20080652 Ver 3_More Info Received_20080609

L? urban design planning cM[ engineering landscape architecture
TRANSMITTAL
223 North Graham Street, Charlotte, NC 28202 ? $ " ? ? s a.. V 3
V: 704.333.0325 F: 704.332.3246
DATE: 6/6/2008
PROJECT NAME: Hadley
TO: Joesphn Gyamfi
NCDENR
2321 Crabtree Blvd. Suite 250
Raleigh
NC 27604
CC
WE ARE SENDING:
VIA:
NUMBER OF PAGES: 1
PROJECT #: 1007154
BUS. PHONE:
BUS. FAX: D R @ 9 r=3
BUS. MOBILE: {`J
JUN 9 2008
DENR - WATER OUAUTY
WETLANDS AND STORMWATER BRANCH
PURPOSE:
DRAWINGS ? MAIL ? APPROVAL
? SPECIFICATIONS ? FAX ? YOUR USE
® APPLICATIONS ? COURIER ? YOUR INFORMATION
? FEES ? FEDEX GROUND ? REVIEW/ COMMENT
? REDLINES Lil FEDEX OVERNIGHT ? YOUR REQUEST
? DISK/ CD ? HAND DELIVERY ? SIGNATURE
? OTHER ? PICKUP
? EMAIL
QUANTITY: ITEM: DESCRIPTION:
3 set 24 x 36 plan sheet Revised SMP Submittal
3 sets Forms BMP Supplement and Required Items Check List
Operation and Maintenance Agreements
3 sets Agreements Comment Response Letter
2 Letters Revised Engineering Calculations
2 Books Revised Stormwater Narrative
3 Narrative
NOTES:
FROM: Frank J. McMahan, PE fjm
If this document was delivered via FAX, the accompanying transmission contains confidential information intended only for the use of the individual of the entity named above.
If you are not the intended recipient, you are hereby notified that any disclosure, copying, distribution or the taking of any action in reliance on the contents of this facsimile
information is strictly prohibited. If you have received this FAX in error, please immediately notify us by telephone to arrange for disposition or return of the documents to us.
Charlotte NC
Washington DC Tampa FL Asheville NC Pinehurst NC Charlotte NC Nashville TN Beijing PRC
LandDesign..
urban design planning civil engineering branding landscape architecture
June 5, 2008
Cyndi Karoly, Supervisor
Division of Water Quality
401 Oversight/Express Review Permitting Unit
1650 Mall Service Center
Raleigh, NC 27699
C ? 0W p
5
JUN 9 2008
DENR • WAi ER QUAL11Y
WETLANDS AND STORMWATER BRANCH
RE: Review comment response for
Hadley Subdivision
LandDesign PN: 1007154
Dear Cyndi:
Listed below are LandDesign's responses to the request for more information for Hadley Subdivision.
1. All Wet Ponds:
a. Please resize the wet ponds using the appropriate Surface Area to Drainage (S/A) ratio
corresponding to the average pond depth determined by dividing the permanent pool
surface area into the permanent pool volume.
RESPONSE:
Wet Pond #1 -We have revised the pool bottom from Elevation 612.0 to Elevation 610.5
in order to maintain the 4 foot average depth which was used for the SA/DA ratio. Wet
Pond #1 maintains an average depth of 4.06 feet which is more than the required 4 feet.
The average depth was calculated from the Sediment Removal Elevation of 612.37
(Forebay and Main Pond) to the Permanent Pool Elevation of 618.0.
Wet Pond #2 - We have revised the SA/DA ratio to be 1.90 which requires an average
depth of 3.84 feet, Wet Pond #2 has been designed to maintain an average depth of 3.84
feet. The average depth was calculated from the Sediment Removal Elevation of 597.5
(Forebay) and 596.0 (Main Pond) to the Permanent Pool Elevation of 602.0. The required
surface area required for the permanent pool at this ratio is 7,862 square feet, we have
provided 21,687 square feet which is more than the required area. The supplement form
has been revised accordingly.
Wet Pond #3 - We have revised the SA/DA ratio to be 2.97 which requires an average
depth of 3.27 feet, Wet Pond #2 has been designed to maintain an average depth of 3.27
feet. The average depth was calculated from the Sediment Removal Elevation of 618.5
(Forebay and Main Pond) to the Permanent Pool Elevation of 623.0. The required surface
area required for the permanent pool at this ratio is 19,871 square feet, we have provided
21,690 square feet which is more than the required area. The supplement form has been
revised accordingly.
b. Please revise the drawdown calculations using the appropriate driving head.
RESPONSE:
All the drawdown calculations have been revised using the orifice equation and then
dividing the Storage Volume Provided by the calculated flow in the orifice equation. As
discussed the driving head is taken from the Temporary Water Quality Elevation to the
Permanent Pool Elevation.
Wet Pond #1 - 2.93 days Washington DC
Wet Pond #2 - 2.65 days Charlotte NC
Wet Pond #3 - 2.72 days
The supplement forms have been revised accordingly. Pinehurst NC
223 North Graham Street
Charlotte, NC 28202 Asheville NC
Tampa FL
V: 704.333.0325
F: 704.332.3246 Nashville TN
www.LandDesign.com N:L2007\1007154\DOCS\REVIEW COMMENT RESPONSE_DWO.DOC Beijing PRC
Cyndi Karoly
June 5, 2008
c. Please label as many contours of the BMP as possible.
LandDesign PN: 1007154
Page 2 of 2
RESPONSE:
Additional contour labels have been added to the BMP's as requested.
d. Please revise the section views of the BMPs using 1":20' scale so that all components
appear dimensionally correct. For example, the littoral shelves are less than 10' on a
1":10' scale, side slopes appear steeper than they should appear.
RESPONSE:
All cross sections have been revised on Sheet C-4.12 and are scaled 1 "=20' in both the
horizontal and vertical directions.
2. Wet Pond 2:
a. Please re-grade the contours and/or create a diversion structure to direct stormwater
from the southern and western portions of the BMP into the forebay. Stormwater from
these areas appears to bypass the forebay.
RESPONSE:
A temporary diversion ditch has been graded in from the southern and western portions
of the BMP to direct water to the forebay as requested please refer to Sheet C-4.10.
b. The left corner of the riprap apron at the end of the BPM outlet pipe appears to be in the
footprint of the stream bed and bank. Please reconfigure your outlet protection device to
avoid unauthorized stream impacts.
RESPONSE:
As discussed the Rip Rap Apron has been reconfigured to avoid any stream impacts.
Please refer to sheet C-4.10 for revision.
3. Wet Pond 3:
a. Please extend the baffle to the temporary pool elevation or higher.
RESPONSE:
The baffle within Wet Pond #3 has been revised to meet the Temporary Pool Elevation of
624.64. A label has been added to indicating the Top of Berm Elevation of 624.64. Please
.refer to Sheet C-4.11.
Best regar
AA.
Fra . McMahan, P.E.
ociate
LandDesign I Charlotte, NC
704.333.0325
Washington DC
Charlotte NC
Pinehurst NC
Asheville NC
Tampa FL
Nashville TN
N:\_2007\1007154\DOCS\REVIEW COMMENT RESPONSE DWQ .DOC
Beijing PRC
Wet Pond 1 Stage Storage
Pond 1 - Main Pool

