20001061 Ver 2_Stormwater Info_20090630

WITHERS RAVENEL
ENGINEERS I PLANNERS I SURVEYORS
iii MacKenan Drive
CARY, NORTH CAROLINA, 27511
[phone]
FAX [phone]
To: NC DWQ
Wetlands Branch
2321 Crabtree Blvd
Raleigh, NC 276o4
WE ARE SENDING YOU
? Shop Drawings
? Copy of Letter
® Attached
? Prints
? Change order
COPIES DATE NO. DESCRIPTION

)K
06- o-0
1 ? i
Project Narrative
X5 o6- o-0 2 Drainage Area Ma DENR-WATER QUALITY
a
X5 o6- o-o Stormwater Management Details
x5 o6- o-o Calculations
X 5 o6- o-o Level Spreader Worksheet and Checklist
X5 o6- o-0 6 Preliminary 0&M Manual

THESE ARE TRANSMITTED as checked below:
® For approval ? Approved as submitted ? Resubmit copies for approval
? For your use ? Approved as noted ? Submit copies for distribution
? As requested ? Returned for corrections ? Return corrected prints
? For review and comment ?
? FOR BIDS DUE 20 ? PRINTS RETURNED AFTER LOAN TO US
REMARKS: Annette - per our discussion last Friday, please find the submittal information attached
for your approval. A detailed narrative is included describing the project.
Kathryn Hobby with Wake County has stated that she has no firther comments on the drawines.
If you have any questions or comments, please call anvtime. /I _/
COPY TO: file SIGNED: Hunter C. Freeman
lfenclosures arenotasnoted, kindlynotify us at once.
LETTER OF ll ° ° NSW77i QL
DATE o6- o-o JOB No. 020 o18 .o0
ATTENTION Annette Lucas
PHONE #
919-715-3425
RE: Hasentree
Pond SC-o1 (Sports Club / Phase 6A)

? Under separate cover via the following items:
? Plans ? Samples ? Specifications
? Diskette ? ,-.•,
L 5 r•+ LE; e L 14-11 bv?
fJJlH
WITHERS ?`:; RAVENEL
ENGINEERS I PLANNERS I SURVEYORS
MEMORANDUM
TO: Annette Lucas, NCDWQ
FROM: Hunter Freeman, PE
CC: file
DATE: June 26, 2009
SUBJECT: Hasentree Pond SC-01
This memo accompanies design drawings, calculations and supporting documents for a
modification to the stormwater plan for the Hasentree Community. This modification relates only to
Neuse River Basin diffuse flow requirements.
The Hasentree community is a partially completed residential development located in the
unincorporated areas of Wake County, near the intersection of NC-98 and Keith Road. The original
plan totals 761.45 acres and includes an 18-hole golf course and 432 proposed single family
residential units. An overall stormwater management plan for the Hasentree development was
approved by Wake County in 2006. The proposed development includes a net impervious density
of 19.24% across the entire project.
Pond SC-01 was originally designed by the CE Group as part of the overall stormwater management
plan. Withers & Ravenel completed construction drawings for the dry pond in August 2006 and
included a level spreader in the design. The pond was modified and re-approved in March 2007.
Pond construction is complete, and the area surrounding the pond includes the completed
recreational facilities for the development. At Wake County's request, a retrofit is planned for the
pond outlet to incorporate a level spreader, which was not shown on the revised plan.
Wake County staff has asked that a level spreader be designed in accordance with current
requirements. To meet this request, a riprap plunge pool with a splitter weir is proposed at the pond
outlet. The weir will divert small storm events to the level spreader swale, while large storm events
bypass the level spreader. The splitter weir is designed to divert all storm events up to and including
the 1-year event to the level spreader lip.
A riprap bypass channel will convey large flows through the buffer with minimal potential for
erosion. The completed rip rap channel will occupy approximately 1105 square feet within the
buffer (Zone 1 - 714 sf, Zone 2 - 391 sf). Allowing for construction activity, temporary disturbance
within the buffer will be an additional 650 sf (Zone 1 - 230 sf, Zone 2 - 420 so. All disturbed areas
within the buffer will be replanted to riparian buffer standards. The precise alignment of the channel
may vary slightly from design to ensure that significant trees are preserved during construction.
