SW4090601_HISTORICAL FILE_20090923

STORMWATER DIVISION CODING SHEET
POST -CONSTRUCTION PERMITS
PERMIT NO.
SW
DOC TYPE
❑ CURRENT PERMIT
❑ APPROVED PLANS
HISTORICAL FILE
DOC DATE
YYYYMMDD

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STORMWATER MANAGEMENT .PLAN
WALKER.TOWN HIGH SCHOOL
5801 SULLIVA:NTOWN ROAD
WALKERTOWN'. N`C 28051
PREPARM>J BY:
Dav;s-Marth Powell 3 Associates
6415 OLD PLANS ROAD
HIGH i'C.1117.'NC �7'?f�
PHONE (336) SS6-482I
FAX (336)8S6-4458
-02 -l5
RECEfvED
N.0 p,,... �vs�
SEP 2 3 2gpg
_Rrgfonal 6ffice

Justifications.
Proposed drainage easement and public right of way.
Boundaries of drainage easement.
This project is located on public property. Any personnel wishing to visit the site, will
need to check in with the school as they would at any school site.

Wet Detention Pond Design
Pond 1
'PERMANENT -WET'DETENT.ION PONDDESIGN
f I I
I I
PROJECT: IWalkertown
HS I
I
INDEX NO: 80139
(Pond
1
I
CHECKED BY: JNG
LOCATION:
Sullivantown Road
DATE: 5/21/2009
REVISED:( 7- ♦-
!
I
I
I
SITE DATA I
1
TOTAL SITE AREA =1
42.03 acres
WATERSHED =1
'PROPOSED BUILT UPON AREA =1
19.94 acres)
CLASSIFICATION: WS -1
FUTURE BUILT UPON AREA-=1
0.00 acres)
TOTAL ON -SITE -BUILT UPON AREA=1
19.94 acres)
� PERCENT BUILT -UPON =1
47.44%1
(GWA/WCA) =I
ON -SITE DRAINAGE AREA TO POND =1
42.03 acres)
MAX. OFF -SITE B.U_ .% = I
OFF -SITE DRAINAGE AREA TO -POND =1
0.00 acres)
TOTAL WATERSHED AREA TO POND =1
42.03 acres)
I
I DISTURBED AREA =1
42.00 acres]
j
TEMP. SED. STOR. USED YIN I
Y
I I
I I
DESIGN DATAI I
I
I
!TEMPORARY SEDIMENT. STORAGE
0.5
acre -inch per disturbed acre
(PERMANENT SEDIMENT STORAGE
0:125
acre-inper total drainage area
PPERMANENT WATER QUALITY
1
COMPOSITE B.U. % =1
-47.44
percent
DEPTH (minimum 3 feet)
5.51feet
1 SA/DA (Figure 5.6-2)1
1.85
j percent
]TEMPORARY WATER QUALITY
mm mm
j 1.0 Inch
Irainfall to be controlled
]PRINCIPAL SPILLWAY
I (TYPE
XIcorrugated
aluminum
I reinforced concrete
I
DESIGN STORM
10
year
RAINFALL INTENSITY(
5.81inches
per hour
RUNOFF COEFFICIENT1
0.911
i
EMERGENCY SPILLWAY j
1TYPE
X
grass fined
I
drip -rap lined
1 DESIGN STORMI
100
year
1 RAINFALL INTENSITY
8
inches per hour
1 RUNOFF COEFFICIENT
0.91
POND DATA
I
ELEV. @ BOT. OF POND =J917
SURFACE AREA =131368
SF
ELEV.@ BOT, OF PSS =�917
SURFACE AREA=131368
SF
BOT. OF PWQ =I919
1 .ELEV. @'BOT. OF TWO =I926
1 SURFACE AREA =
SURFACE AREA ={50245
34436 SF _
SF
1 ELEV. @ TOP. OF TWQ=1928.5
I SURFACE AREA=162188
SF
ELEV. @.EMER. SPILLWAY =1929.5
I
1
ELEV. @ TOP OF DAM =1931
1
1
INVERT OF BARREL =1918
1
1
Davis -Martin -Powell and Associates
Designed by: Jay N. Guffey, PE Printed:7/29/2009

