20050732 Ver 08_More Info Received_20080207

TIC JOHN R. McADAMS COMPANY, INC.
LETTER OF TRANSMITTAL
To: Ms. Cyndi Karoly Date: February 7, 2008
NC Division of Water Quality
2321 Crabtree Boulevard -Suite 250
Raleigh, North Carolina 27604 "`* HAND DELIVER "`*
919-733-9502
Re: Briar Chapel -Phase 5 North Job No.: NEW-06030
I am sending you the following item(s):
COPIES DATE NO. DESCRIPTION
2 Res onse to Comments Letter dated Februar 7, 2008
2 Co of DWQ Comments Letter dated Februa 1, 2008
2 Revised BMP Su lement Forms w/ L:W Ratio Exhibit
2 1 Ori final/1 Cop -Revised Inspection & Maintenance A reement
2 Revised PH 5 North WQ Pond/BC Pk West Extension CD's

These are transmitted as checked below:
^ As requested ^ For your use
® For approval ^ Signature
^ For review and comment ^
Remarks: Please do not hesitate to contact me with any questions or requests. Thank you!
Copy to: Signed:
J r my Finch, PE
Project anager
FOR INTERNAL USE ONLY
^ Copy Letter of Transmittal Only to File ~ ~ ~ ~~~
s
® Copy Entire Document to File ~ _ ~-~
FF~ 7 X008
CIVIL ENGINEERING LAND PLANNING SURVEYING
GcNR `~iAiEk uUALlI~
PO Box 14005 Research Triangle Park, NC 27709 [phone] fax (919) 36W~~f,~lDS -aNO STp~!416h'ATlrk Dr.~'lNCH
www.joh n nncadams.com

~l- - THE
Si~ec 1979
JOHN R. McADAMS COMPANY, INC.
February 7, 2008
Ms. Cyndi Karoly
North Carolina Division of Water Quality
401 OversightBxpress Review Permitting
2321 Crabtree Boulevard, Suite 250
Raleigh, North Carolina 27604
Re: Briar Chapel -Phase 5 North
Response to Comments dated February 1, 2008
NEW-06030
Dear Ms. Karoly:
~~ ~
~t , ~
E- F E, ~ 2008
'."r ~.u?if~.a ~;t~!L a i JRMWAT ~~{ (3~iAftC;ly
Below please find our response to your comments for the Express Review on
the above referenced project:
Comment I: For each Wet Pond location, please provide a site investigation
report describing the soil profile (the various soil layers and
thicknesses) to a depth equal to the bottom elevation of each
pond. In particular, please include the elevation of the Seasonal
High Water Table (SHWT). The concept is to have the
permanent pool elevation as close to the SHWT as possible, such
that the permanent pool shall remain filled with water during
normal rainfall conditions. If the SHWT is far below the
permanent pool elevation, please provide a clay liner or soil of
suitable permeability to keep the permanent pool water from
infiltrating quickly into the soil.
Response 1: A clay liner has been added to the construction drawings (see
wet pond sectional views and notes/specifications) for both wet
pond #7 and wet pond #8.
Research Triangle Park, NC
Post Office Box 14005
Research Triangle Park,
North Carolina 27709
2905 Meridian Parkway
Durham, North Carolina 27713
800-733-5646
919-361-5000
919-361-2269 Fax
Charlotte, NC
5311 Seventy-Seven Center Drive,
Suite 66
Charlotte, North Carolina 28217
800-733-5646
704-527-0800
704-527-2003 Fax
www.johnrmcadams.com
Comment 2: Please use the most current version of the BMP Supplement available
on the DWQ website at http://h2o.enr.state.nc.uslsu/bmp forms.htm.
The submitted version is outdated.
Response 2: Included in the resubmittal are revised BMP Supplements for
both wet ponds using the most current version (Version 3)
from the DWQ website.
Comment 3: Please revise the permanent pool volume and corresponding
average head calculations as follows: When calculating the
permanent pool volume, please start from the sediment cleanout
elevation instead of the basin bottom elevation. For example, for
Wet pond 7, the incremental volume at elevation 444.0 feet
Comprehensive Land Development Design Services
We help our clients succeed.