Upon completion, the level spreader will be maintained by the Hasentree HOA, and a maintenance
agreement will be recorded and placed on file with the County if one does not already exist.
iii MacKenan Drive Cary, North Carolina 27511 te1:919.469.3340 fax:[phone]oo8 www.withersravenel.com

Forebay LS Weir
Project Description
Solve For Discharge
Input Data
Headwater Elevation 351.00 ftl--- 'fi't--•
Crest Elevation 350.50 ft-". r L »
Tailwater Elevation 350.00 ft
Crest Surface Type Gravel
Crest Breadth 2.00 It
Crest Length 6.00 ft
Results
Discharge. 6.49 ft-/s e.- C" "Are,, ?. cFS
Headwater Height Above Crest 0.50 ft
Tailwater Height Above Crest -0.50 ft
Weir Coefficient 3.06 US
Submergence Factor 1.00
Adjusted Weir Coefficient 3.06 US
Flow Area 3.00 ft'
Velocity 2.16 ft/s
Wetted Perimeter 7.00 ft
Top Width 6.00 ft
Bentley Systems, Inc. Haestad Methods Solution Center Bentley FlowMaster [08.01.071.00]
613512009 1:12:23 PM 27 Slemons Company Drive Suite 200 W Watertown, CT 06795 USA +1.203.755-1666 Page 1 of 1
Pond SC-07 B ass Channel
Project Description
Friction Method Manning Formula
Solve For Normal Depth
Input Data
Roughness Coefficient 0.069 1 ?f
Channel Slope 0.08000 ft/ft L..1?.Q. C.rdiLi-?1??'1D?1S
Left Side Slope 3.00 ft/ft (H;V)
Right Side Slope 3 00 ft/ft (H:V)
Bottom Width 5.00 ft
Discharge 50.00 ft'/s Y
Results

Normal Depth
1.14
ft i

Flow Area 9.63 ftz 14 FT
Wetted Perimeter 12.22 ft
T
Width
op 11.85 ft
Critical Depth 1,15 ft r >
?
Critical Slope 0,07730 ftlft ?'????`
Velocity 5.19 fus , i
Velocity Head GA2 ft
Specific Energy 1.56 ft
$'d?
FroudeNumtfer 1,02
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 1.14 ft
Critical Depth 1.15 ft
Channel Slope 0.08000 ft/ft
Critical Slope 0.07730 ft/ft
Bentley Systems, Inc. Haestad Methods Solution Center Bentley FlowMaster (08.01.071.00]
011712009 9,21:59 AM 27 Slemons Company Drive Sulte 200 W Watertown, CT 06795 USA +1.203.755.1666 Page 1 of 1
0
Table 8.05f Manning's Roughness Coefficient
a -value
n value for Depth Ranges
Lining Category Lining Type 0-0,5 ft 0.5-2.0 ft 2.0 ft
0.15 cm 15-60 cm a 60 cm)
Algid Concrete 0.015 0.013 0.013
Grouted Riprap 0.040 0.030 0.028
Stone Masonry 0.042 0.032 0.030
Soil Cement 0.025 0.022 0.020
Asphalt 0.018 0.016 0.016
Unlined Bare Soil 0.023 0.020 0.020
Rock Cut 0.045 0.035 0.025
Gravel Riprap 1-inch (2.5-cm) D50 0,044 0.033 0.030
2-inch (5-cm) D5o 0.066 0.041 0.034
Rock Riprap 6-inch (15-cm) D5o 0.104 0.069 0.035
12-inch (30-cm) D5o 0.078 0.040
Note: Values listed are representative values for the respective depth ranges. Manning's roughness coefficients, n, vary with the flow depth.
DETERMINING SHEAR STRESS
Shear stress, T, at normal depth is computed for the lining by the following
equation:
T=yds
Td = Permissible shear stress
where:
T shear stress in lb/ft2
y = unit weight of water, 62.4 lb/ft3
d = flow depth in ft
s = channel gradient in ft/ft,
If the permissible shear stress, Td, given in Table 8.05g is greater than the
computed shear stress, the riprap or temporary lining is considered acceptable.
