20080656 Ver 1_401 Application_20080408

(SEPI
V ENGINEERING GROUP
1025 Wade Avenue
Raleigh, NC 27605
Tel [phone]
Fax [phone]
sepiengineering.com
~~ 3 c~.. -~ ' 0 8 0 6 5 6
A ri17 2008 ~ ~~~~~~ D
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North Carolina Division of Water Quality APR 8 208
401 Water Quality Certification DENR-wATEka A R
Attention: Cyndi Karoly y~ETLANDS AND STORMW
2321 Crabtree Blvd., Suite 250
Raleigh, NC 27604
Re: Sycamore Creek Elementary School, Neuse River Buffer Authorization
Dear Ms. Karoly:
SEPI Engineering Group, Inc (SEPI), on behalf of the City of Raleigh Public Utilities
Department, submits this Neuse River buffer authorization request. The project is located off of
Leesville Road in Raleigh, North Carolina. To accommodate construction of 8" ductile iron pipe
sewer line for the proposed elementary school, the City of Raleigh requests a Neuse buffer
authorization.
Project Description
The proposed project involves the construction of a new gravity fed sewer line to accommodate
the construction of the Sycamore Creek Elementary School, also commonly referred to as `E-
17'. Wake County Public School System intends to construct an elementary school to
accommodate 900 students.
Project Site Investigation
The site for the proposed elementary school and sewer line has been reviewed for wetlands,
streams and buffers. For the proposed school site, the Wake County soil maps depicts two
drainage on the school site, whereas the US Geologic Survey map does not show a drainage.
S&ME conducted a review of the site, and they delineated wetlands. It was determined that
there were not drainages on the tract that were subject to the Neuse buffer, and Mr. Eric Kulz of
the NC Division of Water Quality (NCDWQ) agreed with this determination (see attached letter
dated May 1, 2006).
SEPI Engineering Group has reviewed the area associated with the proposed sewer line. This
review determined that the drainage, depicted on the Wake County soils map but was not
depicted on the USGS map, was not subject to the Neuse buffer rules. However, SEPI
determined that the pond, and subsequently downstream of the pond, to be subject to the Neuse
buffer rules. Ms. Lauren Cobb of the NCDWQ conducted a site, and agreed with SEPI
determination. Ms. Cobb provided a letter stating this work (see attached letter dated August 4,
2007).

~ESEPI
-/
Page 2 . , `'
Project Impacts
The layout of the elementary school alignment has been designed to avoid any wetland impacts.
Table 1 summarizes impacts to waters of the United States.
Table 1. Project Impacts from the Proposed Elementary School and Sewer Line
Stream Impacts (acres) 0 acre
Wetland impacts (acres) 0 acre
Open Water impacts (acres) 0 acre
Total Impact to waters of US (acres) 0 acre
Total Stream Impacts (feet) 0 acre
However, to accommodate construction of the sewer line, impacts to the Neuse buffer rules must
occur. There are not any other practicable alternatives to avoid or minimize impacts to the
buffer.
The proposed sewer line is a gravity fed system. The existing topography and development in
the area limits possible routes for the sewer system. SEPI reviewed the existing area, and there
are practicable alternative than to place the sewer line in Zone 1 adjacent to the existing pond.
The alignment is constrained by an existing structure. As noted on the attached drawing, the
project will involve a parallel impact the buffer. Per the Neuse buffer rules, this impact is
allowable with mitigation.
The Wake County Public School System is proposing to pay into the Riparian Buffer Fund to
compensate for impact to the Neuse buffers. Table 2 summarizes the impacts to the buffers and
the required payment.
Table 2. Impacts to Neuse buffers and mitigation payment
Buffer
Zone Impact Area
s uare feet) Mitigation
Ratio Total Mitigation
Area (s . ft.) Mitigation
Costs
1 3,628 3 10,884.00 $10,557.48
2 2,207 1.5 3,310.50 $3,211.19
Total 15,391.50 $13,768.67
On behalf of the City of Raleigh, SEPI has coordinated the payment into the Riparian Buffer
Fund with the Ecosystem Enhancement Program. The EEP has agreed to provide the required
buffer compensation (see attached letter dated XX).

