20001061 Ver 2_Stormwater Info_20090904

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
00- 10(0I
LETTER OF T° ° NSfl MALE
DATE 09-03-09 JOB No. 020 018 .oo
ATTENTION Annette Lucas
PHONE# [phone]
RE: Hasentree
Pond SC-os (Sports Club / Phase 6A)

® Attached ? Under separate cover via
? Prints ? Plans ? Samples
? Change order ? Diskette ?
? Resubmit
? Submit
? Return
COPIES DATE NO. DESCRIPTION
1 09-03-09 1 Project Narrative
1 09- o -0 2 Stormwater Management Details
1 09-03-09 Calculations
1 09-03-09 PowerMulch Compost Blanket Specifications
1 09-03-09 Level Spreader Worksheet and Checklist

THESE ARE TRANSMITTED as checked below:
® For approval ? Approved as submitted
? Foryour use ? Approved as noted
? As requested ? Returned for corrections
? For review and comment ?
? FOR BIDS DUE 20 ? PRINTS RETURNED AFTER LOAN TO US
REMARKS: Annette - per our meeting on august 26th, please find the submittal information attached
for your approval. A detailed narrative is included describing the project. n,;(( r,5?! nr?,//i
DENR - WATER QUALITY
If you have any questions or comments, please call anytime. .1171
COPY TO: file
copies for approval
copies for distribution
corrected prints
the following items:
? Specifications
SIGNED: Hunter C. Freeman
ff enclosures are not as noted, kindly notify us at once.
WITHERS RAVENEL
ENGINEERS I PLANNERS I SURVEYORS
MEMORANDUM
TO: Annette Lucas, NCDWQ
FROM: Hunter Freeman, PE
CC: file
DATE: September 3, 2009
SUBJECT: Hasentree Pond SC-01 Level Spreader
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. This memo follows a site meeting regarding
comments received after the first level spreader submittal in June 2009.
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.
Per our site meeting on August 26, 2009, the modified plan now shows a revised plunge pool
detail. A low weir will divert low flow to the level spreader. At the request of DWQ, the low-flow
pond outlet was revised from a 10" diameter opening to 2 - 6" diameter openings. This will restrict
the low flow during small storm events to 3.60 cfs.
The level spreader has been designed in accordance with the most recent construction
specifications, and includes a concrete lip. Downstream of the level spreader a grassed filter strip
will be constructed in zone 2 of the NRB. Due to existing elevation constraints adjacent to the
existing retaining wall, theslope of the filter strip will approach 10%. The filter strip will be graded
with a consistent and constant slope, and will be vegetated with thick grass cover. A natural
compost blanket will be used to stabilize the area immediately after construction.
The dry pond will also be cleaned out and permanent vegetation will be installed to bring it into
compliance with planting requirements listed in the current BMP manual.
Upon completion, the level spreader, scour hole and filter strip 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.withersravenet.com
I o?aF wnrF9oc

A y
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NCDENR p T
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION APPLICATION FORM
LEVEL SPREA DER, 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)I
I. PROJECTINFORMATION
Project name Hasentree Phase 6A - Pond SC-01
Contact name Hunter Freeman, PE
Phone number 919-469-3340
Date September 3, 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 3.60 cfs
For Level Spreaders Receiving Flow from the Drainage Area Do not complete this section of the worksheet.
Drainage area 795,841.00 ftz 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 5.00 min
Rainfall intensity, 10-yr storm 7,22 in/hr Do not complete this section of the worksheet.
Peak flow from the 10-yr storm 46.17 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) 15' wide Grass Filter Strip
Filter Strip or Riparian Buffer Characterization (if applicable)
Width of grass 15.00 ft
Width of dense ground cover 35.00 ft
Width of wooded vegetation 0.00 ft
Total width 50.00 ft
Elevation at downslope base of level lip 348.00 fmsl
Elevation at top of bank of the receiving water 344.00 fmsl
Slope (from level lip to to top of bank) 8.00 %
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 3.60 cfs
Is a bypass device provided? Y (Y or N) OK
Form SW401-Level Spreader, Fitter Strip, Restored Riparian Buffer-Rev.5 Parts I. and It. 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
45.00 ft Level spreader is not long enough.