Elev
Area (sf) Inc
Storage
cf Total Storage
(cf)
612.37 8,695 0 0
614.00 10,140 15,351 15,351
616.00 12,039 22,179 37,530
618.00 15,915 27,954 65,484

Pond 1 - For bay

Elev
Area (sf) Inc
Storage
cf Total Storage
(cf)
612.37 1790 0 0
614.00 2437 3,445 3,445
616.00 3290 5,727 9,172
618.00 4363 7,653 16,825

Volume (cf)
Surface Area (sf)
ige Depth (ft)
Forbay Volume Req. (20%)
Forbay Provided (cf)
82,309
20,278
= 4.06
16,462
= 16,825
Pond 1 - Temp WQ Pool

Elev
Area (sf) Inc
Storage
cf Total Storage
(cf)
618.00 20,278 0 0
620.10 25685 48,261 48,261

S6DImenl Rcrnov#9 r
JE LiF V09'r/ 0,*4
t V# 00A
0.20
WET POND #1
DESIGN: WATER QUALITY TO MEET 85% TSS REMOVAL
GIVEN:
DRAINAGE AREA TO FACILITY = 16.38 Ac.
LAND USE = MULTI FAMILY
CALCULATED PERCENT IMPERVIOUS = 81%
DESIGNED PERCENT IMPERVIOUS = 81%
PREDOMINANT SOIL TYPE = CeB,CuB,EnB,MkB,Mo,Ur,WkB,WkD,WkE,WkD
1) POST CONSTRUCTION MANUAL WATER QUALITY PROTECTION VOLUME CALCULATIONS
COMPUTE RUNOFF COEFFICIENT, Rv
Rv= 0.05 + 0.009(1)
1= 81%
Rv= 0.05 + 0.009 (81)
Rv= .779
PROVIDE VOLUME TO DETAIN THE 1" STORM EVENT ABOVE THE ELEVATION
ALLOCATED AS A PERMANENT POOL
THE VOLUME FOR THE 1" STORM EVENT CAN BE CALCULATED AS:
WQv= 3630"1 "*Rv*A
WQv= 3630"1'.779'16.38
WQv= 46,318 FT'
SA/ DA
SA= (2.84/100)*(16.38)
SA=.465 AC = 20,256 SF
2) Pond Drawdown Time (Ogle-711?091- mC1'40 p 1/6G--1j) sG" wc-xf
`PsOd Height above Orifice= 620.100 feet 7 I()[:?9'e R4-Qt) C--5
Onfie lnvert Elevation= 618.000 feet 7% 0
Pond Surface Area at Height Abovebr ' e = 25,685 square feet
Pond Surface Area at Orifice Invert Elevation 0,278 square feet
Orifice Diameter (D) = 3.00 ches = 0.25 feet
Orifice Area (a) = 0.0491 square t
5/28/2008 2:37 PM Page 1 of 2