If a lining is unacceptable, select a lining with a higher permissible shear stress
and repeat the calculations for normal depth and shear stress. In some cases it
may be necessary to alter channel dimensions to reduce the shear stress.
Computing tractive force around a channel bend requires special considerations
because the change in flow direction imposes higher shear stress on the channel
bottom and banks. The maximum shear stress in a bend, Tb, is given by the
following equation:
Tb = KbT
where:
Tb = bend shear stress in lb/ft2
Kb = bend factor
T = computed stress for straight channel in lb/ft2
The value of Kb is related to the radius of curvature of the channel at its center
line, Rc, and the bottom width of the channel, B, Figure 8.05e. The length of
channel requiring protection downstream from a bend, Lp, is a function of the
roughness of the lining material and the hydraulic radius as shown in Figure
8.05f.
8,05.12
Rev. 1219:

Appendices
Table 8.05g
permissible Shear Stresses
Permissible Unit Shear Stress, To
-
for Riprap and Temporary )
Lining Category Lining Type (lb/ft
Liners Temporary Woven Paper Net 0.15
Jute Net 0.45
Fiberglass Roving:
Single 0.60
Double 0.85
Straw with Net 1.45
Curled Wood mat 1,55
Synthetic Mat 2.00
d50 Stone Size (inches)
Gravel Riprap 1 0.33
2 0.67
Rock Riprap 6 2.00
g 3.00
12 4.00
15 5.00
18 6.00
21 7.80
24 B.00
Adapted From: FHWA, FMC-15, April 1983, pgs. 17 & 37.
Design Procedure- The following is a step-by-step procedure for designing a temporary liner for a
Temporary Liners channel. Because temporary liners have a short period of service, the des gn 0
may be reduced. For liners that are needed for six months or less, the 2-yr
frequency storm is recommended.
Step 1. Select a liner material suitable for site conditions and application.
Determine roughness coefficient from manufacturer's specifications or [able
8.05e, pg. 8.05.10.
Step 2. Calculate the normal flow depth using Manning's equation (I igure
8.054). Check to see that depth is consistent with that assumed for select on of
Manning's n in Figure 8,05d, pg. 8.05.11. For smaller runoffs Figure 8.115d is
not as clearly defined. Recommended solutions can be determined by usi 1g the
Manning equation.
Step 3. Calculate shear stress at normal depth.
Step 4. Compare computed shear stress with the permissible shear stre >s for
the liner.
Step 5. If computed shear is greater than permissible shear, adjust ct,annel
dimensions to reduce shear or select a more resistant lining and repeat s:eps 1
through 4.
Design of a channel with temporary lining is illustrated in Sample Pr )blem
8.05b, pg. 8.05.14.
Rev. 1V93 805.13
1Y
-A?
NCDENR
OaO` W AT ?R?G
h r
O Y
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
LEVEL SPREADER, FILTER STRIP AND RESTORED RIPARIAN BUFFER SUPPLEMENT
This form must be completely filled out, printed and submitted.
DO NOT FORGET TO ATTACH THE REQUIRED ITEMS CHECKLIST AND ALL REQUIRED ITEMS (NEXT WORKSHEET)!
jl. PROJECT INFORMATION
Project name Hasentree Phase 6A - Pond SC-01
Contact name Hunter Freeman, PE
Phone number 919-469-3340
Date June 30, 2009
Drainage area number SC-01 Outlet
II. DESIGN INFORMATION'
For Level Spreaders Receiving Flow From a BMP
Type of BMP Dry Pond
Drawdown flow from the BMP 6.02 cfs
For Level Spreaders Receiving Flow from the Drainage Area Do not complete this section of the worksheet.
Drainage area 795,841.00 ft2 Do not complete this section of the worksheet.
Impervious surface area 218,671.00` ft2 Do not complete this section of the worksheet.
Percent impervious 27.48 % Do not complete this section of the worksheet.
Rational C coefficient 0.35 Do not complete this section of the worksheet.