Wet Detention Pond Design
Pond 1
! I I
POND DESIGN
1 I
TEMPORARY 'SEDIMENT STORAGE VOLUME
REQUIRED I 76230 Cubic Feet
I
I I
VOLUME PROVIDED
I 1
1 I
ELEV. @7BOT. OF POND=I917:00
l
'SURFACE AREA
31368 Square Feet
ELEV. @ BOT. OF TWO=1926.00
I
SURFACE AREA=150245
Square Feet
! I
ALLOW 75% OF BASIN VOLUME TO WQ ORIFICE _
.275443 Cubic Feet
OK
I I I I
PERMANENT SEDIMENT STORAGE VOLUME�REQUIRED I
19071 Cubic -Feet
�
I
VOLUME PROVIDED
_
ELEV. @ BOT. OF PSS=1917.00
SURFACE AREA=I31368
Square Feet
ELEV. @ BOT. OF PWQ=1919.00
SURFACE AREA=134436
Square Feet
E
I
! VOLUME PROVIDED
65804 Cubic Feet
_
I
I OK
I
I
I
PERMANENT -WATER QUALITY SURFACE AREA REQ'D
I 33870 Square Feet
� I
! NORMAL POOL ELEVATION =!
926.00
SURFACE AREA PROVIDED=1
50245 Square Feet
I
I OK
I I I
I
TEMPORARY WATER QUALITY STORAGE REQUIRED
0.477 in/in
!
f Rv=1
I VOLUME REQUIRED-1
72772 Cubic Feet
_
VOLUME PROVIDED I
I
ELEV. @ BOT. OF TWQ=1926.00
1 SURFACE AREA=150245
Square Feet
ELEV. @ TOP OF TWO =1928.50
1 SURFACE AREA=162188
Square Feet
I
I
VOLUME PROVIDED =!
140541 Cubic Fee
I
1 OK
Davis -Martin -Powell and Associates
Designed by: Jay N. Guffey, PE Printed:712912009

Wet Detention Pond Design
Pond 1
I I I I
I E I I
WATER QUALITY RELEASE HOLE
I i
ELEV. @ BOT. OF WATER QUALITY RELEASE HOLE =
926.00
MAXIMUM RELEASE RATE =
I 5 Days
MINIMUM RELEASE RATE = 1
2 Days
MAXIMUM HOLE SIZE = I 1 0.0763858981
3.74 in. dia.
MINIMUM HOLE SIZE = I I 0.1909647461
5.92 in. dia.
I I I
I
EMERGENCY SPILLWAY I
�
I
I
I
I
ELEV. @ EMER. SPILLWAY =
1
1 929.5
DESIGN STORM PEAK FLOW =
1
{ 306.0 CFS
FLOW THROUGH EMER. SPILLWAY =
1 84.1 CFS
HEAD ABOVE TOP OF RISER =
I
1
BOTTOM WIDTH =
_
I 28.05
i I
I
I
FLOTATION OF RISER
I
I
I
E
�
ELEV. @ TOP OF RISER =I
928.50
ELEV. @ BOT. OF PSS =
917.00
H=
1 11.50ft
AREA OF RISER
12.6 SF
VOLUME OF -RISER =
144.5 Cubic Feet
--
AREA OF BARREL =
1 7.1 SF
EXPOSED LENGTH =
1 10.00 ft
VOLUME OF BARREL -1
1 70.7 Cubic Feet
WEIGHT OF WATER DISPLACED =1
1 13428,42 lb
FACTOR OF SAFETY (10%)1
14771.27 lb
VOLUME OF CONCRETE ANCHOR
98.5 Cubic Feet
Davis -Martin -Powell and Associates
Designed by:.Jay N. Guffey, PE Printed:712912009