Average-Surface Area (A) =
Gravitational"Constatnt (g) =
-Head (H) =
Discharge Coefficient (C) =
Time (t)ea
22,982 square feet
32.2 ft/sec2
1.98 feet
0.6
273,299 seconds = 3.16 days
Note:
The above calculation is based on the Bernoulli Equation where:
-2xA IN
t: x a x (2g)° A (O - Ho.5)
?Cgv?rEV !`?E?"Har]
Z 1 '7
C
e /9
V roviDic- D
9
?9
t = 25ypp5sec
zz z. 93 i?A s
2Hi;i5/28/2008 2:37 PM Page 2 of 2

WET POND #2
DESIGN: WATER QUALITY TO MEET 85% TSS REMOVAL
GIVEN:
DRAINAGE AREA TO FACILITY = 9.5 Ac.
LAND USE = MULTI FAMILY
CALCULATED PERCENT IMPERVIOUS = 54%
DESIGNED PERCENT IMPERVIOUS = 54%
PREDOMINANT SOIL TYPE= CeB,CuB,EnB,MkB,Mo,Ur,WkB,WkD,WkE,WkD
1) WATER QUALITY PROTECTION VOLUME CALCULATIONS
COMPUTE RUNOFF COEFFICIENT, Rv
Rv= 0.05 + 0.9(I)
1= 54%
Rv= 0.05 + 0.009 (54)
Rv= .536
PROVIDE VOLUME TO DETAIN THE 1" STORM EVENT ABOVE THE ELEVATION
ALLOCATED AS A PERMANENT POOL
THE VOLUME FOR THE 1" STORM EVENT CAN BE CALCULATED AS:
WQv= 3630*1 "*Rv*A
WQv= 3630*1*.536*9.5
WQv= 18,484 FT3
SA/ DA
SA= (1.90/100)*(9.5)
SA= .1805 AC = 7,862 SF
2) Pond Drawdown Time 601P/C-71/1'9-- Iv
Fond.Height above Orifice =
Orifice-Invert Elevation =
Pond Surface Area at Height Above Orifice.=
Pond Surface Area at Orifice Invert Elevation =
1 Edo:
602.900
602.000
24,074
-21..,.624
9 1/6,i)
feet
feet
square feet
square feet
Orifice Diameter (D) = 2.50 inches = 0.21 feet
Orifice Area (a) = 0.0341 square feet-
6/5/2008 11:13 AM Page 1 of 2
%v r? age Surface Area (A) = 22,849 square feet
aravi atonal Constatnt (g) = 32.2 ft/sec2
Head (H) =
Discharge fficient (C) = 0.80 feet
0.6
= 248,374 seconds = 2.87 days
Note:
The above calcula`on is based on the Bernoulli Equation where:
-2xA
t o x (0 o.s).
;xax (2g)
Vrer7'o /Vj e- 71-12
6(03d/) FZ(aa.z)C9 a?
C?= , 09cFs

ZZ8Psec,
6/5/2008 11:13 AM Page 2 of 2
WET POND #3
DESIGN: WATER QUALITY TO MEET 85% TSS REMOVAL
GIVEN:
DRAINAGE AREA TO FACILITY = 15.36 Ac.
LAND USE = MULTI FAMILY
CALCULATED PERCENT IMPERVIOUS = 75%
DESIGNED PERCENT IMPERVIOUS = 75%
PREDOMINANT SOIL TYPE = CeB,CuB,EnB,MkB,Mo,Ur,WkB,WkD,WkE,WkD
1) WATER QUALITY CALCULATIONS
COMPUTE RUNOFF COEFFICIENT, Rv
Rv= 0.05 + 0.009(1)
1= 75%
Rv= 0.05 + 0.9 (75)
Rv= .725
PROVIDE VOLUME TO DETAIN THE 1" STORM EVENT ABOVE THE ELEVATION
ALLOCATED AS A PERMANENT POOL
THE VOLUME FOR THE 1" STORM EVENT CAN BE CALCULATED AS:
WQv= 1.0'Rv"A/12
WQv= (1.0'.725'`15.36)/12
WQv= 40,423 FT'
SA/ DA
SA= (2.97/100)"(15.36)
SA=.46 AC = 19,871 SF
2) Pond Drawdown Time
and Height above Orifice = 624.640 feet 21- f . v
'fice Invert Elevation = 623.000 feet
Pond Surface Area at Height ve Orifice = 28,420 square feet
Pond Surface Area at Orifice Invert ation = 21,690 square feet
Orifice Diameter (D) - 3.00 inches = 0.25 feet
Orifice Area (a) _ .491 square feet
Average Surface Area (A) = 25,0 square feet
Gravitational Constatnt (g) = 32.2 c2
Head (H) = 1.51 feet
6/5/2008 11:14 AM Page 1 of 2
Coefficient (C) = 0.6
Time (t) = 260,956 seconds = 3.02 days
Note:
The above c lation is based on the Bernoulli Equation where:
t = , -2 x A ?`?, _Hos)
o x
,xax(2g)