Peak flow from the 1 in/hr storm 6.39 cfs Do not complete this section of the worksheet.
Time of concentration min
Rainfall intensity, 10-yr storm in/hr Do not complete this section of the worksheet.
Peak flow from the 10-yr storm cfs Do not complete this section of the worksheet.
Where Does the Level Spreader Discharge?
To a grassed bioretention cell? N (Y or N)
To a mulched bioretention cell? N (Y or N)
To a wetland? N (Y or N)
To a filter strip or riparian buffer? Y (Y or N) Please complete filter strip characterization below.
Other (specify)
Filter Strip or Riparian Buffer Characterization (if applicable)
Width of grass 65.00 ft
Width of dense ground cover 0.00 ft
Width of wooded vegetation 0.00 ft
Total width 65.00 ft
Elevation at downslope base of level lip 349.00 fmsl
Elevation at top of bank of the receiving water 344.00 fmsl
Slope (from level lip to to top of bank) 7.69 %
Are any draws present? N (Y or N) OK
Level Spreader Design
Forebay surface area sq ft No forebay is needed.
Feet of level lip needed per cfs 13 ft/cfs
Answer "Y" to one of the following:
Length based on the 1 in/hr storm? N (Y or N)
Length based on the 10-yr storm? N (Y or N)
Length based on the BMP discharge rate? Y (Y or N)
Design flow 6.02 cfs
Is a bypass device provided? Y (Y or N) OK
Form SW401-Level Spreader, Filter Strip, Restored Riparian Buffer-Rev.5 Parts I. and II. Design Summary, page 1 of 3
Length of the level lip
Are level spreaders in series?
Bypass Channel Design (if applicable)
Does the bypass discharge through a wetland?
Does the channel enter the stream at an angle?
Dimensions of the channel (see diagram below):
M
B
W
y
Peak velocity in the channel during the 10-yr storm
Channel lining material

------------
M
85.00 ft
N (Y or N)
N (Y or N)
Y (Y or N)
3.00 ft
5.00 ft
12.00 ft
2.00 ft
5.19 cfs
Class I RipRap
V
B
M
#VALUE!

Form SW401-Level Spreader, Filter Strip, Restored Riparian Buffer-Rev.5 Parts I. and ll. Design Summary, page 2 of 3
III. REQUIRED ITEMS CHECKLIST
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.
Pagel Plan
Ini ' Is Sheet No.
70A 1. Plans (1" - 50' or larger) of the entire site showing: `'? t ?? ?? •Se? 0-10 &I-C
- Design at ultimate build-out, 'Fi v L tACAoW
- 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.
"UPtLS0117- 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.
71ML St. 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. A date-stamped photograph of the filter strip that clearly shows the type of vegetation that is present.
•5. A construction sequence that shows how the level spreader will be protected from sediment until the entire
drainage area is stabilized.
?Y4) 6. The supporting calculations.
7. A copy of the signed and notarized operation and maintenance (0&M) agreement.
_ 8. A copy of the deed restrictions (if required).
Form SW401-Level Spreader, Filter Strip, Restored Riparian Buffer-Rev.5 Part III, page 3 of 3
STORMWATER DEVICE MAINTENANCE AGREEMENT
PROJECT: Hasentree Family Activity Center
RESPONSIBLE PARTY: CRM Hasentree, LLC PHONE NO.:
ADDRESS: 8521 Six Forks Rd., Suite 255
Raleigh, NC 27615
I. Monthly or after every runoff producing rainfall, whichever comes first:
A. Remove debris from area.
B. Check and clear of any obstructions.
C. Remove trash, repair eroded areas before next rainfall.
D. Replace plants that may have died with approved plants.
E. Weeds should be removed and plants should be pruned.
919.870.4747
II. Annually
A. Check ground cover and repair any eroded areas and re-seed any bare areas.
B. Check corrugated pipe for cracks and repair as needed.
C. Check washed stone at inlet and replace as needed.
III. General
A. All components of impoundment system to be kept in good working order.
B. Additional planting is encouraged.
C. Fertilizer should be used sparingly. Apply lime as needed.
D. In case the ownership of the device transfers, the current owner shall, within thirty (30) days of transfer of
ownership, notify Wake County Environmental Services of such ownership transfer.