Wet Detention Pond Design
Volumes Pond 1
Pond Volumes Permanent Sediment Storage
EL
AREA
AV AREA
VOL
SUM VOL
917
31368
32127
32127
918
32886
32127
33661
33661
919
34436
65788
Pond
Volumes Permanent Pool
EL.
AREA
AV AREA
VOL
SUM VOL
919
34436
35227.05
35227.05
920
36018.1
35227,05
36825.2
36825.2
921
37632.3
72052.25
38455.35
38455.35
922
39278.4
110507.6
40117.5
40117.5
923
40956.6
150625A
41811.65
41811.65
924
42666.7
192436.75
43537.35
43537.35
925
44408
235974.1
47326.4
47326.4
926
50244.8
283300.5
Pond
Volumes Temporary Pool
EL.
AREA
AV AREA
VOL
SUM VOL
926
50244.8
53587.35
53587.35
927
56929.9
53587.35
58675A5
58675A5
928
60421
112262.8
61304A
30652.2
0
928.5
62187.8
142915
Forebay Volumes
EL
AREA
AV AREA
VOL
SUM VOL
919
7369.5
7807.8
7807.8
920
8246.1
7807.8
8538.3
8538.3
921
8830.5
16346.1
9132.25
9132.25
922
9434
25478.35
9745.2
9745.2
923
10056.4
35223.5E
10377.1
10377.1
924
10697.8
45600.6E
11027.45
11027.45
925
11357.1
56628.1
Designed by: Jay N. Guffey, PE Davis -Martin -Powell and Associates Printed:7/29/2009

dmp
Client \AJ S
Job No. n t 1 o 139
Project Description V VALK�_-MyVM t4 _
Calculations For ��Av�/ v�lN "DIME �b N C) i
D"IS-MARTIN-POWELL & ASSOCIATES. INC.
218 GATEWOOD AVE_ SUITE 102, HIGH POINT, NC 27262
Computed By
Date 7 — 7-01- Dq
Checked By J �
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(Revised, Superseded, and Void Calculations Must Be Clearly Identified,
Initialed, and Dated by the Responsible Individual)

Justifications.
Proposed drainage easement and public right of way.
Boundaries of drainage easement.
This project is located on public property. Any personnel wishing to visit the site, will
need to check in with the school as they would at any school site.

Wet Detention Pond Design
Pond 2
PERMANENT WET DETENTION POND DESIGN
PROJECT:
Walkertown HS
I
INDEX NO:
80139
CHECKED BY:
JNG
LOCATION:
Sullivantown Road
DATE:
5/21/2009
1
1
REVISED:1
7/29/2009
SITE DATA
I I
I
TOTAL SITE AREA =
30.90 acres
WATERSHED =
PROPOSED BUILT UPON AREA =
10.00 acres
CLASSIFICATION: WS -
FUTURE BUILT UPON AREA =
0.00 acres
TOTAL ON -SITE BUILT UPON AREA =
10.00 acres
PERCENT BUILT -UPON =
32.36%
(GWA/WCA) _
ON -SITE DRAINAGE AREA TO POND =
22.50 acres
MAX. OFF -SITE B.U.% _
OFF -SITE DRAINAGE AREA TO POND =
8.40 acres
TOTAL WATERSHED AREA TO POND =
30.90 acres
DISTURBED AREA =
5.00 acres
TEMP. SED. STOR. USED (Y/N)
Y
TEMPORARY SEDIMENT STORAGE 0.5 acre -inch per disturbed acre
PERMANENT SEDIMENT STORAGE 0.125 acre -in per total drainage area
PERMANENT WATER QUALITY
COMPOSITE B.U. % = 32.36 percent
DEPTH (minimum 3 feet) 4.3 feet
SA/DA (Figure 5.6-2) 1.58 percent
TEMPORARY WATER QUALITY 1.0 Inch rainfall to be controlled
TYPE XIcorrugated aluminum
_I reinforced concrete
DESIGN STORM 10 year
RAINFALL INTENSITY 5.8 inches per hour
RUNOFF COEFFICIENT 0.911
X grass lined
1ri_-raDo lined
DESIGN STORM 100 year
RAINFALL INTENSITY 81inches per hour
RUNOFF COEFFICIENT 0.91
ELEV. @ BOT. OF POND = 922 I SURFACE AREA = 12331 SF
ELEV.@ BOT. OF PSS = 922 SURFACE AREA = 12331 SF
ELEV. @ BOT. OF PWQ = 924 SURFACE AREA = 14336 SF
ELEV. @ BOT. OF TWQ = 930 SURFACE AREA = 26999 SF
ELEV. @ TOP. OF TWQ = 932 SURFACE AREA = 33521 SF
ELEV. @ EMER. SPILLWAY = 933
ELEV. @_TOP OF DAM_ =1934
INVERT OF BARREL = 922
Designed by: Jay N. Guffey, PE Davis -Martin -Powell and Associates Printed :7/30/2009