N (Y or N)
N (Y or N)
Y (Y or N)
S.uu n
5.00 ft
12.00 ft
2.00 ft
5.19 cfs
Class I RipRap
•

,
-------------
t i
-------------

Y

-------------i

t
M
M
B
Form SW401-Level Spreader, Filter Strip, Restored Riparian Buffer-Rev.5 Parts I. and II. 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.
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.
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. 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.
6. The supporting calculations.
0LI t!2t 7. A copy of the signed and notarized operation and maintenance (0&M) agreement.
fiLe 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
?;
.? '
Level Spreader Weir
Project Description
Solve For Discharge
Input Data
Headwater Elevation 349.00 ft
Crest Elevation 348.50 ft
Tailwater Elevation 348.00 ft
Crest Surface Type Gravel
Crest Breadth 2.00 ft
Crest Length 4.00 ft
Results

Discharge 4.32 W/s
3 . ?D cfi5
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 2.00 ftZ
Velocity 2.16 ft/s
Wetted Perimeter 5.00 ft
Top Width 4.00 ft
Bentley Systems, Inc. Haestad Methods Solution Center Bentley FlowMaster 108.01.071.00]
9/312009 3:10:11 PM 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA [phone] Page 1 of 1
Bypass Channel
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
Manning Formula
Normal Depth
Supercritical
0.069
0.09000 ft/ft
3.00 ft/ft (H:V)
3.00 ft/ft (H:V)
5.00 ft
50.00 ft3/s
1.11 ft
9.23 ft2
12.01 ft
11.65 ft
1.15 ft
0.07730 ft/ft
5.42 ft/s
0.46 ft
1.56 ft
1.07
0.00 ft
0.00 ft
0
0.00 ft
0.00 ft
Infinity ft/s
Infinity ft /s
1.11 ft
1.15 ft
0.09000 ft/ft
0.07730 ft/ft
Bentley Systems, Inc. Haestad Methods Solution Center Bentley FlowMaster [08.01.071.00]
9/3/2009 3:09:17 PM 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA [phone] Page 1 of 1
Standard Specifications for
Compost for Erosion/Sediment Control
Completed by:
Ron Alexander
R. Alexander Associates, Inc.
1212 Eastham Drive
Apex, NC 27502
Telephone - 919-367-8350
Fax - 919-367-8351
E-mail - [e-mail]
Website - www.alexassoc.net
* These specifications contain all of the technical text found in the `Official' American
Association of State Highway & Transportation Officials (AASHTO) versions found
in their 2003 AASHTO Provisional Standards manual. The Compost for Erosion /
Sediment Control `Filter Berms' is designated as specification MP 9 - 03, and the
`Compost Blankets' as specification MP 10 - 03. For copy of the official AASHTO
specifications, contact AASHTO's Publications and Communications Technical
Assistant at 202-624-5800
Copywritten: R. Alexander Associates, Inc, 2003
Standard Specification for
Compost for Erosion/Sediment Control (Compost Blanket)
SCOPE
This specification covers compost produced from various organic by-products, for use as a surface mulch for
erosion/sediment control on sloped areas. This technique may be used for both temporary and permanent
erosion/sediment control applications.
This technique is appropriate for slopes up to a 2:1 grade (horizontal distance : vertical distance), and should only be used
in areas that have sheetflow drainage patterns (not areas that receive concentrated flows). This technique may also be
used on up to 1:1 slopes with proper consideration to length of slope and compost application rates (depth).
GENERAL DESCRIPTION
Compost is the product resulting from the controlled biological decomposition of organic material, occurring under aerobic
conditions, that has been sanitized through the generation of heat and stabilized to the point that it is appropriate for its
particular application. Active composting is typically characterized by a high-temperature phase that sanitizes the product
and allows a high rate of decomposition, followed by a lower-temperature phase that allows the product to stabilize while
still decomposing at a slower rate. Compost should possess no objectionable odors or substances toxic to plants, and
shall not resemble the raw material from which if was derived. Compost contains plant nutrients but is typically not
characterized as a fertilizer.
Compost may be derived from a variety of feedstocks, including agricultural, forestry, food, or industrial residuals;
biosolids (treated sewage sludge); leaf and yard trimmings; manure; tree wood; or source-separated or mixed solid waste.
Proper thermophilic composting, meeting the US Environmental Protection Agency's definition for a 'process to further
reduce pathogens' (PFRP), will effectively reduce populations of human and plant pathogens, as well as destroy noxious
weed seeds and propagules.