I, CRM Hasentree, LLC, c/o Kempton Shields , hereby acknowledge that I am the financially responsible party
for maintenance of this impoundment. I will perform the maintenance as outlined above, as part of the Certificate of
Compliance with Stormwater Regulations received for this project.
Signature:
I, _
County of
personally appeared before me this
execution of the forgoing instrument.
Date:
a Notary Public for the State of
do hereby certify that
day of
Witness my hand and official seal,
,20 and acknowledge due
Seal My commission expires
Pond and Dam Maintenance Agreement
NORTH CAROLINA
WAKE COUNTY
Property of:
KNOWN ALL MEN BY THESE PRESENTS that,
being the owners of property surrounding that Dry Detention Ponds SC01 & SC02 as well as the
ponds themselves, located in Wake County, North Carolina designated as Hasentree Family
Activity Center and particularly described on plat in Book of Maps 2006 Page 830 Wake County
Registry (labeled as Future Sports Complex),
DO HEREBY AGREE AND COVENANT with all persons, firms or corporations, now
owning or hereafter acquiring and ownership and or riparian right to the pond as referenced
above, that all are hereby subjected to the following Pond and Dam Maintenance Agreement,
running with said properties by whomever owned, to wit:
The parties acknowledge that the dams are located within the property of Hasentree
Family Activity Center described in Book of Maps 2003 Page 1271-1272 Wake County
Registry (labeled as Future Sports Complex). The parties further acknowledge that the
spillway for said dams are located on the property of CRM Hasentree. LLC Pin Number
1811.73-7845 with emergency spillways being on the property of CRM Hasentree, LLC.
2 As CRM Hasentree, LLC is planning to develop the tract or parcel of land upon which the
dam and pond are located, CRM Hasentree, LLC does agree to perform any and all
maintenance and repair required by the appropriate governmental authorities to bring
the pond, dam and spillways into compliance with current applicable governmental
regulations.
3. CRM Hasentree, LLC, gives, grants, and conveys unto Wake County, the right and easement
to come upon their property for the purpose of cleaning, improving and repairing any
portion of the pond, dam and spillway which may be required by the appropriate
governmental authorities to bring the pond, dam and spillways into compliance with
current governmental requirements.
4. Upon completion of the initial improvements (whether or not the same are actually
required by the appropriate governmental authorities), the parties of this Agreement, for
themselves as well as their successors in interest, agree that thereafter all
maintenance, improvements, upkeep and maintenance of the pond, dam and spillways
shall be the responsibility of the CRM Hasentree, LLC, their heirs, successors, and assigns,
regardless of whether the required work is to the dam, pond or spillways. To
accomplish such upkeep and maintenance, the parties to this agreement hereby grant
to the other party reciprocal easements for the purpose of going upon the property of
the other, for construction and maintenance of the required improvements and or
repairs.
5. While CRM Hasentree, LLC is in the process of developing the parcel, and to insure that the
pond, dam and spillways are at all times operable, CRM Hasentree, LLC will obtain periodic
maintenance services on the pond, dam and spillways. The cost of said maintenance
shall be the responsibility of the CRM Hasentree, LLC .
Maintenance services should include but are not limited to:
• Removal of all trees with four inch diameter or greater from the dam.
• Inspection of riser and spillway to insure proper functionality.
• Debris and sediment removal from riser and barrel.
• Maintain proper pond depth.
• Repair any eroded areas.
• Repair any broken pipes.
• Mow side slopes according to season.
6. Upon completion of development by CRM Hasentree, LLC, then the homeowners association
as established by CRM Hasentree, LLC - shall select a person or firm to undertake the
responsibility of periodic pond, dam and spillway maintenance. In the event that said
association or its successors to the task of maintenance do not perform the necessary
maintenance, then CRM Hasentree, LLC or their successors in title, as applicable, may have
the pond, dam and or spillways maintained as needed and apportion the cost to the
Hasentree Homeowners Association.