~ESEPI
Page 3
Closing
SEPI asks that the NCDWQ issue a buffer authorization for the proposed construction of the
sewer line. This proposed action is an allowable action with mitigation under the Neuse buffer
rules.
If you have any questions regarding this buffer authorization, please contact me at (919) 789-
9977. Thank you for your prompt attention to this matter.
n Manager

~ ~-0 3 d -~-
Office Use Only: Form Version March OS
~08 0 65 6
USACE Action ID No. DWQ No.
(If any particular item is not applicable to this project, please enter "Not Applicable" or "N/A".)
I. Processing
1. Check all of the approval(s) requested for this project:
^ Section 404 Permit ® Riparian or Watershed Buffer Rules
^ Section 10 Permit ^ Isolated Wetland Permit from DWQ
^ 401 Water Quality Certification ^ Express 401 Water Quality Certification
2. Nationwide, Regional or General Permit Number(s) Requested: n/a
3. If this notification is solely a courtesy copy because written approval for the 401 Certification
is not required, check here: ^
4. If payment into the North Carolina Ecosystem Enhancement Program (NCEEP) is proposed
for mitigation of impacts, attach the acceptance letter from NCEEP, complete section VIII,
and check here:
5. If your project is located in any of North Carolina's twenty coastal counties (listed on page
4), and the project is within a North Carolina Division of Coastal Management Area of
Environmental Concern (see the top of page 2 for further details), check here: ^
II. Applicant Information U ~~~ ~~~ D
1. Owner/Applicant Information
APR S 2008
Name: City of Raleigh -Public Utilities Department DENR-wATEk UUAIJTY
"- ~-- • • ' '"etiiaiivrtrzri BRANCH
Mailing Address: Attention: Donna Jackson, PE
3324 Lake Woodard Drive
Raleigh, NC 27604
Telephone Number: [phone] Fax Number: [phone]
E-mail Address: Donna.Jackson(a~ci.raleigh.nc.us
2. Agent/Consultant Information (A signed and dated copy of the Agent Authorization letter
must be attached if the Agent has signatory authority for the owner/applicant.)
Name: Phillip Todd
Company Affiliation: SEPI En 'neerin~ Group
Mailing Address: 1025 Wade Avenue
Raleigh, NC 27605
Telephone Number:[phone] Fax Number: (9191789-9591
E-mail Address: ptodd(a~,sepien ingi eering.com
Page 5 of 12

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III. Project Information
Attach a vicinity map clearly showing the location of the property with respect to local
landmarks such as towns, rivers, and roads. Also provide a detailed site plan showing property
boundaries and development plans in relation to surrounding properties. Both the vicinity map
and site plan must include a scale and north arrow. The specific footprints of all buildings,
impervious surfaces, or other facilities must be included. If possible, the maps and plans should
include the appropriate USGS Topographic Quad Map and NRCS Soil Survey with the property
boundaries outlined. Plan drawings, or other maps may be included at the applicant's discretion,
so long as the property is clearly defined. For administrative and distribution purposes, the
USACE requires information to be submitted on sheets no larger than 11 by 17-inch format;
however, DWQ may accept paperwork of any size. DWQ prefers full-size construction
drawings rather than a sequential sheet version of the full-size plans. If full-size plans are
reduced to a small scale such that the final version is illegible, the applicant will be informed that
the project has been placed on hold until decipherable maps are provided.
1. Name of proj ect: Sycamore Creek Elementary School or E-17
2. T.I.P. Project Number or State Project Number (NCDOT Only): N/A
3. Property Identification Number (Tax PIN): 0778990390
4. Location
County: Wake Nearest Town: Ralei~h/Leesville
Subdivision name (include phase/lot number): N/A
Directions to site (include road numbers/names, landmarks, etc.): From I-540, take Exit 7
~o north on Leesvillle Road -School will be on LEFT;ust after Farless Rd intersection
5. Site coordinates (For linear projects, such as a road or utility line, attach a sheet that
separately lists the coordinates for each crossing of a distinct waterbody.)
Decimal Degrees (6 digits minimum): 35.9187 °N 78.7328 °W
6. Property size (acres): 17.24 acres
7. Name of nearest receiving body of water: Sycamore Creek
8. River Basin: Neuse River Basin
(Note -this must be one of North Carolina's seventeen designated major river basins. The
River Basin map is available at http://h2o.enr.state.nc.us/admin/maps/.)
9. Describe the existing conditions on the site and general land use in the vicinity of the project
at the time of this application: school tract forested; properties for sewer line are
agriculture and residential
Page 6 of 12