rnn
""' THE JOHN R.
Ms. Cyndi Karoly
February 5, 2008
NEW-06030
Page 2
8yp ~ ~~lff ~~
McADAMS COM~I~NY, INC.
would be zero (0) resulting in a total permanent pool volume of
84,095 cubic feet instead of 100,772 cubic feet. The forebay
volume is consequently reduced to 17,403 cubic feet. Use
similar reasoning to revise the corresponding values for Wet
Pond 8.
Response 3: The bottom elevation of both wet pond #7 and wet pond #8
were lowered an additional 1 foot to account for the sediment
storage%leanout elevation. Since both ponds were lowered an
additional 1 foot, the previously submitted design calculations
are still valid and did not require revisions.
Comment 4: The flow path length in both wet ponds is too short resulting in a
flow path length to width ratio of 1.5. The DWQ recommends a
flow path length to width ratio of 3:1. This may be achieved by
installing baffles within the ponds or rearranging the inlet and
outlet locations or realigning the entire BMP to increase the
distance between the inlet and outlet.
Response 4: Per our telephone conversation, the previously submitted BMP
supplements contained a conservative calculation of the ,flow
length to width ratio for both wet ponds. After further
discussion and recalculation of the flow length to width ratio, it
was agreed that the previously submitted wet pond design
contained flow length to width ratios of at least 2:1, meaning
they are acceptable as previously submitted without revision.
Included in the resubmittal package are exhibits detailing the
recalculation of the revised flow length to width ratio for both
wet ponds, along with revised BMP Supplements for both
facilities containing the corrected flow length to width ratios.
Comment 5: The orifice sizes and drawdown rates were verified to be
appropriate. In future, please use one-third of the head above the
permanent pool elevation as the driving head instead of one-half.
See section 3.5.2 of the NC-DWQ Stormwater BMP Manual for
more details.
Response S: So noted All future submittals to the DWQ will be in
accordance with this guidance.

~~`-~`~' THE JOHN I~. McAD~1VIS COMl'~NY INC.
Ms. Cyndi Karoly
~ February 5, 2008
NEW-06030
Page 3
Comment 6: The DWQ recommends only on-time fertilizer application of all
vegetated areas of the BMP in order not to defeat the nutrient
removal purpose for which the BMP will be installed. The
fertilization shall be done only during initial vegetation
establishment. Please revise the seeding schedule and
maintenance notes to reflect only aone-time application.
Response 6: The seeding schedules for both wet pond #7 and wet pond #8
have been revised to indicate aone-time fertilizer application
during the initial establishment of vegetation for each facility.
Comment 7: Instead of 1.0 foot, please use 2.0 feet depth for the wet ponds'
scour holes, and 2.5 feet depth for the scour holes in the low
density areas for optimum energy dissipation. It may be
necessary to increase the size of the scour holes in the low
density areas to attenuate the flow and diffuse the runoff at a
much slower rate. These recommendations are based on the fact
that the flow rates to, and the slopes downgrade of the scour
holes were found to be too high, and the photos for the filter
strips do not indicate the existence of dense vegetation.
Response 7: The depths of the preformed scour hole/level spreaders for
both the wet ponds and the low-density areas were revised to
the depths you requested Also, the size of all preformed scour
hole/%vel spreaders were increased accordingly to
accommodate the increased depth.
Consideration of this response is greatly appreciated. If you should have any
questions or require additional information, please do not hesitate to contact
me at [phone].
Sincerely,
THE JOHN R. MCADAMS COMPANY, INC.
A-e,
v '~~
rer~V. Finch, PE
Project Manager
Stormwater and Environmental Department
Enclosures