CL j Z3 ?3)
=.6 (.09/) V&, Z)Q, dy3)
/7,5'eFs
vr
t-Z3Sy80sec
??ys
t Z 72
6/5/2008 11:14 AM Page 2 of 2
Permit Number: '?A - O Lo S a u 3
(to be provided by DWQ)
Drainage Area Number:
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 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.3 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 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.3 Page 2 of 4
Permit Number:
(to be provided by DWQ)
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.
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 1.87 feet in the main pond, the
sediment shall be removed.
When the permanent pool depth reads 1.87 feet in the forebay, the sediment
shall be removed.
BASIN DIAGRAM
(fill in the blanks)
Sediment Removal
Bottom
0 Permanent Pool Elevation 618
612.37 j;Pe manen Pool
•-----Volume Sediment Removal Elevation 612.37 Volume
-------------------------------------------- ------
610.5 -ft Min.
Sediment Bottom Elevation 610.5 1-ft n
Storage Sedimet
Storage
FOREBAY MAIN POND
Form SW401-Wet Detention Basin O&M-Rev.3 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:HADLEY
BMP drainage area number.SB-1
Print name:MATT BROWDER
Title:ASSOCIATE
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, , bnCl q PC
jg-;'?&n , a Notary Public for the State of
L" 4-h ICO 1 inn, , County of 1 , do hereby certify thatp
personally appeared before me this lq
day of. 66CAA4 and acknowledge the due execution of the
forgoing wet detention basin maintenance requirements. Witness my hand and official
seal,
92
lc c
Zn ocoUmbly
0
A/?CA R
nnnn10
SEAL
My commission expires 9 (A-7 103
Form SW401-Wet Detention Basin O&M-Rev.3 Page 4 of 4
Address: 1600 _CAMDEN ROAD CHARLOTTE, NORTH CAROLINA 28203
Permit Number:
(to be provided by DWQ)
Drainage Area Number:
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 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.3 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 lants 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.3 Page 2 of 4
Permit Number:
(to be provided by DWQ)
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 re air.
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 1.5 feet in the main pond, the sediment
shall be removed.
When the permanent pool depth reads 2.0 feet in the forebay, the sediment
shall be removed.
BASIN DIAGRAM
(fill in the blanks)
Permanent Pool Elevation 602
Sediment Removal 597.5 T Pe anen
-------------- -- Volume
Bottom Elevatio 596 -ft Min.
Sediment
Storage
FOREBAY
Pool
-----Sediment Removal Elevation 596 -- Volume
----------------------------------- ------
Bottom Elevation 594 * 1-ft -
MAIN POND
Form SW401-Wet Detention Basin 0&M-Rev.3 Page 3 of 4
Storage
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:HADLEY
BMP drainage area number:SB-2
Print name:MATT BROWDER
Title:ASSOCIATE
Address: 1600 CAMDEN ROAD CHARLOTTE NORTH CAROLINA 28203
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, ?)6yl%nn ?t°? uvtQxn , a Notary Public for the State of
V3at? car o1? , County of iG ?.,n rr , do hereby certify that
?&-personally appeared before me this
day of and acknowledge the due execution of the
forgoing wet detention basin maintenance requirements. Witness my hand and official
seal,
NX \P f RE E4 f S 4F
. O
No;°'N pJO`?N
IMOO
SEAL
My commission expires_ I IaZ IU?
Form SW401-Wet Detention Basin O&M-Rev.3 Page 4 of 4
Date: 5//6 VP
Permit Number:
(to be provided by DWQ)
Drainage Area Number:
Wet Detention Basin Operation and Maintenance Agreement
I will keep a maintenance record on this BNIP. This maintenance record will be kept in a
log in a known set location. Any deficient BNM 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 BUT.
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 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.3 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 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 lants rather than s ra rig.
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.3 Page 2 of 4
Permit Number:
(to be provided by DWQ)
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.
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 1.5 feet in the main pond, the sediment
shall be removed.
When the permanent pool depth reads 1.5 feet in the forebay, the sediment
shall be removed.
BASIN DIAGRAM
(fill in the blanks)
Sediment Removal
Permanent Pool Elevation 623
618.5
/ermanen
Pool VolSediment Removal Elevation 618.5Volume
Min. - - - - - -
Sediment Bottom Elevation 617 1-ft n
Storage Sedimer
Storage
MAIN POND
Bottom
FOREBAY
Form SW401-Wet Detention Basin O&M-Rev.3 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:HADLEY
BMP drainage area number:SB-3
Print name:MATT BROWDER
Title:ASSOCIATE
Note: The legally responsible parry 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, -Z?r?-nQPsP?rY,ean , a Notary Public for the State of
??N4?C4Aeztl,nn , County of o ?1 v??txr? , do hereby certify that
?1c.?J ^D • Y p?,.7ee e personally appeared before me this R+Ii
day of , AM
, and acknowledge the due execution of the
forgoing wet detention basin maintenance requirements. Witness my hand and official
seal, (}? , u u
Nototy Public
union county
ti
nni+?
SEAL
My commission expires r? 'a1 / &g
Form SW401-Wet Detention Basin O&M-Rev.3 Page 4 of 4
Address: 1600 CAMDEN ROAD CHARLOTTE. NORTH CAROLINA 28203
STORMWATER MANAGEMENT NARATIVE FOR HADLEY
Purpose
The purpose of this study is to analyze the Water Quality/ Detention for Pre and Post
conditions and size the proposed Wet Ponds.
Stormwater Management
The objective of the BMP is to minimize the effects of the development by meeting the
runoff characteristics of the pre developed state of the project site. The main objective of
the BMP is to remove pollutants. The removal mechanisms used for this project are Wet
Detention Basins. Within the Wet Detention Basin forebays are utilized as settling basins
near the inlet to dissipate energy of the incoming stormwater and to settle the larger
incoming sediment particles. The Wet Detention Basins have been designed to achieve
85 Percent TSS removal efficiency, this was achieved by using the surface area to
drainage area ratio tables.
Engineering Background
Detention
Wet Pond #1, Wet Pond #2 and Wet Pond #3 will match the pre development peak storm
water release rates for the 2 and 10 year, 24 hour storm events for the on site drainage
area. The offsite drainage areas will bypass the aforementioned Wet Ponds. However, the
bypass flow and the flow from Wet Ponds #2 and #3 have the same discharge point,
therefore it will be demonstrated within these calculations that the pre and post developed
flows for Wet Pond #2, Wet Pond #3 and the bypass flow will be combined.
Wet Pond #1 has also been designed to detain the additional 2.36 acres from the CATS
Volume #3 plans as requested by CATS. Wet Pond #1 has been adjusted so that the pre
development peak storm water release rates for the 2 and 10 year storm events for the on
site drainage areas.
Water Ouality
Wet Pond #1, Wet Pond #2, and Wet Pond #3 have been designed to provide detention
for the 1" storm event above the Permanent Pool Elevation. The detention provided for
the 1" storm event is for on site drainage areas. The water quality volume formulas used
were based on the SA/DA Ratio.
Wet Pond #1 has been designed to provide detention for the additional 2.36 acres from
the CATS Volume #3 plans as requested by CATS for the 1" storm event above the
Permanent Pool Elevation.
Summary of Results
Wet Pond #1
• Temporary Water Quality Pool Volume:
Required:
Provided:
• Forebay Volume:
Required:
Provided:
• 2 year, 24 hour Design Storm
Pre Developed Runoff:
Post Developed Runoff (no control):
Post Developed (w\ pond):
Max. Stage:
• 10 year, 24 hour Design Storm
Pre Developed Runoff:
Post Developed Runoff (no control)
Post Developed (w\ pond):
Max. Stage:
Pond #2 and Wet Pond #3
46,318 cf
48,261 cf @ Elevation 620.1
16,462 cf
16,825 cf (20%)
9.39 cfs
53.26 cfs
1.92 cfs
621.38
22.94 cfs
91.23 cfs
21.54 cfs
622.67
• Temporary Water Quality Pool Volume (Wet Pond #2):
Required: 18,484 cf
Provided: 20,593 cf @ Elevation 602.90
• Forebay Volume (Wet Pond #2):
Required: 16,666 cf
Provided: 20,319 cf (24%)
• Temporary Water Quality Pool Volume (Wet Pond #3):
Required: 40,423 cf
Provided: 41,209 cf @ Elevation 624.64
• Forebay Volume (Wet Pond #3):
Required: 14,193 cf
Provided: 14,010 cf (19%)
• 2 year, 24 hour Design Storm (Wet Pond #2, #3 and Bypass)
Pre Developed Runoff: 104.69 cfs
Post Developed Runoff (no control): 167.61cfs
Post Developed (w\ pond): 91.28 cfs
Max. Stage: 604.46 (Wet Pond #2)
625.62 (Wet Pond #3)
• 10 year, 24 hour Design Storm (Wet Pond #2, #3 and Bypass)
Pre Developed Runoff: 194.20 cfs
Post Developed Runoff (no control): 285.39 cfs
Post Developed (w\ pond): 190.32 cfs
Max. Stage: 605.34(Wet Pond #2)
626.51 (Wet Pond #3)
Conclusion
The engineering analysis presented herein this document demonstrates the ability that
Wet Pond #1, Wet Pond #2, and Wet Pond #3 to meet the design requirements for water
quality and detention.
The calculations show the Wet Ponds have sufficient volume to meet the requirements
for BMPs. Moreover, the routing calculations show the Wet Ponds ability to detain flows
to pre-developed rates.
Permit No. 8- D LOS A V
(to be provided by DWQ)
of W A TF9
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.
f., RFOJEGT:1NFbRN1AT10N " ' 4
Project name HADLEY
Contact person FRANK J. MCMAHAN, PE
Phone number 704-333-0325
Date 28-May-08
Drainage area number SB-1