Compost is typically characterized as a finely screened and stabilized product that is used as a soil amendment. However,
most composts also contain a wood based fraction (e.g., bark, ground brush and tree wood, wood chips, etc.) which is
typically removed before use as a soil amendment. This coarser, woody fraction of compost plays an important role when
compost is used in erosion and sediment control. It is even possible to add fresh, ground bark or composted, properly
sized wood based material to a compost product, as necessary, to improve its efficacy in this application.
Compost products acceptable for this application must meet the chemical, physical and biological properties outlined in
the section below.
PRODUCT PARAMETERS
Compost products specified for use in this application are described in Table 1. The product's parameters will
vary based on whether vegetation will be established on the treated slope.
Only compost products that meet all applicable state and federal regulations pertaining to its production and distribution
may be used in this application. Approved compost products must meet related state and federal chemical contaminant
(e.g., heavy metals, pesticides, etc.) and pathogen limit standards pertaining to the feedstocks (source materials) in which
it is derived.
6
Table 1 - Compost Blanket Parameters
Parameters 1,4 Reported as Surface Mulch to be Surface Mulch to be
units of measure Vegetated left Un-vegetated
pH2 pH units 5.0-8.5 N/A
Soluble Salt dS/m (mmhos/cm) Maximum 5 Maximum 5
Concentration2
(electrical conductivity)
Moisture Content %, wet weight basis 30 - 60 30 - 60
Organic Matter Content %, dry weight basis 25 - 65 25-100
Particle Size % passing a selected 3" (75 mm), 100% 3" (75 mm), 100%
mesh size, dry weight passing passing
basis 1" (25mm), 90% to 1" (25mm), 90% to
100% passing 100% passing
• 3/4" (19mm), 65% to 3/4" (19mm), 65% to
100%passing 100%passing
• 1/4" (6.4 mm), 0% to • 1/4" (6.4 mm), 0% to
75% passing 75% passing
• Maximum particle length • Maximum particle length
of 6" (152mm) of 6" (152mm)
Stability3
Carbon Dioxide mg COrC per g OM per < 8 N/A
Evolution Rate
-- day

Physical Contaminants
T
dry weight basis
< 1
< 1
(man-made inerts)
' Recommended test methodologies are provided in Test Methods for the Examination of Composting and Compost (TMECC, The US
Composting Council)
2 Each specific plant species requires a specific pH range. Each plant also has a salinity tolerance rating, and maximum
tolerable quantities are known. When specifying the establishment of any plant or turf species, it is important to understand their pH and
soluble salt requirements, and how they relate to the compost in use.
Stability/Maturity rating is an area of compost science that is still evolving, and as such, other various test methods could be considered.
Also, never base compost quality conclusions on the result of a single stability/maturity test.
4 Landscape architects and project (field) engineers may modify the allowable compost specification ranges based on specific field conditions
and plant requirements.
Very coarse compost should be avoided if the slope is to be landscaped or seeded as it will make planting and
crop establishment more difficult.
In regions subject to higher rates of precipitation and/or rainfall intensity, higher compost application rates should be used.
In these particular regions, as well as regions subject to wind erosion, coarser compost products are preferred.
Notes: Specifying the use of compost products that are certified by the US Composting Council's Seal of
Testing Assurance (STA) Program (www.compostingcouncil.org) will allow for the acquisition of products that
are analyzed on a routine basis, using the specified test methods. STA participants are also required to provide
a standard product label to all customers, allowing easy comparison to other products.
Where water quality is an issue, or in areas in proximity to sensitive water bodies, the appropriate compost
product should be used, and vegetating the compost blanket should be considered.

FIELD APPLICATION
The following steps shall be taken for the proper installation of compost as a soil blanket for erosion/sediment control on
sloped areas.
Slightly roughen (scarify) slopes and remove large clods, rocks, stumps, roots larger than 2 inches in diameter and debris
on slopes where vegetation is to be established. This soil preparation step may be eliminated where approved by the
Project Engineer or Landscape Architect/Designer, or where seeding or planting is not planned.
Where practical, track (compact) perpendicular to contours on the slope using a bulldozer before applying compost as soil
blanket.
Apply compost at the rates specified in Table 2.