o~o~ W A rF9pt:
~_
~ .. ~

Michael F. Easley, Governor
William G. Ross Jr., Secretary
North Carolina Depardnent of Environment and Natural Resources
Coleen H. Sullins, Director
Division of Water Quality
February 1, 2008
DWQ EXP No. 05-0732v8
Chatham County
CERTIFIED MAIL: RETURN RECEIPT REQUESTED (~ !~? ,~
NNP-Briar Chapel, LLC [) 1.~~~" ~-=~'~ ~4?
Attn: Mr. Mitch Barran, Vice President Newland Communities
5850 Fayetteville Road, Suite ZOI ~~ ~ ~ > ~'`%
Durham, NC 27713
Subject Property: Briar Chapel Community, Phase 5 Narth ~^7t=Ti ~'~`''' ``~~`
REQUEST FOR MORE INFORMATION (STORMWATER MANAGEMENT PLAN) -
EJfQ~RESS REVIEW
Dear Mr. Barron:
The Division of Water Quality (DWQ) has. reviewed the Stormwater Management Plans submitted by Mr.
Jeremy Finch, P.E. of John R. McAdams Company, Inc., in order to meet certain conditions of the
Individual Water Quality Certification issued on May 9, 2006. The DWQ has. determined that your
application will requve additional information. Please provide the following information so that we
may continue to review your project and prevent denial of your application as required by 15A NCAC
2H .0506:
Additional Information Requested
I . For each Wet Pond location, please provide a site investigation report describing the soil profile (the
various soil layers and thicknesses} to a depth equal to the bottom elevation of each pond. In
particular, please include the elevation of the Seasonal High Water Table (SHWT). The concept is to
have the permanent pool elevation as close to the SHWT as possible, such that the permanent pool
shall remain filled with water during normal rainfall conditions. If the SHWT is far below the
permanent pool elevation, please provide a clay liner or soil of suitable permeability to keep the
permanent pool water from infiltrating quickly into the soil.
2. Please use the most current version of the BMP Supplement available on the DWQ website at
http://h2o.enr.state.nc.us/sutbmp forms.htm. The submitted version is outdated.
3. Please revise the permanent pool, volume and corresponding average head calculations as follows:
When calculating the permanent pool volume, please start from the sediment cleanout elevation
instead of the basin bottom elevation. For example, for Wet pond 7, the incremental volume at
elevation 444.0 feet would be zero (0} resulting in a total permanent pool volume of 84,095 cubic feet
instead of 100,772 cubic feet. The forebay volume is consequently reduced to 17,403 cubic feet. Use
similar reasoning to revise the corresponding values for Wet Pond 8.
4. The flow path. length in both wet ponds is too short resulting in a flowpath length to width ratio of
1.5. The DWQ recommends a flow path length to width ratio of 3:1. This may be achieved by
installing baffles within the ponds or rearranging the inlet and outlet locations or realigning the entire
BMP to increase the distance between the inlet and outlet.
Noo° Carol~na
4010versight/Express Review Permitting flnit ~tllCllf!!,
1650 Mail Service Center, Ralegh, North Carolina 27699-1650
2321 Crabtree Boulevard, Suite 250, Raleigh, North Carolina 27604
Phone: [phone] FAX [phone]! Internet httq:/lh2o.enr.state.nc.us/ncwetlands
An Equal OpportunitylAtfirmative Adion Empbyer- 50% Recyded/10°~ Post Consumer Paper

