t _1 , a Notary Public for the State of
of do hereby certify that
personally appeared before me this ZJ_
dof , and acknowledge the due execution of the
forgoing Ater strip, riparian buffer, and/or level spreader maintenance requirements.
Witness my hand and official seal,

SEAL

My commission expires I -- ? 1- ?-_)b 0
Form SWU401-Level Spreader, Filter Strip, Restored Riparian Buffer O&M-Rev.3 Page 3 of 3
Title: 4?
y
Address: Z 4 L_l wGs r1? s,, , Z - c %-?o C.-V Y 'V C Z_ 7 S-
13
Permit Number:
(to be provided by DWQ)
Drainage Area Number: ?2
Wet Detention Basin Operation and Maintenance Agreement
I will keep a maintenance record on this BMP. This maintenance record will be kept in a
log in a known set location. Any deficient BMP elements noted in the inspection will be
corrected, repaired or replaced immediately. These deficiencies can affect the integrity
of structures, safety of the public, and the removal efficiency of the BMP.
The wet detention basin system is defined as the wet detention basin,
pretreatment including forebays and the vegetated filter if one is provided.
This system (check one):
K does ? does not
This system (check one):
? does X does not
incorporate a vegetated filter at the outlet.
incorporate pretreatment other than a forebay.
Important maintenance procedures:
- Immediately after the wet detention basin is established, the plants on the
vegetated shelf and perimeter of the basin should be watered twice weekly if
needed, until the plants become established (commonly six weeks).
- No portion of the wet detention pond should be fertilized after the first initial
fertilization that is required to establish the plants on the vegetated shelf.
- Stable groundcover should be maintained in the drainage area to reduce the
sediment load to the wet detention basin.
- If the basin must be drained for an emergency or to perform maintenance, the
flushing of sediment through the emergency drain should be minimized to the
maximum extent practical.
- Once a year, a dam safety expert should inspect the embankment.
After the wet detention pond is established, it should be inspected once a month and
within 24 hours after every storm event greater than 1.0 inches (or 1.5 inches if in a
Coastal County). Records of operation and maintenance should be kept in a known set
location and must be available upon request.
Inspection activities shall be performed as follows. Any problems that are fqund shall
be repaired immediately.
BMP element: Potential problem: How I will remediate the problem:
The entire BMP Trash/debris is resent. Remove the trash/ debris.
The perimeter of the wet Areas of bare soil and/or Regrade the soil if necessary to
detention basin erosive gullies have formed. remove the gully, and then plant a
ground cover and water until it is
established. Provide lime and a
one-time fertilizer application.
Vegetation is too short or too Maintain vegetation at a height of
long. a roximatel six inches.
Form SW401-Wet Detention Basin O&M-Rev.4 Page 1 of 4
Permit Number:
(to be prm,ielerl l) y DWQ)
Drainage Area Number: I I
BMP element: Potential problem: How I will rernediate the problem:
The inlet device: pipe or The pipe is clogged. Unclog the pipe. Dispose of the
swale
T sediment off-site.
The pipe is cracked or Replace the pipe.
otherwise damaged.
Erosion is occurring in the Regrade the swale if necessary to
swale. smooth it over and provide erosion
control devices such as reinforced
turf matting or riprap to avoid
future problems with erosion.
The forebay Sediment has accumulated to Search for the source of the
a depth greater than the sediment and remedy the problem if
original design depth for possible. Remove the sediment and
sediment storage. dispose of it in a location where it
will not cause impacts to streams or
the BMP.
Erosion has occurred. Provide additional erosion
protection such as reinforced turf
matting or riprap if needed to
prevent future erosion problems.
Weeds are present. Remove the weeds, preferably by
hand. If pesticide is used, wipe it on
the 121ants rather than spraying.
The vegetated shelf Best professional practices Prune according to best professional
show that pruning is needed practices
to maintain optimal plant
health.
Plants are dead, diseased or Determine the source of the
dying. problem: soils, hydrology, disease,
etc. Remedy the problem and
replace plants. Provide a one-time
fertilizer application to establish the
ground cover if a soil test indicates
it is necessary.
Weeds are present. Remove the weeds, preferably by
hand. If pesticide is used, wipe it on
the plants rather than spraying.
The main treatment area Sediment has accumulated to Search for the source of the
a depth greater than the sediment and remedy the problem if
original design sediment possible. Remove the sediment and
storage depth. dispose of it in a location where it
will not cause impacts to streams or
the BMP.
Algal growth covers over Consult a professional to remove
50% of the area. and control the algal growth.
Cattails, phragmites or other Remove the plants by wiping them
invasive plants cover 50% of with pesticide (do not spray).
the basin surface.
Form SW401-Wet Detention Basin O&M-Rev.4 Page 2 of 4
Permit Number:
(to be prnvideel ky DPYO)
Drainage Area Number: _13,-Tf10- 2-
BMP element: Potential problem: How I will remediate the problem:
The embankment Shrubs have started to grow Remove shrubs immediately.
on the embankment.
Evidence of muskrat or Use traps to remove muskrats and
beaver activity is present. consult a professional to remove
beavers.
A tree has started to grow on Consult a dam safety specialist to
the embankment. remove the tree.
An annual inspection by an Make all needed repairs.
appropriate professional
shows that the embankment
needs repair. if applicable)
The outlet device Clogging has occurred. Clean out the outlet device. Dispose I
of the sediment off-site.
The outlet device is damaged Repair or replace the outlet device.
The receiving water Erosion or other signs of Contact the local NC Division of
damage have occurred at the Water Quality Regional Office, or
outlet. the 401 Oversight Unit at 919-733-
1786.
The measuring device used to determine the sediment elevation shall be such
that it will give an accurate depth reading and not readily penetrate into
accumulated sediments.
When the permanent pool depth reads `) feet in the main pond, the
sediment shall be removed.
When the permanent pool depth reads 5 feet in the forebay, the sediment
shall be removed.
BASIN DIAGRAM
fll in the blanks)
Sediment Removal
Bottom
0 Permanent Pool Elevation 36-5
>'C- l Pe ianen Pool
- - - - - - - - - - - - - - - - - - Volume Sediment Removal Elevation 360
Volume
? =? • ' `l
----
-ft Min.
------------------------------------
---- - -
Sediment Bottom Elevation `361 1-ft 4n.
Storage Sediment
Storage
FOREBAY MAIN POND
Form SW401-Wet Detention Basin O&M-Rev.4 Page 3 of 4
Permit Number:
(to be provided by DWQ)
I acknowledge and agree by my signature below that I am responsible for the
performance of the maintenance procedures listed above. I agree to notify DWQ of any
problems with the system or prior to any changes to the system or responsible party.
Project name: J L S 7-6/A/ POwD
BMP drainage area number: 41?yo #2
Print name: .Tt
• Title:
+, ?s •
Address: Zq ol Lti?C'?y N& a7?
Phone; `!? -? 3 coo
Sill
Date;
Note: The legally responsible party should not be a homeowners association unless more than 50% of
the lots have been sold and a resident of the subdivision has been named the president.
I, _?? .-.? "/2-1, ,._., r- , '. ) , a Notary Public for the State of
w-vk O'V County of ?'J - , do hereby certify that
personally appeared before me this Q_I_
ay of a1 , and acknowledge the due execution of the
forgoing wet detention basin maintenance requirements. Witness my hand and official
seal,
gyp 2
?I?,,? wwJJ
,Y""rltlNlf Ilill»ti??
SEAL ?y,14
My commission expires
Form SW401-Wet Detention Basin O&M-Rev.4
J
Page 4 of 4
Permit Number:
(to be provided by DWQ)
Drainage Area Number: 'eJ7'?_l .4?_ 3
Wet Detention Basin Operation and Maintenance Agreement
I will keep a maintenance record on this BMP. This maintenance record will be kept in a
log in a known set location. Any deficient BMP elements noted in the inspection will be
corrected, repaired or replaced immediately. These deficiencies can affect the integrity
of structures, safety of the public, and the removal efficiency of the BMP.
The wet detention basin system is defined as the wet detention basin,
pretreatment including forebays and the vegetated filter if one is provided.
This system (check one):
? does N does not
This system (check one):
? does [Rj does not
incorporate a vegetated filter at the outlet.
incorporate pretreatment other than a forebay.
Important maintenance procedures:
- Immediately after the wet detention basin is established, the plants on the
vegetated shelf and perimeter of the basin should be watered twice weekly if
needed, until the plants become established (commonly six weeks).
- No portion of the wet detention pond should be fertilized after the first initial
fertilization that is required to establish the plants on the vegetated shelf.
- Stable groundcover should be maintained in the drainage area to reduce the
sediment load to the wet detention basin.
- If the basin must be drained for an emergency or to perform maintenance, the
flushing of sediment through the emergency drain should be minimized to the
maximum extent practical.
- Once a year, a dam safety expert should inspect the embankment.
After the wet detention pond is established, it should be inspected once a month and
within 24 hours after every storm event greater than 1.0 inches (or 1.5 inches if in a
Coastal County). Records of operation and maintenance should be kept in a known set
location and must be available upon request.
Inspection activities shall be performed as follows. Any problems that are found shall
be repaired immediately.
BMP element: Potential problem: How I will remediate the problem.
The entire BMP Trash/debris is resent. Remove the trash/debris.
The perimeter of the wet Areas of bare soil and/or Regrade the soil if necessary to
detention basin erosive gullies have formed. remove the gully, and then plant a
ground cover and water until it is
established. Provide lime and a
one-time fertilizer application.
Vegetation is too short or too Maintain vegetation at a height of
long. a roximatel six inches.
Form SW401-Wet Detention Basin O&M-Rev.4 Page 1 of 4
Permit Number:
_
(to be provided by DWQ)
Drai nage Area Number: _411?
BMP element: Potential problem: How I will remediate the problem:
The inlet device: pipe or The pipe is clogged. Unclog the pipe. Dispose of the
swale sediment off-site.
The pipe is cracked or Replace the pipe.
otherwise damaged.
Erosion is occurring in the Regrade the swale if necessary to
swale. smooth it over and provide erosion
control devices such as reinforced
turf matting or riprap to avoid
future problems with erosion.
The forebay Sediment has accumulated to Search for the source of the
a depth greater than the sediment and remedy the problem if
original design depth for possible. Remove the sediment and
sediment storage. dispose of it in a location where it
will not cause impacts to streams or
the BMP.
Erosion has occurred. Provide additional erosion
protection such as reinforced turf
matting or riprap if needed to
prevent future erosion problems.
Weeds are present. Remove the weeds, preferably by
hand. If pesticide is used, wipe it on
the plants rather than s ra in .
The vegetated shelf Best professional practices Prune according to best professional
show that pruning is needed practices
to maintain optimal plant
health.
Plants are dead, diseased or Determine the source of the
dying. problem: soils, hydrology, disease,
etc. Remedy the problem and
replace plants. Provide a one-time
fertilizer application to establish the
ground cover if a soil test indicates
it is necessary.
Weeds are present. Remove the weeds, preferably by
hand. If pesticide is used, wipe it on
the plants rather than spraying.
The main treatment area Sediment has accumulated to Search for the source of the
a depth greater than the sediment and remedy the problem if
original design sediment possible. Remove the sediment and
storage depth. dispose of it in a location where it
will not cause impacts to streams or
the BMP.
Algal growth covers over Consult a professional to remove
50% of the area. and control the algal growth.
Cattails, phragmites or other Remove the plants by wiping them
invasive plants cover 50% of with pesticide (do not spray).
the basin surface.
Form SW401-Wet Detention Basin O&M-Rev.4 Page 2 of 4
Permit Number:
(to be p) -owded by UPVQ)
Drainage Area Number: S, ' '?-
BMP element: Potential problem: How I will remediate the problem:
The embankment Shrubs have started to grow Remove shrubs immediately.
on the embankment. _
Evidence of muskrat or Use traps to remove muskrats and
beaver activity is present. consult a professional to remove
beavers.
A tree has started to grow on Consult a dam safety specialist to
the embankment. remove the tree.
An annual inspection by an Make all needed repairs.
appropriate professional
shows that the embankment
needs repair. if a licable
The outlet device Clogging has occurred. Clean out the outlet device. Dispose
of the sediment off-site.
The outlet device is damaged Repair or replace the outlet device.
The receiving water Erosion or other signs of Contact the local NC Division of
damage have occurred at the Water Quality Regional Office, or
outlet. the 401 Oversight Unit at 919-733-
1786.
The measuring device used to determine the sediment elevation shall be such
that it will give an accurate depth reading and not readily penetrate into
accumulated sediments.
When the permanent pool depth reads feet in the main pond, the
sediment shall be removed.
When the permanent pool depth reads feet in the forebay, the sediment
shall be removed.
BASIN DIAGRAM
(fill in the blanks)
V Permanent Pool Elevation
Sediment Removal L . 377 YPe iane n Pool
- - - - - - - - - - - - Volume Sediment Removal Elevation '77 Volinne
BottomElevaiioi "j7(-, t Min. -------------------------?-----------ediment Bottom Elevation °? 7L 1-ft n
Storage Sedsnier
Storage
FOREBAY MAIN POND
Form SW401-Wet Detention Basin O&M-Rev.4 Page 3 of 4
Permit Number:
(to be provided by DWQ)
I acknowledge and agree by my signature below that I am responsible for the
performance of the maintenance procedures listed above. I agree to notify DWQ of any
problems with the system or prior to any changes to the system or responsible party.
?5!'Url:" %sJJr
Project name:
BMP drainage area number: I-qJ/T1/F #
Print name: j,//-
.Title: 6?P?.r?,?_
Address. 27goi W 657Akl Aeet,.? -l Svr m ? 3 c?Qy AIC 2 r13
iJel - tiff-30a
. J1,?Il
Date.

--?, 1-f1

Note: The legally responsible party should not be a homeowners association unless more than 50% of
the lots have been sold and a resident of the subdivision has been named the president.
I, V D-, s Q ? y a Notary Public for the State of
1 In ?_ C?8 f c ,`County of L-J , do hereby certify that
personally appeared before me this
da of C,,< Gr!I, and acknowledge the due execution of the
forgoii et detention basin maintenance requirements. Witness my hand and official
seal,

My commission expires 4-_ .0-01S.
Form SW401-Wet Detention Basin O&M-Rev.4 Page 4 of 4
Permit Number:_ _
(to be provided by DWQ)
Drainage Area Number:, L
Filter Strip, Restored Riparian Buffer and Level Spreader
Operation and Maintenance Agreement
I will keep a maintenance record on this BMP. This maintenance record will be kept in a
log in a known set location. Any deficient BMP elements noted in the inspection will be
corrected, repaired or replaced immediately. These deficiencies can affect the integrity
of structures, safety of the public, and the removal efficiency of the BMP.
Important maintenance procedures:
- Immediately after the filter strip is established, any newly planted vegetation
will be watered twice weekly if needed until the plants become established
(commonly six weeks).
- Once a year, the filter strip will be reseeded to maintain a dense growth of
vegetation
- Stable groundcover will be maintained in the drainage area to reduce the
sediment load to the vegetation.
- Two to three times a year, grass filter strips will be mowed and the clippings
harvested to promote the growth of thick vegetation with optimum pollutant
removal efficiency. Turf grass should not be cut shorter than 3 to 5 inches and
may be allowed to grow as tall as 12 inches depending on aesthetic requirements
(NIPC,1993). Forested filter strips do not require this type of maintenance.
- Once a year, the soil will be aerated if necessary.
- Once a year, soil pH will be tested and lime will be added if necessary.
After the filter strip is established, it will be inspected quarterly and within 24 hours
after every storm event greater than 1.0 inch (or 1.5 inches if in a Coastal County).
Records of operation and maintenance will be kept in a known set location and will be
available upon request.
Inspection activities shall be performed as follows. Any problems that are found shall
be repaired immediately.
BMP element: Potential problem: How I will remediate the problem:
The entire filter strip Trash/ debris is present. Remove the trash/ debris.
system
The flow splitter device The flow splitter device is Unclog the conveyance and dispose
(if applicable) -clogged. of an sediment off-site.
The flow splitter device is Make any necessary repairs or
damaged. replace if damage is too large for
repair.
Form SWU401-Level Spreader, Filter Strip, Restored Riparian Buffer O&M-Rev.3 Page 1 of 3
BMP element: Potential problem: How I will remediate the problem:
The swale and the level The swale is clogged with Remove the sediment and dispose
lip sediment. of it off-site.
The level lip is cracked, Repair or replace lip.
settled, undercut, eroded or
otherwise damaged.
There is erosion around the Regrade the soil to create a berm
end of the level spreader that that is higher than the level lip, and
shows stormwater has then plant a ground cover and
bypassed it. water until it is established. Provide
lime and a one-time fertilizer
application.
Trees or shrubs have begun Remove them.
to grow on the swale or just
downslo e of the level lip.
The bypass channel Areas of bare soil and/or Regrade the soil if necessary to
erosive gullies have formed. remove the gully, and then
reestablish proper erosion control.
Turf reinforcement is Study the site to see if a larger
damaged or ripap is rolling bypass channel is needed (enlarge if
downhill. necessary). After this, reestablish
the erosion control material.
The filter strip Grass is too short or too long Maintain grass at a height of
if a licable . approximately three to six inches.
Areas of bare soil and/or Regrade the soil if necessary to
erosive gullies have formed. remove the gully, and then plant a
ground cover and water until it is
established. Provide lime and a
one-time fertilizer application.
Sediment is building up on Remove the sediment and
the filter strip. restabilize the soil with vegetation if
necessary. Provide lime and a one-
time fertilizer application.
Plants are desiccated. Provide additional irrigation and
fertilizer as needed.
Plants are dead, diseased or Determine the source of the
dying. problem: soils, hydrology, disease,
etc. Remedy the problem and
replace plants. Provide a one-time
fertilizer application.
Nuisance vegetation is Remove vegetation by hand if
choking out desirable species. possible. If pesticide is used, do not
allow it to get into the receiving
water.
The receiving water Erosion or other signs of Contact the NC Division of Water
damage have occurred at the Quality local Regional Office, or the
outlet. 401 Oversight Unit at 919-733-1786.
Form SWU401-Level Spreader, Filter Strip, Restored Riparian Buffer O&M-Rev.3 Page 2 of 3
Permit Number:
(to be provided by DWQ)
I acknowledge and agree by my signature below that I am responsible for the
performance of the maintenance procedures listed above. I agree to notify DWQ of any
problems with the system or prior to any changes to the system or responsible party.
Project name: 41_STa&j /' wn
BMP drainage area number:
Print name: Tv L` A rJ
• Title:
240'1 W&',70
elI ? - y ?l - Sao V
Date: ? i-
< v %i€ 2a 3
Note: The legally responsible party should not be a homeowners association unless more than 50% of
the lots have been sold and a resident of the subdivision has been named the president.
I, a Notary Public for the State of
???- ounty of , do hereby certify that
G.., c personally appeared before me this
d• of and acknowledge the due execution of the
forgoing filter strip, riparian buffer, and/or level spreader maintenance requirements.
Witness my hand and official seal,
'r?Jff'fjPO ' k0'!y``>
.•+?TffTR7lS+•••-
SEAT, J l r?-
My commission expiresF ? - _x 1- -;*13
Form SWU401-Level Spreader, Filter Strip, Restored Riparian Buffer O&M-Rev.3 Page 3 of 3
Permit Number:
(to be provided by DWQ)
Drainage Area Number: /? p may
Wet Detention Basin Operation and Maintenance Agreement
I will keep a maintenance record on this BMP. This maintenance record will be kept in a
log in a known set location. Any deficient BMP elements noted in the inspection will be
corrected, repaired or replaced immediately. These deficiencies can affect the integrity
of structures, safety of the public, and the removal efficiency of the BMP.
The wet detention basin system is defined as the wet detention basin,
pretreatment including forebays and the vegetated filter if one is provided.
This system (check one):
0 does ? does not incorporate a vegetated filter at the outlet.
This system (check one):
? does ® does not incorporate pretreatment other than a forebay.
Important maintenance procedures:
- Immediately after the wet detention basin is established, the plants on the
vegetated shelf and perimeter of the basin should be watered twice weekly if
needed, until the plants become established (commonly six weeks).
- No portion of the wet detention pond should be fertilized after the first initial
fertilization that is required to establish the plants on the vegetated shelf.
- Stable groundcover should be maintained in the drainage area to reduce the
sediment load to the wet detention basin.
- If the basin must be drained for an emergency or to perform maintenance, the
flushing of sediment through the emergency drain should be minimized to the
maximum extent practical.
- Once a year, a dam safety expert should inspect the embankment.
After the wet detention pond is established, it should be inspected once a month and
within 24 hours after every storm event greater than 1.0 inches (or 1.5 inches if in a
Coastal County). Records of operation and maintenance should be kept in a known set
location and must be available upon request.
Inspection activities shall be performed as follows. Any problems that are found shall
be repaired immediately.
BMP element: Potential problem: How I will remediate the problem:
The entire BMP Trash/ debris is resent. Remove the trash/ debris.
The perimeter of the wet Areas of bare soil and/or Regrade the soil if necessary to
detention basin erosive gullies have formed. remove the gully, and then plant a
ground cover and water until it is
established. Provide lime and a
one-time fertilizer application.
Vegetation is too short or too Maintain vegetation at a height of
long. approximately six inches.
Form SW401-Wet Detention Basin O&M-Rev.4 Page 1 of 4
Permit Number: _
(to be provided by DWQ)
Drainage Area Number:
BMP element: Potential problem: How I will remediate the problem:
The inlet device: pipe or The pipe is clogged. Unclog the pipe. Dispose of the
swale sediment off-site.
The pipe is cracked or Replace the pipe.
otherwise damaged.
Erosion is occurring in the Regrade the swale if necessary to
swale. smooth it over and provide erosion
control devices such as reinforced
turf matting or riprap to avoid
future problems with erosion.
The forebay Sediment has accumulated to Search for the source of the
a depth greater than the sediment and remedy the problem if
original design depth for possible. Remove the sediment and
sediment storage. dispose of it in a location where it
will not cause impacts to streams or
the BMP.
Erosion has occurred. Provide additional erosion
protection such as reinforced turf
matting or riprap if needed to
prevent future erosion problems.
Weeds are present. Remove the weeds, preferably by
hand. If pesticide is used, wipe it on
the plants rather than s ra in .
The vegetated shelf Best professional practices Prune according to best professional
show that pruning is needed practices
to maintain optimal plant
health.
Plants are dead, diseased or Determine the source of the
dying. problem: soils, hydrology, disease,
etc. Remedy the problem and
replace plants. Provide a one-time
fertilizer application to establish the
ground cover if a soil test indicates
it is necessary.
Weeds are present. Remove the weeds, preferably by
hand. If pesticide is used, wipe it on
the plants rather than spraying.
The main treatment area Sediment has accumulated to Search for the source of the
a depth greater than the sediment and remedy the problem if
original design sediment possible. Remove the sediment and
storage depth. dispose of it in a location where it
will not cause impacts to streams or
the BMP.
Algal growth covers over Consult a professional to remove
50% of the area. and control the algal growth.
Cattails, phragmites or other Remove the plants by wiping them
invasive plants cover 50% of with pesticide (do not spray).
the basin surface.
Form SW401-Wet Detention Basin O&M-Rev.4 Page 2 of 4
Permit Number:
(to be proilided by D i,VQ)
Drainage Area Number:_ Y
BMP element: Potential problem: How I will remediate the problem:
The embankment Shrubs have started to grow Remove shrubs immediately.
on the embankment.