Table 2 - Compost Blanket Application Rates
Annual Total Precipitation Application Rate Application Rate
Rainfall/Flow & Rainfall Erosivity For Vegetated* For Unvegetated
Rate Index Compost Surface Compost Surface
Mulch Mulch
Low 1-25", '/ - % " ill -1 '/"
20-90 (12.5 mm - 19 mm) (25 mm - 37.5mm)
Average 26-50", 9/, -1" 1 '/2" - 2"
91-200 (19 mm - 25 mm) (37 mm - 50 mm)
High 51" and above, 1-2" 2-4"
201 and above (25 mm - 50 mm) (50mm -100mm)
*these lower application rates should only be used in conjunction with seeding, and for compost blankets applied during
the prescribed planting season for the particular region.
Compost blanket application rates should be modified based on specific site (e.g., soil characteristics, existing vegetation)
and climatic conditions, as well as particular project related requirements. The severity of slope grade, as well as slope
length, will also influence compost application rates.
In regions subjected to higher rates of precipitation and/or rainfall intensity, higher compost application rates should be
used. In these regions, as well as those with spring snow melt, and on sites possessing severe grades or long slope
lengths, the compost blanket may be used in conjunction with a compost filter berm. The filter berm may be 1-2 feet high
(30 cm - 60 cm), by 2-4 feet wide (60 cm - 120 cm), and may be placed at the top or base (or both) of the slope. In these
particular regions, as well as regions subject to wind erosion, coarser compost products are also preferred.
In regions subject to lower rates of precipitation and/or rainfall intensity, lower compost application rates may be used.
Specific regions may receive higher rainfall rates, but this rainfall is received through low intensity rainfall events (e.g., the
Northwestern U.S.). These regions may use lower compost application rates.
Compost shall be uniformly applied using an approved spreader unit, including bulldozers, side discharge manure
spreaders, etc. Alternatively, apply compost using a pneumatic (blower) unit, or other unit that propels the product directly
at the soil surface, thereby preventing water from moving between the soil-compost interface. Thorough watering may be
used to improve settling of the compost. Apply compost layer approximately 3 feet (90 cm) over the top of the slope, or
overlap it into existing vegetation.
On highly unstable soils, use compost in conjunction with appropriate structural measures.
Dry or hydraulic seeding may be completed following compost application, as required, or during the compost application
itself, where a pneumatic unit is used to apply the compost.
8
APPENDIX FOR SPECIFICATIONS
COMPOST SAMPLING AND CHARACTERIZATION OF COMPOST
Sampling procedures to be used for purposes of this specification (and the Seal of Testing Assurance program) are as
provided in 02.01 Field Sampling of Compost Materials, 02.01-B Selection of Sampling Locations for Windrows and Piles
of the Test Methods for the Examination of Compost and Composting (TMECC), Chapter 2, Section One, Sample
Collection and Laboratory Preparation, jointly published by the USDA and USCC (2002 publishing as a part of the USDA
National Resource Conservation Technical Bulletin Series). The sample collection section is available online at
http://tmecc.org/tmecc/.
Test Methods to be used for purposes of this specification are as provided in The Test Methods for the Examination of
Compost and Composting (TMECC), Jointly published by the USDA and USCC (2002 publishing as a part of the USDA
National Resource Conservation Technical Bulletin Series). A list of such methods is provided in the table below and
online at http://tmecc.orq/tmecc/.
Test Methods for Compost Characterization
Compost Reported as Test Method Test Method Name
Parameters
pH TMECC 04.11-A Electrometric pH
Determinations for Compost.
1:5 Slur Method
Soluble salts dS/m (mmhos/cm) TMECC 04.10-A Electrical Conductivity for
Compost. 1:5 Slurry Method
Mass Basis
Primary plant nutrients: as-is (wet) & dry weight
basis
Nitrogen Total N TMECC 04.02-D Nitrogen. Total Nitrogen by
Combustion
Phosphorus P205 TMECC 04.03-A Phosphorus. Total
Phosphorus
Potassium K20 TMECC 04.04-A Potassium. Total Potassium
Calcium Ca TMECC 04.04-Ca Secondary and Micro-Nutrient
Content. Calcium
Magnesium Mg TMECC 04.04-Mg Secondary and Micro-Nutrient
Content. Magnesium
Moisture content wet weight basis TMECC 03.09-A Total Solids and Moisture at
70±5°C
Organic matter content dry weight basis TMECC 05.07-A Matter Method. Loss On
Ignition Organic Matter
Method
Particle size Screen size passing through TMECC 02.12-B Laboratory Sample
Preparation. Sample Sieving
for Aggregate Size
Classification.