10. Describe the overall project in detail, including the type of equipment to be used: track
hoes, grader
11. Explain the purpose of the proposed work: construct sewer line to provide services for new
elementary school
IV. Prior Project History
If jurisdictional determinations and/or permits have been requested and/or obtained for this
project (including all prior phases of the same subdivision) in the past, please explain. Include
the USACE Action ID Number, DWQ Project Number, application date, and date permits and
certifications were issued or withdrawn. Provide photocopies of previously issued permits,
certifications or other useful information. Describe previously approved wetland, stream and
buffer impacts, along with associated mitigation (where applicable). If this is a NCDOT project,
list and describe permits issued for prior segments of the same T.I.P. project, along with
construction schedules. buffer review (see attached letter) for school, buffer review for sewer
line (see attached letterl
V. Future Project Plans
Are any future permit requests anticipated for this project? If so, describe the anticipated work,
and provide justification for the exclusion of this work from the current application.
None are anticipated at this time
VI. Proposed Impacts to Waters of the United States/Waters of the State
It is the applicant's (or agent's) responsibility to determine, delineate and map all impacts to
wetlands, open water, and stream channels associated with the project. Each impact must be
listed separately in the tables below (e.g., culvert installation should be listed separately from
riprap dissipater pads). Be sure to indicate if an impact is temporary. All proposed impacts,
permanent and temporary, must be listed, and must be labeled and clearly identifiable on an
accompanying site plan. All wetlands and waters, and all streams (intermittent and perennial)
should be shown on a delineation map, whether or not impacts are proposed to these systems.
Wetland and stream evaluation and delineation forms should be included as appropriate.
Photographs may be included at the applicant's discretion. If this proposed impact is strictly for
wetland or stream mitigation, list and describe the impact in Section VIII below. If additional
space is needed for listing or description, please attach a separate sheet.
1. Provide a written description of the proposed impacts: buffer impacts associated with
the installation of a sewer line to accommodate construction of Sycamore Creek ElementarX
School (E-17)
Page 7 of 12

2. Individually list wetland impacts. Types of impacts include, but are not limited to
mechanized clearing, grading, fill, excavation, flooding, ditching/drainage, etc. For dams,
separately list impacts due to both structure and flooding.
Wetland Impact
Site Number
(indicate on map)
Type of Impact Type of Wetland
(e.g., forested, marsh,
herbaceous, bog, etc.) Located within
100-year
Floodplain
(yes/no) Distance to
Nearest
Stream
(linear feet) Area of
Impact
(acres)
N/a

Total Wetland Impact (acres) N/a
3. List the total acreage (estimated) of all existing wetlands on the property: acres
4. Individually list all intermittent and perennial stream impacts. Be sure to identify temporary
impacts. Stream impacts include, but are not limited to placement of fill or culverts, dam
construction, flooding, relocation, stabilization activities (e.g., cement walls, rip-rap, crib
walls, gabions, etc.), excavation, ditching/straightening, etc. If stream relocation is proposed,
plans and profiles showing the linear footprint for both the original and relocated streams
must be included. To calculate acreage, multiply length X width, then divide by 43,560.
Stream Impact
Number
(indicate on ma
Stream Name
Type of Impact Perennial or
Intermittent? Average
Stream Width
Before Im act Impact
Length
(linear feet) Area of
Impact
acres)

Total Stream Impact (by length and acreage) N/a
5. Individually list all open water impacts (including lakes, ponds, estuaries, sounds, Atlantic
Ocean and any other water of the U.S.). Open water impacts include, but are not limited to
fill_ excavatien_ dred~in~_ fleodin~. drainage. bulkheads. etc.
Open Water Impact
Site Number
(indicate on ma) Name of Waterbody
(if applicable)
Type of Impact Type of Waterbody
(lake, pond, estuary, sound, bay,
ocean, etc.) Area of
Impact
(acres)
N/a