Evidence of muskrat or _
Use traps to remove muskrats and
beaver activity is present. consult a professional to remove
beavers.
A tree has started to grow on Consult a dam safety specialist to
the embankment. remove the tree.
An annual inspection by an Make all needed repairs.
appropriate professional
shows that the embankment
needs repair. fife_plicable)
The outlet device Clogging has occurred. Clean out the outlet device. Dispose
of the sediment off-site.
The outlet device is damaged Repair or replace the outlet device.
The receiving water Erosion or other signs of Contact the local NC Division of
damage have occurred at the Water Quality Regional Office, or
outlet. the 401 Oversight Unit at 919-733-
1786.
The measuring device used to determine the sediment elevation shall be such
that it will give an accurate depth reading and not readily penetrate into
accumulated sediments.
When the permanent pool depth reads feet in the main pond, the
sediment shall be removed.
When the permanent pool depth reads feet in the forebay, the sediment
shall be removed.
BASIN DIAGRAM
ill in the blanks)
Sediment Removal
Bottom
V Permanent Pool Elevation '3q 3
'
?q Pe ntanen Pool
L volume

f
----
Mi Sediment Removal Elevation
--------------------- Volume
-
t
n.
Sediment
Bottom Elevation '3:31f
1-ft n.
Storage Sediment
Storage
FOREBAY MAIN POND
Form SW401-Wet Detention Basin O&M-Rev.4 Page 3 of 4
Permit Number:
(to be provided by DWQ)
I acknowledge and agree by my signature below that I am responsible for the
performance of the maintenance procedures listed above. I agree to notify DWQ of any
problems with the system or prior to any changes to the system or responsible party.
Project name: ,/- ILS7z>
BMP drainage area number: f 3c' I /f
Print name: JUi. A-i - k4-t,1!s
• Title:
Address: Z-Elul WE57u 0 ;,?,QCCVAY s'v; r? ze3 6+p ,eve ? 7 -/,?
Phone: 1 qi - Jq 8 t
Date: ( f /--31 -1
Note: The legally responsible party should not be a homeowners association unless more than 50% of
the lots have been sold and a resident of the subdivision has been named the president.

County of
do hereby certify that
personally appeared before me this
da of _ , and acknowledge the die execution of the
forgoin wet detention basin maintenance requirements. Witness my hand and official
cPal
yyy?r4yHa??lue?yj?i
r ? ?J
N+rrlain?Y`? yyy
SEAL
My commission expires - - 13
a Notary Public for the State of
Form SW401-Wet Detention Basin O&M-Rev.4 Page 4 of 4
Permit N
A N.
NCDENR
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
WET DETENTION BASIN SUPPLEMENT
This form must be filled out, printed and submitted.
The Required Items Checklist (Part lll) must be printed, filled out and submitted along with all of the required information.
(to be provided by DWQ)
V AFT .-
€. PROJECT INFORMATION
_
Project name Alston Pond
Contact person Alwyn V. Smith III, P.E.
Phone number 919) 469-3340
Date 22-Dec-10
Drainage area number 1
II. DESIGN INFORMATION
Site Characteristics
Drainage area 1,415,700 ftz
Impervious area, post-development 680,407 fe
% impervious 48.06 %
Design rainfall depth 1.0 in
Storage Volume: Non-SA Waters
Minimum volume required
Volume provided
Storage Volume: SA Waters
1.5" runoff volume
Pre-development 1-yr, 24-hr runoff
Post-development 1-yr, 24-hr runoff
Minimum volume required
Volume provided
Peak Flow Calculations
Is the pre/post control of the 1yr 24hr storm peak flow required?
1-yr, 24-hr rainfall depth
Rational C, pre-development
Rational C, post-development
Rainfall intensity: 1-yr, 24-hr storm
Pre-development 1-yr, 24-hr peak flow
Post-development 1-yr, 24-hr peak flow
Pre/Post 1-yr, 24-hr peak flow control
Elevations
Temporary pool elevation
Permanent pool elevation
SHWT elevation (approx. at the perm. pool elevation)
Top of 1Oft vegetated shelf elevation
Bottom of 1 Oft vegetated shelf elevation
Sediment cleanout, top elevation (bottom of pond)
Sediment cleanout, bottom elevation
Sediment storage provided
Is there additional volume stored above the state-required temp. pool?
Elevation of the top of the additional volume
56,930 ft3 OK
73,486 ft3 OK, volume provided is equal to or in excess of volume required.
ft3
ft3
ft3
ft3
ft3
y (Y or N)
3.0 in
(unitless)
(unitless)
0.13 in/hr OK
15.61 ft3/sec
11.47 ft3/sec
-4.14 ft3/sec
343.80 fmsl
342.00 fmsl
fmsl
342.50 fmsl
341.50 fmsl
338.00 fmsl
337.00 fmsl
1.00 ft
n (Y or N)
fmsl
Form SW401-Wet Detention Basin-Rev 8-9117109 Parts I & 11 Design Summary, Page 1 of 2
Permit No.
(to be provided by DWQ)
II. DESIGN INIF M_ATION _
Surface Areas
Area, temporary pool 45,229 fe
Area REQUIRED, permanent pool 28,314 ff
SAIDA ratio 2.00 (unitless)
Area PROVIDED, permanent pool, A?mjw, 34,308 ft` OK
Area, bottom of 1 Oft vegetated shelf, 4.1 ahen 28,442 ft1
Area, sediment cleanout, top elevation (bottom of pond), &t-d 21,265 ft`
Volumes
Volume, temporary pool 73,486 ft3 OK
Volume, permanent pool, \?,,_, 104,707 ft3
Volume, forebay (sum of forebays if more than one forebay) _ ft3
Forebay % of permanent pool volume %
SAIDA Table Data
Design TSS removal 85 %
Coastal SAIDA Table Used? n (Y or N)
Mountain/Piedmont SA/DA Table Used? y (Y or N)
SAIDA ratio 2.00 (unitless)
Average depth (used in SAIDA table):
Calculation option 1 used? (See Figure 10-2b) n (Y or N)
Volume, permanent pool, \?.
_pod 104,707 W
Area provided, permanent pool, Awm,?j 34,308 ft`
Average depth calculated ft Need 3 ft min.
Average depth used in SAIDA, 4, (Round to nearest 0.5ft) ft
Calculation option 2 used? (See Figure 10-2b) y (Y or N)
Area provided, permanent pool, 'P? _pwj 34,308 fe
Area, bottom of 1 Oft vegetated shelf, A01 shell 28,442 ft'
Area, sediment cleanout, top elevation (bottom of pond), &I-pd 21,265 ft3
"Depth" (distance b/w bottom of 1 Oft shelf and top of sediment) 3.50 ft
Average depth calculated 3.50 ft OK
Average depth used in SAIDA, 4, (Round to nearest 0.5ft) 3.0 ft Insufficient. Check calculation.
Drawdown Calculations
Drawdown through orifice? y (Y or N)
Diameter of orifice (if circular) 4.00 in
Area of orifice (if-non-circular) in2
Coefficient of discharge (CD) 0.60 (unitless)
Driving head (FL) 1.80 ft
Drawdown through weir? n (Y or N)
Weir type 0.3 (unitless)
Coefficient of discharge (C4) 0.51 (unitless)
Length of weir (L) ft
Driving head (H) ft
Pre-development 1-yr, 24-hr peak flow 15.61 ft3lsec
Post-development 1-yr, 24-hr peak flow 11.47 ft3lsec
Storage volume discharge rate (through discharge orifice or weir) 0.54 ft3lsec
Storage volume drawdown time 2.00 days OK, draws down in 2-5 days.
Addkional Information
Vegetated side slopes 3 :1 OK
Vegetated shelf slope 10 :1 OK
Vegetated shelf width 10.0 ft OK
Length of flowpath to width ratio 4 :1 OK
Length to width ratio 4.0 :1 OK
Trash rack for overflow & orifice? y (Y or N) OK
Freeboard provided 0.8 ft Insufficient freeboard, minimum of 1-ft required
Vegetated filter provided? n (Y or N) Insufficient Vegetated filter required.
Recorded drainage easement provided? y (Y or N) OK
Capures all runoff at ultimate build-out? y (Y or N) OK
Drain mechanism for maintenance or emergencies is: Pump required
Form SW401-Wet Detention Basin-Rev B-9/17/09 Parts I & 11 Design Summary, Page 2 of 2
Permit No
AN"A'
NCDENR
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
WET DETENTION BASIN SUPPLEMENT
This form must be filled out, printed and submitted.
The Required Items Checklist (Part 111) must be printed, filled out and submitted along with all of the required information.
(to be provided by DWQ)
c ;,2 A I,,
r
LID U -, G 19_
I. PROJECT: INFORMATION
Project name Alston Pond
Contact person Alwyn V. Smith III, P.E.
Phone number 919) 469-3340
Date
Drainage area number
11. DESIGN INFORMATION
Site Characteristics
Drainage area 1,589,940 ft2
Impervious area, post-development 816,750 ft2
% impervious 51.37 %
Design rainfall depth 1.0 in
Storage Volume: Non-SA Waters
Minimum volume required 67,881 ft3 OK
Volume provided 84,332 ft3 OK, volume provided is equal to or in excess of volume required.
Storage Volume: SA Waters
1.5" runoff volume
Pre-development 1-yr, 24-hr runoff
Post-development 1-yr, 24-hr runoff
Minimum volume required
Volume provided
Peak Flow Calculations
Is the pre/post control of the 1yr 24hr storm peak flow required?
1-yr, 24-hr rainfall depth
Rational C, pre-development
Rational C, post-development
Rainfall intensity: 1-yr, 24-hr storm
Pre-development 1-yr, 24-hr peak flow
Post-development 1-yr, 24-hr peak flow
Pre/Post 1-yr, 24-hr peak flow control
Elevations
Temporary pool elevation
Permanent pool elevation
SHWT elevation (approx. at the perm, pool elevation)
Top of 1 Oft vegetated shelf elevation
Bottom of 1 Oft vegetated shelf elevation
Sediment cleanout, top elevation (bottom of pond)
Sediment cleanout, bottom elevation
Sediment storage provided
Is there additional volume stored above the state-required temp. pool?
Elevation of the top of the additional volume
10
ft3
ft3
ft3
ft3
ft3
y (Y or N)
3.0 in
0.30 (unitless)
0.51 (unitless)
0.13 in/hr OK
15.61 ft3/sec
11.47 ft3/sec
4.14 ft3/sec
367.40 fmsl
365.00 fmsl
fmsl
365.50 fmsl
364.50 fmsl
360.00 fmsl
359.00 fmsl
1.00 ft
n (Y or N)
fmsl
Form SW401-Wet Detention Basin-Rev B-9/17/09 Parts I & 11 Design Summary, Page 1 of 2
Permit No.
(to be provided by DWQ)
II, DESIGN INFORMATION _
Surface Areas
Area, temporary pool 39,090 ff
Area REQUIRED, permanent pool 28,142 fl2
SAIDA ratio 1.77 (unitless)
Area PROVIDED, permanent pool, Pp°,
Area, bottom of 1 Oft vegetated shelf,
Area, sediment cleanout, top elevation (bottom of pond), &I.d
Volumes
Volume, temporary pool
Volume, permanent pool, \?,,,_pw
Volume, forebay (sum of forebays if more than one forebay)
Forebay % of permanent pool volume
SAIDA Table Data
Design TSS removal
Coastal SAIDA Table Used?
Mountain/Piedmont SAIDA Table Used?
SAIDA ratio
Average depth (used in SAIDA table):
Calculation option 1 used? (See Figure 10-2b)
Volume, permanent pool, V,,,_pw
Area provided, permanent pool,
Average depth calculated
Average depth used in SAIDA, 4, (Round to nearest 0.5ft)
Calculation option 2 used? (See Figure 10-2b)
Area provided, permanent pool, /e?_pw
Area, bottom of 1Oft vegetated shelf, !fit a,1l
Area, sediment cleanout, top elevation (bottom of pond), JL-P d
"Depth" (distance blw bottom of IN shelf and top of sediment)
Average depth calculated
Average depth used in SAIDA, cL, (Round to nearest 0.5ft)
Drawdown Calculations
Drawdown through orifice?
Diameter of orifice (if circular)
Area of orifice (if-non-circular)
Coefficient of discharge (Cq)
Driving head (Ft)
Drawdown through weir?
Weir type
Coefficient of discharge (C.)
Length of weir (L)
Driving head (H)
Pre-development 1-yr, 24-hr peak flow
Post-development 1-yr, 24-hr peak flow
Storage volume discharge rate (through discharge orifice or weir)
Storage volume drawdown time
Additional Information
Vegetated side slopes
Vegetated shelf slope
Vegetated shelf width
Length of flowpath to width ratio
Length to width ratio
Trash rack for overflow & orifice?
Freeboard provided
Vegetated filter provided?
Recorded drainage easement provided?
Capures all runoff at ultimate build-out?
Drain mechanism for maintenance or emergencies is
28,282 ft? OK
23,027 if
13,943 if
84,332 ft3 OK
94,500 ft3
ft3
85 %
n (Y or N)
y (Y or N)
1.77 (unitless)
n (Y or N)
94,500 fe
28,282 W
ft
ft
y (Y or N)
28,282 ff
23,027 ft`
.13,943 ff
4.50 ft
4.10 ft
4.0 ft
y (Y or N)
4.00 in
in2
0.60 (unitless)
2.40 ft
n (Y or N)
(unitless)
(unitiess)
ft
ft
15.61 ft3/sec
11.47 ft3/sec
0.63 ft3/sec
2.00 days
3 :1
10 :1
10.0 ft
3 :1
3.0 :1
y (Y or N)
0.8 ft
n (Y or N)
y (Y or N)
y (Y or N)
Gate valve
Need 3 ft min.
OK
OK
OK, draws down in 2-5 days.
OK
OK
OK
OK
OK
OK
Insufficient freeboard, minimum of 1-ft required
Insufficient. Vegetated filter required.
OK
OK
Form SW401-Wet Detention Basin-Rev 9-9/1 7109 Parts I. & 11 Design Summary, Page 2 of 2
Permit No
NCDENR
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
WET DETENTION BASIN SUPPLEMENT
This form must be filled out, printed and submitted.
The Required Items Checklist (Part III) must be printed, filled out and submitted along with all of the required information.
(to be provided by DWQ)
ry
? e
of fl?i.?.F ?..Jti
I. PROJECT INFORMATION
Project name Alston Pond
Contact person Alwyn V. Smith III, P.E.
Phone number 919) 469-3340
Date 22-Dec-10
Drainage area number 3
II, DESIGN INFORMATION
Site Characteristics
Drainage area 696,960 fe
Impervious area, post-development 271,814 ftz
% impervious 39.00%
Design rainfall depth 1.0 in
Storage Volume: Non-SA Waters
Minimum volume required
Volume provided
Storage Volume: SA Waters
1.5" runoff volume
Pre-development 1-yr, 24-hr runoff
Post-development 1-yr, 24-hr runoff
Minimum volume required
Volume provided
Peak Flow Calculations
Is the pre/post control of the lyr 24hr storm peak flow required?
1-yr, 24-hr rainfall depth
Rational C, pre-development
Rational C, post-development
Rainfall intensity: 1-yr, 24-hr storm
Pre-development 1-yr, 24-hr peak flow
Post-development 1-yr, 24-hr peak flow
Pre/Post 1-yr, 24-hr peak flow control
Elevations
Temporary pool elevation
Permanent pool elevation
SHWT elevation (approx. at the perm. pool elevation)
Top of 1 Oft vegetated shelf elevation
Bottom of 1Oft vegetated shelf elevation
Sediment cleanout, top elevation (bottom of pond)
Sediment cleanout, bottom elevation
Sediment storage provided
Is there additional volume stored above the state-required temp. pool?
Elevation of the top of the additional volume
23,290 ft3 OK
27,791 ft3 OK, volume provided is equal to or in excess of volume required,
ft3
ft3
ft3
ft3
ft3
y (Y or N)
3.0 in
0.30 (unitless)
0.51 (unitless)
0.13 in/hr OK
15.61 ft3/sec
11.47 ft3/sec
-4.14 ft3/sec
382.80 fmsl
381.00 fmsl
fmsl
381.50 fmsl
380.50 fmsl
377.00 fmsl
376.00 fmsl
1.00 ft
(Y or N)
fmsl
Form SW401-Wet Detention Basin-Rev 8-9/17109 Parts I & 11 Design Summary, Page 1 of 2
Permit No
(to be provided by D WQ)
11. DESIGN INFORMATION -
Surface Areas
Area, temporary pool 17,329 f?
Area REQUIRED, permanent pool 11,779 ft'
SAIDA ratio 1.69 (unitless)
Area PROVIDED, permanent pool, PI 12,414 ft OK
Area, bottom of 1 Oft vegetated shelf, 4o, „ 9,710 ft
Area, sediment cleanout, top elevation (bottom of pond), &,_?nd 5,979 ft
Volumes
Volume, temporary pool 27,791 ft3 OK
Volume, permanent pool, V,.,,d 33,021 ft3
Volume, forebay (sum of forebays if more than one forebay) ft3
Forebay % of permanent pool volume %
SAIDA Table Data
Design TSS removal 85 %
Coastal SAIDA Table Used? n (Y or N)
Mountain/Piedmont SAIDA Table Used? y (Y or N)
SAW ratio 1.69 (unitless)
Average depth (used in SAIDA table):
Calculation option 1 used? (See Figure 10-2b) n (Y or N)
Volume, permanent pool, V,,,,_p.i 33,021 ft'
Area provided, permanent pool, 4._pod 12,414 W
Average depth calculated ft Need 3 ft min.
Average depth used in SAIDA, qv, (Round to nearest 0.5ft) ft
Calculation option 2 used? (See Figure 10-2b) y (Y or N)
Area provided, permanent pool, P,,. j., 12,414 ft`
Area, bottom of 1 Oft vegetated shelf, Aa shelf 9,710 ft
Area, sediment cleanout, top elevation (bottom of pond), &lyq,d 5,979 ff
"Depth" (distance blw bottom of IN shelf and top of sediment) 3.50 ft
Average depth calculated 3.30 ft OK
Average depth used in SAIDA, q, (Round to nearest 0.5ft) 3.0 ft Insufficient. Check calculation.
Drawdown Calculations
Drawdown through orifice? y (Y or N)
Diameter of orifice (if circular) 2.00 in
Area of orifice (if-non-circular) in2
Coefficient of discharge (C)) 0.60 (unitless)
Driving head (Ft) 1.80 ft
Drawdown through weir? n (Y or N)
Weir type (unitless)
Coefficient of discharge (CN) (unitless)
Length of weir (L) ft
Driving head (H) ft
Pre-development 1-yr, 24-hr peak flow 15.61 ft3/sec
Post-development 1-yr, 24-hr peak flow 11.47 ft3/sec
Storage volume discharge rate (through discharge orifice or weir) 0.14 ft lsec
Storage volume drawdown time 2.00 days OK, draws down in 2-5 days.
Additional Information
Vegetated side slopes 3 :1 OK
Vegetated shelf slope 10 :1 OK
Vegetated shelf width 10.0 ft OK
Length of flowpath to width ratio 4 :1 OK
Length to width ratio 5.0 :1 OK
Trash rack for overflow & orifice? y (Y or N) OK
Freeboard provided 0.5 ft Insufficient freeboard, minimum of 1-ft required
Vegetated filter provided? n (Y or N) Insufficient. Vegetated filter required.
Recorded drainage easement provided? y (Y or N) OK
Capures all runoff at ultimate build-out? y (Y or N) OK
Drain mechanism for maintenance or emergencies is: gate valve
Form SW401-Wet Detention Basin-Rev-8-9/17/09 Parts I & 11 Design Summary, Page 2 of 2
Permit No
NCQENR
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
WET DETENTION BASIN SUPPLEMENT
This form must be filled out, printed and submitted.
The Required Items Checklist (Part HI) must be printed, filled out and submitted along with all of the required information.
(to be provided by DWQ)
0 61
?UJ C )6!
I. PROJECT INFORMATION
Project name Alslon Pond
Contact person Alwyn V. Smith III, P.E.
Phone number 919) 469-3340
Date 22-Dec-10
Drainage area number 4
14, DESIGN INFORMATION
Site Characteristics
Drainage area 261,360 fe
Impervious area, post-development 113,256 fe
% impervious 43.33 %
Design rainfall depth 1.0 in
Storage Volume: Non-SA Waters
Minimum volume required
Volume provided
Storage Volume: SA Waters
1.5" runoff volume
Pre-development 1-yr, 24-hr runoff
Post-development 1-yr, 24-hr runoff
Minimum volume required
Volume provided
Peak Flow Calculations
Is the pre/post control of the lyr 24hr storm peak flow required?
1-yr, 24-hr rainfall depth
Rational C, pre-development
Rational C, post-development
Rainfall intensity: 1-yr, 24-hr storm
Pre-development 1-yr, 24-hr peak flow
Post-development 1-yr, 24-hr peak flow
Pre/Post 1-yr, 24-hr peak flow control
Elevations
Temporary pool elevation
Permanent pool elevation
SHWT elevation (approx. at the perm. pool elevation)
Top of 1 Oft vegetated shelf elevation
Bottom of 1Oft vegetated shelf elevation
Sediment cleanout, top elevation (bottom of pond)
Sediment cleanout, bottom elevation
Sediment storage provided
Is there additional volume stored above the state-required temp pool?
Elevation of the top of the additional volume
9,584 ft3 OK
9,888 ft3 OK, volume provided is equal to or in excess of volume required.
ft3
ft3
ft3
ft3
ft3
y (Y or N)
3.0 in
0.30 (unitless)
0.51 (unitless)
0.13 Whir OK
15.61 ft3/sec
11.47 ft3lsec
A.14 ft3/sec
343.00 fmsl
344.50 fmsl
Imsl
343.50 fmsl
342.50 fmsl
339.00 fmsl
338.00 fmsl
1.00 ft
(Y or N)
fmsl
Form SW401-Wet Detention Basin-Rev B-9/17/09 Parts 1811 Design Summary, Page 1 of 2
Permit No
(to be provided by D WQ)
111. DESIGN' INFORMATION
Surface Areas
Area, temporary pool 7,756 ft?
Area REQUIRED, permanent pool 4,809 fe
SAIDA ratio 1.84 (unitless)
Area PROVIDED, permanent pool, ?__,.I 4,897 ft' OK
Area, bottom of 10ft vegetated shelf, A,,, ,heIl 3,346 ft`
Area, sediment cleanout, top elevation (bottom of pond), Qol_ood 1,418 ft`
Volumes
Volume, temporary pool 9,888 ft3 OK
Volume, permanent pool, 10,290 ft3
Volume, forebay (sum of forebays if more than one forebay) ft3
Forebay % of permanent pool volume %
SAIDA Table Data
Design TSS removal 85 %
Coastal SAIDA Table Used? n (Y or N)
Mountain/Piedmont SAIDA Table Used? y (Y or N)
SAIDA ratio 1.84 (unitless)
Average depth (used in SAIDA table):
Calculation option 1 used? (See Figure 10-2b) n (Y or N)
Volume, permanent pool, V?m_pcd 10,290 ft'
Area provided, permanent pool, A?,,,,_pw 4,897 ft
Average depth calculated ft Need 3 ft min.
Average depth used in SAIDA, 4, (Round to nearest 0.5ft) ft
Calculation option 2 used? (See Figure 10-2b) y (Y or N)
Area provided, permanent pool, P,,,,,_pd 4,897 ftL
Area, bottom of 1 Oft vegetated shelf, At ,,ejl 3,346 ft`
Area, sediment cleanout, top elevation (bottom of pond), Q„_p d 1,418 fl2
"Depth" (distance b/w bottom of 1 Oft shelf and top of sediment) 3.50 ft
Average depth calculated 3A0 ft OK
Average depth used in SAIDA, 4, (Round to nearest 0.5ft) 3.0 ft OK
Drawdown Calculations
Drawdown through orifice?
Diameter of orifice (if circular)
Area of orifice (if-non-circular)
Coefficient of discharge (CD)
Driving head (F6)
Drawdown through weir?
Weir type
Coefficient of discharge (C„)
Length of weir (L)
Driving head (H)
Pre-development 1-yr, 24-hr peak flow
Post-development 1-yr, 24-hr peak flow
Storage volume discharge rate (through discharge orifice or weir)
Storage volume drawdown time
Additional Information
Vegetated side slopes
Vegetated shelf slope
Vegetated shelf width
Length of flowpath to width ratio
Length to width ratio
Trash rack for overflow & orifice?
Freeboard provided
Vegetated filter provided?
Recorded drainage easement provided?
Capures all runoff at ultimate build-out?
Drain mechanism for maintenance or emergencies is:
y (Y or N)
2.00 in
inz
0.60 (unitless)
1.50 ft
(Y or N)
(unitless)
(unitless)
ft
?ft
15.61 ft3lsec
11.47 ft3lsec
0.13 ft3lsec
2.00 days
OK, draws down in 2-5 days.
3 :1 OK
10 :1 OK
10.0 ft OK
3 :1 OK
3.0 :1 OK
YT (Y or N) OK
0.5 ft Insufficient freeboard, minimum of 1-ft required
n (Y or N) Insufficient Vegetated filter required-
y (Y or N) OK
y (Y or N) OK
pump required
Form SW401-Wet Detention Basin-Rev 8-9117/09 Parts I. & 11 Design Summary, Page 2 of 2