r
Briar Chapel Phase 5 North
Page 2 of 2
February 1, 2008
5. The orifice sizes and drawdown rates were verified to be appropriate. In future, please use one-third
of the head above the permanent pool elevation as the. driving head instead of one-half. See section
3.5.2 of the NC-DWQ Stormwater BMP Manual for more details.
6. The DWQ recommends only one-time fertilizer application of all vegetated areas of the BMP in order
not to defeat the nutrient removal purpose for which the BMP will be installed. The fertilization shall
be done only during initial vegetation establishment. Please revise the seeding schedule and
maintenance notes to reflect only aone-time application.
?. Instead of 1.0 foot, please use 2.0 feet depth for the wet ponds' scour holes, and 2.5 feet depth for the
scour holes in the low density areas for optimum energy dissipation. It may be necessary to increase
the size of the scour holes in the low density areas to attenuate the flow and diffuse the runoff at a
much slower rate. These recommendations are based on the fact that the flow rates to, and the slopes
downgrade of the scour holes were found to be too high, and the photos for the filter strips do not
indicate the existence of dense vegetation.
Please respond within five (5) days of the date of this letter by sending two (2) copies of the above
information in writing. The Express Review Program is a process that requires all parties to participate in a
timely manner.
This letter only addresses the application review and does not authorize any. impacts to wetlands,. waters
or protected buffers. Please be aware that any impacts requested within your application are not
authorized (at this time) by the DWQ..
Please contact Joseph Gyamfi or Lia Myott at 919-733-1786 if you have any questions regarding or
would like to set up a meeting to discuss this matter.
Si erely,
,~
Cyndi Karoly, Supervisor
401 Oversight~Express Review Permitting Unit
CBICljg
cc: James Shern, USACE Raleigh Regulatory Field Office
Lauren Witherspoon, DWQ Raleigh Regional Office
File Copy
Central Files
Jeremy Finch, P.E., John R. McAdams Co., Inc., 29Q5 Meridian Pkwy., Durham, NC 27713

Permit No.
(to be provided by DWQ)
'~y" '
~' O~O~ W A TF9OG
Uj 9
r
YS ~
NCDENR ~ -1
~`
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
401 CERTIFICATION AP PLICATION 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.
1. PROJECT INFORMATION
Project name Briar Chapel-Phase V
Contact person Jeremy Finch, PE
Phone number 919-361-5000
Date 21612008
Drainage area number To WQ Pond #8
11. DESIGN INFORMATION
Site Characteristics
Drainage area 671,098 ft2
Impervious area 360,865 ftz
impervious 53.77232535
Design rainfall depth 1.0 in
Storage Volume: Non-SR Waters
Minimum volume required 55,938 ft3
Volume provided 56,104 ft3
Storage Volume: SR Waters
1-yr, 24-hr runoff depth NIA in
Pre-development 1-yr, 24-hr runoff N/A ft3
Post-development 1-yr, 24-hr runoff NIA ft3
Minimum volume required #VALUE! ft3
Volume provided N/A ft3
Peak Flow Calculations
Is prelpost control of the 1-yr 24-hr peak flow required? No-See Note
(Y or N) ~ N~ : PRE~POS'r CONTRo~ NOT REQUIRED BY 401
1-yr, 24-hr rainfall depth 3.0 in WR?~R QUALITY GER'T1Ff~JE-f10/V, f3UT IS
Rational C, pre-development N/A (unitless) ~EQUItzE~ $Y C~tArNAM CouN'rY
Rational C, post-development N/A (unitless)
Rainfall intensity:1-yr, 24-hr storm N/A inlhr
Pre-development 1-yr, 24-hr peak flow NIA ft3lsec
Post-development 1-yr, 24-hr peak flow N/A ft3/sec
Pre/Post 1-yr, 24-hr peak flow control #VALUE! ft3/sec
Basin Elevations
Basin bottom elevation 455.00 ft
Sediment cleanout elevation 456.00 ft
Bottom of shelf elevation 463.50 ft
Permanent pool elevation 464.00 ft
Top of shelf elevation 464.50 ft
Temporary pool elevation 467.20 ft
Volume and Surface Area Calculations
SAIDA ratio 1.84 (unitless)
Surface area at the bottom of shelf 9757.00 ftz
Volume at the bottom of shelf 45118.00 ft3
Permanent pool, surface area required 12,377 fig
Permanent pool, surface area provided 12,701 ftz OK
Permanent pool volume 50,733 ft3
Average depth for SAIDA tables 3.994409889 ft OK
Surface area at the top of shelf 15237 ft~
Volume at the top of shelf 57717 ff3
Form SW401-Wet Detention Basin-Rev.3 Parts I. 8 II. Design Summary, Page 1 of 2