Total Open Water Impact (acres) n/a
Page 8 of 12

6. List the cumulative impact to all Waters of the U.S. resulting from the project:
Stream Impact (acres): 0
Wetland Impact (acres): 0
Open Water Impact (acres): 0
Total Impact to Waters of the U.S. (acres) 0
Total Stream Impact (linear feet): 0
7. Isolated Waters
Do any isolated waters exist on the property? ^ Yes ®No
Describe all impacts to isolated waters, and include the type of water (wetland or stream) and
the size of the proposed impact (acres or linear feet). Please note that this section only
applies to waters that have specifically been determined to be isolated by the USACE.
8. Pond Creation
If construction of a pond is proposed, associated wetland and stream impacts should be
included above in the wetland and stream impact sections. Also, the proposed pond should
be described here and illustrated on any maps included with this application.
Pond to be created in (check all that apply): ^ uplands ^ stream ^ wetlands
Describe the method of construction (e.g., dam/embankment, excavation, installation of
draw-down valve or spillway, etc.): N/a
Proposed use or purpose of pond (e.g., livestock watering, irrigation, aesthetic, trout pond,
local stormwater requirement, etc.): N/a
Current land use in the vicinity of the pond: N/a
Size of watershed draining to pond: N/a Expected pond surface area:
VII. Impact Justification (Avoidance and Minimization)
Specifically describe measures taken to avoid the proposed impacts. It maybe useful to provide
information related to site constraints such as topography, building ordinances, accessibility, and
financial viability of the project. The applicant may attach drawings of alternative, lower-impact
site layouts, and explain why these design options were not feasible. Also discuss how impacts
were minimized once the desired site plan was developed. If applicable, discuss construction
techniques to be followed during construction to reduce impacts.
There are not impacts to streams or wetlands; only buffers. Proiect occurs in an area that is
already disturbed. Alignment of sewer line constrained by existing house and need to locate the
sewer line away from house. There is no other practicable alternative to the sewer line
alignment.
VIII. Mitigation
DWQ - In accordance with 15A NCAC 2H .0500, mitigation may be required by the NC
Division of Water Quality for projects involving greater than or equal to one acre of impacts to
freshwater wetlands or greater than or equal to 150 linear feet of total impacts to perennial
streams.
Page 9 of 12

USACE - In accordance with the Final Notice of Issuance and Modification of Nationwide
Permits, published in the Federal Register on January 15, 2002, mitigation will be required when
necessary to ensure that adverse effects to the aquatic environment are minimal. Factors
including size and type of proposed impact and function and relative value of the impacted
aquatic resource will be considered in determining acceptability of appropriate and practicable
mitigation as proposed. Examples of mitigation that may be appropriate and practicable include,
but are not limited to: reducing the size of the project; establishing and maintaining wetland
and/or upland vegetated buffers to protect open waters such as streams; and replacing losses of
aquatic resource functions and values by creating, restoring, enhancing, or preserving similar
functions and values, preferable in the same watershed.
If mitigation is required for this project, a copy of the mitigation plan must be attached in order
for USACE or DWQ to consider the application complete for processing. Any application
lacking a required mitigation plan or NCEEP concurrence shall be placed on hold as incomplete.
An applicant may also choose to review the current guidelines for stream restoration in DWQ's
Draft Technical Guide for Stream Work in North Carolina, available at
http://h2o.enr.state.nc.us/ncwetlands/strmgide.html.
1. Provide a brief description of the proposed mitigation plan. The description should provide
as much information as possible, including, but not limited to: site location (attach directions
and/or map, if offsite), affected stream and river basin, type and amount (acreage/linear feet)
of mitigation proposed (restoration, enhancement, creation, or preservation), a plan view,
preservation mechanism (e.g., deed restrictions, conservation easement, etc.), and a
description of the current site conditions and proposed method of construction. Please attach
a separate sheet if more space is needed.
None required as there is impact to streams or wetlands.
2. Mitigation may also be made by payment into the North Carolina Ecosystem Enhancement
Program (NCEEP). Please note it is the applicant's responsibility to contact the NCEEP at
[phone] to determine availability, and written approval from the NCEEP indicating
that they are will to accept payment for the mitigation must be attached to this form. For
additional information regarding the application process for the NCEEP, check the NCEEP
website at http://h2o.enr.state.nc.us/wrp/index.htm. If use of the NCEEP is proposed, please
check the appropriate box on page five and provide the following information:
Amount of stream mitigation requested (linear feet):
Amount of buffer mitigation requested (square feet):
Amount of Riparian wetland mitigation requested (acres):
Amount ofNon-riparian wetland mitigation requested (acres):
Amount of Coastal wetland mitigation requested (acres):
Page 10 of 12