IN TESTIMONY WHEREOF,
has caused this instrument to be executed, by its Manager, and
have hereunto set their hand and seals, this the _ day of
for CRM Hasentree, LLC
(SEAL)

NORTH CAROLINA
WAKE COUNTY
I, the undersigned, a Notary Public in and of the State and County aforementioned do
hereby certify that personally appeared before me this day
and acknowledged the execution of the forgoing instrument, for and in behalf of said Company.
WITNESSED my hand and notarial seal, this the day of
Notary Public
My Commission Expires
NORTH CAROLINA
WAKE COUNTY
I, the undersigned a Notary Public in the State and County aforesaid, do hereby certify
that personally appeared before me this day and acknowledged
the execution of the forgoing instrument.
WITNESSED my hand and notarial seal, this the day of
Notary Public
My Commission Expires
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o HCF 06/30/09 HASENTREE Su U1. D: rR A I hNA N Checked By Job No. AINAGE AREA MAP ENGINEERS I PLANNERS I SURVEYORS p
North Carolina 111 MacKenan Drive Cary, North Carolina 27511 t@L 919.469.3340 www withersraveneLcom License No, 0832
Wake County W&R 02090189.00 o
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~ \ 1 ~ \
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6" THICK PRECAST CONCRETE COVER \ \ W/ MANHOLE COVER ACCESS ° \ \ 355.80 ^e~ ~S `.y, „r U
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PRECAST CONCRETE BOX I
CLASS III OPEN ALL FOUR SIDES 8" i ~ WEIR CREST ~ \ ee eo `361'' < eo e yy
ELEVATION: x-39- i i , _ _ - r' 9,19 ~ ~ fir' t 66 `a` \ `e \ \ \ \ ` \
356.25 \ \
8° .MIN. \ 354.59 ! ~ i~ ~ ~ ` ~ e\ \\e y~ / ~ i ~ ~ s ``3S I'd eel ee \
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GROUT EACH SIDE 10° OPENING IN BOX / - INV: 353aj9• / ~ ` ~ t 354,20 e \ \ , ~
353.00 / . , ,
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JOINT SEALED WITH A-LOCK NEOPRENE ~ • ~4 REBAR 9 - _ GASKET CAST IN MANHOLE WALL ~ . ®2 Ff. OC e` - ,~`.'9~ ~ ~ tie ~ 357.®7 \ `e\ \ \
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CLASS III RCP 353.®® / e , , ,
OUTLET PIPE EI::-353:99- / caNCRER:9 ° b BASE ~ a' ` ~s 2 RI~ERt~g' \ \ STORMWATER `°\c e°e\
a • 352.27 , ~ ',~s~ `,e 352.25 a\\ \y NT~CE `~6 `e
n• ~ ~ ~ a e e\ \ y \ \
WRAP ALL JOINTS WITH 4 • ~
7 OZ. NON-WOVEN : ; • ~ . GEOTEXTILE , , ~ - ~ ~ b `e~ ~ ` ` e e\ \
~ 9 X 9 CONCRETE FOOTING _
(2,500 PSI CONCRETE MIN.) •