Permit No.
(to be provided by DWQ)
II. DESIGN INFORMATION _
Forebay volume 10,601 fta
Forebay % of permanent pool volume 21 % OK
Temporary pool, surface area provided 19,917 ftz
Drawdown Calculations
Treatment volume drawdown time 2.11 days OK
Treatment volume discharge rate 0.41 ft3/s
Pre-development 1-yr, 24-hr discharge See Note ft3/s OK
Post-development 1-yr, 24-hr discharge 0.41 ft3/s OK
Additional Information
Diameter of orifice 3.00 in
Design TSS removal 85
Basin side slopes 3 :1 OK
Vegetated shelf slope 10 :1 OK
Vegetated shelf width 10 ft OK
Length of flowpath to width ratio 2.64 :1 Too short, increase ratio to at least 3:1
Length to width ratio 2.1 :1 OK
Trash rack for overflow & orifice? Y (Y or N) OK
Freeboard provided 1.24 ft
Y
N OK
OK ~ Nom' pUST~N~ pOWNISTRt AAti 'Rt~ARaAN
Vegetated filter provided? See Note or
)
( BUFFER is Bf1Ny urfuzEp AS ~/EC~ET'MiED
Recorded drainage easement provided? Y (Y or N) OK
F'~LTER
Capures all runoff at ultimate build-out? Y (Y or N) OK
Drain mechanism for maintenance or emergencies Y
#VALUE!
Form SW401-Wet Detention Basin-Rev.3 Parts I. 8 II. Design Summary, Page 2 of 2

Permit
(to be provided by DWQ)
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
Initials Sheet No.
Ty F ~8A'+~SD1. Plans (1" - 50' or larger) of the entire site showing:
SWL acff~i9rr-iN _ Design at ultimate build-out,
READRT -Off-site drainage (if applicable),
- Delineated drainage basins (include Rational C coefficient per basin),
-Basin dimensions,
-Pretreatment system,
-High flow bypass system,
- Maintenance access,
- Recorded drainage easement and public right of way (ROW),
-Overflow device, and
-Boundaries of drainage easement.
~l~ ~D SA~-+PD>rD 2• Partial plan (1" = 30' or larger) and details for the wet detention basin showing:
~$ CS -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:
-Side slopes, 3:1 or lower,
-Pretreatment and treatment areas, and
-Inlet and outlet structures.
~_ PA' 8'A 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.
~jL~ SEE'RER~-r 5. A table of elevations, areas, incremental volumes & accumulated volumes for overall pond and for forebay,
to verify volume provided.
TV F Pn-sA 6. An assurance that the installed system will meet design specifications upon initial operation once the
project is complete and the entire drainage area is stabilized.
7VF PbBA 7. A construction sequence that shows how the wet detention basin will be protected from sediment until the
entire drainage area is stabilized.
~[~ SEE 8. The supporting calculations.

TVF SEE REA6KT- 9. A copy of the signed and notarized inspection and maintenance (I&M) agreement.
TY ~ S~paRT 10. A copy of the deed restriction.
Form SW401-Wet Detention Basin-Rev.1 Part III. Required Items Checklist, Page 1 of 1