Wet Detention Pond Design
Pond 2
POND DESIGN
TEMPORARY SEDIMENT STORAGE VOLUME REQUIRED
9075 Cubic Feet
_
VOLUME PROVIDED
ELEV. @ BOT. OF POND=�922.00
SURFACE AREA =
12331 Square Feet
ELEV. @ BOT. OF TWQ =
930.00
SURFACE AREA
Square Feet
I
=26999
ALLOW 75% OF BASIN VOLUME TO WQ ORIFICE _
117990 Cubic Feet
OK
I I I
PERMANENT SEDIMENT STORAGE
VOLUME
REQUIRED _
14021 Cubic Feet
VOLUME PROVIDED I
922.00
SURFACE AREA =
ELEV. @ BOT. OF_PSS =
12331 Square Feet
P ELEV. @ BOT. OF WQ =
924.00
SURFACE AREA =
14336 Square Feet
VOLUME PROVIDED
26667 Cubic Feet
ok
I
I
I
I
PERMANENT WATER QUALITY
SURFACE AREA REQ'D
I 21267 Square Feet
NORMAL POOL ELEVATION =
930.00
SURFACE AREA PROVIDED =
26999 Square Feet
OK
I
I I
I
TEMPORARY WATER QUALITY STORAGE REQUIRED
�—
Rv=
0.341 in/in
_
M VOLUE REQUIRED =
38278 Cubic Feet
VOLUME PROVIDED
—
SURFACE AREA =26999
ELEV. @ BOT. OF TWQ=1930.00
Square Feet
ELEV. @ TOP OF TWQ =
932.00
SURFACE AREA =
33521 Square Feet
_
VOLUME PROVIDED =1
60520 Cubic Feet
Designed by: Jay N. Guffey, PE Davis-Martin-Poweii and Associates Printed :713012009

Wet Detention Pond Design
Pond 2
iF
WATER DUALITY RELEASE HOLE
ELEV. @ BOT. OF WATER QUALITY RELEASE HOLE =
930.00
MAXIMUM RELEASE RATE =
5 Days
MINIMUM RELEASE RATE =
2 Days
MAXIMUM HOLE SIZE =
0.036712566
2.59 in. dia.
MINIMUM HOLE SIZE = I
0,091781415
4.10 in. dia.
I I
I I
EMERGENCY SPILLWAY
ELEV. @ EMER. SPILLWAY =
933
DESIGN STORM PEAK FLOW =
225.0 CFS
FLOW THROUGH EMER. SPILLWAY =
61.9 CFS
HEAD ABOVE TOP OF RISER =
1
BOTTOM WIDTH =
20.62
I I
I
I
FLOTATION OF RISER
ELEV. @ TOP OF RISER =
932.00
ELEV. @ BOT. OF PSS =
922.00
H =
10.00 ft
AREA OF RISER =
12.6 SF
VOLUME OF RISER =
125.7 Cubic Feet
AREA OF BARREL =
7.1 SF
EXPOSED LENGTH =
10.00 ft
VOLUME OF BARREL =
70.7 Cubic Feet
WEIGHT OF WATER DISPLACED =
12252.21 lb
FACTOR OF SAFETY (10%)
13477.43 lb
VOLUME OF CONCRETE ANCHOR =
89.8 Cubic Feet
Designed by: Jay N. Guffey, PE Dads -Martin -Powell and Associates Printed :713012009