A 7-PA (}'r ifFA;itrra
..
NCDENR ^?
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
LEVEL SPREADER - VEGE TATED FILTER STRIP (LS-VFS) SUPPLEMENT
This form must be completely filled out, printed, initialed, and submitted.
1. PROJECT INFORMATION
Project name Alston Pond
Contact name Troy Beasley
Phone number 919-469-3340
Date January 25, 2011
Drainage area number BMP #2
H. DESIGN INFORMATION
The purpose of the LS-VFS Buffer Rule: Diffuse Flow
Stormwater enters LS-VFS from A BMP
Type of VFS Protected riparian buffer (slope < 5%)
Explanation of any "Other" responses above
If Stormwater Enters the LS-VFS from the Drainage Area
Drainage area ftZ Do not complete this section of the form.
Impervious surface area ftz Do not complete this section of the form.
Percent impervious % Do not complete this section of the form.
Rational C coefficient Do not complete this section of the form.
Peak flow from the 1 in/hr storm cfs Do not complete this section of the form.
Time of concentration min Do not complete this section of the form.
Rainfall intensity, 10-yr storm in/hr Do not complete this section of the form.
Peak flow from the 10-yr storm cfs Do not complete this section of the fo+m.
Design storm Pick one:
Maximum amount of flow directed to the LS-VFS cfs Do not complete this section of the form.
Is a flow bypass system going to be used? (Y or N) Do not complete this section of the form.
Explanation of any "Other" responses above
If Stormwater Enters the LS-VFS from a BMP
Type of BMP Wet detention pond
Peak discharge from the BMP during the design storm 0.86 cfs
Peak discharge from the BMP during the 10-year storm 0.86 cfs
Maximum capacity of a 100-foot long LS-VFS 2 cfs
Peak flow directed to the LS-VFS 0.86 cfs
Is a flow bypass system going to be used? y (Y or N)
Explanation of any "Other" responses above
LS-VFS Design
Forebay surface area sq ft
Depth of forebay at stormwater entry point in
Depth of forebay at stormwater exit point in
Feet of level lip needed per cfs 50 fvcfs
Computed minimum length of the level lip needed ft
Length of level lip provided ft
Form SW401 - LS-VFS - 29Nov2010 - Rev 8 page 1 of 3
Width of VFS
Elevation at downslope base of level lip
Elevation at the end of the VFS that is farthest from the LS
Slope (from level lip to the end of the VFS)
Are any draws present in the VFS?
Is there a collector swale at the end of the VFS?
Bypass System Design (if applicable)
Is a bypass system provided?
Is there an engineered flow splitting device?
Dimensions of the channel (see diagram below):
M
B
W
y (flow depth for 10-year storm)
freeboard (during the 10-year storm)
Peak velocity in the channel during the 10-yr storm
Channel lining material
Does the bypass discharge through a wetland?
Does the channel enter the stream at an angle?
Explanation of any "Other" responses above
,
ft
fmsl
fmsl
(Y or N)
(Y or N)
Y (Y or N)
Y (Y or N) Please provide plan details of flow splitter 8, supporting calcs
2.00 ft
4.00 ft
12.00 ft
0-85 ft
1.15 ft
3,84 ft/sec
Pick one: &9 W G41An1Ar_-[-
N (Y or N)
Y (Y or N)
W
N
# L 1
EDIT Please indicate the page or plan sheet numbers where the supporting documentation can be found. An incomplete submittal package will result in
a request for additional information. This will delay final review and approval of the project. Initial in the space provided to indicate the following
design requirements have been met. If the applicant has designated an agent, the agent may initial below. If a requirement has not been met, attach
justification.
Requried Item:
1. Plans (1" - 50' or larger) of the entire site showing:
- Design at ultimate build-out,
Off-site drainage (if applicable),
Delineated drainage basins (include Rational C coefficient per basin),
Forebay (if applicable),
High flow bypass system,
Maintenance access,
Proposed drainage easement and public right of way (ROW), and
Boundaries of drainage easement.
Initials Page or plan sheet number and any notes:
del -S.? ZZ-2`2 -Z
600 t-OTP('t_ 15 00 s?tr Z 3
Form SW401 - LS-VFS - 29Nov2010 - Rev.8 page 2 of 3
2- Plan details (1' = 30' or larger) for the level spreader showing:
Forebay (if applicable),
High flow bypass system,
One foot topo lines between the level lip and lop of stream dank,
Proposed drainage easement, and
Design at ultimate build-gift.
3. Section view of (lie level spreader (3' = 20' or larger) showing:
- Underdrain system (if applicable),
Level lip,
Upslope channel, and
Downs Iope filler fabric.
4. Plan details of the flow splitling device and supporting calculations (if applicable),
5. A construction sequence Ihal shows haw the level spreader will be protected from
sediment until the entire drainage area is stabilized.
6. It a non-engineered VFS is being used, then provide a photograph of the VFS showing
that no draws are present.
7- The supporting calculations.
8. A copy of the signed and notarized operation and maintenance (O&M) agreement.
?t
ZY
I -
I

r Psz0"14 rk I i e_QrI Pc (--r-
PR6V 1?b
Form SW401 - LS-VF5 -29Nov2olo - Rev.8 page 3 of 3
BMP #2 HIGH FLOW BYPASS
Project Description
Friction Method
Solve For
Input Data
Roughness Coefficient
Channel Slope
Left Side Slope
Right Side Slope
Bottom Width
Discharge
Results
Normal Depth
Flow Area
Wetted Perimeter
Top Width
Critical Depth
Critical Slope
Velocity
Velocity Head
Specific Energy
Froude Number
Flow Type
GVF Input Data
Downstream Depth
Length
Number Of Steps
GVF Output Data
Upstream Depth
Profile Description
Profile Headloss
Downstream Velocity
Upstream Velocity
Normal Depth
Critical Depth
Channel Slope
Critical Slope
1/28/20119:05:13 AM
Manning Formula
Normal Depth
Subcritical
0.069
006000 ft/ft
2.00 ft/ft (H:V)
2.00 ft/ft (H:V)
4.00 ft
18.60 Wis
0.85 ft
4.85 ft2
7.80 ft
7.40 ft
0.77 f[
0.08793 ft/ft
3.84 ft/s
0.23 ft
1.08 ft
0.84
0.00 ft
0.00 ft
0
0.00 ft
0.00 ft
Infinity ft/s
Infinity ft/s
0.85 ft
0.77 ft
0.06000 ft/ft
0.08793 ft/ft
Bentley Systems, Inc. Haestad Methods Solution Center Bentley FlowMaster [08.01.071.00]
27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA [phone] Page 1 of 1
HCDEMR

STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
LEVEL SPREADER - VEGETATED FILTER STRIP (LS-VFS) SUPPLEMENT
This form must be completely filled out, printed, initialed, and submitted.
#. PROJECT INFORMATION
Project name Alston Pond
Contact name Troy Beasley
Phone number 919.469-3340
Date January 25, 2011
Drainage area number BMP #4
The purpose of the LS-VFS
Stormwater enters LS-VFS from
Type of VFS
Explanation of any "Other" responses above
If Stormwater Enters the LS-VFS from the Drainage Area
Drainage area
Impervious surface area
Percent impervious
Rational C coefficient
Peak flow from the 1 in/hr storm
Time of concentration
Rainfall intensity, 10-yr storm
Peak flow from the 10-yr storm
Design storm
Maximum amount of flow directed to the LS-VFS
Is a flow bypass system going to be used?
Explanation of any "Other" responses above
If Stormwater Enters the LS-VFS from a BMP
Type of BMP
Peak discharge from the BMP during the design storm
Peak discharge from the BMP during the 10-year storm
Maximum capacity of a 100-foot long LS-VFS
Peak flow directed to the LS-VFS
Is a flow bypass system going to be used?
Explanation of any "Other" responses above
LS-VFS Design
Forebay surface area
Depth of forebay at stormwater entry point
Depth of forebay at stormwater exit point
Feet of level lip needed per cfs
Computed minimum length of the level lip needed
Length of level lip provided
Buffer Rule: Diffuse Flow
A BMP
Engineered filter strip (graded & sodded, slope < 8%)

ft z Do not complete this section of the form.
ft z Do not complete this section of the form-
% Do not complete this section of the form.
Do not complete this section of the form,
cfs Do not complete this section of the form,
min Do not complete this section of the form,
in/hr De not complete this section of the form.
cfs Do not complete this section of the form.
Pick one:
cfs Do not complete this section of the form.
(Y or N) Do not complete this section of the form.