IX. Environmental Documentation (required by DWQ)
1. Does the project involve an expenditure of public (federal/state/local) funds or the use of
public (federal/state) land? Yes ® No ^
2. If yes, does the project require preparation of an environmental document pursuant to the
requirements of the National or North Carolina Environmental Policy Act (NEPA/SEPA)?
Note: If you are not sure whether a NEPA/SEPA document is required, call the SEPA
coordinator at [phone] to review current thresholds for environmental documentation.
Yes ^ No
3. If yes, has the document review been finalized by the State Clearinghouse? If so, please
attach a copy of the NEPA or SEPA final approval letter. Yes ^ No ^
X. Proposed Impacts on Riparian and Watershed Buffers (required by DWQ)
It is the applicant's (or agent's) responsibility to determine, delineate and map all impacts to
required state and local buffers associated with the project. The applicant must also provide
justification for these impacts in Section VII above. All proposed impacts must be listed herein,
and must be clearly identifiable on the accompanying site plan. All buffers must be shown on a
map, whether or not impacts are proposed to the buffers. Correspondence from the DWQ
Regional Office may be included as appropriate. Photographs may also be included at the
applicant's discretion.
1. Will the project impact protected riparian buffers identified within 15A NCAC 2B .0233
(Meuse), 15A NCAC 2B .0259 (Tar-Pamlico), 15A NCAC 02B .0243 (Catawba) 15A NCAC
2B .0250 (Randleman Rules and Water Supply Buffer Requirements), or other (please
identify )? Yes ^ No ^
2. If "yes", identify the square feet and acreage of impact to each zone of the riparian buffers.
If buffer mitigation is required calculate the required amount of mitigation by applying the
buffer multipliers.
* Impact I I Required
Zone Multi Tier
ren„ora fop*1 I~ TiT; 4; ,.,. a: ,....
1 4,330 3 (2 for Catawba) 12,990
2 1,601 1.5 2,401.50
Total ~ I I 15,391.50
* Zone 1 extends out 30 feet perpendicular from the top of the near bank of channel; Zone 2 extends an
additiona120 feet from the edge of Zone 1.
3. If buffer mitigation is required, please discuss what type of mitigation is proposed (i.e.,
Donation of Property, Riparian Buffer Restoration /Enhancement, or Payment into the
Riparian Buffer Restoration Fund). Please attach all appropriate information as identified
within 15A NCAC 2B .0242 or .0244, or .0260. ~ayment into the Riparian Buffer
Restoration Fund will be made
Page 11 of 12

XI. Stormwater (required by DWQ)
Describe impervious acreage (existing and proposed) versus total acreage on the site. Discuss
Stormwater controls proposed in order to protect surface waters and wetlands downstream from
the property. If percent impervious surface exceeds 20%, please provide calculations
demonstrating total proposed impervious level. Total Tract size - 17.24 acres - Existing
impervious - 0%• proposed impervious - 91 % (15 81 acresl' Stormwater detention is planned for
the tract and already approved by the City of Raleigh
XII. Sewage Disposal (required by DWQ)
Clearly detail the ultimate treatment methods and disposition (non-discharge or discharge) of
wastewater generated from the proposed project, or available capacity of the subject facility.
Project will be tyin~ into existing gravity fed sanitary sewer line administered by the City of
Raleigh
XIII. Violations (required by DWQ)
Is this site in violation of DWQ Wetland Rules (15A NCAC 2H .0500) or any Buffer Rules?
Yes ^ No
Is this an after-the-fact permit application? Yes ^ No ^
XIV. Cumulative Impacts (required by DWQ)
Will this project (based on past and reasonably anticipated future impacts) result in additional
development, which could impact nearby downstream water quality? Yes ^ No
If yes, please submit a qualitative or quantitative cumulative impact analysis in accordance with
the most recent North Carolina Division of Water Quality policy posted on our website at
http•//h2o enr.state.nc.us/ncwetlands. If no, please provide a short narrative description:
Constructing the new recreational facility will not result in additional development -
accommodates a school only.
XV. Other Circumstances (Optional):
It is the applicant's responsibility to submit the application sufficiently in advance of desired
construction dates to allow processing time for these permits. However, an applicant may
choose to list constraints associated with construction or sequencing that may impose limits on
work schedules (e.g., draw-down schedules for lakes, dates associated with Endangered and
Threatened Species, accessibility problems, or other issues outside of the applicant's control).
~~ c ~e.~
A~plir.~it~/Agent's Signature Date
s signature is valid only if an authorization letter from the applicant is provided.)
Page 12 of 12