Wet Detention Pond Design
Volumes Pond 2
Pond Volumes Permanent Sediment Storage
EL AREA AV AREA VOL SUM VOL
922 11854.6
12365.85 12365.85
923 12877A 12365.85
13404:7 '13404.7
'924 13932.3 25770.55
'Pond Volumes'Permanent Pool
`EL AREA AV AREA VOL SUM VOL
924 13932.3
14757.8 14757.'8
925 15583.3 14757.8
'16439.85 16439.85
926 17296A 31197.65
18181.2 18181.2 0
927 19066 49378.85
19979.1 19979.1 0
928 208922 69357.95
21833.55 21833,55 0
929 22774.9 91191.5
'24911.55 24911.55 0
930 27048.2 116103.05
Pond Volumes Temporary Pool
'EL. AREA AV AREA VOL SUM VOL
930 .27048.2
29317.55 29317.55
931 31586.9 :29317.55
32679.05 '32679.05
932 33771.2 61996:6
Forebay Volumes
EL AREA AV AREA VOL SUM VOL
924 3128.7
3447.35 3447.35
925 3766 3447.35
4102.45 4102.45
926 4438.9 7549.8
4790 4790
927 5141.1 12339.8
.5507.15 5507.15
928 5873.2 17846.95
6254.05 6254.05
.929 6634.9 24101
Designed by: Jay N. Guffey, PE Davis -Martin -Powell and Associates Printed: 7/29/2009

Client
dMPJob No.
Project Description
Calculations For -1:)MWZ)OV4N MME ?OKL-'> �Z-
DAvIS-MARTIN-POWELL & ASSOCIATES. INC.
218 GATEWOOD AVE,. SUITE 102, HIGH POINT, NC 27262
Computed By tA(q
Date -7 -,� ni
Checked By 1JV6
Date
Page - of
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(Revised, Superseded. and Void Calculations Must Be Clearly Identified.
Initialed, and Dated by the Responsible Individual)

® DAVIS-MARTINI-POWELL & ASSOCIATES, INC.
dMP ENGINEERING o LAND PLANNING + SURVEYING
6415 Old Plank Road, High Point, NC 27265
[phone] * Fax [phone] • www.dmp-inc.com
August 11, 2009
RE: Request for additional Information
Storntwater Proj. No. SW4090601
Walkertown High School
Forsyth County
Brian Lowther
Environmental Engineer REceEvt D
U D'rm of ENF;
St011T1Water Permitting Unit
1617 Mail Service Center FSEP 2 3 200
Raloigh, NC 27699-1617 Mnston•solem
RnIonal ofnre
Dear Mr. Lowther:
]'hank you for your review of the above referenced project. Below is a list of your comments with our
response in italics.
1. Plan Sheet C1.21 has details for the submerged orifice. These are specific to the orifice for
Pond 2. Please provide similar details for Pond I on sheet C1.19 or snake the details apply to
both ponds.
A detail,for the Submerged orifice specific to Pond I is provided..
2. Please provide another set of plans..
Two sets c;e-Wnplete sets of plans are ineludecl..
Once again. thank you for y;ie,.r review and assistance with this project. Should you need additional
inm
9gration please let me know. J
Sincerely,
Davis -Martin -Powell & Associates
6y. Guffey, PE
Cc: File