Wet detentio n pond
0.5 cfs
0.5 cfs
10 cfs
0.5 cfs
y (Y or N)

sq ft
in
in
10 fucfs
ft
ft
Form SW401 - LS-VFS - 29Nov2010 - Rev.8 page 1 of 3
Width of VFS
Elevation at downslope base of level lip
Elevation at the end of the VFS that is farthest from the LS
Slope (from level lip to the end of the VFS)
Are any draws present in the VFS?
Is there a collector swale at the end of the VFS?
Bypass System Design (if applicable)
Is a bypass system provided?
Is there an engineered flow splitting device?
Dimensions of the channel (see diagram below):
M
B
W
y (flow depth for 10-year storm)
freeboard (during the 10-year storm)
Peak velocity in the channel during the 10-yr storm
Channel lining material
Does the bypass discharge through a wetland?
Does the channel enter the stream at an angle?
Explanation of any "Other" responses above
ft
fmsl
fmsl
(Y or N)
(Y or N)
Y (Y or N)
Y (Y or N)
2.00 ft
4.00 ft
12.00 ft
0.62 ft
1.38 ft
4.57 ft/sec
Pick one:
Please provide plan details of flow splitter & supporting calcs.
N (Y or N)
N (Y or N) Redesign channel so that it enters the stream at an angle
Channel enters along wetland edge as stated in the above cell
W

EDIT Please indicate the page or plan sheet numbers where the supporting documentation can be found. An incomplete submittal package will result in
a request for additional information. This will delay final review and approval of the project. Initial in the space provided to indicate the following
design requirements have been met. If the applicant has designated an agent, the agent may initial below. If a requirement has not been met, attach
justification.
Requried Item:
1. Plans (1" - 50' or larger) of the entire site showing:
- Design at ultimate build-out,
- Off-site drainage (if applicable),
- Delineated drainage basins (include Rational C coefficient per basin),
- Forebay (if applicable),
- High flow bypass system,
- Maintenance access,
- Proposed drainage easement and public right of way (ROW), and
- Boundaries of drainage easement.
Initials Page or plan sheet number and any notes:
C)o
Form SW401 - LS-VFS - 29Nov2010 - Rev.8 page 2 of 3
2. Plan details (1" = 30' or larger) for the level spreader showing:
- Forebay (if applicable),
- High flow bypass-system,
- One foot topo lines between the level lip and top of stream bank,
- Proposed drainage easement, and
- Design at ultimate build-out.
3. Section view of the level spreader (1" = 20' or larger) showing:
- Underdrain system (if applicable),
- Level lip,
- Upslope channel, and
- Downslope filter fabric,
4. Plan details of the flow splitting device and supporting calculations (if applicable).
5. A construction sequence thatshows how the level spreader will be protected from
sediment until the entire drainage area is stabilized.
6. If a non-engineered VFS is being used, then provide a photograph of the VFS showing
that no draws are present.
7. The supporting calculations.
8. A copy of the signed and notarized operation and maintenance (O&M) agreement
e L -C'
. ZY
Mt_ 4
y1'1 ?•? ? ? t
I
QRaV'd? +? SWr^ 2ir Pof?'
PROV1?r<D
Form SW401 - LS-VFS - 29Nov2010 - Rev.8 page 3 of 3
BMP #4 HIGH FLOW BYPASS
Project Description
Friction Method Manning Formula
Solve For Normal Depth
Input Data
Roughness Coefficient 0.069
Channel Slope 0.12000 ft/ft
Left Side Slope 2.00 ft/ft (H:V)
Right Side Slope 2.00 ft/ft (H:V)
Bottom Width 4.00 ft
Discharge 14.83 ft'/s
Results
Normal Depth 0.62 ft
Flow Area 3.25 ftZ
Wetted Perimeter 6.77 ft
Top Width 6.48 ft
Critical Depth 0.67 ft
Critical Slope 0.09088 ft/ft
Velocity 4.57 ft/s
Velocity Head 0.32 ft
Specific Energy 0.94 ft
Froude Number 1.14
Flow Type Supercritical
GVF Input Data
Downstream Depth 0.00 ft
Length 0.00 ft
Number Of Steps 0
GVF Output=Data
Upstream Depth 0.00 ft
Profile Description
Profile Headloss 0.00 ft
Downstream Velocity Infinity ft/s
Upstream Velocity Infinity ft/s
Normal Depth 0.62 ft
Critical Depth 0.67 ft
Channel Slope 0.12000 ft/ft
Critical Slope 0.09088 ft/ft
Bentley Systems, Inc. Haestad Methods Solution Center Bentley FlowMaster (08.01.071.00]
1/28120119:15:56 AM 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA [phone] Page 1 of 1
WITHERS & RAVENEL
Alston Pond
Stormwater Management Plan
Fuquay-Varina, North Carolina
Prepared For:
North Broad Street, LLC
2401 Weston Parkway, Suite 203
Cary, NC 27513
Prepared By:
WITHERS & RAVENEL, INC
111 MacKenan [give
Cary, North Carolina 27511
January 2011
W&R Project No. 02100349
i
ALWY V. SMITH III, P.E.
INTRODUCTION
The purpose of this study is to document pre- and post-development peak stormwater discharges
for the 1-year and io-year design storm events as well as study the loo-year water surface elevations
in the stormwater BMPs. The goal is to provide adequate stormwater detention devices to safely
maintain a discharge less than or equal to the pre-development peak discharges after the site has
been developed as well as to provide storage for the post-development volume in excess of the pre-
development runoff volume.
Wet detention basins are proposed for this development to meet all town and DWQ criteria for peak
attenuation and water quality.
METHODOLOGY
The stormwater study was conducted using the natural drainage features as depicted by field survey
data and proposed development within the drainage areas. The drainage areas of each pond were
entered into the model as a single drainage area based on natural and proposed drainage patterns,
to evaluate post development peak discharge rates and runoff volumes.
There are four stormwater devices proposed for the site to meet peak attenuation, water quality and
storage requirements. Stormwater is collected in catch basins and conveyed via storm sewer to the
wet detention basins.
The scope of work included the following analyses:
Hydrolo?y
? Estimation of the s.o" runoff volume and the i-year 24 hour runoff volume
? Estimation of the time of concentration for the pre- and post-development conditions
? Simulation of the 1-year, io-year and soo-year rainfall events for the Fuquay-Varina area
? Formulation of the 1-year, to-year and ioo-year flood hydrographs for the pre- and post-
development drainage areas
Hydraulic
? Routing the 1-year, 1o-year and loo-year flood hydrographs for post development runoff
through the proposed infiltration system.
Culvert Sizing
? There are 3 culvert crossings on site, sized for the 25-year storm and to not overtop the
road in the soo-year storm
The results of the hydrology calculations are used in the hydraulic analyses. The hydraulic design
requires the development of stage-storage and stage-discharge functions for the wet ponds. The
rainfall/runoff hydrographs, stage-storage and stage-discharge functions have been compiled to
create a routing computer simulation model using Bentley PondPack vso.o software. This PondPack
model was then used to assess the impact of the peak discharges for the design rainfall events. The
PondPack modeling results are provided as appendices to this report.
SITE DESCRIPTION
The proposed residential development is located on a 138 acre parcel, which is anticipated to be
approximately 31% impervious. The existing site is generally gently sloping, draining to the
northeast. Existing land use is approximately 75% forested and 25% agricultural fields Wetlands and
streams on site are within the Neuse River basin and are tributaries to Basal Creek (Stream Index #27-
43-15-3, Classification B;NSW), which is on the eastern boundary of the property.
HYDROLOGY
The SCS Method was used to develop runoff hydrographs for the Type II, 24-hour duration, 1-year
storm and NOAA Atlas 14 rainfall data was used for the 1o-year and loo-year storm events for the
Fuquay-Varina area. This method requires three basic parameters: a curve number (CN), time of
concentration (Q, and drainage area. Curve numbers were based on soil type and land use. Soil
types were delineated from the Soil Survey of Wake County, North Carolina. Land use for existing
conditions was based on the most recent Wake County aerial photographs. Post development land
use is residential based on the proposed site plan. Time of concentration was calculated using
methods described in the SCS publication "Urban Hydrology for Small Watersheds, TR-55" and the
flow time through the storm sewer, as calculated by our Storm CAD Model for each drainage area, in
conjunction with field survey data. Drainage areas were delineated from the proposed grading plans
for post development conditions. A summary of data used to formulate hydrographs and peak
discharges are included in the appendices of this report.
HYD RAU ?Z'S
Computer simulated reservoir routing of the 1-year, 1o-year and loo-year design storms utilized
stage-storage and stage-discharge functions. Stage-storage functions were derived from the
proposed contours for each pond. A non-linear regression relation for surface area versus elevation
was derived for each pond. This relation estimates the incremental volume of the basin to the stage
or elevation of the basin. Stage-discharge functions were developed to size the outlet structure for
each pond.
CONCLUSIONS
Based on the routing study, the post development peak discharge from the entire site is less than
the pre-development peak for the 1-year, and 1o-year design storms. All BMPs provide at least 6" of
freeboard in the loo-year storm. Additionally, the ponds discharge at non-erosive velocities through
at least 30' of natural wetlands in place of a constructed vegetated filter strip. The table below
summarizes the peak attenuation results.
TABLE 1. PRE DEVELOPMENT RUNOFF SUMMARY
1 Outflow
-year Q
eak 10-year Qpeak loo-year Qpeak
p Outflow Outflow

Pre Development
Runoff
15.61 cfs
117.62 cfs
256.79 cfs
TABLE 2. PEAK ATTENUATION SUMMARY FOR THE 1-YEAR DESIGN STORM
1-year Qpeaklnflow 1-year Qpeak Outflow
BMP 1 50.63 3.92
BMP 2 62.72 3.87
BMP 3 22.76 1.47
BMP 4 13.06 4.58
Untreated
2.55
y?
Post Development Runoff 11.47 cfs
TABLE 3. PEAK ATTENUATION SUMMARY FOR THE 10-YEAR DESIGN STORM
1o-year Qpeak Inflow 1o-year Qpeak Outflow
BMP 1 111.20 34.61
BMP 2 137.77 18.60
BMP 3 62.23 31.19
BMP 4 31.11 14.83
Untreated 30.86

Post Development Runoff
A 115
.60 cfs
WET DETENTION POND OUTLET SUMMARY
BMP1
• 6'x6' Inlet Box with slab top - Crest = 345.20 (6'x 6' I.D.)
• 4" diameter drawdown orifice - Invert @ 342.00
• 3x 4' wide x 6" high peak attenuation orifices @ 343.80
• 54" dia. RCP outlet barrel - INV UP = 340.33, INV DN = 340.00
• Top of Berm = 347.00
• loo-year freeboard = 0.8'
BMW2
• 6'x6' Inlet Box with slab top - Crest = 370.00 (6'x 6' I.D.)
• 2.3" diameter drawdown orifice - Invert @ 365.00
• 4' wide x 6" high peak attenuation orifice @ 367.4
• 42" dia. RCP outlet barrel - INV UP = 359.00, INV DN = 358.58
• Top of Berm = 372.00
• soo-year freeboard = 0.8'
BMW 3
• 5'x5' Inlet Box with slab top - Crest = 384.25 (5'x 5' I.D.)
• 2" diameter drawdown orifice - Invert @ 381.00
• 2.5' wide x 12" high peak attenuation orifice @ 382.80
• 36" dia. RCP outlet barrel - INV UP = 376.00, INV DN = 372.00
• 33' Emergency Spillway @ 383.80
• Top of Berm = 385.00
• loo-year freeboard = 0.5'
BMP 4
• 4'x4' Inlet Box with slab top - Crest = 346.00 W x 4' I.D.)
• 2" diameter drawdown orifice - Invert @ 343.00
• 2.5' wide x 12" high peak attenuation orifice @ 344.50
• 24" dia. RCP outlet barrel - INV UP = 338.00, INV DN = 337.00
• Top of Berm = 347.00
0 loo-year freeboard = 0.5'
STQRMWATER
CALCULATIONS
Job File: K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\ALSTON POND BMPS.PPW
Rain Dir: K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\
JOB TITLE
-----------------
Project Date: 12/3/2010
Project Engineer: asmith
Project Title: Alston Pond
Project Comments :
S/N:
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Table of Contents
i
Table of Contents
********************** MASTER SUMMARY **********************
Watershed....... Master Network Summary ............. 1.01
****************** DESIGN STORMS SUMMARY *******************
RDU NOAA 14 Desi Design Storms ...................... 2.01
RDU NOAA 14 Desi 10
Design Storms ...................... 2.02
********************** TC CALCULATIONS ********************
DA 1............ Tc Calcs ........................... 3.01
DA 2............ Tc Calcs ........................... 3.03
DA 3............ Tc Calcs ........................... 3.05
DA 4............ Tc Calcs ........................... 3.07
PRE-DEV AREA.... Tc Calcs ........................... 3.09
UNTREATED....... Tc Calcs ........................... 3.11
********************** CN CALCULATIONS *********************
DA 1............ Runoff CN-Area ..................... 4.01
DA 2............ Runoff CN-Area ..................... 4.02
DA 3............ Runoff CN-Area ..................... 4.03
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Table of Contents
ii
Table of Contents (continued)
DA 4............ Runoff CN-Area ..................... 4.04
PRE-DEV AREA.... Runoff CN-Area ..................... 4.05
UNTREATED....... Runoff CN-Area ..................... 4.06
*********************** POND VOLUMES ********************
BMP 1........... Vol: Elev-Area ..................... 5.01
BMP 2........... Vol: Elev-Area ..................... 5.02
BMP 3........... Vol: Elev-Area ..................... 5.03
BMP 4........... Vol: Elev-Area ..................... 5.04
********************** POND ROUTING ********************
BMP 1........... Pond E-V-Q Table ................... 6.01
BMP 2........... Pond E-V-Q Table ................... 6.04
BMP 3........... Pond E-V-Q Table ................... 6.08
BMP 4........... Pond E-V-Q Table ................... 6.11
SIN:
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Type.... Master Network-Summary Page 1.01
Name.... Watershed
File.... K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\Alston Pond BMPs.ppw
MASTER DESIGN STORM SUMMARY
Network Storm Collection: RDU NOAA 14 Desi
Total
Depth Rainfall
Return Event in Type RNF ID
-
--
------------
10 ------
4.9800 ----------------
Time-Depth Curve -----------
--
RDU NOAA 10yr
100 7.3700 Time-Depth Curve RDU NOAA 100yr
1 3.0000 Synthetic Curve TypeII 24hr
MASTER NETWORK SUMMARY
SCS Unit Hydrograph Method
(*Node=Outfall; +Node=Diversion;)
(Trun= HYG Truncation: Blank=None; L=Left; R=Rt; LR=Left&Rt)
Max
Retur3i HYG Vol Qpeak Qpeak Max WSEL Pond Storage
Node 1D Type Event ac-ft Trun hrs cfs ft ac-ft
---------
-----
BMP ------
I ------
IN ----
POND ------
10 ----------
7.541 -- --------
12.1500 --------
111.20 -------- ---
BMP I IN POND 100 13.336 12.1500 161.24
F3MP 1 IN POND 1 3.219 12.0000 50.63
BMP 1 OUT POND 10 7.456 R 12.4500 34.61 345.18 3.201
BMP 1 OUT POND 100 13.248 R 12.3500 98.76 346.17 4.381
BMP 1 OUT POND 1 3.139 R 13.1500 3.92 343.88 1.766
BMP 2 IN POND 10 9.747 1.2.1500 137,77
BMP 2 IN POND 100 15.322 12.1500 196.85
BMP 2 IN POND 1 3.802 12.0000 62.72
f3MP 2 OUT POND 10 8.681 R 12.6000 18.60 370.08 4.535
BMP 2 OUT POND 100 15.253 R 12.3000 119.49 371.25 5.790
BMP 2 OUT POND 1 3.741 R 13.4000 3.87 367.64 2.143
BMP 3 IN POND 10 3.244 12.1000 62.23
EMP 3 IN POND 100 5.970 12.1000 93.45
!3tii 3 IN POND 1 1.281 11.9500 22.76
5/N:
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12121,12010
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Name.... Watershed
File.... K:\10\10-0340\100349-Pre3ton - Alston Pond\H-H\Pondpak\Alston Pond BMPs.ppw
MASTER NETWORK SUMMARY
SCS Unit Hydrograph Method
(*Node=Outfall; +Node=Diversion;)
(True= HYG Truncation: Blank=None; L=Left; R=Rt; LR=Left&Rt)
Return HYG Vol
Node ID Type Event ac-ft Trun
------------
BMP 3 -----
OUT ----
POND ------
10 ----------
3.199 --
R
BMP 3 OUT POND 100 5.920 R
BMP 3 OUT POND 1 1.241 R
BMP 4 IN POND 10 1.632
BMP 4 IN POND 100 2.833
BMP 4 IN POND 1 .722
BMP 4 OUT POND 10 1.630
BMP 4 OUT POND 100 2.830
BMP 4 OUT POND 1 .719
DA 1 AREA 10 7.541
DA 1 AREA 100 13.336
DA 1 AREA 1 3.219
DA 2 AREA 10 8.747
DA 2 AREA 100 15.322
DA 2 AREA 1 3.802
DA 3 AREA 10 3.244
DA 3 AREA 100 5.970
DA 3 AREA 1 1.281
DA 4 AREA 10 1.632
DA 4 AREA 100 2.833
DA 4 AREA 1 .722
*POST-DEV JCT 10 24.684 R
*POST-DEV JCT 100 46.307 R
"POST-DEV JCT 1 9.587 R
'PRE-DEW JCT 10 13.314
*PRE-DEV JCT 100 30.634
'PRE-DEV JCT 1 3.149
Max
Qpeak Qpeak Max WSEL Pond Storage
hrs cfs ft ac-ft
---------
12.2500 --------
31.19 --------
384.11 ------------
1.180
12.1500 82.47 384.50 1.352
13.2500 1.47 382.91. A79
12.1000 31.11
12.1000 43.55
11.9500 13.06
12.2500 14.83 345.98 .517
12.2000 29.49 346.47 .627
12.1000 4.58 344.87 .291
12.1500 111.20
12.1500 161.24
12.0000 50.63
12.1500 137.77
12.1500 196.85
12.0000 62.72
12.1000 62.23
12.1000 93.45
11.9500 22.76
12.1000 31.11
12.1000 43.55
11.9500 13.06
12.3000 115.60
12.3000 354.18
13.1000 11.47
12.4000 117.62
12.3500 256.79
12.3000 15.61
S/N: Bentley Systems, Inc.
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Type.... Master Network Summary Page 1.03
Name.... Watershed
File.... K:\10\10-0340\100349-Preston - Alston Fond\H-H\Pondpak\Alston Pond BMPs.ppw
MASTER NETWORK SUMMARY
SCS Unit Hydrograph Method
(*Node=Outfall; +Node=Diversion;)
(Trun= HYG Trun cation: Blank=None; L=Left; R=Rt; LR=Left&Rt)
Return HYG Vol Qpeak Qpeak
Node ID Type Event ac-ft Trun hrs cfs
--------
---------------
PRE-DEV AREA -- ----
AREA ------
10 ----------
13.314 -- --------
12.4000 -
117.62
PRE-DEV AREA AREA 100 30.634 12.3500 256.79
PRE-DEV AREA AREA 1 3.149 12.3000 15.61
UNTREATED AREA 10 3.718 12.4000 30.86
UNTREATED AREA 100 9.056 12.4000 74.44
UNTREATED AREA 1 .747 12.3500 2.55
WN:
Bentley PondPack (10.00.027.010) 2:28 I'M
Max
Max WSEL Pond Storage
ft ac-ft
-------- ------------
Bentley Systems, Inc.
12/21/2010
Type.... Design Storms
Name.... RDU NOAA 14 Desi
Page 2.01
File.... K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\Alston Pond BMPs.ppw
Title... Project Date: 12/3/2010
Project Engineer: asmith
Project Title: Alston Pond
Project Comments:
DESIGN STORMS SUMMARY
Design Storm File,ID = RDU NOAA 14 Desi
Storm Tag Name = 10
Data Type, File, ID = Time-Depth Curve RDU NOAA 10yr
Storm Frequency = 10 yr
Total Rainfall Depth= 4.9800 in
Duration Multiplier = 1
Resulting Duration = 23.9904 hrs
Resulting Start Time= .0000 hrs Step= .0833 hrs End= 23.9904 hrs
Storm Tag Name = 100
Data Type, File, ID = Time-Depth Curve RDU NOAA 100yr
Storm Frequency = 100 yr
Total Rainfall Depth= 7.3700 in
Duration Multiplier = 1
Resulting Duration = 23.9990 hrs
Resulting Start Time= .0000 hrs Step= .0833 hrs End= 23.9990 hrs
Storm Tag Name = 1
Data Type, File, ID = Synthetic Storm TypeII 24hr
Storm Frequency = 1 yr
Total Rainfall Depth= 3.0000 in
Duration Multiplier = 1
Resulting Duration = 24.0000 hrs
Resulting Start Time= .0000 hrs Step= .1000 hrs End= 24.0000 hrs
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Type.... Design Storms Page 2.02
Name.... RDU NOAA 14 Desi Event: 10 yr
File.... K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\Alston Pond BMPs.ppw
Storm... RDU NOAA 10yr Tag: 10
DESIGN STORMS SUMMARY
Design Storm File,ID = RDU NOAA 14 Desi
Storm Tag Name = 10
Data Type, File, ID = Time-Depth Curve RDU NOAA 10yr
Storm Frequency = 10 yr
Total Rainfall Depth= 4.9800 in
Duration Multiplier = 1
Resulting Duration = 23.9904 hrs
Resulting Start Time= .0000 hrs Step= .0833 hrs End= 23.9904 hrs
Storm Tag Name = 100
Data Type, File, ID = Time-Depth Curve RDU NOAA 100yr
Storm Frequency = 100 yr
Total Rainfall Depth= 7.3700 in
Duration Multiplier = 1
Resulting Duration = 23.9990 hrs
Resulting Start Time= .0000 hrs Step= .0833 hrs End= 23.9990 hrs
Storm Tag Name = 1
Data Type, File, ID = Synthetic Storm TypeII 24hr
Storm Frequency = 1 yr
Total Rainfall Depth= 3.0000 in
Duration Multiplier = 1
Resulting Duration = 24.0000 hrs
Resulting Start Time= .0000 hrs Step= .1000 hrs End= 24.0000 hrs
SIN:
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Type.... Tc Calcs
Name.... DA 1
Page 3.01
File.... K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\Alston Pond BMPs.ppw
........................................................................
........................................................................
TIME OF CONCENTRATION CALCULATOR
........................................................................
........................................................................
Segment #1: Tc: User Defined
Segment #1 Time: .0812 hrs
------------------------------------------------------------------------
Segment #2: Tc: TR-55 Sheet
Mannings n .2000
Hydraulic Length 50.00 ft
2yr, 24hr P 3.4400 in
Slope. .025000 ft/ft
Avg.Velocity .13 ft/sec
Segment #2 Time: .1041 hrs
-----------_--------------------------------------------_-----------------_
Total Tc: .1853 hrs
SIN: Bentley Systems, Inc.
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Type.... Tc Calcs
Name.... DA 1
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File.... K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\Alston Pond BMPs.ppw
------------------------------------------------------------------------
Tc Equations used...
-------------------------------------------------------------------------
-_== User Defined
Tc = Value entered by user
Where: Tc = Time of concentration
_=== SCS TR-55 Sheet Flow _______________
Tc = (.007 * ((n * Lf)**0.8)) / ((P**.5) * (Sf**.4))
Where: Tc = Time of concentration, hrs
n = Mannings n
Lf = Flow length, ft
P = 2yr, 24hr Rain depth, inches
Sf = Slope, %
SIN: Bentley Systems, Inc.
Bentley Fond Pack (10.00.027.00) 2:23 PM 12/21/2010
Tv;:ye .... Tc Ca 1 cs
tvanie.... DA 2
Page 3.03
F'ile.... K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\Alston Pond BMPs.ppw
TIME OF CONCENTRATION CALCULATOR
........................................................................
Segment #1: Tc: TR-55 Sheet
Mannings n
Hydraulic Length
2yr, 24hr P
Slope
Avg.Velocity
.2000
50.00 ft
3.4400 in
025000 ft/ft
13 ft/sec
Segment #1 Time: .1041 hrs
------------------------------------------------------------------------
Segment #2: Tc: TR-55 Channel
Flow Area
Wetted Perimeter
Hydraulic Radius
Slope
Mannings n
Hydraulic Length
1.2300 sq.ft
3.93 ft
.31 ft
.039000 ft/ft
.0130
2073.00 ft
Avg.Velocity 10.43 ft/sec
Segment #2 Time: .0552 hrs
------------------------------------------------------------------------
Total. Tc: .1593 hrs
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Type.... Tc Calcs
Name.... DA 2
Page 3.04
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------------------------------------------------------------------------
Tc Equations used...
------------------------------------------------------------------------
==== SCS TR-55 Sheet Flow ___ __
Tc = (.007 * ((n * Lf)**0.8)) / ((P**.5) * (Sf**.4))
Where: Tc = Time of concentration, hrs
n = Mannings n
Lf = Flow length, ft
P = 2yr, 24hr Rain depth, inches
Sf = Slope, o
==_= SCS Channel Flow
R = Aq / Wp
V = (1.49 * (R**(2/3)) * (Sf**-0.5)) / n
Tc = (Lf / V) / (3600sec/hr)
Where: R
Aq
Wp
V
Sf
n
Tc
Lf
Hydraulic radius
Flow area, sq.ft.
Wetted perimeter, ft
Velocity, ft/sec
Slope, ft/ft
Mannings n
Time of concentration, hrs
Flow length, ft
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Type.... Tc Calcs
Name.... DA 3
Page _x.05
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........................................................................
........................................................................
TIME OF CONCENTRATION CALCULATOR
........................................................................
........................................................................
------------------------------------------------------------------------
Segment #1: Tc: User Defined
Segment #1 Time: .0833 hrs
------------------------------------------------------------------------
Total Tc: .0833 hrs
Calculated TC < Min.Tc:
Use Minimum Tc...
Use Tc = .0833 hrs
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Type.... Tc Calcs
Name.... DA 3
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---------------------------------------------- -------------------------
Tc Equations used...
----------- -------------------------------------------------------------
User Defined ====-
Tc = Value entered by user
Where: Tc = Time of concentration
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Type.... Tc Calcs
Name.... DA 4
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File.... K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\Alston Pond BMPs.ppw
...................................
TIME OF CONCENTRATION CALCULATOR
Segment #1: Tc: User Defined
Segment #1 Time: .0833 hrs
------------------------------------------------------------------------
Total Tc: .0833 hrs
Calculated Tc < Min.Tc:
Use Minimum Tc...
Use Tc = .0833 hrs
S/N: Bentley Systems, Inc.
Bentley PondPack (10.00.027.00) 2:28 PM 12/21/2010
Type.... Tc Calcs
Name.... DA 4
Page 3.08
File.... K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\Alston Pond BMPs.ppw
-------------------------------------------------------------------------
Tc Equations used...
------------------------------------------------------------------------
User Defined ================-=----___---°--
Tc = Value entered by user
Where: Tc = Time of concentration
S/N:
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2:28 PM
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12/21/2010
Type.... Tc Calcs
Name.... PRE-?EV AREA
Page 3.09
File.... K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\Alston Pond BMPs.ppw
TIME OF CONCENTRATION CALCULATOR
Segment #1: Tc: Kirpich (TN)
Hydraulic Length 5597.00 ft
Slope .019700 ft/ft
Multiplier 1.000 (Tc Adjustment)
Avg.Velocity 3.43 ft/sec
Segment #1 Time: .4534 hrs
------------------------------------------------------------------------
Total Tc: .4534 hrs
-----------
S /N:
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2.28 1+1
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12/21./20LO