WET POND #8 ---- - ------- ----_-~ =_- _.
GBAPHIC-S£A-T,1 ~ - _ - -
_ FLOW LENGTH TO -----ao --- ~__zo -pro ~%-so, -
WIDTH RATIO = 2.64:1 __--- --- -- ~ -
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- - . ~ - - -
WET POND #8 ~ _ _ - - - _ _ _
~ FLOW LENGTH PATH ' - - ~ ~ - - ' _
_ ,.~ -
LENGTH = 185 FT - ~ ' ~ ~ - ~ ' -
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WET POND #8
FLOW WIDTH
AVG WIDTH = 70 FT
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® PRwBCr No. NEW-06030
THE JOHN R. McADAMS
~ "'~"""B` NEwo6030SW B CHAPEL COMPANY, INC.
C SCALB: w
~ ~ 40~ ~,,~D
CHATI'~AM COUNIY, NOKI~I CAROLINA BNGINBBRS~PLANNBRS~SURVBYORS
~
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~ ~~ ~8~~~;~~H ~~0 RBSBARCH TRIANGLE PARK, NC
P.O. BOX 14005 ZIP 27709-4005
~' DA7Bc 02-04-2008 (919) asl-5oo0

Permit No.
(to be provided by DWQ)
O~O~ W ATF9QG
,~! ~ v
~s ~ ~ y
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 T
Project name Bnar Chapel-Phase V
Contact person Jeremy Finch, PE
Phone number 919-361-5000
Date 2/612008
Drainage area number To WQ Pond #7
II. DESIGN INFORMATION
Site Characteristics
Drainage area 913,453 ft2
Impervious area 503,766 ftz
impervious 55.1496355
Design rainfall depth 1.0 in
Storage Volume: Non-SR Waters
Minimum volume required
Volume provided
Storage Volume: SR Waters
1-yr, 24-hr runoff depth
Pre-development 1-yr, 24-hr runoff
Post-development 1-yr, 24-hr runoff
Minimum volume required
Volume provided
Peak Flow Calculations
Is pre/post control of the 1-yr 24-hr peak flow required?
1-yr, 24-hr rainfall depth
Rational C, pre-development
Rational C, post-development
Rainfall intensity:1-yr, 24-hr storm
Pre-development 1-yr, 24-hr peak flow
Post-development 1-yr, 24-hr peak flow
PrelPost 1-yr, 24-hr peak flow control
Basin Elevations
Basin bottom elevation
Sediment cleanout elevation
Bottom of shelf elevation
Permanent pool elevation
Top of shelf elevation
Temporary pool elevation
Volume and Surface Area Calculations
SA/DA ratio
Surface area at the bottom of shelf
Volume at the bottom of shelf
Permanent pool, surface area required
Permanent pool, surface area provided
Permanent pool volume
Average depth for SAIDA tables
Surface area at the top of shelf
Volume at the top of shelf
76,121 ft3
96,358 ft3
N/A in
N/A ft3
NIA ft3
#VALUE! ft3
N/A ft3
No-See Note (Y or N) ~ hJ0'(ir' ~R~FbST CON'iROL NOT REQu1RED BY 401
3.0 in ~//kTpZ Q~1W~y C~lFfCikt?Dl~~ BtJT IS
N/A (unitless) 'jZi~WIREDBY CNkt'HAAd Covrt'rY.
N/A (unitless)
N/A in/hr
NIA ft3/sec
NIA ft3/sec
#VALUE! ft3lsec
442.00 ft
443.00 ft
447.50 ft
448.00 ft
448.50 ft
450.80 ft
2.02 (unitless)
23353.00 ftz
87940.00 ft3
18,481 ftz
27,975 ff2 OK
100,772 ft3
3.602216265 ft OK
31646 ftz
115677 ft3
Form SW401-Wet Detention Basin-Rev.3 Parts I. & II. Design Summary, Page 1 of 2