0 0.3 0.6 0.9 1.2 1.5 km ~~ G
0 4.2 0.4 0.6 0.8 1 mi
UTM 17 704531E 3977287N (NAD83/WGS84)
USGS Bayleaf (NC) Quadrangle M=_g,78
Projection is UTM Zone 17 NAD83 Datum G-1.33

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pROGItAM
April 1, 2008
Donna Jackson, PE
City of Raleigh Public Utilities Dept.
3324 Lake Woodard Dr.
Raleigh, NC 27604 Expiration of Acceptance: Octoher 1, 2008
Project: Sycamore Creek Elementary School County: Wake
The purpose of this letter is to notify you that the North Carolina Ecosystem Enhancement Program (NCEEP) is willing to
accept payment for impacts associated with the above referenced project. Please note that this decision does not assure that
the payment will be approved by the permit issuing agencies as mitigation for project impacts. It is the responsibility of the
applicant to contact these agencies to determine if payment to the NCEEP will be approved.
This acceptance is valid for six months from the date of this letter and is not transferable. If we have not received a copy of
the issued 404 Permit/401 CertificationlCAMA permit within this time frame, this acceptance will expire. It is the
applicant's responsibility to send copies of the permits to NCEEP. Once NCEEP receives a copy of the permit(s) an invoice
wilt be issued based on the required mitigation in that permit and payment must be made prior to conducting the authorized
work. The amount of the In Lieu Fee to be paid to NCEEP by an applicant is calculated based upon the Fee Schedule and
policies listed at www.nceep.net.
Based on.the information supplied;by_y¢u.the.impacts.that may require compensatory mitigation are summarized in the___-_
followine table.
Neuse
030202014 Stream (feet} ~ Wetlands (acres) Buffer I
(Sq. Ft.) Buffer II
(Sq. Ft.}
• Cold Cool Warm Ri orlon Non-lZi arian Coastal Marsh
Impacts 0 0 0 0 0 0 3,628 2,207
Credits 0 0 0 0 0 0 10,884 3,310.50
Upon receipt of payment, EEP will take responsibility for providing the compensatory mitigation. If the regulatory agencies
require mitigation credits greater than indicated above, and the applicant wants NCEEP to be responsible for the additional
mitigation, the applicant will need to submit a mitigation request to NCEEP for approval prior to permit issuance. The
mitigation will be performed in accordance with the Memorandum of Understanding between the N. C. Department of
Environment and Natural Resources and the U. S. Army Corps of Engineers dated November 4, 1948.
If you have any questions or need additional information, please contact Valerie Mitchener at [phone].
Sincerely,
Willis D. Gilmore, PE
Director
ce: Cyndi Karoly, NCDWQ Wetlands/401 Unit
Jamie Shern, USACE-Raleigh
Amy Chapman, NCDWQ-Wetlands/401 Unit
Phillip Todd, agent
File
R:~StoYLK~... ~ ... Pro~~ OGt.~ Stuff

North Carolina Ecosystem Enhancement Program, 1652 Mail Service Center, Raleigh, NC 27699-1652 ! 919-715-04761 www.nceep.net

SEPI ENGINEERING GROUP 200' 0 200' 400' SYCAMORE CREEK ELEMENTARY SCHOOL
~. ~ ~
Io25 wADE AvENUE WAKE COUNTY
RALEIGH, NORTH CAROLINA 27605 ~~ , MARCH 7, 2008
TELEPHONE: [phone] HORIZONTAL SCALE: 1 =200
FAX: [phone] ZONE IMPACT ANALYSIS
CITY OF RALEIGH PAGE 1 OF 2