Site Characteristics
Drainage area 713,513.00 ft2
Impervious area 577,946.00 ft2
% impervious 81.00 %
Design rainfall depth 1.00 in
Storage Volume: Non-SR Waters
Minimum volume required 46,318.00 ft3
Volume provided 48,261.00 ft3
Storage Volume: SR Waters
1-yr, 24-hr runoff depth N/A in
Pre-development 1-yr, 24-hr runoff ft3
Post-development 1-yr, 24-hr runoff ft3
Minimum volume required ft3
Volume provided ft3
Peak Flow Calculations
1-yr, 24-hr rainfall depth 2.64 in
Rational C, pre-development 0.25 (unitless)
Rational C, post-development 0.70 (unitless)
Rainfall intensity: 1-yr, 24-hr storm 0.11 in/hr
Pre-development 1-yr, 24-hr peak flow 6.15 ft3/sec
Post-development 1-yr, 24-hr peak flow 42.43 ft3/sec
Pre/Post 1-yr, 24-hr peak flow control 36.28 ft3/sec
Basin Elevations
Basin bottom elevation 612.00 It
Sediment cleanout elevation 613.50 It
Bottom of shelf elevation 617.50 ft
Permanent pool elevation 618.00 ft
SHWT elevation * see attachment ft
Top of shelf elevation 618.50 ft
Temporary pool elevation 621.00 ft
Form SW401-Wet Detention Basin-Rev.4 Parts I. & II. Design Summary, Page 1 of 2
Permit No.
(to be provided by DWQ)
11 bES1G FORMATION . ?ti:', a`-?:_
Volume and Surface Area Calculations
SA/DA ratio 2.84 (unitless)
Surface area at the bottom of shelf 13,521.00 ftz
Volume at the bottom of shelf 19,170.00 ft3
Permanent pool, surface area required 20,256.00 ftz
Permanent pool, surface area provided 20,278.00 ft2 OK
Permanent pool volume 82,309.00 ft3
Average depth for SA/DA tables 4.06 ft OK
Surface area at the top of shelf 17,860.00 ft2
Volume at the top of shelf 8,426.00 ft3
Forebay volume 16,825.00 ft3
Forebay % of permanent pool volume 20.44 % OK
Temporary pool, surface area provided 25,685.00 ft2
Drawdown Calculations
Treatment volume drawdown time 2.93 days OK
Treatment volume discharge rate 0.19 ft3/s
Pre-development 1-yr, 24-hr discharge 6.15 ft3/s OK
Post-development 1-yr, 24-hr discharge 0.75 ft3/s OK
Additional Information
Diameter of orifice 3 in
Design TSS removal 85 %
Basin side slopes 3.00 :1 OK
Vegetated shelf slope 10.00 :1 OK
Vegetated shelf width 10.00 ft OK
Length of flowpath to width ratio 3.73 :1 OK
Length to width ratio 3.78 :1 OK
Trash rack for overflow & orifice? Y (Y or N) OK
Freeboard provided 1.65 ft OK
Vegetated filter provided? N (Y or N) Design must be based on 90% TSS removal
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 DRAIN VALVE
Form SW401-Wet Detention Basin-Rev.4 Parts I. & II. Design Summary, Page 2 of 2
* per discussions with the Geotechnical engineer the SHWT is significantly deeper than
the pond bottoms on site. Furthermore, all pond will have a clay liner and will not have
an effect on the SHWT.
Permit No.
(to be provided by DWQ)