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EVEL PREA ER CONSTRUCTION SE UENCE P®N SC 01 L S D ~ ~te \ \ \ ~ \e \ y \
\ \ ° 1 \ \ \ \ \
1. INSTALL SILT FENCE ALONG NEUSE RIVER BUFFER, OR VERIFY .THAT. EXISTING ~ , ~ \ ` \ `e e y \ \ \ \ `
SILT FENCE IS IN GOOD CONDITION AND FUNCTIONING AS INTENDED. ~ ? ~ ~ 1 y \ \ \ \ . t \ \ \ \
~ E%. GRaIND 1 2. INSTALL BYPASS CHANNEL FROM END OF EXISTING DISSIPATER PAD TO STREAM. ~ - e \ e y \ \ \ \ \ ee. \ ~`~e .y \ \ \ \ \
3. INSTALL LEVEL SPREADER SWALE AND LIP y 1 1 1 \ \ tS \ \
. - - - 4. REMOVE EXISTING RIPRAP OUTLET PROTECTION. ~ ~
`I i 1= ,;c M~, =1 I I- 5. INSTALL PLUNGE POOL ENERGY DISSIPATER AS SHOWN ON PLANS ~ \ 11I 1 ! 1f1 t \ \ \ \
_ ' M~• - ~ 6. STABILIZE ALL DISTURBED AREAS • I- \ ee\ I I ~ I \ , \ \ \ \
- 7. CONTACT WAKE COUNTY FOR FINAL SITE INSPECTION ~ I- i \ \
- ~ _ 8. UPON APPROVAL FROM WAKE COUNTY, REMOVE SILT FENCE ~ -~-----__LI f - ---e 1~\~ ~ ~ y \y \ a\\ \1\ - - ~ ~ I ~ I
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w SECTION A ® N :CONTRACTOR MAY REV6SE ALIGNMENF IN FIELD TD MINIMIZE IMPACT TO YEY'ETATK)N. OTE _ _ - _ - \ e
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~ olvERSIa~T MEIR. To
~ ii'-0' B'-0° P AT~N = ~ ~ ~ 1
N FILL SLOPE tEYEI SPREADER U ELEY 1r" ''t" .,4. t' ~ ~-G' HIGHER EXISRNG SLOPE ON ~ Y Y w Y-lr i'~ ~ 35i.i7 B'-0° O.OOX SLOPE ON TOP Of OOWN,SIREAII 9~ Y ,~„~y `SCALE: 1" _ 2~,
GIRTER (FIAT B.OPE~
o ELEVarIDN of APROFI Y` ~ Y r N HATCH EXISTII~ StE Ptah Fag LEVEL. ~ Y Y-
c ~ LENGTH FLARED END ~CTgN ,1r. ~ I 2 c ~ 2 FLa~Y AIP RAP ~ y' r
! a „ DIFFUSED RAW J THRaK,'N BUFFER
I Y. STC c Y' Y" Y` ST ATBt MANAGEMlrNT N o ~ eo~
~ ~g° NCIX9T 'B' RIPAAp P P CRON W T 12.AB8 A THI' THI5 STORMWATER' DRY POND HAS BEEN DESIGNED TO ME~f' WAKE COUN'tYY
` 3'-tl' `r lr- DEI NATURAL slo UNDISNRBED GROUND ~ ANI DEVELOPMENT ORDINANCE REQUIREMENTS FOR 1 YEAR PEAK FLOW ATTENUATION t`•~I'
~ X57°WASHm STONE ~ staNE ~ ELEV d AND NEUSE RIVER BASlN WATER QUALffY REGULATIONS FOR DIFFUSED FLOW TO RIPARIAN BUFFERS. ALL CONSTRUCTION DISTURBANCE .WITHIN THE BUFFER
~OS4YNTt~TIC FABRIC i'-B° -THICK - 4 nI~K ((M1~I_N~)__~ COMPACTED TO NIRAFI l40FL 1 (~OtEXRIE MITH !B° OVET~AP AT ALL SEAMS (TYP.) UNDERIIN~ SUBt;RADE GRASS UNED CIWWiiID:l. Y- ~ WIL .WILL BE REVEGETATED TO RIPARIAN BUFFER STANDARDS.
, G' DEEP, 1 WIDE Y~ srn>~u~u SLOPE o ~E PLANS FOR LENGTH AND ELEVATION Y-
N T 8 NOTE: EROSION CONTROL NETIDIG TO ~ INSERTED 1
v, AND $ECUIiED IN GRASS UNED CHANNEL ~ ~ DIMENSIONS ELEV.