Stability (respirometry) mg C02-C per g TS per day TMECC 05.08-B Respirometry. Carbon
Mg C02-C per OM per day Dioxide Evolution Rate
Maturity (Bioassay) TMECC 05.05-A Biological Assays. Seedling
Percent Emergence % (average) Emergence and Relative
Relative Seedling Vigor % (average) Growth
9
ADDITIONAL INFORMATION
For additional information on regional precipitation rates or rainfall erosivity indexes go on-line at
http://www.cr)c.ncep.noaa.gov/products/analyses monitoring/regional monitoring/us 12-month precig.html or
http://danpatch.ecn.purdue.edu/-wepphtml/wepp/wepptutfjhtml/imagedir/usa.gif
US Composting Council Seal of Testing Assurance Program documents, at httr)://tmecc.org/sta/, or
REFERENCES
ASTM Standards:
-D 2977, Standard Test Method for Particle Size Range of Peat Materials for Horticultural Purposes.
US EPA Test Methods:
- US EPA Test Methods for Evaluating Solid Waste, Physical/Chemical Methods. SW-846. 3rd
Edition.
TMECC Sampling and Test Methods:
- Test Methods for the Examination of Compost and Composting (TMECC), Jointly published by the
USDA and USCC (2002 publishing as a part of the USDA National Resource Conservation Technical
Bulletin Series).
Other Standards:
- US Composting Council Seal of Testing Assurance Program documents.
Development of Landscape Architecture Specifications for Compost Utilization, The U.S. Composting
Council and the Clean Washington Center. 1997.
* These specifications contain all of the technical text found in the `Official' American
Association of State Highway & Transportation Officials (AASHTO) versions found
in their 2003 AASHTO Provisional Standards manual. The Compost for Erosion /
Sediment Control `Filter Berms' is designated as specification MP 9 - 03, and the
`Compost Blankets' as specification MP 10 - 03. For copy of the official AASHTO
specifications, contact AASHTO's Publications and Communications Technical
Assistant at 202-624-5800
This material is based on work supported by the Federal Highway Administration
under Cooperative Agreement Number DTFH61-98-X-00095 through the Recycled
Materials Resource Center at the University of New Hampshire, Durham, New
Hampshire.
Copywritten: R. Alexander Associates, Inc, 2003
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(2,500 PSI CONCRETE MIN.) E ATIONS ~ t 35~.5~°° ~ ° ~ ~ s