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.
Page/ Plan
Initia Sheet No.
L- q. -7C- .
C-2.2; C-2.3

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),
Basin dimensions,
Pretreatment system,
High flow bypass system,
Maintenance access,
Proposed drainage easement and public right of way (ROW),
Overflow device, and
Boundaries of drainage easement.
6J 9_Z401 2. Partial plan (1" = 30' or larger) and details for the wet detention basin showing:
Outlet structure with trash rack or similar,
Maintenance access,
Permanent pool dimensions,
Forebay and main pond with hardened emergency spillway,
Basin cross-section,
Vegetation specification for planting shelf, and
Filter strip.
C° e.l.l 3. Section view of the dry detention basin (1" = 20' or larger) showing:
C- 2.3 Side slopes, 3:1 or lower,
Pretreatment and treatment areas, and
Inlet and outlet structures.
C-4.5. 4. If the basin is used for sediment and erosion control during construction, clean out of the basin is specified
on the plans prior to use as a wet detention basin.
5. A table of elevations, areas, incremental volumes & accumulated volumes for overall pond and for forebay,
to verify volume provided.
C-2 .es--v 6-2• t 6. A construction sequence that shows how the wet detention basin will be protected from sediment until the
entire drainage area is stabilized.
C z' /s 7. The supporting calculations.
8. A copy of the signed and notarized operation and maintenance (0&M) agreement.
9. A copy of the deed restrictions (if required).
"' 10. A soils report that is based upon an actual field investigation, soil borings, and infiltration tests. County
soil maps are not an acceptable source of soils information.
Form SW401-Wet Detention Basin-Rev.4 Part III. Required Items Checklist, Page 1 of 1
Permit No.
(to be provided by DWQ)
OF w A TFR