growOA
A.0
MCDENR
North Carolina Department of Environment and Natural Resources
Division of Water Quality
Beverly Eaves Perdue
Governor
Mr. Darrel Walker
Winston-Salem/Forsyth County Schools
1605 Miller Street
Winston Salem, NC 27 t03
Dear Mr. Walker:
Coleen H. Sullins
Director
August 11, 2009
Subject: Request for Additional Information
Stormwater Project No. SW4090601
Walkertown High School
Forsyth County
Dee Freeman
Secretary
The Division of Water Quality Central Office received_ additional information to a Stormwater Management Permit
Application for the subject project on August 6, 2009, A preliminary review of that information has determined
that the application is not complete. The following information is needed to continue the stormwater review:
Plan sheet C 1.21 has details for the submerged orifice. These are specific to the orifice for Pond 2.
Please provide similar details for Pond I on sheet C1.19 or make the details apply to both ponds.
2. Please provide another set of plan sheets.
Please note that this request for additional information is -in response to a preliminary review. The requested
information should be received by this Office prior to September 1, 2009, or the application will be returned as
incomplete. The return of a project will necessitate resubmittal of all required items, including the application fee.
If you need additional time to submit the information, please mail or fax your request for a time extension to the
Division at the address and fax number at the bottom of this letter. The request must indicate the date by which you
expect to submit the required information. The Division is allowed 90 days from the receipt of a completed
application to issue the permit.
Please reference the State assigned project number on all correspondence. Any original documents that need to be
revised have been sent to the engineer or agent. All original documents must be returned or new originals must be
provided. Copies are not acceptable. If you have any questions concerning this matter please feel free to call me at
[phone].
Sincerely,
Brian Lowther
Environmental Engineer
Stormwater Permitting Unit
cc: Winston Salem Regional Office
DWQ Central Files
Stormwater Permitting Unit Files
Davis -Martin -Powell & Associates ATTN: Jay N. Guffey, PE
Wetlands and Stormwater Branch One
1617 Mail Service Center, Raleigh, North Carolina 27699-1617 North Caro li n a
Location: 5 Salisbury St. Raleigh, North Carolina 04 ��itlll a�jlf
Phone: 919-8-8D7-63D0 l FAX: [phone] Customerr Service: 1-877-623-6748
Internet: www.ncwaterquality.org
An Equal opportunity 1 Affirmalive Action Employer

® DAVIS-MARTIN-ROWELL & ASSOCIATES, INC.
dMP ENGINEERING • LAND PLANNING a SURVEYING
6415 Old Plank Road, High Point, NC 27265
® [phone] • Fax [phone] • www.dmp-ine.com
August 5, 2009
RE: Request for additional Information
Stormwater Proj. No. SW4090601
Walkertown High School
Forsyth County
Brian Lowther
Environmental Engineer
Stormwater Permitting Unit
1617 Mail Service Center
Raleigh, NC 27699-1617
Dear Mr. Lowther:
Thank you for your review of the above referenced project. Below is a list of your comments with our
response in italics.
The narrative with the application states that approximately 2.62 acres of impervious area
will not be treated. All new impervious surfaces must be treated. Please revise and submit
the plans and calculations to include this area.
The narrative is misleading and has been modified. A revised narrative is included with
this submission. Pond I treats all of the proposed impervious with the exception of2.62
acres. Pond 2 treats 1.29 acres ofproposed impervious which leaves 1.33 acres of
proposed impervious area that is not treated. Pond 2 also treats 5.80 acres of existing
impervious areas. A meeting was set up with Mike Randall on May 26. 2009 to discuss
this project prior to submittal to define the requirements of the Stormrt ater
Management Plan. At that meeting, Mr. Randall and I discussed the requirements of
treating all proposed impervious. Some of the proposed impervious areas can not drain
to either pond. Mr. Randall said that we had to treat an equal or greater amount of
impervious areas than we proposed. Mr. Randall said that we could treat some existing
impervious in lieu of the 2.62 acres that was not treated by pond 1. This is
accomplished by pond 2 treating 5.80 acres of existing impervious along with a 1.29
acres of the existing impervious that is not treated by pond 1. Pond 2 is over designed
for a maximum of 10 acres of impervious area draining to the pond. The treatment of
4.51 acres of existing impervious and the ability to treat an additional 2.89 acres of
impervious area, results in this project treating 4.51 acres more than proposed
impervious and the ability to treat 7.32 acres more than proposed.