Page .3. 10
File.... K:110\10-0340\100343-Pre.st=ori - Alston Pond1H-H\Pondpak\A1ston Pond BMPs.ppw
------------------------------------------------------------------------
Tc Equations used...
------------------------------------------------------------------------
==== Kirpich (TN)
Tc = 0.00013 * (Lf**0.77) * (Sf**-0.385) * Mt
Where: Tc = Time of concentration, hrs
Lf = Flow length, ft
Sf = Slope, ft/ft
Mt = Tc Multiplier (Tc adjustment)
SIN: Bentley Systems, Inc.
:Beni ;ey Pond Pack 110.00.027.00) 2:28 PM 1712:1.12010
Type.... Tc Calcs
Name.... UNTREATED
Pane 3.11
file,... Ii:\10\10-0390\100349-Preston - Alston Pond\H-H\Pondpak\Alston Fond BMPs.ppw
........................................................................
........................................................................
TIME OF CONCENTRATION CALCULATOR
........................................................................
........................................................................
Segment #1: Tc: Kirpich (TN)
Hydraulic Length 5597.00 ft
Slope .019700 ft/ft
Multiplier 1.Q00 (Tc Adjustment)
Avg.Velocity 3.43 ft/sec
Segment #1 Time: .4534 hrs
------------------------------------------------------------------------
Total Tc: .4534 hrs
SIN: Bentley Sy;sterns, Inc:.
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Name.... UNTREATED
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------------------------------------------------------------------------
Tc Equations used...
------------------------------------------------------------------------
Kirpich (TN) _____----- __________________
Tc = 0.00013 * (Lf**0.77) * (Sf**-0.385) * Mt
Where: Tc = Time of concentration, hrs
Lf = Flow length, ft
Sf = Slope, ft/ft
Mt = Tc Multiplier (Tc adjustment)
SIN:
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Type.... Runoff CN-Area
Name.... DA 1
Page 4.01
File.... K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\Alston Pond BMPs.ppw
RUNOFF CURVE NUMBER DATA
..........................................................................
..........................................................................
Impervious
Area Adjustment Adjusted
Soil/Surface Description CN acres oC oUC CN
-------------------------------- ---- --------- ----- ----- ------
Impervious Areas - Paved parking to 98 15.620 98.00
Open space (Lawns,parks etc.) - Goo 61 16.880 61.00
COMPOSITE AREA & WEIGHTED CN ---> 32.500 78.78 (79)
...........................................................................
...........................................................................
S/N: Bentley Systems, Inc.
Bentley PondPack (10.00.027.00) 2:28 PM 12/21/2010
Type.... Runoff CN-Area
Name.... DA 2
Page 4.02
File.... K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\Alston Pond BMPs.ppw
RUNOFF CURVE NUMBER DATA
..........................................................................
..........................................................................
Impervious
Area Adjustment Adjusted
Soil/Surface Description CN acres %C %UC CN
-------------------------------- ---- --------- ------
Impervious 98 18.750 98.00
Open Space 61 17.750 61.00
COMPOSITE AREA & WEIGHTED CN ---> 36.500 80.01 (80)
...........................................................................
...........................................................................
SIN: Bentley Systems, Inc.
Bentley PondPack (10.00.027.00) 7:28 PM 12/21/2010
Type.... Runoff CN-Area
Name.... DA 3
Sage 4 .03
File.... K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\Alston Pond BMPs.ppw
RUNOFF CURVE NUMBER DATA
..........................................................................
..........................................................................
Impervious
Area Adjustment Adjusted
Soil/Surface Description CN acres %C %UC CN
-------------------------------- ---- --------- ----- ----- ------
Impervious 98 6.240 98.00
Open Space 61 9.760 61.00
COMPOSITE AREA & WEIGHTED CN ---> 16.000 75.43 (75)
...........................................................................
...........................................................................
SIN:
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Type.... Runoff CN-Area
Name.... DA 4
Page 4.04
File.... K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\Alston Pond BMPs.ppw
RUNOFF CURVE NUMBER DATA
..........................................................................
..........................................................................
Impervious
Area Adjustment Adjusted
Soil/Surface Description CN acres %C %UC CN
-------------------------------- ---- --------- ----- -----
Impervious 98 3.600 98.00
Open Space 61 3.000 61.00
COMPOSITE AREA & WEIGHTED CN ---> 6.600 81.18 (81)
...........................................................................
...........................................................................
SIN: Bentley Systems, Inc.
Bentley PondPack (10.00.027.00) 2:28 PM 12/21/2010
Type.... Runoff CN-Area
Name.... PRE-DEV AREA
Page 4.05
File.... K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\Alston Pond BMPs.ppw
RUNOFF CURVE NUMBER DATA
..........................................................................
..........................................................................
Impervious
Area Adjustment Adjusted
Soil/Surface Description CN acres oC oUC CN
-------------------------------- ---- --------- ----- ----- ------
Woods - grass combination - good 58 138.000 58.00
COMPOSITE AREA & WEIGHTED CN -- 138.000 58.00 (58)
SIN:
Bentley PondPack (10.00.027.00)
2:28 PM
Bentley Systems, Inc.
12/21/2010
Type.... Runoff CN-Area
Name.... UNTREATED
Pack 4.06
File.... K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\Alston Pond BMPs.ppw
RUNOFF CURVE NUMBER DATA
..........................................................................
..........................................................................
Impervious
Area Adjustment Adjusted
Soil/Surface Description CN acres %C %UC CN
----------------------- ---------- ---- --------- ------
Woods - goon 55 46.000 55.00
COMPOSITE AREA & WEIGHTED CN ---> 46.000 55.00 (55)
...........................................................................
...........................................................................
SIN: Bentley Systems, Inc.
Bentley PondPack (10.00.027.00) 2:28 PM 1212112010
Type.... Vol: Elev-Area
Name.... BMP 1
Page 5.01
File.... K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\Alston Pond BMPs.ppw
Elevation Planimeter Area Al+A2+sgr(Al*A2) Volume Volume Sum
(ft) (sq.in) (sq.ft) (sq.ft) (ac-ft)
---- (ac-ft)
-------------
------------
342.00 ---------------------
--°-- 34307 ----------------
0 -------
.000 .000
343.00 °---- 42222 114588 .677 .87'7
344.QO ----- 45931 132264 1.012 1..'989
345.00 ----- 49805 143641 1.099 2.988
346.00 ----- 53691 155208 1.188 4.176
347.00 ----- 57637 166957 1.278 5.453
POND VOLUME EQUATIONS
* Incremental volume computed by the Conic Method for Reservoir Volumes.
Volume = (1/3) * (EL2-EL1) * (Areal + Area2 + sq.rt.(Area1*Area2))
where: EL1, EL2 = Lower and upper elevations of the increment
Areal,Area2 = Areas computed for EL1, EL2, respectively
Volume = Incremental volume between EL1 and EL2
SIN:
Bentley PondPack (10.00.027.00)
2:28 PM
Bentley Systems, Inc.
12/21/2010
T''ypi.... Vol: Flev-area
Namr.... BMP 2
Page 5.02
File.... K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\Alston Pond BMPs.ppw
Elevation Planimeter Area Al+A2+sgr(A1*A2) Volume Volume Sum
(ft) (sq.in) (sq.ft) (sq.ft) (ac-ft)
-
----- (ac-ft)
-------------
------------
365.00 ---------------------
----- 28282 ----------------
0 ---
-
.000 .000
366.00 ----- 35498 95465 .731 .731.
367.00 °- - 38109 11.0387 .845 1.575
368.00 ----- 40561 117986 .903 2.478
369.00 ----- 42917 125200 .958 3.436
370.00 ----- 45270 132265 1.012 4.448
371.00 ----- 47736 139493 1.067 5.516
372.00 ----- 49967 146542 1.121 6.637
POND VOLUME EQUATIONS
* Incremental volume computed by the Conic Method for Reservoir Volumes.
Volume = (1/3) * (EL2-EL1) * (Areal + Area2 + sq.rt.(Area1*Area2))
where: EL1, EL2 - Lower and upper elevations of the increment
Areal,Area2 = Areas computed for EL1, EL2, respectively
Volume = Incremental volume between EL1 and EL2
S/N: Bentley :`ystems, inc.
Bentley PondPack (10.00.027.00) 2:28 PM 1212112010
Type.... Vol: Elev-Area
Name.... BMP 3
Page 5.03
File.... K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\Alston Pond BMPs.ppw
Elevation Planimeter Area Al+A2+sgr(Al*A2) Volume Volume Sum
(ft) (sq.in) (sq.ft) (sq.ft) (ac-ft)
-
--- (ac-ft)
-------------
------------
38]..00 ---------------------
----- 12414 ----------------
0 -----
-
.000 .000
382.00 ----- 16187 42777 .327 .327
383.00 ----- 17614 50686 .388 .715
384.00 ----- 18753 54542 .417 1.133
385.00 ----- 1991.9 57999 .444 1.576
386.00 ----- 20043 59943 .459 2.035
POND VOLUME EQUATIONS
* Incremental volume computed by the Conic Method for Reservoir Volumes.
Volume = (1/3) * (EL2-EL1) * (Areal + Areal + sq.rt.(Area1*Area2))
where: ELI, EL2 = Lower and upper elevations of the increment
Areal,Area2 = Areas computed for ELI, EL2, respectively
Volume = Incremental volume between ELI and EL2
SIN:
Bentley PondPack (10.00.027.00)
2:28 PM
Bentley Systems, Inc.
12/21/2010
Tyrir- Vol: Elev-Area
Name. . . . [3111I1 4
Page 5.04
File.... K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\Alston Pond BMPS.ppw
Elevation Planimeter Area Al+A2+sgr(Al*A2) Volume Volume Sum
(ft) (sq.in) (sq.ft) (sq.ft) (ac-ft)
-
-
- (ac-ft)
-------------
------------
343.00 ---------------------
----- 4897 -----------------
0 --
--
-
-
.000 .000
344.00 ----- 7179 18005 .138 .138
345.00 ----- 8334 23248 .1.78 .316
346.00 ------ 9550 26805 .205 .521
347.00 ----- 10822 30533 .234 .754
POND VOLUME EQUATIONS
* Incremental volume computed by the Conic Method for Reservoir Volumes.
Volume = (1/3) * (EL2-EL1) * (Areal + Area2 + sq.rt.(Areal*Area2))
where: EL1, EL2 = Lower and upper elevations of the increment
Areal,Area2 = Areas computed for EL1, EL2, respectively
Volume = Incremental volume between EL1 and EL2
S/N:
Bentley PondPack (10.00.027.00)
2:28 PM
Bentley Systems, Inc.
12/21/2010
Type.... Pond E-V-Q Table Page 6.01
taarne.... BMP 1
File.... K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\Alston Pond BMPs.ppw
LEVEL POOL ROUTING DATA
HYG Dir = K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\
Inflow HYG file = work_pad.hyg - BMP 1 IN 10
Outflow HYG file = work pad.hyg - BMP 1 OUT 10
Pond Node Data = BMP 1
Pond Volume Data = BMP 1
Pond Outlet Data = BMP1 Outlets
No Infiltration
INITIAL CONDITIONS
Starting WS Elev = 342.00 ft
Starting Volume = .000 ac-ft
Starting Outflow = .00 cfs
Starting Infiltr. _ .00 cfs
Starting Total Qout= .00 r_fs
Time Increment = .0500 hrs
Elevation Outflow Storage Area lnfilt. Q Total 2S/t + 0
ft cfs ac-ft sq.ft cfs
-
--- cfs
------------ cfs
----------
-------------
342.00 -----------
.00 ---------
.000 ------------
34307 ------
-
.00 .00 .00
342.10 .02 .080 35062 .00 .02 38.56
342.20 .07 .161 35824 .00 .07 77.99
342.30 .14 .244 36595 .00 .14 118.28
342.40 .20 .329 37374 .00 .20 159.44
342.50 .24 .416 38162 .00 .24 201.45
342.60 .28 .504 38958 .00 .28 244.33
342.70 .31 .595 39761 .00 .31 288.09
342.80 .33 .687 40573 .00 .33 332.74
342.90 .36 .781 41394 .00 .36 378.30
343.00 .38 .877 42222 .00 .38 424.78
343.10 .41 .974 42591 .00 .41 471.93
343.20 .43 1.072 42961 .00 .43 519.48
343.30 .4• 1.171 43333 .00 .45 567.43
343.40 1? 1.271 43706 .00 .47 615.81
343.50 .48 1.372 44081 .00 .48 664.60
343.60 .5O 1.474 44458 .00 .50 713.81
343.70 J2 1.576 44837 .00 .52 763.43
343.80 .54 1.680 45216 .00 .54 813.47
343.90 4.64 1.784 45598 .00 4.64 868.03
SIN:
Bentley PondPack (10.00.027.00)
2:2F3 PM
Bentley Systems, Inc.
12/21/2010
Type
ta,3 rn?:... .
Pond E-V-Q Table
BMP 1
Page 6.02
K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\Alston Pond BMPs.ppw
LEVEL POOL ROUTING DATA
HYG Dir = K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\
Inflow HYG file = work pad.hyg - BMP 1 IN 10
Outflow HYG file = work pad.hyg - BMP 1 OUT 10
Pond Node Data = BMP I
Pond Volume Data = BMP 1
Pond Outlet Data = BMP1 Outlets
No Infiltration
INITIAL CONDITIONS
--------
Starting -------------
WS Elev = --------
342.00 ----
ft -
Starting Volume = .000 ac- ft
Starting Outflow = .00 cfs
Starting Infiltr. _ .00 cfs
Starting Total Qout= .00 cfs
Time Increment = .0500 hrs
Elevation Outflow Storaqe Area Infiit. Q Total 2S/t + 0
ft cfs ar:-ft sq. ft cfs cfs
-
- cfs
----------
----- ------
344.00 -------------
8.73 --------
1.889 ---- --------
45981 -----------
.00 ---------
-
8.73 923.00
344.10 12.84 1.995 46357 .00 12.84 978.41
344.20 1.6.94 2.1.02 46734 .00 16.94 1034.23
344.30 21.01 2.210 47112 .00 21.01 1090.43
344.40 22.94 2.318 47492 .00 22.94 1144.92
344.50 29.76 2.428 47874 .00 24.76 1199.72
344.60 26.42 2.538 48257 .00 26.42 1254.79
344.70 27.98 2.649 48642 .00 27.98 1310.19
344.80 29.50 2.761 49028 .00 29.50 1365.96
344.90 30.88 2.874 49416 .00 30.88 1422.02
345.00 32.23 2.988 49805 .00 32.23 1478.50
345.10 33.55 3.103 50187 .00 33.55 1535.38
345.20 34.80 3.219 50571 .00 34.80 1592.61
345.30 38.26 3.335 50955 .00 38.26 1652.45
345.40 43.54 3.453 51342 .00 43.54 171.4.57
345.50 50.03 3.571 51730 .00 50.03 1778.32
345.60 57.55 3.690 52119 .00 57.55 1843.54
345.70 63.88 3.810 52510 .00 63,88 1908.01
345.80 70.52 3.931 52902 .00 70.52 1973.20
345.90 `17.66 4.053 53296 .00 77.66 2039.34
SIN:
Bentley PondPack (10.00.027.00)
2:28 PH
Bentley Systems, Inc.
12/21/2010
Type.... Pond E-V-Q Table Page 6.03
Name.... BMP 1
File.... K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\Alston Pond BMPs.ppw
LEVEL POOL ROUTING DATA
HYG Dir = K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\
Inflow HYG file = work pad.hyg - BMP 1 IN 10
Outflow HYG file = work-pad.hyg - BMP 1 OUT 10
Pond Node Data = BMP 1
Pond Volume Data = BMP 1
Pond Outlet Data = BMPI Olztlets
No Infiltration
INITIAL CONDITIONS
Starting W6 Elev = 342.00 ft
Starting Volume = .000 ac-ft
Starting Outflow = .00 cfs
Starting Infiltr. _ .00 cfs
Starting Total Qout= .00 cfs
Time Increment = .0500 hrs
Elevation Outflow Storage Area Infilt. Q Total 2S/t t 0
ft cfs ac-ft sq.ft cfs cfs cfs
--
-------------
346.00 -----------
85.38 ---------
4.176 ------------
53691 -----------
.00 ------------
85.38 --------
2106.49
346.10 93.39 4.300 54079 .00 93.39 2174.38
346.20 101.64 4.424 54469 .00 101.64 2242.94
346.30 110.18 4.550 54860 .00 110.18 2312.20
346.40 118.85 4.676 55253 .00 118.85 2382.05
346.50 127.47 4.803 55647 .00 127.47 2452.28
346.60 135.82 4.932 56042 .00 135.82 2522.69
346.70 143.03 5.061 56439 .00 143.03 2592.39
346.80 148.09 5.191 56837 .00 148.09 2660.36
346.90 150.44 5.322 57236 .00 150.44 2726.09
347.00 152.54 5.453 5763) .00 152.54 2']92.02
5/N:
Bentley €1ond€'ack (10.00.027.00)
2:28 PM
Bentley Systems, Inc.
12/21/2010
Type.....
Name...
File....
Pond E-V-Q Table
BMP 2
Page 6.04
K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\Alston Pond BMPs.ppw
LEVEL POOL ROUTING DATA
HYG Dir = K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\
Inflow HYG file = work __pad.hyg - BMP 2 IN 10
Outflow HYG file = work pad.hyg - BMP 2 OUT 10
Pond Node Data = BMP 2
Pond Volume Data = BMP 2
Pond Outlet Data = BMP2 Outlets
No Infiltration
INITIAL CONDITIONS
Starting WS Elev = 365.00 It
Starting Volume = .000 ac-ft
Starting Outflow = .00 cfs
Starting Infiltr. _ .00 cfs
Starting Total Qout= .Ora cfs
Time Increment = .0500 hrs
Elevation Outflow Storage Area Infilt. Q Total 25/t + 0
ft cfs ac-ft sq.ft CIS cfs
--------- CIS
----------
------------
365.00 ------------
.00 ---------
.000 ------------
28282 -----------
.00 ---
.00 .00
365.10 .02 .066 28967 .00 .02 31.83
365.20 .07 .133 29660 .00 .07 64.45
365.30 .14 .202 30361 .00 .14 97.85
365.40 .20 .272 31070 .00 .20 132.05
365.50 .24 .345 31788 .00 .24 167.01
365.60 .28 .418 32513 .00 .28 202.77
365.70 .30 .494 33247 .00 .30 239.33
365.80 .33 .571 33989 .00 .33 276.70
365.90 .36 .650 34740 .00 .36 314.91
365.00 .38 .731 35498 .00 .38 353.96
366.10 .41 .812 35755 .00 .41 393.57
366.20 .43 .895 36013 .00 .43 433.46
366.30 .45 .978 36272 .00 .45 473.63
366.40 .46 1.061 36531 .00 .46 514.10
366.50 .49 1.145 36792 .00 .49 554.86
366.60 .50 1.230 37054 .00 .50 595.90
366.70 .52 1.316 37316 .00 .52 637.24
366.80 .53 1.401 37579 .00 .53 678.85
366.90 .55 1.488 37844 .00 .55 720.77
S/N:
Bentley Pond Pack (10.00.02-1.00)
2:25 PM
Bentley Systems, Inc.
12/21/2010
Type.... Pond E-V-Q Table
Name.... BMP 2
Page 6.05
File.... K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\Alston Pond BMPs.ppw
LEVEL POOL ROUTING DATA
HYG Dir = K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\
Inflow HYG file = work pad.hyg - BMP 2 IN 10
Outflow HYG file = work pad.hyg - BMP 2 OUT 10
Pond Node Data = BMP 2