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.
I. PROJECT.INFORMATION
Project name HADLEY
Contact person FRANK J. MCMAHAN, PE
Phone number 704-333-0325
Date 28-May-08
Drainage area number SB-2
1I: -DESIGN INFCRMATION..
Site Characteristics
Drainage area 413,820.00 ftz
Impervious area 223,453.00 ft
% impervious 54.00 %
Design rainfall depth 1.00 in
Storage Volume: Non-SR Waters
Minimum volume required 18,484.00 ft3
Volume provided 20,593.00 ft3
Storage Volume: SR Waters
1-yr, 24-hr runoff depth N/A in
Pre-development 1-yr, 24-hr runoff ft3
Post-development 1-yr, 24-hr runoff ft3
Minimum volume required ft3
Volume provided ft3
Peak Flow Calculations
1-yr, 24-hr rainfall depth 2.64 in
Rational C, pre-development 0.25 (unitless)
Rational C, post-development 0.70 (unitless)
Rainfall intensity: 1-yr, 24-hr storm 0.11 in/hr
Pre-development 1-yr, 24-hr peak flow 85.27 ft3/sec
Post-development 1-yr, 24-hr peak flow 134.07 ft3/sec
Pre/Post 1-yr, 24-hr peak flow control 48.80 ft3/sec
Basin Elevations
Basin bottom elevation 594.00 ft
Sediment cleanout elevation 596.00 ft
Bottom of shelf elevation 601.50 ft
Permanent pool elevation 602.00 ft
SHWT elevation ' see attachment ft
Top of shelf elevation 602.50 ft
Temporary pool elevation 605.20 ft
Form SW401-Wet Detention Basin-Rev.4 Parts I. R II. Design Summary, Page 1 of 2
Permit
(to be provided by DWQ)
II. DESIGN INFORMATION
Volume and Surface Area Calculations
SA/DA ratio 1.90 (unitless)
Surface area at the bottom of shelf 17,745.00 ftz
Volume at the bottom of shelf 24,825.00 ft3
Permanent pool, surface area required 7,862.00 ftz
Permanent pool, surface area provided 21,687.00 ftz OK
Permanent pool volume 83,332.00 ft3
Average depth for SA/DA tables 3.84 ft OK
Surface area at the top of shelf 25,820.00 ft
Volume at the top of shelf 11,877.00 ft3
Forebay volume 20,319.00 ft3
Forebay % of permanent pool volume 24.38 % Must be approx. 20%, Adjust pond dimensions
Temporary pool, surface area provided 21,687.00 ftz
Drawdown Calculations
Treatment volume drawdown time 2.65 days OK
Treatment volume discharge rate 0.09 ft3/s
Pre-development 1-yr, 24-hr discharge 85.27 ft3/s OK
Post-development 1-yr, 24-hr discharge 70.35 ft3/s OK
Additional Information
Diameter of orifice 2.5 in
Design TSS removal 85 %
Basin side slopes 3.00 :1 OK
Vegetated shelf slope 10.00 :1 OK
Vegetated shelf width 10.00 ft OK
Length of flowpath to width ratio 4.15 :1 OK
Length to width ratio 4.46 :1 OK
Trash rack for overflow & orifice? Y (Y or N) OK
Freeboard provided 1.16 ft OK
Vegetated filter provided? N (Y or N) Design must be based on 90% TSS removal
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 DRAIN VALVE
Form SW401-Wet Detention Basin-Rev.4 Parts I. & II. Design Summary, Page 2 of 2
* per discussions with the Geotechnical engineer the SHWT is significantly deeper than
the pond bottoms on site. Furthermore, all pond will have a clay liner and will not have
an effect on the SHWT.
Permit No.
(to be provided by DWQ)
,R -- - l' gg-
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.
Page/ Plan
Initi Sheet No.
3 1. Plans (1" - 50' or larger) of the entire site showing:
C 4-4- _ I?.8 Design at ultimate build-out,
C - 7; CR q. ra Off-site drainage (if applicable),
C 2.2, C ?. 3 Delineated drainage basins (include Rational C coefficient per basin),
Basin dimensions,
Pretreatment system,
High flow bypass system,
Maintenance access,
Proposed drainage easement and public right of way (ROW),
Overflow device, and
Boundaries of drainage easement.
(4.10; 6-5.0 2. Partial plan (1" = 30' or larger) and details for the wet detention basin showing:
Outlet structure with trash rack or similar,
Maintenance access,
Permanent pool dimensions,
Forebay and main pond with hardened emergency spillway,
Basin cross-section,
Vegetation specification for planting shelf, and
Filter strip.
3. Section view of the dry detention basin (1 20' or larger) showing:
C-2 Side slopes, 3:1 or lower,
Pretreatment and treatment areas, and
Inlet and outlet structures.
4. If the basin is used for sediment and erosion control during construction, clean out of the basin is specified
on the plans prior to use as a wet detention basin.
5. A table of elevations, areas, incremental volumes & accumulated volumes for overall pond and for forebay,
to verify volume provided.
6-2.0-. C-2,1 6. A construction sequence that shows how the wet detention basin will be protected from sediment until the
entire drainage area is stabilized.
Ef? 7. The supporting calculations.
AV 6AV V 8. A copy of the signed and notarized operation and maintenance (0&M) agreement.
9. A copy of the deed restrictions (if required).
fem.
10. A soils report that is based upon an actual field investigation, soil borings, and infiltration tests. County
soil maps are not an acceptable source of soils information.
Form SW401-Wet Detention Basin-Rev.4 Part III. Required Items Checklist, Page 1 of 1
Permit No.
(to be provided by DWQ)
OF W ATFR
r
NCDENR T
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.
T. PRNFDRMa?QN
Project name HADLEY
Contact person FRANK J. MCMAHAN, PE
Phone number 704-333-0325
Date 28-May-08
Drainage area number SB-3
II. DESI ') AJ009 ; , -
Site Characteristics
Drainage area 669,082.00 ft2
Impervious area 501,811.00 it'
% impervious 75.00 %
Design rainfall depth 1.00 in
Storage Volume: Non-SR Waters
Minimum volume required 40,243.00 ft3
Volume provided 41,209.00 ft3
Storage Volume: SR Waters
1-yr, 24-hr runoff depth N/A in
Pre-development 1-yr, 24-hr runoff ft3
Post-development 1-yr, 24-hr runoff ft3
Minimum volume required ft3
Volume provided ft3
Peak Flow Calculations
1-yr, 24-hr rainfall depth 2.64 in
Rational C, pre-development 0.25 (unitless)
Rational C, post-development 0.70 (unitless)
Rainfall intensity: 1-yr, 24-hr storm 0.11 in/hr
Pre-development 1-yr, 24-hr peak flow 85.27 ft3/sec
Post-development 1-yr, 24-hr peak flow 134.07 ft3/sec
Pre/Post 1-yr, 24-hr peak flow control 48.80 ft3/sec
Basin Elevations
Basin bottom elevation 617.00 ft
Sediment cleanout elevation 618.50 ft
Bottom of shelf elevation 622.50 ft
Permanent pool elevation 623.00 ft
SHWT elevation * see attachment ft
Top of shelf elevation 623.50 ft
Temporary pool elevation 625.40 ft
Form SW401-Wet Detention Basin-Rev.4 Parts I. & It. Design Summary, Page 1 of 2
Permit No
(to be provided by DWQ)