2. If you would like for the engineer to receive a copy of future correspondence, please
complete the Agent Authorization section of the application form on page 4 with their
information.
Please include the design engineer in all,future correspondence. The Agent
Authorization section is included and provided. We kindly ask that you insert this
information into the project.
3. The application form indicates 4 different drainage areas. These drainage areas for the
application need to correspond with a BMP. It looks as if the first wet detention pond is only
for drainage area 1 however the table does not show the drainage area for the second pond.
The./bur drainage basins delineated on site actually converge where West Belews Creek
leaves the property. The form could have just as easily indicated I drainage basin. The
four basins were delineated based upon treatment. Basin 1 has the bulk of'the proposed
impervious and has a BMP (Pond 1) in the basin. Basins 2 and 3 have very little
additional impervious area and no BMP is associated with these basins. Basin 4 has a
BMP (Pond 2) associated with this basin and it treats a greater amount of existing
impervious than what is proposed in Basins 2 and 3 and what impervious areas that are
not treated by Pond 1. Enlarged views of each basin are included. See comment
response 1 for explanation as to why Basins 2 and 3 have proposed impervious yet no
BMP associated with it.
4. Some items seem to be missing on the application in III. Required Item Checklist for Wet
Detention Basin #I . Most of the items under the first checklist are not on the plan sheet
SWMPI . The include design of ultimate build out, 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. Some of these items
are on other sheets. However please indicate there location correctly and make sure all of
them are included. Items from list 2 are missing as well: Permanent poll dimensions, basin
cross-section. A partial cross section was included, but one of the entire wet basin detention
basin is needed. Similar items are missing for Wet Detention Basin #2. Please revise plans to
include these items.
The corrected location of the items on Required Item Checklist are shown.
S. More detail of the inlet pipe to the basins is needed. A note on the plans states that inlets
must discharge water in a manner to prevent erosion, Details on the plan sheets must be
included to show how this will be done.
Energy dissapators have been sized for each inlet to the each pond. Dimensions are on
the plans. Previous submittal had the erosion control measures turned off far clarity
since the erosion control measure.for the inlets into the pond was shown on the erosion
control plan sheets of the project. This information is now shown on the pond plans.
6. A minimum of F of sediment storage is required in the bottom of the basin. This is an
additional F that must be excavated below the bottom elevation of the pond. The F
sediment accumulation depth is not included in the average depth calculation or the volume
calculations. Please revise the plans and supplement to show this additional sediment
storage.

Two feet of permanent sediment storage is provided for each pond. The permanent
sediment storage has been removed_from calculations concerning average depth and all
volume calculations.
7. Please show the calculations for the orifice drawdown time
Drawdown time calculations are included.
The wet detention basin 41 shows an orifice of 5" on the plan sheet C1.19 but on the
supplement sheet it is 4". Please revise to make consistent.
The 4" orifice is correct. Plan Sheet C1.19 has been revised to the correct orifice
dimension.
9. The orifice on plan sheet C1.19 and C1.21 states the orifice will have a trash guard but more
detail is needed. In Chapter 10 of the BMP Manual, Diagram 10-4 shows one example that
simplifies maintenance and reduces the potential for obstruction.
A detail of the trash guard as shown in Chapter 10 of the BMP Manual is included on
the plans.
10. 7lie emergency spillway shown on C1.19 and C1.21 must be designed with hardened
materials at the points where extreme conditions might compromise the integrity of the
structure. Please revise the plans to include specifications of materials for the harden
spillway.
The spillways of both ponds are lined with matting material at points where the
conditions might compromise the integrity of the embankment
11. For the tables, Pond Area and 1~orebay Areas on C 1.19 and C1.21, please include elevations
up to the temporary pool.
Tables on C1.19 and C1.21 have been revised to include incremental elevations and
cumulative volumes for Sediment Storage, Permanent Pool, Temporary Pool and
Forebay. Elevations are taken to the top of the Temporary Pool.
Once again, thank you for your review and assistance with this project. Should you need additional
information please let me know. I am available to sit down and discuss this project at your
convenience.
Sincerely,
Davis -Martin -Powell & Associates
L A IL,1L
J y Guffey, PE
Cc: File