Pond Volume Data = BMP 2
Pond Outlet Data = BMP2 Outlets
No Infiltration
INITIAL CONDITIONS
Starting WS Elev = 365.00 ft
Starting Volume = .000 ac-ft
Starting Outflow = .00 cfs
Starting Infiltr. _ .00 cfs
Starting Total Qout= .00 cfs
Time Increment = .0500 hrs
Elevation Outflow Storage Area Infilt. Q Total 2S/t + O
ft cfs ac-ft sq.ft cfs
---------- cfs
------------ cfs
----------
------------
367.00 ------------
.57 ----------
1.575 -----------
38109 -
.00 .57 762.99
367.10 .58 1.663 38351 .00 .58 805.48
367.20 .60 1.751 38593 .00 .60 848.25
367.30 .61 1.840 38837 .00 .61 891.26
367.40 .63 1.930 39081 .00 .63 934.57
367.50 2.00 2.020 39325 .00 2.00 979.51
357.60 3.37 2.110 39571 .00 3.37 1024.71
367,70 4.75 2.201 39817 .00 4.75 1070.19
367.80 5.12 2.293 40064 .00 6.12 1115.94
367.90 7.51 2.385 40312 .00 7.51 1161.98
368.00 8.17 2.478 40561 .00 8.17 1207.57
368.10 8.77 2.571 40794 .00 8.77 1253.37
368.20 9.34 2.665 41027 .00 9.34 1299.40
368.30 9.88 2.760 41261 .00 9.88 1345.64
368.40 10.37 2.855 41495 .00 10.37 1392.12
358.50 10.86 2.950 41731 .00 10.86 1438.84
368.60 11.32 3.046 41967 .00 11.32 1485.81
368.70 11.77 3.143 42203 .00 11.77 1533.02
368.80 12.20 3.240 42440 .00 12.20 1580.46
368.90 12.60 3.338 42678 .00 12.60 1628.16
S/N:
Bentley PondPack (10.00.027.00) 1:28 PM
Bentley Systems, Inc.
12/21/2010
Type .... Pond E-V-Q Table
Name. ... BMP 2
Page 6.06
'il.e.... K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\Alston Pond BMPs.ppw
LEVEL POOL ROUTING DATA
HYG Dir - K:\10\10-0340\100349-Pre3ton - Alston Pond\H-H\Pondpak\
Inflow HYG file = work-.Pad.hyg - BMP 2 IN 10
Outflow HYG file = work pad.hyg - BMP 2 OUT 10
Pond Node Data = BMP 2
Pond Volume Data = BMP 2
Pond Outlet Data - BMP2 Outlets
No Infiltration
INITIAL CONDITIONS
Starting WS Elev = 365.00 ft
Starting Volume = .000 ac-ft
Starting Outflow = .00 cfs
Starting Infiltr. _ .00 cfs
Starting Total Qout= .00 cfs
Time Increment = .0500 hrs
Elevation Outflow Storage Area Infilt. Q Total 2S/t + 0
ft cfs ac-ft sq.ft cfs cfs
-
--------- cfs
----------
-------------
369.00 -----------
13.00 ---------
3.436 ------------
42917 -----------
.00 -
-
13.00 1676.11
369.10 13.39 3.535 43149 .00 13.39 1724.31
369.20 13.76 3.634 43383 .00 13.76 1772.77
369.30 14.11 3.734 43616 .00 14.11 1821.43
369.40 14.47 3.835 43851 .00 14.47 1870.39
369.50 14.82 3.935 44086 .00 14.82 1919.59
369.60 15.15 4.037 44321 .00 15.15 1969.04
369.70 15.50 4.139 44558 .00 15.50 2018.77
369.80 15.81 4.242 44794 .00 15.81 2068.71
369.90 16.14 4.345 45032 .00 16.14 2118.94
370.00 16.45 4.448 45270 .00 16.45 2169.42
370.10 19.02 4.553 45514 .00 19.02 2222.44
370.20 23.49 4.657 45758 .00 23.49 2277.62
370.30 29.17 4.763 46003 .00 29.17 2334.26
370.40 35.84 4.868 46249 .00 35.84 2392.18
370.50 43.37 4.975 46495 .00 43.37 2451.25
370.60 51.64 5.082 46742 .00 51.64 2511.31
370.70 60.64 5.190 46989 .00 60.64 2572.39
370.80 70.26 5.298 47238 .00 70.26 2634.35
370.90 80.49 5.406 47486 .00 80.49 2697.20
S/N:
Bentley PondPack (10.00.027.00)
2:28 PM
Bentley Systems, Inc.
12/21/2010
"P +]3?7i .... Pond E-V-Q Table
Cs?iiti+n .... BMP 2
Page 6.07
rile.... K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\Alston Pond BMPs.ppw
LEVEL POOL ROUTING DATA
HYG Dir = K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\
Inflow HYG file = work pad.hyg - BMP 2 IN 10
Outflow HYG file = work-pad.hyg - BMP 2 OUT 10
Pond Node Data = BMP 2
Pond Volume Data = BMP 2
Pond Outlet Data = BMP2 Outlets
No Infiltration
INITIAL CONDITIONS
---------
Starting ------------
WS Elev = ---------
365.00 ----
ft
Starting Volume = .000 ac-ft
Starting Outflow = .00 cfs
Starting Infiltr. _ .00 cfs
Starting Total Qout= .00 cfs
Time Increment = .0500 hrs
Elevation Outflow Storage Area Infilt. Q Total 2S/t + 0
ft cfs ac-ft sq.ft cfs
- cfs
------------ cfs
----------
--------------
371.00 ------------
91.27 ---------
5.516 -----------
47736 --
--------
.00 91.27 2760.88
371.10 102.54 5.626 47957 .00 102.54 2825.33
371.20 114.28 5.736 48178 .00 114.28 2890.47
371.30 124.85 5.847 48400 .00 124.85 2954.69
371.40 134.46 5.958 48622 .00 134.46 3018.20
371.50 143.66 6.070 48845 .00 143.66 3081.55
371.60 151.75 6.182 49069 .00 151.75 3144.04
371.70 155.28 6.295 49292 .00 155.28 3202.22
371.80 156.02 6.409 49517 .00 156.02 3257.84
371.90 156.76 6.523 49742 .00 156.76 3313.73
372.00 157.50 6.637 49967 .00 157.50 3369.86
S/N:
Bentley PondPack (10.00.027.00)
2:28 PM
Bentley Systems, Inc.
12/21/2010
Type.... Pond E-V-Q Table Page 6.08
Name.... BMP 3
File-.... K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\Alston Pond BMPs.ppw
LEVEL POOL ROUTING DATA
HYG Dir = K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\
Inflow HYG file = work_pad.hyg - BMP 3 IN 10
Outflow HYG file = work pad.hyg - BMP 3 OUT 10
Pond Node Data = BMP 3
Pond Volume Data = BMP 3
Pond Outlet Data = BMP3 Outlets
No Infiltration
INITIAL CONDITIONS
Starting WS Elev = 381.00 ft
Starting Volume = _000 ac-ft
Starting Outflow = .00 cfs
Starting Infiltr. _ .00 cfs
Starting Total Qout= .00 cfs
Time Increment = .0500 hrs
Elevation Outflow Storage Area Infilt. Q Total
ft cfs ac-ft sq.ft cfs cfs
-
----_--------
381.00 ------------
.00 --------
.000 ------------
12414 -----------
.00 ----
-----
.00
381.10 .01 .029 12769 .00 .01
381.20 .04 .059 13129 .00 .04
381.30 .05 .089 13493 .00 .05
381.40 .06 .121 13863 .00 .06
381.50 .07 .153 14238 .00 .07
381.60 .08 .186 14618 .00 .08
381.70 .08 .220 15003 .00 .08
381.80 .09 .255 15392 .00 .09
381.90 .09 .291 15787 .00 .09
382.00 .10 .327 16167 .00 .10
382.10 .11 .365 16327 .00 .11
382.20 .11 .402 16468 .00 .11
382.30 .12 .440 16609 .00 .12
382.40 .12 .479 16751 .00 .12
382.50 .12 .517 16893 .00 .12
382.60 .13 .556 17036 .00 .13
382.70 .13 .595 17180 .00 .13
382.80 .14 .635 17324 .00 .14
382.90 1.35 .675 17469 .00 1.35
2S/t + 0
cfs
.00
14.00
28.41
43.21
58.42
74.04
90.08
106.55
123.43
140.76
158.53
176.60
194.83
213.20
231.74
250.44
269.29
288.31
307.48
328.01
SIN: Bentley Systems, Inc.
Bentley PondPack (10.00.027.00) 2:28 PM 12/21/2010
Type .... Pond E-V-Q Table
Name .... BMP 3
Page 6.09
File.... K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\Alston Pond BMPs.ppw
LEVEL POOL ROUTING DATA
HYG Dir = K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\
Inflow HYG file = work_pad.hyg - BMP 3 IN 10
Outflow HYG file = work pad.hyg - BMP 3 OUT 10
Pond Node Data = BMP 3
Pond Volume Data = BMP 3
Pond Outlet Data = BMP3 Outlets
No Infiltration
INITIAL CONDITIONS
Starting WS Elev = 381.00 ft
Starting Volume = .000 ac- ft
Starting Outflow = .00 cfs
Starting Infiltr. _ .00 cfs
Starting Total Qout= .00 cfs
Time Increment = .0500 hrs
Elevation Outflow Storage Area Infilt. Q Total 2S/t + 0
ft cfs ac-ft sq.ft cfs
-- cfs
------------ cfs
----------
------------
383.00 -------------
2.55 --------
.715 ---- --------
17614 ---------
.00 2.55 348.71
383.10 3.76 .756 17726 .00 3.76 369.56
383.20 4.97 .797 17839 .00 4.97 390.52
383.30 6.17 .838 17952 .00 6.17 411.60
383.40 7.38 .879 18065 .00 7.38 432.82
383.50 8.58 .921 18179 _00 8.58 454.16
383.60 9.79 .962 18293 .00 9.79 475.64
383.70 10.99 1.005 18408 .00 10.99 497.22
383.80 12.21 1.047 18522 .00 12.21 518.96
383.90 15.93 1.090 18637 .00 15.93 543.32
384.00 22.21 1.133 18753 .00 22.21 570.38
384.10 30.17 1.176 18868 .00 30.17 599.24
384.20 39.48 1.219 18983 .00 39.48 629.57
384.25 44.56 1.241 19041 .00 44.56 645.22
384.30 50.66 1.263 19099 .00 50.66 661.90
384.40 65.24 1.307 19215 .00 65.24 697.78
384.50 82.12 1.351 19332 .00 82.12 736.08
384.60 100.86 1.396 19448 .00 100.86 776.35
384.70 121.24 1.440 19566 .00 121.24 818.41
384.80 143.13 1.485 19683 .00 143.13 862.10
SIN:
Bentley PondPack (10.00.027.00)
Bentley Systems, Inc.
2:28 PM
12/21/2010
Type.... Pond E-V-Q Table Page 6.10
Name.... BMP 3
Fa.le.... K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\Alston Pond BMPs.ppw
LEVEL POOL ROUTING DATA
HYG Dir = K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\
Inflow HYG file = work_pad.hyg - BMP 3 IN 10
Outflow HYG file = work pad.hyg - BMP 3 OUT 10
Pond Node Data = BMP 3
Pond Volume Data = BMP 3
Pond Outlet Data = BMP3 Outlets
No Infiltration
INITIAL CONDITIONS
Starting WS Elev - 381.00 ft
Starting Volume - .000 ac-ft
Starting Outflow = .00 cfs
Starting Infiltr. _ .00 cfs
Starting Total Qout= .00 cfs
Time Increment = .0500 hrs
Elevation Outflow Storage Area Infilt. Q Total 23/t- + 0
ft cfs ac-ft sq.ft efs cfs
--- cfs
----------
------------
384.90 -------------
166.44 --------
1.531 ------------
19801 -----------
.00 ---------
166.44 907.34
385.00 191.01 1.576 19919 .00 191.01 953.99
385.10 216.89 1.622 19931 .00 216.89 1002.00
385.20 243.22 1.668 19944 .00 243.22 1050.50
385.30 267.61 1.714 19956 .00 267.61 1097.04
385.40 292.12 1.760 19969 .00 292.12 1143.73
385.50 315.94 1.805 19981 .00 315.94 1189.75
385.60 337.03 1.851 19993 .00 337.03 1233.05
385.70 357.86 1.897 20006 .00 357.86 1276.10
385.80 379.23 1.943 20018 .00 379.23 1319.71
385.90 401.13 1.989 20031 .00 401.13 1363.85
386.00 423.52 2.035 20043 .00 423.52 1408.51
S/N: Bentley Systems, Inc.
Bentley PondPack (10.00.027.00) 2:28 PM 12/21/2010
Typp .. .
Name....
Film....
Pond E-V-Q Table
BMP 4
Page 6.11
K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\Alston Pond BMPs.ppw
LEVEL POOL ROUTING DATA
HYG Dir = K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\
Inflow HYG file = work_pad.hyg - BMP 4 IN 10
Outflow HYG file = work pad.hyg - BMP 4 OUT 10
Pond Node Data = BMP 4
Pond Volume Data = BMP 4
Pond Outlet Data = BMP4 Outlets
No Infiltration
INITIAL CONDITIONS
Starting WS Elev = 343.00 ft
Starting Volume = .000 ac- ft
Starting Outflow = .00 cfs
Starting Infiltr. _ .00 cfs
Starting Total Qout= .00 cfs
Time Increment = .0500 hrs
Elevation Outflow Storage Area Infilt. Q Total 2S/t + 0
ft cfs ac-ft sq.ft cfs
-
- cfs
-
---------- cfs
----------
-------------
343.00 ------------
.00 --------
.000 ---- --------
4897 --------
-
.00 -
.00 .00
343.10 .01 .011 5106 .00 .01 5.57
343.20 .04 .023 5319 .00 .04 11.38
343.30 .05 .036 5536 .00 .05 17.43
343.40 .06 .049 5758 .00 .06 23.71
343.50 .07 .062 5984 .00 .07 30.24
343.60 .07 .076 6214 .00 .07 37.02
343.70 .08 .091 6449 .00 .08 44.07
343.80 .09 .106 6688 .00 .09 51.37
343.90 .10 .122 6931 .00 .10 58.94
344.00 .10 .138 7179 .00 .10 66.79
344.10 .11 .154 7291 .00 .11 74.83
344.20 .11 .171 7403 .00 .11 83.00
344.30 .12 .188 7516 .00 .12 91.29
344.40 .12 .206 7631 .00 .12 99.71
344.50 .13 .223 7746 .00 .13 108.26
344.60 1.33 .241 7862 .00 1.33 116.14
344.70 2.54 .260 7978 .00 2.54 128.14
344.80 3.75 .278 8096 .00 3.75 138.28
344.90 4.96 .297 8215 .00 4.96 148.5E
SIN: Bentley Systems, Inc.
Bentley PondPack (10.00.027.00) 2:28 PM 12/21/2010
Type.... Pond E-V-Q Table Page 6.12
Name.... BMP 4
File.... K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\Alston Pond BMPs.ppw
LEVEL POOL ROUTING DATA
HYG Dir = K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\
Inflow HYG file = work_pad.hyg - BMP 4 IN 10
Outflow HYG file = work pad.hyg - BMP 4 OUT 10
Pond Node Data = BMP 4
Pond Volume Data = BMP 4
Pond Outlet Data = BMP4 Outlets
No Infiltration
INITIAL CONDITIONS
Starting WS Elev = 343.00 ft
Starting Volume = .000 ac- ft
Starting Outflow = .00 cfs
Starting Infiltr. _ .00 cfs
Starting Total Qout= .00 cfs
Time Increment = .0500 hrs
Elevation Outflow Storage Area Infilt. Q Total 2S/t + O
ft cfs ac-ft sq.ft cfs cfs
----------- cfs
----------
-------------
345.00 -----------
6.16 ---------
.316 ---- --------
8334 -----------
.00 -
6.16 158.95
345.10 7.37 .335 8452 .00 7.37 169.48
345.20 8.57 .354 8571 .00 8.57 180.14
345.30 9.78 .374 8690 .00 9.78 190.94
345.40 10.99 .394 8810 .00 10.99 201.87
345.50 12.20 .415 8932 .00 12.20 212.94
345.60 12.79 .435 9054 .00 12.79 223.53
345.70 13.35 .456 9177 .00 13.35 234.22
345.80 13.89 .478 9300 .00 13.89 245.02
345.90 14.41 .499 9425 .00 14.41 255.94
346.00 14.91 .521 9550 .00 14.91 266.98
346.10 16.91 .543 9674 .00 16.91 279.66
346.20 20.15 .565 9798 .00 20.15 293.71
346.30 24.18 .588 9923 .00 24.18 308.70
346.40 27.73 .611 10049 .00 27.73 323.35
346.50 30.17 .634 10176 .00 30.17 337.03
346.60 32.47 .658 10304 .00 32.47 350.70
346.70 34.44 .681 10432 .00 34.44 364.19
346.80 35.71 .705 10561 .00 35.71 377.12
346.90 36.10 .730 10691 .00 36.10 389.32
Bentley Systems, Inc.
12/21/2010
SIN:
Bentley PondPack (10.00.027.00)
2:28 PM
Type.... Pond E-V-Q Table Page 6.13
Name.... BMP 4
File.... K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\Alston Pond BMPs.ppw
LEVEL POOL ROUTING DATA
HYG Dir = K:\10\10-0340\100349-Preston - Alston Pond\H-H\Pondpak\
Inflow HYG file = work_pad.hyg - BMP 4 IN 10
Outflow HYG file = work pad.hyg - BMP 4 OUT 10
Pond Node Data = BMP 4
Pond Volume Data = BMP 4
Pond Outlet Data = BMP4 Outlets
No Infiltration
INITIAL CONDITIONS
Starting WS Elev = 343.00 ft
Starting Volume = .000 ac-ft
Starting Outflow = .00 cfs
Starting Infiltr. _ .00 cfs
Starting Total Qout= .00 cfs
Time Increment = .0500 hrs
Elevation Outflow Storage Area Infilt. Q Total 2S/t + 0
ft cfs ac-ft sq.ft cfs cfs cfs
----------------------
--------------
347.00 -----------
36.44 ---------
.754 -----------------------
10822 .00 36.44 401.61
SIN: Bentley Systems, Inc.
Bentley PondPack (10.00.027.00) 2:28 PM 12/21/2010
Appendix A
Index of Starting Page Numbers for ID Names
A-1
---- - B -----
BMP 1... 5.01, 6.01
BMP 2... 5.02, 6.04
BMP 3... 5.03, 6.08
BMP 4... 5.04, 6.11
----- D -----
DA 1... 3.01, 4.01
DA 2... 3.03, 4.02
DA 3... 3.05, 4.03
DA 4... 3.07, 4.04
----- P -----
PRE-DEV AREA... 3.09, 4.05
----- R -----
RDU NOAA 14 Desi... 2.01, 2.02
----- U -----
UNTREATED... 3.11, 4.06
----- W -----
Watershed... 1.01
SIN:
Bentley PondPack (10.00.027.00)
2:28 PM
Bentley Systems, Inc.
12/21/2010
DWQ Supplements
Permit
A7A.
NCDENR
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
WET DETENTION BASIN SUPPLEMENT
This form must be filled out, printed and submitted.
The Required Items Checklist (Part III) must be printed, filled out and submitted along with all of the required information.
(to be provided by DWQ)
t?t7 .'1A' A r?-.%Yq
P
bwGLt C!
!. PROJECT INFORMATION
Project name Alston Pond
Contact person Alwyn V. Smith III, P.E.
Phone number 919) 469-3340
Date 22-Dec-10
Drainage area number 1
Ill. DESIGN INFORMATION
Site Characteristics
Drainage area 1,415,700 ftz
Impervious area, post-development 680,407 fe
% impervious 48.06 %
Design rainfall depth 1.0 in
Storage Volume: Non-SA Waters
Minimum volume required
Volume provided
Storage Volume: SA Waters
1.5" runoff volume
Pre-development 1-yr, 24-hr runoff
Post-development 1-yr, 24-hr runoff
Minimum volume required
Volume provided
Peak Flow Calculations
Is the pre/post control of the l yr 24hr storm peak flow required?
1-yr, 24-hr rainfall depth
Rational C, pre-development
Rational C, post-development
Rainfall intensity: 1-yr, 24-hr storm
Pre-development 1-yr, 24-hr peak flow
Post-development 1-yr, 24-hr peak flow
Pre/Post 1-yr, 24-hr peak flow control
Elevations
Temporary pool elevation
Permanent pool elevation
SHWT elevation (approx. at the perm. pool elevation)
Top of 1 Oft vegetated shelf elevation
Bottom of 1 Oft vegetated shelf elevation
Sediment cleanout, top elevation (bottom of pond)
Sediment cleanout, bottom elevation
Sediment storage provided
Is there additional volume stored above the state-required temp pool?
Elevation of the top of the additional volume
56,930 ft3 OK
73,486 ff3
OK, volume provided is equal to or in excess of volume required.
ft3
ft3
ft3
ft3
ft3
y (Y or N)
3.0 in
(unitless)
(unitless)
0.13 in/hr OK
15.61 ft3/sec
11.47 ft3/sec
4.14 ft3/sec
343.80 fmsl
342.00 fmsl
fmsl
342.50 fmsl
341.50 fmsl
338.00 fmsl
337.00 fmsl
1.00 ft
n (Y or N)
fmsl
Form SW401-Wet Detention Basin-Rev 8-9/17/09 Parts I & 11 Design Summary, Page 1 of 2
Permit
(to be provided by DWQ)
It. DESIGN INFORMATION_ _
Surface Areas
Area, temporary pool 45,229 fe
Area REQUIRED, permanent pool 28,314 ff
SAIDA ratio 2.00 (unitiess)
Area PROVIDED, permanent pool, ?,,,,
,cd 34,308 le OK
_
Area, bottom of 10ft vegetated shelf, " 28,442 if
Area, sediment cleanout, top elevation (bottom of pond), 21,265 ff
Volumes
Volume, temporary pool 73,486 If OK
Volume, permanent pool,l 104,707 ft'
Volume, forebay (sum of forebays if more than one forebay) fe
Forebay % of permanent pool volume %
SAIDA Table Data
Design TSS removal
Coastal SAIDA Table Used?
Mountain/Piedmont SAIDA Table Used?
SAIDA ratio
Average depth (used in SA/DA table):
Calculation option 1 used? (See Figure 10-2b)
Volume, permanent pool,
Area provided, permanent pool, 1e,, d
Average depth calculated
Average depth used in SAIDA, (L, (Round to nearest 0.5ft)
Calculation option 2 used? (See Figure 10-2b)
Area provided, permanent pool, Pwm_,d
Area, bottom of 1 Oft vegetated shelf, kI "nor
85%
n (Y or N)
y (Y or N)
2.00 (unifless)
n (Y or N)
104,707 ft'
34.308 fe
ft
ft
y (Y or N)