D
fjj,.
Volume and Surface Area Calculations
SA/DA ratio 2.97 (unitless)
Surface area at the bottom of shelf 18,501.00 ftz
Volume at the bottom of shelf 25,601.00 ft3
Permanent pool, surface area required 19,871.00 ff
Permanent pool, surface area provided 21,690.00 fe OK
Permanent pool volume 70,966.00 ft3
Average depth for SA/DA tables 3.27 ft OK
Surface area at the top of shelf 25,098.00 ftz
Volume at the top of shelf 11,697.00 ft3
Forebay volume 14,010.00 ft3
Forebay % of permanent pool volume 19.74 % OK
Temporary pool, surface area provided 28,420.00 ftz
Drawdown Calculations
Treatment volume drawdown time
Treatment volume discharge rate
Pre-development 1-yr, 24-hr discharge
Post-development 1-yr, 24-hr discharge
Additional Information
Diameter of orifice
Design TSS removal
Basin 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
2.72 days OK
0.18 ft3/s
85.27 ft3/s OK
70.35 ft3/s OK
3 in
85 %
3.00 :1 OK
10.00 :1 OK
10.00 ft OK
3.30 :1 OK
1.55 :1 OK
Y (Y or N) OK
1.84 ft OK
N (Y or N) Design must be based on 90% TSS removal
Y (Y or N) OK
Y (Y or N) OK
DRAIN VALVE
Form SW401-Wet Detention Basin-Rev.4 Parts I. & II. Design Summary, Page 2 of 2
* per discussions with the Geotechnical engineer the SHWT is significantly deeper than
the pond bottoms on site. Furthermore, all pond will have a clay liner and will not have
an effect on the SHWT.

Permit
(to be provided by DWQ)

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.
Page/ Plan
Initi Sheet No.
C-41 -7.i C. 41 EiC

'Ape
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),
Basin dimensions,
Pretreatment system,
High flow bypass system,
Maintenance access,
Proposed drainage easement and public right of way (ROW),
Overflow device, and
Boundaries of drainage easement.
CAJ-. C4, f' 2. Partial plan (1" = 30' or larger) and details for the wet detention basin showing:
Outlet structure with trash rack or similar,
Maintenance access,
Permanent pool dimensions,
Forebay and main pond with hardened emergency spillway,
Basin cross-section,
Vegetation specification for planting shelf, and
Filter strip.
3. Section view of the dry detention basin (1" = 20' or larger) showing:
C-Z. 3 Side slopes, 3:1 or lower,
Pretreatment and treatment areas, and
Inlet and outlet structures.
• ° ( 4. If the basin is used for sediment and erosion control during construction, clean out of the basin is specified
on the plans prior to use as a wet detention basin.
" 5. A table of elevations, areas, incremental volumes & accumulated volumes for overall pond and for forebay,
to verify volume provided.
CLZL, 0; 6- 2d 6. A construction sequence that shows how the wet detention basin will be protected from sediment until the
entire drainage area is stabilized.
OTC Wt 7. The supporting calculations.
8. A copy of the signed and notarized operation and maintenance (0&M) agreement.
v 9. A copy of the deed restrictions (if required).
10. A soils report that is based upon an actual field investigation, soil borings, and infiltration tests. County
soil maps are not an acceptable source of soils information,
Form SW401-Wet Detention Basin-Rev.4 Part III. Required Items Checklist, Page 1 of 1