c srasaE uNO~u~o ~ A B PREADER CROSS SECTION. 01~ ~ ~ ~ ~0.5o DETAIL OF LEVELS POND BOTTOM N A' 353.00
~ 111 TOP OF DAM WIDTH 10' SEE SPOT ELEVAl10NS
y MAINTENANCE y' ~ TOP OF ANTI-FLOATATION 9' x 9' 353.00
INSPECT THE LEVEL SPREADER AFTER EVERY RAINFALL. UNTT. V9:GETAl10N IS ESTABLISHED 35i. i7 ~ii.0 AND PROPERLY MAKE ANY N®ED. FAIRS. AFTER THE AREA HAS BEEN STA~LRED, ~ 5'x5' RISER CREST (4) x 5'x8" 356.25
MAKE PERIODS INSPECRONS AND KEEP V1:GETAnON IN A I~I.THY, VIGOROUS CONDITION. ~ OUTLET PIPE INVERT IN 30" RCP 352.27
~ Y~,° OUTLET PIPE INVERT OUT 48 LF ®2.29 351;17
~o° RGP C ° ~ ~ ~ EtF/AlION PONi15 DRAWDOWN OUTLET 10" 353.00
ALL AELEVAI~N
m Y coFlsTRiK:TTiON sPECIFxAnoNS
~ 9. THE MATTING SHOULD BE A MINIMUM OF 4 FEET WIDE EXTEN011~ 6 INCHES OVER THE UP AND ~ x BURIm 6 INCHES CEP IN A YERTICAl.1RENCH ON THE LOWER EDGE. TF~ UPPER EDGE St10UlD ~ 1 FL S Y
8U1T AGAINST SMOOTHLY CUT SOD AND BE tEIY-HELD IN PLACE WRH ,CLOSELY SPACED ~ y HEAVY DULY WRtE STAPLES AT LEAST 12 INCHES LONG: ~
2. ENSIK9E THAT TI# SPREADER IS LEVEL, FOR UNIFORM SPRFNXI~ OF STORM RUNOFF. i ii'-O' 6'-O° 3. CONSTRUCT THE LEVEL SPI~ADER ON UNDISTURBED SOIL. NOT ON FlLL Peak Water Freeboard .!'®```e®®Ca
4. CONSTRUCT A ZO F00T TRANSRION SECTbN FROM THE D ION CHAN EL TO BLEND SMOOTHLY Storm .Event Surface Elevation (from 359.00) Peak .Outflow .®~p~~~ ~~•~OC~ ti• NOTE: ®®®®?EESSID °°~~ti,9
WITH ~ WIDTH AND DEPTH ~ THE LEVEL SPREADER. SPREADER UP -CONSTRUCT THE LEVEL. UP ON UNDISTURBED SOiI TO UN~ORM HEIGHT AND ZERO PLAN 5. DISPERSE RUNOFF FROM 'THE SPREADER ACROSS A PROPERLY STABILIZED SLOPE, NOT TO EXCEED GRADE OVER THE LENGTH OF THE SPREADER. d 1-Year - 356.58° 2.44` 6.64 cfs AS-BUILT SURVEYING DATA PROVIDED, BY: Q S •
c 10X, MAKE SURE THAT THE SLOPE IS SUFFlCIENTLY SMOOTH TO KEEP THE FLOW FROM CONCENTRATRIG. OURET AREA -THE OUR,ET DISPOSN. AREA MUST BE GENERALLY SLOTH AND WELL _ 6. IMMEDIATELY AFTER ITS CONS1TtUCiION, APPROPRIATELY SEED AND MULCH THE ENTIRE DISNRBED VEGETATED Wlni A MAXIMUM SLOPE ~ 90X.
~ ' ARFA OF TIC .LEVEL SPREMER. 10-Year 357.40' 1.60' 45.90 cfs CHANCE SURVEYING COMPANY 6900 FIELD HILL ROAD s S=
b ~ BASIN ATBL VEGETATE ALL DISTURBED AREAS rn - 50-Year 358.34° 0.66' 51.77 cfs RALEIGH; NC 27603 °°°~~Gy,~c,~E~~~'e•'~
0
4 100-Year 358.ZT 0.23' 54.23 cfs 919-329-5795 °°,,~eFR"C®~~~~~.•

i
wa raw HAFEAMIRY PORTS COFACMMIUNTYITY
~ STORMWATER AF ~~11° WAKE COUNTY NORTH unouwA rE'r'.' - MANAGEM- ENT POND SC01 WITHERS RAVENEL
ENGINEERS I PLANNERS I SURVEYORS 1 of 1
111 MacKenan Drive Cary, North Carolina 27511 tel: [phone] fax: [phone] www.withersrovenel.com
IL