Permit No.
(to be provided by DWQ)
11. DESIGN INFORMATION _
Forebay volume 20,962 fts
Forebay % of permanent pool volume 21 % OK
Temporary pool, surface area provided 37,211 ft2
Drawdown Calculations
Treatment volume drawdown time 3.58 days OK
Treatment volume discharge rate 0.35 ft3/s
Pre-development 1-yr, 24-hr discharge See Note ft3/s OK
Post-development 1-yr, 24-hr discharge 0.62 ft3ls OK
Additional Information
Diameter of orifice 3.00 in
Design TSS removal 85
Basin side slopes 3 :1 OK
Vegetated shelf slope 10 :1 OK
Vegetated shelf width 10 ft OK
Length of flowpath to width ratio 2.06 :1 Too short, increase ratio to at least 3:1
Length to width ratio 2.2 :1 OK
Trash rack for overflow & orifice? Y (Y or N) OK
Freeboard provided 1.17 ft OK
Vegetated filter provided? See Note (Y or N) OK .~ Np?E ~ ~ist~~f~ DoWI~LSTREJIM '~?AwkrJ BuFFE~.
Recorded drainage easement provided? Y (Y or N) OK 1S BE~N~ frnuza:~ /ES vEUE'rA^~u Flr~2
Capures all runoff at ultimate build-out? Y (Y or N) OK
Drain mechanism for maintenance or emergencies Y

#VALUE!
Form SW401-Wet Detention Basin-Rev.3 Parts I. & II. Design Summary, Page 2 of 2

Permit
(to be provided by DWQ)
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
Initials Sheet No.
~~ ~IDD 7D 1. Plans (1" - 50' or larger) of the entire site showing:
SWZ ExNf811" i~J _ 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,
- Recorded drainage easement and public right of way (ROW),
-Overflow device, and
-Boundaries of drainage easement.
7yF ~QD~D 2. Partial plan (1" = 30' or larger) and details for the wet detention basin showing:
p~r7-LS -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.
~F~- 3. Section view of the dry detention basin (1" = 20' or larger) showing:
-Side slopes, 3:1 or lower,
-Pretreatment and treatment areas, and
-Inlet and outlet structures.
~[~ Po-7A 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.
ZG F SEE ~f27" 5. A table of elevations, areas, incremental volumes & accumulated volumes for overall pond and for forebay,
to verify volume provided.
~[~ PD-7A 6. An assurance that the installed system will meet design specifications upon initial operation once the
project is complete and the entire drainage area is stabilized.
~~ i~-7A 7. A construction sequence that shows how the wet detention basin will be protected from sediment until the
entire drainage area is stabilized.
TVF y~ 8. The supporting calculations.
~'t~ ~- 9. A copy of the signed and notarized inspection and maintenance (I&M) agreement.
~3L~ ,5~ E~R~f 10. A copy of the deed restriction.
Form SW401-Wet Detention Basin-Rev.1 Part III. Required Items Checklist, Page 1 of 1

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- _ - ~ ~ ~ WET POND #7
~' ~ ~ ~ \' -' ~ `' ~ ~ `\ ~ ~ FLOW LENGTH PATH \
~~ '\~~ \~'--'~/ `~'~~\\~` \ ~ LENGTH = 245 FT ~ -
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WIDTH RATIO = 2.06:1 ~~ ~ +~ ~ i / ~ / j/ // // / / /
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\ ~~`~ ~\ i WET POND 7 ~~
\ ~~\~ ~ ~%~i~~ ~\ ~ \~ i FLOW WIDTH ~/ ~~~
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FILBNAYB:
B CHAPEL THE JOHN R. McADAMS

COMPANY
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C~~1~IAlVi COUI~TIY, NO1rl.~I r' OIdNA 6NG[N66R$/PLANNBR3~3URVEYORS

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WQ AND ~ ' l~~T ~ ~; RA~O ~~ RESEARCH TRIANGLE PARK, NC
P.O. BOX 14003 ZIP 277'09-4005
~ DATB: 02-04-2008 [phone]