® ~ TOP OF DAM = _ ° ~ ~ E°END \ ING ®WALL ° ° ° °
RISER & DRAWDOWN DEVICE DETAIL ' x,48 LF. ~.30"..RCP ~ .13~-~`..y, r
NTS ~ ,1; 9~ , ~ e° ° ~•t•a \ ° ° URA
' 30,,...,~EADWALL ~a4° ® ~\i `°`a•• ` °LEVEL`° S R ° ° ° , ° °TENN,~ po
` ~ \ ~ • ~ C~HANN SE`E ETAIL ° ° INVERT. =~~-1-9~- ~ ° °
- - ° , - ~ 35117" ~ ~ ~ • ° ° COUNT
XTEN WING -.WALL 7'- , °~4 ~ \ ° N °1 \
1 1 e \ ` ° e ~ ~ - e \ e ° ° 1 0 ! \ ° °
3' S' EX. GROUND E%. GROUND 1 ~ ° ° 1 \ \ 6 d 49.9 ~ \ ~ ° 1` A° m\\ ®
1 1 YPASSCHANNEL ° w ° 4~~- -a, LAVE SHE D ft °
- - - - - - -I I 3~ i° MIN. 'ti, - _ I I I- -III- 2' t~N. "r1 = - I i i- 1 (SEE DETAIL) ; .r a,°°x 34q \ ~rw ° _ _ _ A
i ~ 1' MIN. - I- 1.5' MIN. - 1 348.0 X\ w ° ® 1 ° ° m \
- - ( - - e ~ \ ~ ° w r ~ .5 , ~ , `I 11 EX~iSTIN~ ° ° \°a PROPOSED LIMITS ~ ~ ~ ,i v ° °
- ~ I- - - - - - = I- - - Q10 . 45.9 CFS 1 OF DISTURBANCE ~ ` ' ~ \ w ` '"4 ~ SEG~~IENTl~L B ~ K °m
III ~ ,r I, ~ ~ ~ , ; v ; ° 1 f~ `RETA~IING°°WA L
CLASS I RIP-RAP -III III-i I I-III-III--III- -III III-I I i-iii-iii-i I ~ V 10:6.1 FT~S 1 CLASS IRIP-RAP ~ d50=0.75' MIN. t' MIN. d50-0.75 MIN. 1.5' MIN. 11 ~ ~ I 7 ~ ° \ w d "7 i ! 1A \ tr'~
S : 9.0% 1 tiC °t I \ ~ g\ ~ 9~ i t °e ° °m ~o \ d A ° ° e
1\ ~ ~ ~ e ~ ~ ~ ~ ~ i ~ A ° °e
NOTE :CONTRACTOR MAY REVISE ALIGNMENT IN FlELD TO MINIMIZE IMPACT TO VEGETATION. NOTE :CONTRACTOR MAY REVISE ALIGNMENT IN FlELD TO MINIMIZE IMPACT TO VEGETATION. ~
\ e \ ° \ > \ ~ D~ o i ~ \ \ °
V i _ ~ ~~~I ' l 9. Al A ° ° ° °t
LEVEL SPREADER CHANNEL DETAIL BYPASS CHANNEL DETAIL a ~ .I_f to < \ ° ° ,
~ NTS TOTAL BUFFER DISTURBANCE A m P ~ I A < a \ ° ° I~ A \ \ ° \
BYPASS CHANNEL ° ,r ~ A \ ° D \ ° A ° °t. ° \ ° o
~ i° ~ ° ° ° v ° cs° ° A
ZONE 1: 1,300 S.F. t e ° ° o \ tii AV m• ~ 9 ® ° \ D AA 4V °
ZONE 2: 750 S.F. e. e ° ° D ° ° 4 °
TENNIS COURT - FILTER STRIP \ wt ~A6 ° \ ~ ° t
_ - _ ~t - LEVEL SPREADER LIP ELEVATION = 348.50 ZONE 1: 0 S.F. ° °
2 ~ ~ 2 I (=I = ~ * 4"-6"HIGHER EXISTING SLOPE ON DOWNSTREAM SIDE
~ ~ .I * 0.00% SLOPE ON TOP OF GUTTER (FLAT SLOPE) ZONE 2: 1,600 S.F. I i„ 5'.~ _ _ _ EXISTING \ i A! A' f ~ i i b ti 15 VE~ETATE~' ~FIL1'~i~ S.ZRIP i
I= - = SEGMENTAL BLOCK RETAINING ; F~ t;~SEE NOTE, BELOW)°~ ~ ~
- - 5' WALL \ ~''a A ~ I 1° t ~
i s s
NEUSE RIVER FILL SLOPE BUFFER ` ` NEUSE' RIVER BUFFER ®1®, ; \ t A °
~ SECTION A SECTION 8 ZONE 1 _ I ` t ° ~ ~ 1 1
0 r I 1A ' t °