34,308 It'
28.442 ft`
Area, sediment cleanout, top elevation (bottom of pond), &_Po d 21,265 fe
"Depth" (distance blw bottom of 10ft shelf and top of sediment) 3.50 ft
Average depth calculated 3,50 ft
Average depth used in SAIDA, ¢,,, (Round to nearest 0.5ft) 3.0 it
Drawdown Calculations
Drawdown through orifice?
Diameter of orifice (if circular)
Area of orifice (if-non-circular)
Coefficient of discharge (Cc)
Driving head (K)
Drawdown through weir?
Weir type
Coefficient of discharge (CN)
Length of weir (L)
Driving head (H)
Pre-development 1-yr, 24-hr peak flow
Post-development 1-yr, 24-hr peak flow
Storage volume discharge rate (through discharge orifice or weir)
Storage volume drawdown time
Additional Information
Vegetated side slopes
Vegetated shelf slope
Vegetated shelf width
Length of flowpath to width ratio
Length to width ratio
Trash rack for overflow & orifice?
Freeboard provided
Vegetated filter provided?
Recorded drainage easement provided?
Capures all runoff at ultimate build-out?
Drain mechanism for maintenance or emergencies is:
y (Y or N)
4.00 in
in'
0.60 (unitiess)
1.80 ft
n (Y or N)
0.3 (unitiess)
0.51 (unitiess)
ft
ft
15.61 fe/sec
11.47 W/sec
0.54 felsec
2.00 days
Need 3 It min.
OK
Insufficient. Check calculation.
OK, draws down in 2-5 days
3 :1 OK
10 :1 OK
10.0 ft OK
4 :1 OK
4.0 :1 OK
y (Y or N) OK
0.8 It Insufficient freeboard, minimum of 1-ft required
n (Y or N) Insufficient. Vegetated filter required.
y (Y or N) OK
y (Y or N) OK
Pump required
Form SW401-Wet Detention Basin-Rev.e-9117/09 Parts I & II. Design Summary, Page 2 of 2
Permit No.
(to be provided by DWQ)
A WA 615?
NCDEMR'
STORMWATER MANAGEMENT PERMIT APPLICATION FORM %' "ter
401 CERTIFICATION APPLICATION FORM
WET DETENTION BASIN SUPPLEMENT
This form must be filled out, printed and submitted.
The Required Items Checklist (Part III) must be printed, filled out and submitted along with all of the required information.
I. PROJECT INFORMATION
Project name Alston Pond
Contact person Alwyn V. Smith III, RE
Phone number 919) 469-3340
Date 22-Dec-10
Drainage area number 2
II, DESIGN INFORMATION
Site Characteristics
Drainage area 1,589,940 fe
Impervious area, post-development 816,750 ftz
% impervious 51.37 %
Design rainfall depth 1.0 in
Storage Volume: Non-SA Waters
Minimum volume required
Volume provided
Storage Volume: SA Waters
1.5" runoff volume
Pre-development 1-yr, 24-hr runoff
Post-development 1-yr, 24-hr runoff
Minimum volume required
Volume provided
Peak Flow Calculations
Is the pre/post control of the lyr 24hr storm peak flow required?
1-yr, 24-hr rainfall depth
Rational C, pre-development
Rational C, post-development
Rainfall intensity: 1-yr, 24-hr storm
Pre-development 1-yr, 24-hr peak flow
Post-development 1-yr, 24-hr peak flow
Pre/Post 1-yr, 24-hr peak flow control
Elevations
Temporary pool elevation
Permanent pool elevation
SHWT elevation (approx. at the perm. pool elevation)
Top of 1Oft vegetated shelf elevation
Bottom of 1 Oft vegetated shelf elevation
Sediment cleanout, top elevation (bottom of pond)
Sediment cleanout, bottom elevation
Sediment storage provided
Is there additional volume stored above the state-required temp pool?
Elevation of the top of the additional volume
67,881 ft3 OK
84,332 ft3 OK, volume provided is equal to or in excess of volume required.
ft3
ft3
ft3
ft3
ft3
y (Y or N)
3.0 in
0.30 (unitless)
0.51 (unitless)
0.13 in/hr OK
15.61 ft3/sec
11.47 ft3/sec
-4.14 ft3/sec
367.40 fmsl
365.00 fmsl
fmsl
365.50 fmsl
364.50 fmsl
360.00 fmsl
359.00 fmsl
1.00 ft
(Y or N)
fmsl
Form SW401-Wet Detention Basin-Rev B-9/17109 Parts I & 11 Design Summary, Page 1 of 2
Permit No.
(to be provided by DWQ)
I!. DESIGN INFORMATIM
Surface Areas
Area, temporary pool
Area REQUIRED, permanent pool
SAIDA ratio
Area PROVIDED, permanent pool, A?,m_,w
Area, bottom of 1 Oft vegetated shelf, Ac(_"[
Area, sediment cleanout, top elevation (bottom of pond), Qb, d
Volumes
Volume, temporary pool
Volume, permanent pool,l6,,,,_,w
Volume, forebay (sum of forebays if more than one forebay)
Forebay % of permanent pool volume
SAIDA Table Data
Design TSS removal
Coastal SA/DA Table Used?
Mountain/Piedmont SAIDA Table Used?
SA/DA ratio
Average depth (used in SAIDA table):
Calculation option 1 used? (See Figure 10-2b)
Volume, permanent pool,1E,,,,,_pw
Area provided, permanent pool, Aw,,,_pw
Average depth calculated
Average depth used in SAIDA, d,,, (Round to nearest 0.5ft)
Calculation option 2 used? (See Figure 10-2b)
Area provided, permanent pool, {e,,,,,I
Area, bottom of 1 Oft vegetated shelf, /mod,
Area, sediment cleanout, top elevation (bottom of pond), "
39,090 f?
28,142 fiz
1.77 (unilless)
28,282 W OK
23,027 If
13,943 fr
84,332 ft'
94,500 It'
ft3
85 %
n (Y or N)
y (Y or N)
1.77 (unitless)
n (Y or N)
94,500 ft'
28,282 ft'
ft
ft
y (Y or N)
28,282
23.027 ft
13,943 fe
"Depth' (distance b/w bottom of 1Oftshelf and top of sediment) 4.50 It
Average depth calculated 4.10 ft
Average depth used in SAIDA, d,,, (Round to nearest 0.5ft) 4.0 ft
Drawdown Calculations
Drawdown through orifice?
Diameter of orifice (if circular)
Area of orifice (if-non-circular)
Coefficient of discharge (C))
Driving head (K)
Drawdown through weir?
Weir type
Coefficient of discharge (CN)
Length of weir (L)
Driving head (H)
Pre-development 1-yr, 24-hr peak flow
Post-development 1-yr, 24-hr peak flow
Storage volume discharge rate (through discharge orifice or weir)
Storage volume drawdown time
Additional Information
Vegetated side slopes
Vegetated shelf slope
Vegetated shelf width
Length of flowpath to width ratio
Length to width ratio
Trash rack for overflow & orifice?
Freeboard provided
Vegetated filter provided?
Recorded drainage easement provided?
Capures all runoff at ultimate build-out?
Drain mechanism for maintenance or emergencies is:
Y (Y or N)
4.00 in
in'
0.60 (unitless)
2.40 ft
n (Y or N)
(unilless)
(unilless)
ft
ft
15.61 ft'Isec
11.47 It'isec
0.63 ft'Isec
2.00 days
3 :1
10A
10.0 fl
3 :1
3.0 :1
y - (Y or N)
OT 9
n (Y or N)
y (Y or N)
y (Y or N)
Gate valve
OK
Need 3 It min.
OK
OK
OK, draws down in 2-5 days.
OK
OK
OK
OK
OK
OK
Insufficient freeboard, minimum of 1-ft required
Insufficient, Vegetated filter required.
OK
OK
Form SW401-Wet Detention Basin-Rev.8-9/17/09 Parisi & II. Design Summary, Page 2 of 2
Permit No
ARA
14CDENR
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
WET DETENTION BASIN SUPPLEMENT
This form must be filled out, printed and submitted.
The Required Items Checklist (Part III) must be printed, filled out and submitted along with all of the required information.
(to be provided by DWQ)
!. PROJECT INFORMATION
Project name Alston Pond
Contact person Alwyn V. Smith III, P.E.
Phone number 919) 469-3340
Date 22-Dec-10
Drainage area number 3
II. DESIGN INFORMATION
Site Characteristics
Drainage area 696,960 fe
Impervious area, post-development 271,814 fe
% impervious 39.00 %
Design rainfall depth 1.0 in
Storage Volume: Non-SA Waters
Minimum volume required
Volume provided
Storage Volume: SA Waters
1.5" runoff volume
Pre-development 1-yr, 24-hr runoff
Post-development 1-yr, 24-hr runoff
Minimum volume required
Volume provided
Peak Flow Calculations
Is the pre/post control of the lyr 24hr storm peak flow required?
1-yr, 24-hr rainfall depth
Rational C, pre-development
Rational C, post-development
Rainfall intensity: 1-yr, 24-hr storm
Pre-development 1-yr, 24-hr peak flow
Post-development 1-yr, 24-hr peak flow
Pre/Post 1-yr, 24-hr peak flow control
Elevations
Temporary pool elevation
Permanent pool elevation
SHWT elevation (approx. at the perm. pool elevation)
Top of 1Oft vegetated shelf elevation
Bottom of 1Oft vegetated shelf elevation
Sediment cleanout, top elevation (bottom of pond)
Sediment cleanout, bottom elevation
Sediment storage provided
Is there additional volume stored above the state-required temp pool?
Elevation of the top of the additional volume
23,290 ft3 OK
27,791 ft3 OK, volume provided is equal to or in excess of volume required.
ft3
ft3
ft3
ft3
ft3
y (Y or N)
3.0 in
0.30 (unitless)
0.51 (unitless)
0.13 in/hr OK
15.61 ft3/sec
11.47 ft3/sec
A.14 ft3/sec
382.80 fmsl
381.00 fmsl
fmsl
381.50 fmsl
380.50 fmsl
377.00 fmsl
376.00 fmsl
1 00 ft
n (Y or N)
imsl
Form SW401-Wet Detention Basin-Rev 6-9/17/09 Parts 18 11 Design Summary, Page 1 of 2
Permit No
(to be provided by DWQ)
II. DESIGN INFORMATION
Surface Areas
Area, temporary pool 17,329 fe
Area REQUIRED, permanent pool 11,779 fe
SAIDA ratio 1.69 (unitless)
Area PROVIDED, permanent pool,, 12,414
Area, bottom of 1 Oft vegetated shelf," 9,710 ?
Area, sediment cleanout, top elevation (bottom of pond), &_,)nd 5,979 ft`
Volumes
Volume, temporary pool 27,791 fe
Volume, permanent pool, l? 33,021 fts
Volume, forebay (sum of forebays if more than one forebay) fe
Forebay % of permanent pool volume %
SAIDA Table Data
Design TSS removal 85%
Coastal SAIDA Table Used? n (Y or N)
Mountain/Piedmont SAIDA Table Used? y (Y or N)
SAIDA ratio 1.69 (unitless)
Average depth (used in SAIDA table):
Calculation option 1 used? (See Figure 10-2b) in (Y or N)
Volume, permanent pool, l(" 33.021 W
Area provided, permanent pool, P,,,,_pw 12,414 e
Average depth calculated ft
Average depth used in SAIDA, 4,,, (Round to nearest 0.5ft) it
Calculation option 2 used? (See Figure 10-2b) y (Y or N)
Area provided, permanent pool, P,,,,,_pw 12,414 ft`
Area, bottom of 10ft vegetated shelf, kI.,men 9,710 ft`
Area, sediment cleanout, top elevation (bottom of pond), kixnd 5,979 fly
"Depth" (distance b/w bottom of 1Oft shelf and top of sediment) 3.50 ft
Average depth calculated 3.30 ft
Average depth used in SAIDA, rb,,, (Round to nearest 0.5ft) 3.0 it
Drawdown Calculations
Drawdown through orifice?
Diameter of orifice (if circular)
Area of orifice (if-non-circular)
Coefficient of discharge (CD)
Driving head (K)
Drawdown through weir?
Weir type
Coefficient of discharge (C? )
Length of weir (L)
Driving head (H)
Pre-development 1-yr, 24-hr peak flow
Post-development 1-yr, 24-hr peak flow
Storage volume discharge rate (through discharge orifice or weir)
Storage volume drawdown time
Additional Information
Vegetated side slopes
Vegetated shelf slope
Vegetated shelf width
Length of flowpath to width ratio
Length to width ratio
Trash rack for overflow & orifice?
Freeboard provided
Vegetated filter provided?
Recorded drainage easement provided?
Capures all runoff at ultimate build-out?
Drain mechanism for maintenance or emergencies is:
y (Y or N)
2.00 in
in2
0.60 (unitless)
1.80 ft
in (Y or N)
(ulliiless)
(unitless)
it
it
15.61 fOlsec
11.47 fOlsec
0.14 ft3lsec
2.00 days
3 .1
10 1
10.0 It
4 :1
5.0 1
Y (Y or N)
0.5 It
n (Y or N)
y (Y or N)
y (Y or N)
gate valve
OK
OK
Need 3 It min.
OK
Insufficient. Check calculation,
OK, draws down in 2-5 days.
OK
OK
OK
OK
OK
OK
Insufficient freeboard, minimum of 1-ft required
Insufficient Vegetated filter required.
OK
OK
Form SW401-Wet Detention Basin-Rev 8.9117109 Parts I & 11 Design Summary. Page 2 of 2
Permit No.
(to be provided by DWQ)
?. f
NCDENR r
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
WET DETENTION BASIN SUPPLEMENT
This form must be filled out, printed and submitted.
The Required Items Checklist (Part III) must be printed, filled out and submitted along with all of the required information.
1, PROJECT INFORMATION
Project name Atsso i Pcno
Contact person Alwyn V. Smith III, P.E.
Phone number 919) 469-3340
Date 22-Dec-10 _
Drainage area number 4
11. DESIGN INFORMATION
Site Characteristics
Drainage area 261,360 fe
Impervious area, post-development 113,256 fe
% impervious 43.33%
Design rainfall depth 1.0 in
Storage Volume: Non-SA Waters
Minimum volume required
Volume provided
Storage Volume: SA Waters
1.5" runoff volume
Pre-development 1-yr, 24-hr runoff
Post-development 1-yr, 24-hr runoff
Minimum volume required
Volume provided
Peak Flow Calculations
Is the pre/post control of the lyr 24hr storm peak flow required?
1-yr, 24-hr rainfall depth
Rational C, pre-development
Rational C, post-development
Rainfall intensity: 1-yr, 24-hr storm
Pre-development 1-yr, 24-hr peak flow
Post-development 1-yr, 24-hr peak flow
Pre/Post 1-yr, 24-hr peak flow control
Elevations
Temporary pool elevation
Permanent pool elevation
SHWT elevation (approx. at the perm. pool elevation)
Top of 1Oft vegetated shelf elevation
Bottom of 1 Oft vegetated shelf elevation
Sediment cleanout, top elevation (bottom of pond)
Sediment cleanout, bottom elevation
Sediment storage provided
Is there additional volume stored above the state-required temp pool?
Elevation of the top of the additional volume
9,584 ft3 OK
9,888 ft3
OK, volume provided is equal to or in excess of volume required.
ft3
ft3
ft3
ft3
ft3
y (Y or N)
3.0 in
0.30 (unitless)
0.51 (unitless)
0.13 in/hr OK
15.61 ft3/sec
11.47 ft3/sec
-4.14 ft3/sec
343.00 fmsl
344.50 fmsl
fmsl
343.50 fmsl
342.50 fmsl
339.00 fmsl
338.00 fmsl
1.00 ft
(Y or N)
fmsl
Form SW401-Wet Detention Basin-Rev e-9/17109 Parts I & 11 Design Summary, Page 1 of 2
Permit No
(to be provided by DWQ)
IL DESIGN INFORMATION
Surface Areas
Area, temporary pool 7,756 fe
Area REQUIRED, permanent pool 4,809 fig
SAIDA ratio 1.84 (unitless)
Area PROVIDED, permanent pool, / ,,m_pw 4,897 fe OK
Area, bottom of 1 Oft vegetated shelf, / I 3,346 It'
Area, sediment cleanout, top elevation (bottom of pond), &tyooa 1,418 fl`
Volumes
Volume, temporary pool 9,888 fe OK
Volume, permanent pool, \?,,,,_pw 10,290 ft3
Volume, forebay (sum of forebays if more than one forebay) fe
Forebay % of permanent pool volume %
SAIDA Table Data
Design TSS removal 85%
Coastal SAIDA Table Used? n (Y or N)
Mountain/Piedmont SAIDA Table Used? y (Y or N)
SAIDA ratio 1.84 (unitless)
Average depth (used in SAIDA table):
Calculation option 1 used? (See Figure 10-2b) n (Y or N)
Volume, permanent pool, l?,r,_pw 10.290 fl'
Area provided, permanent pool, /o,,,,_pw 4,897 fr
Average depth calculated it Need 3 It min.
Average depth used in SAIDA, ¢,,, (Round to nearest 0.5ft) ft
Calculation option 2 used? (See Figure 10-2b) Y (Y or N)
Area provided, permanent pool, 4.897 ft'
Area, bottom of 1Oft vegetated shelf, / dw 3,346 fl°
Area, sediment cleanout, top elevation (bottom of pond), 1,418 W
"Depth' (distance blw bottom of 1Oftshelf and top of sediment) 3.50 it
Average depth calculated 3.00 ft OK
Average depth used in SAIDA, C (Round to nearest 0.5ft) 3.0 ft OK
Drawdown Calculations
Drawdown through orifice?
Diameter of orifice (if circular)
Area of orifice (if-non-circular)
Coefficient of discharge (Cc)
Driving head (F6)
Drawdown through weir?
Weir type
Coefficient of discharge (t4 )
Length of weir (L)
Driving head (H)
Pre-development 1-yr, 24-hr peak flow
Post-development 1-yr, 24-hr peak flow
Storage volume discharge rate (through discharge orifice orweir)
Storage volume drawdown time
Additional Information
Vegetated side slopes
Vegetated shelf slope
Vegetated shelf width
Length of flowpath to width ratio
Length to width ratio
Trash rack for overflow & orifice?
Freeboard provided
Vegetated filter provided?
Recorded drainage easement provided?
Capures all runoff at ultimate build-out?
Drain mechanism for maintenance or emergencies is:
Y (Y or N)
2.00 in
in1
HD (unilles5)
1.50 ft
n (Y or N)
(unities)
(unitless)
it
ft
15.61 fOlsec
11.47 fe/sec
0.13 fP/sec
2.00 days
OK, draws down in 2-5 days.
3 A OK
10 :1 OK
10.0 ft OK
3 :1 OK
3.0 :1 OK
Y (Y or N) OK
0.5 ft Insufficient freeboard, minimum of 1-ft required
n (Y or N) Insufficient. Vegetated filter required.
y (Y or N) OK
y (Y or N) OK
pump required
Form SW401-Wet Detention Basin-Rev.e-9/17109 Parts I. & II. Design Summary, Page2 of 2
Culvert Calculations
Culvert Designer/Analyzer Report
Crossing 1 - (HW1)
Analysis Component
Storm Event
Design Discharge
r 73.43 cfs
Peak Discharge Method: Rational
Design Return Period 25 year Check Return Period 100 year
Design Peak Discharge 73.43 cfs Check Peak Discharge 90.49 cfs
Total Area 85.50 acres Time of Concentration 60.00 min
Rational Coefficient 0.30 Intensity 3.50 in/hr
Area
Subwatershed(acres) C
1 85.50 0.30
Tailwater Conditions: Constant Tailwater
Tailwater Elevation N/A ft
Name Description Discharge HW Elev. Velocity
Culvert-1 1-66 inch Circular 56.40 cfs 363.19 ft 14.79 ft/s
Culvert-2 1-66 inch Circular 17.05 cfs 363.19 ft 10.59 ft/s
Weir Roadway (Constant E levatioi%00 cfs 363.19 ft N/A
Total - 73.45 cfs 363.19 ft N/A
Title: Alston Pond Project Engineer: asmith
k:\. \h-h\culvert master\alston pond culverts cvm Withers & Ravenel Engineering CulvertMaster v3.1 [03 01 010 001
12/22/10 09:03:46Odntley Systems, Inc Haestad Methods Solution Center Watertown, CT 06795 USA [phone] Page 1 of4
Culvert Designer/Analyzer Report
Crossing 1 - (HW1)
Component:Culvert-1
Culvert Summary
Computed Headwater Elevi
Inlet Control HW Elev.
Outlet Control HW Elev.
Headwater Depth/Height 363.19 ft
362.78 ft
363.19 ft
0.58 Discharge 56.40 cfs
Tailwater Elevation N/A ft
Control Type Entrance Control