ORIGINAL
Permit Number:
(to be provided by DWQ)
Drainage Area Number: ?0 W Q Pore( t~7
Wet Detention Basin Inspection 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. .
-~- /dOfE ~ U lu zEp RS EVE SATE D A PTPt~ N BUFFER tS ~INQ
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 inspection 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 roblem: How I will remediate the roblem:
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 a lication.
Vegetation is too short or too Maintain vegetation at a height of
lon a roximatel six inches.
Form SW401-Wet Detention Basin I&M-Rev.2

Permit Number:
(to be provided by DWQ)
Drainage Area Number: T ~Q ~yQ( t~~
BMP element: Potential roblem: How I will remediate the roblem:
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 dama ed.
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 roblems 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
revent future erosion roblems.
Weeds are present. Remove the weeds, preferably by
hand. If pesticide is used, wipe it on
the lants rather than s ra in .
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 aone-time
fertilizer application to establish the
ground cover if a soil test indicates
it is necessa
Weeds are present. Remove the weeds, preferably by
hand. If pesticide is used, wipe it on
the lants rather than s ra in .
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 al al owth.
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 I&M-Rev.2

Permit Number:
(to be provid d by DWQ)
Drainage Area Number: TG(1 ~~ ~# 7
BMP element: Potential roblem: How I will remediate the roblem:
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 dama ed Re air or re lace 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 5V0 feet in the main pond, the sediment
shall be removed.
When the permanent pool depth reads 5V0 feet in the forebay, the sediment
shall be removed.
BASIN DIAGRAM
ill in the blanks)
Sediment Removal E`~. 443.0
Permanent Pool Elevation 448.0
--------------=-- Volume
Bottom Elevatio 442.0 -ft Min.
Sediment
Storage
FOREBAY
Form SW401-Wet Detention Basin I&M-Rev.2
Pool
\ - Sediment Removal Elevation 443.0- - - - - - - - - - - Volume
Bottom Elevation 442.0 j 1-ft
MAIN POND
Storage

ORIGINAL Permit Number:
(to be provided by DWQ)
Drainage Area Number: T(~Q r1~ QT'S
Wet Detention Basin Inspection 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 avegeta~te-d filter at the outlet.
-aE-1~07'E ~ ~X(STfl~f DOUV~+4~AT~ ~LR~. BUFFER 1S Bf/N~
IJtlcrzED ,~s
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 inspection 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 roblem: How I will remediate the roblem:
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 a lication.
Vegetation is too short or too Maintain vegetation at a height of
lon a roximatel six inches.
Form SW401-Wet Detention Basin I&M-Rev.2

Permit Number:
(to be provided by DWQ)
Drainage Area Number: ~ G(JQ ~bvld #S
BMP element: Potential roblem: How I will remediate the roblem:
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 dama ed.
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 roblems 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
revent future erosion roblems.
Weeds are present. Remove the weeds, preferably by
hand. If pesticide is used, wipe it on
the lams rather than s ra in .
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 aone-time
fertilizer application to establish the
ground cover if a soil test indicates
it is necessa
Weeds are present. Remove the weeds, preferably by
hand. If pesticide is used, wipe it on
the lams rather than s ra in .
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 al al owth.
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 I&M-Rev.2

Y
Permit Number:
(to be provided by DWQ)
Drainage Area Number: ~G(JQ ~D~
BMP element: Potential roblem: How I will remediate the roblem:
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 dama ed Re air or re lace 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 8~0 feet in the main pond, the sediment
shall be removed.
When the permanent pool depth reads 8~0 feet in the forebay, the sediment
shall be removed.
BASIN DIAGRAM
X11 in the blanks)
Sediment Removal
Bottom
Permanent Pool Elevation 464.0
456.0 ~ 1
-----------------
~455.0 1
FOREBAY
Volume
ft Min.
Sediment.
Storage
Pool
- - - - -Sediment Removal Elevation 456.0- - - - - - - - - - Volume
Bottom Elevation 455.0 j 1-ft
MAIN POND
Storage
Form SW401-Wet Detention Basin I&M-Rev.2