~ A B 15' GRASSED DIVERSION WEIR TO VEGETATED ° r l •t ~ AA ° ° a 1 .i t ~-l A \ ° ° °
LEVEL SPREADER 16'-O" EL. 348.50 6,_~. FILTER STRIP r ° °
EX 30" RCP 351.17
z 4,-~. _ _ 349.00 i~
W =1 I I-1 I ,r ~ ,r ~ Z FLOW z~ MAx _ ,T- Y' y-
~,.y- Q III- _ Y' ST®RME SC•01 DETAIL a
~ _ _ ~ i ELEVATION OF 10% MAX GRASS- = I I ~ ~ ~ ~'>Y
v, III- 2 I 2 APRON MATCH ~ W - ° EXISTING - _ _ =I I 1~ "'Y -1 I I-_ ~ ~ 1 ~ 1 - - - _ I ~ ~ ,r SCALE: 1" = 20'
- 34 67 I GRADE =I I (=III I I ®I ~ Y` Y ~tiv- _ I I_I I _ - - - 3 = I I=III-III- I I I I-III I I I-~ ~ ~ Y- ~ ~
~ NCDOT CLASS B -III-_' - III NCDOT
- ~ RIPRAP = I ` - ~-"-~`I'.- =I CLASS B COMPACTED SUBGRADE Y~ ~ ,Y 4 w POND SC-01 LEVEL SPREADER CONSTRUCTION SEQUENCE STORMWATER MANAGEMENT NOTE:
o - _ _ - - _ - RIPRAP UNDISTURBED EARTH 7 WASHED STONE - 4•" THICK MIN ~ ~ ~ 'Y' J NATURAL GROUND ZONE 1 BUFFER 5 ( ) ~ THIS STORMWATER DRY POND HAS BEEN DESIGNED TO MEET WAKE COUNTY ~ 1. INSTALL SILT FENCE ALONG NEUSE RIVER BUFFER, OR VERIFY THAT EXISTING DEVELOPMENT ORDINANCE REQUIREMENTS FOR 1 YEAR PEAK FLOW ATTENUATION
o ( ) ERMAMENT GEOTEXTILE .y~- r o UNDERLINER ~ ~ N 1'-6" 57 STONE SILT FENCE IS IN GOOD CONDITION AND FUNCTIONING AS INTENDED. AND NEUSE RIVER BASIN WATER QUALITY REGULATIONS FOR DIFFUSED FLOW
~ MIRAFI 140N GEOSYNTHETIC FABRIC + -THICK ~ ~ 2. fNSTALL BYPASS CHANNEL FROM END OF EXISTING DISSIPATER PAD TO STREAM. TO RIPARIAN BUFFERS. ALL CONSTRUCTION DISTURBANCE WITHIN THE BUFFER
PAT ALL SEAMS TYP. \ ~ ~ WITH 18" OVERLA ( ) l~ N SECTION C LEVEL SPREADER CROSS SECTION A•A ~ 3. INSTALL LEVEL SPREADER SWALE AND LIP WILL BE REVEGETATED TO RIPARIAN BUFFER STANDARDS. 4. REMOVE EXISTING RIPRAP OUTLET PROTECTION
,r' EL~1+ d ~ s NTS ~ Pt~ ~ 5. INSTALL PLUNGE POOL ENERGY DISSIPATER AS SHOWN ON PLANS
~ Y' o ~ ~ STABIL2ED SLOPE i~~ ~ 6. STABILIZE ALL DISTURBED AREAS
N ~ y ~ Y.. o 7. CONTACT WAKE COUNTY FOR FINAL SITE INSPECTION VEGETATED FILTER STRIP NOTE: 8. UPON APPROVAL FROM WAKE COUNTY, REMOVE SILT FENCE FILTER STRIP TO BE GRASSED EVENLY AND LEVEL PERPENDICULAR TO FLOW.
'N TO LEVEL ~ SPREADER ~ J
STABLE UNOISTIAtBED ~ SLOPE SHALL NOT EXCEED 10% PARALLEL TO FLOW AND SHALL BE CONSTANT ALONG ENTIRE LENGTH OF WIDTH OF LEVEL SPREADER. FILTER STRIP SHALL
°v 348.50 p` B O~ aREA ~ ~ ~ ~ 4' 0" y" ~ t>~li BE SODDED OR SEEDED AND COVERED WITH NATURAL COMPOST UNTIL
o ~ III VEGETATION IS WELL ESTABLISHED.