Grades
Upstream Invert
Length 360.00 ft
126.00 ft Downstream Invert
Constructed Slope 356.00 ft
0.031746 ft/ft

Hydraulic Profile
Profile S2
Slope Type Steep
Flow Regime Supercritical
Velocity Downstream 14.79 ft/s Depth, Downstream
Normal Depth
Critical Depth
Critical Slope 1.20 ft
1.14 ft
2.05 ft
0.003223 ft/ft

Section
Section Shape
Section Material
Section Size
Number Sections Circular
Concrete
66 inch
1 Mannings Coefficient
Span
Rise 0.013
5.50 ft
5.50 ft

Outlet Control Properties
Outlet Control HW Elev.
Ke 363.19 ft
0.50 Upstream Velocity Head
Entrance Loss 0.76 ft
0.38 ft

Inlet Control Properties
Inlet Control HW Elev. 362.78 ft
Inlet Type Square edge w/headwall
K 0.00980
M 2.00000
C 0.03980
Y 0.67000 Flow Control
Area Full
HDS 5 Chart
HDS 5 Scale
Equation Form Unsubmerged
23.8 ft2
1
1
1
Title: Alston Pond Project Engineer: asmith
k:\.. \h-h\culvert master\alston pond culverts.cvm Withers & Ravenel Engineering CulvertMaster v3 1 [03.01 010 00]
12/22/10 09:03:46UUdntley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA [phone] Page 2 of 4
Culvert Designer/Analyzer Report
Crossing 1 - (HW1)
Component:Culvert-2
Culvert Summary
Computed Headwater Elev< 363.19 ft Discharge 17.05 cfs
Inlet Control HW Elev. 362.92 ft Tailwater Elevation N/A ft
Outlet Control HW Elev. 363.19 ft Control Type Entrance Control
Headwater Depth/Height 0.31
Grades
Upstream Invert
Length 361.50 ft
126.00 ft Downstream Invert
Constructed Slope 358.00 ft
0.027778 ft/ft

Hydraulic Profile
Profile
Slope Type
Flow Regime
Velocity Downstream S2
Steep
Supercritical
10.59 ft/s Depth, Downstream
Normal Depth
Critical Depth
Critical Slope 0.66 ft
0.66 ft
1.11 ft
0.003270 ft/ft

Section
Section Shape
Section Material
Section Size
Number Sections Circular
Concrete
66 inch
1 Mannings Coefficient
Span
Rise 0.013
5.50 ft
5.50 ft

Outlet Control Properties
Outlet Control HW Elev.
Ke 363.19 ft
0.50 Upstream Velocity Head
Entrance Loss 0.39 ft
0.19 ft

Inlet Control Properties
Inlet Control HW Elev. 362.92 ft
Inlet Type Square edge w/headwall
K 0.00980
M 200000
C 0.03980
Y 0.67000 Flow Control
Area Full
HDS 5 Chart
HDS 5 Scale
Equation Form Unsubmerged
23.8 ft2
1
1
1
Title: Alston Pond Project Engineer: asmith
k:\...\h-h\culvert master\alston pond culverts.cvm Withers & Ravenel Engineering CulvertMaster v3.1 [03.01 010 00]
12/22/10 09:03:46cAB6ntley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA [phone] Page 3 of 4
Culvert Designer/Analyzer Report
Crossing 1 - (HW1)
Component:Weir
Hydraulic Component(s): Roadway (Constant Elevation)
Discharge 0.00 cfs Allowable HW Elevation 363.19 ft
Roadway Width 80.00 ft Overtopping Coefficient 2.90 US
Length 100.00 ft Crest Elevation 385.00 ft
Headwater Elevation N/A ft Discharge Coefficient (Cr) 2.90
Submergence Factor (Kt) 1.00
Sta (ft) Elev. (ft)
0.00 385.00
100.00 385.00
Title: Alston Pond Project Engineer: asmith
k:\.. \h-h\culvert master\alston pond culverts.cvm Withers & Ravenel Engineering CulvertMaster v3.1 [03.01.010 00]
12122110 09:03:46cWntley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA [phone] Page 4 of 4
Culvert Designer/Analyzer Report
Crossing 2 (HW3)
Analysis Component
Storm Event Design Discharge 16.46 cfs

Peak Discharge Method: Rational
Design Return Period 25 year Check Return Period 25 year
Design Peak Discharge 16.46 cfs Check Peak Discharge 16.46 cfs
Total Area 14.80 acres Time of Concentration 43.00 min
Rational Coefficient 0.30 Intensity 3.68 in/hr
Area
Subwatershed(acres) C
1 14.80 0.30
Tailwater Conditions: Constant Tailwater
Tailwater Elevation NIA ft
Name Description Discharge HW Elev. Velocity
Culvert-1 1-48 inch Circular 16.47 cfs 391.20 ft 12.91 ft/s
Weir Roadway (Constant Elevatiolq00 cfs 391.20 ft NIA
Total 16.47 cfs 391.20 ft NIA
Title: Alston Pond Project Engineer: asmith
k:\ . \h-h\culvert master\alston pond culverts.cvm Withers & Ravenel Engineering CulvertMaster v3.1 [03.01 010 00]
12/22/10 09:10:09oUdntley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA [phone] Page 1 of 3
Culvert Designer/Analyzer Report
Crossing 2 (HW3)
Component:Culvert-1
Culvert Summary
Computed Headwater Elevi 391.21 ft Discharge 16 47 cfs
Inlet Control HW Elev. 391.01 ft Tailwater Elevation N/A ft
Outlet Control HW Elev. 391.21 ft Control Type Entrance Control
Headwater Depth/Height 0.43

Grades
Upstream Invert 389.50 ft Downstream Invert 386.50 ft
Length 50.00 ft Constructed Slope 0.060000 ft/ft

Hydraulic Profile
Profile S2 Depth, Downstream 0.63 ft
Slope Type Steep Normal Depth 0.59 ft
Flow Regime Supercritical Critical Depth 1.19 ft
Velocity Downstream 12.91 ft/s Critical Slope 0.003537 ft/ft

Section
Section Shape Circular Mannings Coefficient 0.013
Section Material Concrete Span 4.00 ft
Section Size 48 inch Rise 4.00 ft
Number Sections 1

Outlet Control Properties
Outlet Control HW Elev. 391.21 ft Upstream Velocity Head 0.43 ft
Ke 0.20 Entrance Loss 0.09 ft

Inlet Control Properties
Inlet Control HW Elev 391.01 ft Flow Control N/A
Inlet Type Groove end projecting Area Full 12.6 ft2
K 0.00450 HDS 5 Chart 1
M 2.00000 HDS 5 Scale 3
C 0.03170 Equation Form 1
Y 069000
Title: Alston Pond Project Engineer: asmith
k:\. \h-h\culvert master\alston pond culverts cvm Withers & Ravenel Engineering CulvertMaster v3 1 [03 01 010 00]
12/22/10 09:10:09cWntley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA [phone] Page 2 of 3
Culvert Designer/Analyzer Report
Crossing 2 (HW3)
Component:Weir
Hydraulic Component(s): Roadway (Constant Elevation)
Discharge 0.00 cfs Allowable HW Elevation 391.20 ft
Roadway Width 40.00 ft Overtopping Coefficient 2.90 US
Length 100.00 ft Crest Elevation 396.00 ft
Headwater Elevation N/A ft Discharge Coefficient (Cr) 2.90
Submergence Factor (Kt) 1.00
Sta (ft) Elev. (ft)
0.00 396.00
100.00 396.00
Title: Alston Pond Project Engineer: asmith
k:\...\h-h\culvert master\alston pond culverts cvm Withers & Ravenel Engineering CulvertMaster v3.1 [03.01 010 00]
12/22/10 09:10:09c?Wntley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA [phone] Page 3 of 3
Culvert Designer/Analyzer Report
Crossing 3 - (FES601)
Analysis Component
Storm Event Design Discharge 8.43 cfs

Peak Discharge Method: Rational
Design Return Period 25 year Check Return Period 25 year
Design Peak Discharge 8.43 cfs Check Peak Discharge 8.43 cfs
Total Area 6.60 acres Time of Concentration 32.00 min
Rational Coefficient 0.30 Intensity 4.22 in/hr
Area
Subwatershed(acres) C
1 6.60 0.30
Tailwater Conditions: Constant Tailwater
Tailwater Elevation N/A ft
Name Description Discharge HW Elev. Velocity
Culvert-1 1-18 inch Circular 6.69 cfs 386.03 ft 11.03 ft/s
Weir Roadway (Constant Elevatiort)77 cfs 386.03 ft N/A
Total -- -- 8.47 cfs 386.03 ft N/A
Title: Alston Pond Project Engineer: asmith
k:\...\h-h\culvert master\aston pond culverts.cvm Withers & Ravenel Engineering CulvertMaster v3.1 [03 01.010.00]
12/22/10 09:10:27c/1Mntley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA [phone] Page 1 of 3
Culvert Designer/Analyzer Report
Crossing 3 - (FES601)
Component: Culvert-1
Culvert Summary
Computed Headwater Elev, 386.03 ft
Inlet Control HW Elev. 385.96 ft
Outlet Control HW Elev. 386.03 ft
Headwater Depth/Height 1.02 Discharge 6.69 cfs
Tailwater Elevation N/A ft
Control Type Entrance Control

Grades
Upstream Invert
Length 384.50 ft
366.00 It Downstream Invert
Constructed Slope 368.00 ft
0.045082 ft/ft

Hydraulic Profile
Profile
Slope Type
Flow Regime
Velocity Downstream S2
Steep
Supercritical
11.03 ft/s Depth, Downstream
Normal Depth
Critical Depth
Critical Slope 0.56 ft
0.56 ft
1.00 ft
0.006591 ft/ft

Section
Section Shape
Section Material
Section Size
Number Sections Circular
Concrete
18 inch
1 Mannings Coefficient
Span
Rise 0.013
1.50 ft
1.50 ft

Outlet Control Properties
Outlet Control HW Elev.
Ke 386.03 ft
0.20 Upstream Velocity Head
Entrance Loss 0.44 ft
0.09 ft

Inlet Control Properties
Inlet Control HW Elev. 385.96 ft
Inlet Type Beveled ring, 45° bevels
K 0.00180
M 2.50000
C 0.03000
Y 0.74000 Flow Control
Area Full
HDS 5 Chart
HDS 5 Scale
Equation Form N/A
1.8 ft2
3
A
1
Title: Alston Pond Project Engineer: asmith
k:\ ..\h-h\culvert master\alston pond culverts cvm Withers & Ravenel Engineering CulvertMaster v3 1 [03.01 010.00]
12/22/10 09:10:27c Mntley Systems, Inc. Haestad Methods Solution Center Watertown, CT 06795 USA [phone] Page 2 of 3
Culvert Designer/Analyzer Report
Crossing 3 - (FES601)
Component:Weir
Hydraulic Component(s): Roadway (Constant Elevation)
Discharge 1.77 cfs Allowable HW Elevation 386.03 ft
Roadway Width 40.00 ft Overtopping Coefficient 2.91 US
Length 100.00 ft Crest Elevation 386.00 ft
Headwater Elevation 386.03 ft Discharge Coefficient (Cr) 2.91
Submergence Factor (Kt) 1.00
Sta (ft) Elev. (ft)
0.00 386.00
100.00 386.00
Title: Alston Pond Project Engineer: asmith
k:\.. \h-h\culvert master\aston pond culverts.cvm Withers & Ravenel Engineering CulvertMaster v3 1 [03.01.010.00]
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