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AREA OF DISTURBANCE = 2207 SF
SEPI ENGINEERING GROUP
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1025 WADE AVENUE
RALEIGH, NORTH CAROLINA 27605
TELEPHONE: [phone]
FAX: [phone]
CITY OF RALEIGH
40' 0 40' 80'
HORIZONTAL SCALE: 1 "=40'
(SYCAMORE CREEK ELEMENTARY SCHOOL
WAKE COUNTY
MARCH 7. 2008
ZONE IMPACT ANALYSIS
PAGE 2 OF 2

Sycamore Creek Elementary School
Stormwater Drainage Summary
Proiect Site•
Total Site Area
2-year Pre-Development Flow
2-year Post-Development Flow (without detention)
2-year Post-Development Flow (with detention)
Pond #1 Discharge
Pond #2 Discharge
Onsite are directly offsite
10-year Pre-Development Flow
10-year Post-Development Flow (without detention)
10-year Post-Development Flow (with detention)
Pond #1 Discharge
Pond #2 Discharge
Onsite are directly offsite
Total Area On-Site (To Detention)
Total Drainage On-Site (To Detention 2yr)
Total Drainage On-Site (To Detention l0yr)
Total Area On-Site (Not to Detention)
Total Drainage On-Site (Not to Detention 2yr)
Total Drainage On-Site (Not to Detention 10 yr)
Total Area Off-Site (To Detention)
Total Drainage Off-Site (To Detention 2yr)
Total Drainage Off-Site (To Detention 10 yr)
Total Area (To Detention)
Total Drainage (To Detention 2yr)
Total Drainage (To Detention l0yr)
15.81 ac
20.03 cfs (C=0.22)
43.46 cfs (C=0.48)
19.27 cfs < 20.03 cfs
4.75 cfs
6.24 cfs
8.28 cfs
25.11 cfs (C=0.22)
54.47 cfs (C=0.48)
22.56 cfs < 25.11 cfs
5.30 cfs
6.89 cfs
10.37 cfs
11.32 ac
33.97 cfs
42.66 cfs
4.49 ac
8.28 cfs (C = 0.32)
10.37 cfs (C = 0.32)
7.04 ac
20.96 cfs (C=0.513)
26.22 cfs (C=0.513)
18.36 ac
54.68 cfs
68.66 cfs

Detention Pond #1:
2-year peak outflow 4.75 cfs
10-year peak outflow 5.30 cfs
On-Site Drainage Area to Detention #1 4.15 ac
On-Site Drainage to Detention #1 (2 yr) 10.75 cfs (C= 0.45)
On-Site Drainage to Detention #1 (10 yr) 13.55 cfs (C= 0.45)
Off-Site Drainage Area to Detention #1 6.07 ac
Off-Site Drainage to Detention #1 (2 yr) 17.48 cfs (C=0.50)
Off-Site Drainage to Detention #1 (10 yr) 21.85 cfs (C=0.50)
Total Drainage Area to Detention #1 10.22 ac
Total Drainage to Detention #1 (2 yr) 28.23 cfs (C=0.48)
Total Drainage to Detention #1 (10 yr) 35.40 cfs (C=0.48)
Detention Pond #2:
2-year peak outflow 6.24 cfs
10-year peak outflow 6.89 cfs
On-Site Drainage Area to Detention #2 7.17 ac
On-Site Drainage to Detention #2 (2 yr) 23.22 cfs (C= 0.559)
On-Site Drainage to Detention #2 (10 yr) 29.11 cfs (C= 0.559)
Off-Site Drainage Area to Detention #2 0.97 ac
Off-Site Drainage to Detention #2 (2 yr) 3.48 cfs (C=0.60)
Off-Site Drainage to Detention #2 (10 yr) 4.37 cfs (C=0.60)
Total Drainage Area to Detention #2 8.14 ac
Total Drainage to Detention #2 (2 yr) 26.70 cfs (C= 0.564)
Total Drainage to Detention #2(10 yr) 33.48 cfs (C= 0.564)