y' Ali
" MAINTENANCE ~ y- ~ NC NOTE:
351.17 cG 349.00 INSPECT THE LEVEL SPREADER AFTER EVERY RAINFALL UNTIL VEGETATION IS ESTABLISHED y- AND PROPERLY MAKE ANY NEEDED REPAIRS. AFTER THE AREA HAS BEEN STABILIZED, ~ AS AS-BUILT SURVEYING DATA PROVIDED BY: ~ 1
~ELEY MAKE PERIODIC INSPECTIONS AND KEEP VEGETATION IN A HEALTHY, VIGOROUS CONDTfION. y' ~
347.7 ~ OE Q CHANCE SURVEYING COMPANY
a 30" RCP :1 ~ 2:1 ~ aN sa~o~~1N~ 69 s C CONSTRICTION SPECIFICATIONS ro ~ ALL AT SAME EIEVAliON 6900 FIELD HILL ROAD RALEIGH, NC 27603 S L P 2~C9
= 1. THE MATi1NG SHOULD BE A MINIMUM OF 4 FEET WIDE EXTENDING 6 INCHES OVER THE UP AND ,r' 9 ~ 919-329-5795 pE~.~AT~Rau~1T~
I BURIED 6 INCHES DEEP IN A VERTICAL TRENCH ON THE LOWER EDGE. THE UPPER EDGE SHOULD = BUTT AGAINST 51uCOTHLY CUT SOD AND BE SECURELY HELD IN PLACE WITH CLOSELY SPACED
HEAVY DUTY WIRE STAPLES AT LEAST 12 INCHES LONG. y- 2. ENSURE THAT THE SPREADER IS LEVEL, FOR UNIFORM SPREADING OF STORM RUNOFF. Y' PT. AS•BUILT ELEVATIONS POND SC010UTFL W SUMMARY '~s~°ST~~"'~T£RBRAMCt~ °Dp00000D0000p000
3. CONSTRUCT THE LEVEL SPREADER ON UNDISTURBED SOIL NOT ON FlLL) CONCRETE UP I i3 4. CONSTRUCT A 20 FOOT TRANSmON SECTION FROM THE ON RSION CHANNEL TO BLEND SMOOTHLY DIMENSIONS ELEV. Peak Water Freeboard °°°~~~Hp~ARO~oo°°°
WITH THE WIDTH AND DEPTH OF THE LLVEL SPREADER. °°°~~°•°o'<~ssio °°°~y
5. DISPERSE RUNOFF FROM THE SPREADER ACROSS A PROPERLY STABILIZED SLOPE, NOT TO EXCEED Pf 10~, MAKE SURE THAT THE SLOPE IS SUFFlCIENTLY SMOOTH TO KEEP THE FLOW FROM CONCENTRA111C. SPREADER UP -CONSTRUCT THE LEVEL LIP ON UNDISTURBED SOIL TO UNIFORM HaGHT AND ZERO POND BOTTOM N A 353.00 Storm Event Surface Elevation (from 359.00) Peak Outflow o Q~ N9~~o9 °o
6. IMMEDIATELY AFTER IT'S CONSTRUCTION, APPROPRIATELY SEED AND MULCH THE ENTIRE DISTURBED T( _ AREA OF THE LEVEL SPREADER. GRADE OVER THE LENGTH OF 1HE SPREADER. TOP OF DAM WIDTH 10'-5= SEE SPOT ELEVATIONS 1-Year 356.56' 2.44' 6.64 cfs °
m OUTLET AREA -THE OUTLET DISPOSAL AREA MUST BE GENERALLY SMOOTH AND WEII T~ 16'-0" 6'-0" VEGETATED WI1T1 A MAXIMUM SLOPE OF 10%. 5~ TOP OF ANTI-FLOATATION 9' x 9' 353.00 PEE ~ ,AE1,Y
5'x5' RISER CREST (41 x 5'x8" 356.25 10-Year 357.40' 1.60' 45.90 cfs a .s ~ 8 0 ~ o
cy) PLAN VIEW
VEGETATE ALL DISTURBED AREAS 01 OUTLET PIPE INVERT IN 30" RCP 352.80- 352.27 °°°,yG~^°~N~iNEo
PLUNGE BASIN ENERGY DISSIPATER LEVEL SPREADER o NTS M5 D "0. Rev" Date ~ ~ Sc* AS SHOM HASENTREE GOLF COMMUNITY 09/03/09 FAMILY SPORTS FACILITY STORMWATER M By LEVEL SPRI OUTLET PIPE INVERT OUT 48 LF ® 2.29% 351.00 351.17 50-Year 358.34 0.66 51.77 cfs
DRAWDOWN OUTLET 10" 3 5 3. 353.00 100-Year 358.77' 0.23' 54.23 cfs ep°0ppjpp00
11 A
"E MANAGEMENT POND SC-01 WITHER RAV E N E L
1 SPREADER REVISIONS ENGINEERS I PLANNERS I SURVEYORS 1
pyyMp ~yy,~ WAKE COUNTY NORTH CAROLINA 111 MacKenon Drive Cary, North Carolina 27511 tel: [phone] fax: [phone] www.withersravenel.com