STORM WATER MANAGEMENT
REVIEW CHECKLIST – DEVELOPMENT PLANS
COUNTY CASE #:
FYI: IT IS THE OWNERS/DEVELOPER’S RESPONSIBILITY TO BE IN COMPLIANCE WITH APPLICABLE
NATIONAL POLLUTION DISCHARGE ELIMINATION SYSTEM (NPDES) PERMIT AND CLEAN WATER ACT
Abbreviations: DR - Development Regulations | FPMO - Floodplain Management Ordinance | RDNR - Rules of the
Department of Natural Resources | ESCO – Erosion and Sediment Control Ordinance | SSFISS – Stormwater Systems and
Facilities Installation Standards and Specifications
For Official Use
... Note to reviewer, for CDP cases, initial submittal did not contain some or all storm water data. Enter remaining storm
water data into permit plan prior to approving permit.
... Note to reviewer, for CDP cases, check condition holds to see if applicable conditions have been placed for As-built
hydrology study and BMP Maintenance bond prior to approving permit.
... Walk Through
... Drop-Off, include a copy of these comments and one set of plans, do not drop off money or easement documents.
Bring to Suite 275- 2nd floor One Justice any day of the week. Allow up to 5 business days for re-review.
... Section Re-Review, include a copy of these comments and one set of plans, do not drop off money or easement
documents. Bring to Suite 275- 2nd floor One Justice any day of the week. Allow up to 10 business days for re-review.
FYI if all comments are not addressed after the third review, a meeting will be required with County Staff, Designer and
1) ... Number all pipes and structures on plan. (DR 10.2.7c)
2) ... Show Grading of and number all open channels on plan. (DR 8.1.8 and DR 10.2.7c)
3) ... Show topography at a 2’ contour interval or less. (DR 8.1.2)
4) ... Provide a grading plan showing building pad locations for subdivisions with zoning requiring lot sizes less
than 12,000 square feet or a density of four units per acre or more. (DR 8.1.7)
GWINNETT COUNTY SWM – REVIEW CHECKLIST – PLANS Page 1 of 13
5) ... Show grading for roads in residential subdivisions. (DR 8.1.8)
6) ... Show drainage easement on pipes consistent with table 7-A of the Development Regulations. (DR 7.4.2)
EASEMENTS FOR STORM DRAIN PIPES
MAXIMUM PIPE INVERT DEPTH (FT)
PIPE SIZE (FT)
MINIMUM EASEMENT WIDTH (FT)
NA 4 5 6 7 8 9 10 11 12 13 14 15 16
1.25 20 20 20 20 20 25 25 30 30 30 35 35 40
1.5 20 20 20 20 20 25 25 30 30 30 35 35 40
2.0 20 20 20 20 20 25 25 30 30 30 35 35 40
2.5 20 20 20 20 25 25 25 30 30 35 35 35 40
3.0 20 20 20 20 25 25 25 30 30 35 35 35 40
3.5 NA 20 20 20 25 25 30 30 30 35 35 40 40
4.0 NA 20 20 20 25 25 30 30 30 35 35 40 40
4.5 NA NA 20 25 25 25 30 30 35 35 35 40 40
5.0 NA NA 20 25 25 25 30 30 35 35 35 40 40
5.5 NA NA NA 25 25 30 30 30 35 35 40 40 40
6.0 NA NA NA 25 25 30 30 30 35 35 40 40 40
8) ... Show regulatory and 100-year floodplain contour, elevation and floodway limits and indicate information source.
(DR 10.2.5l) (FPMO 1.3.1)
9) ... Indicate on plan the regulatory and the 100-year water elevation of the lake.
10) ... Provide storm water note(s) indicated below in a notes section on grading and drainage plan.
1. ... Select appropriate Floodplain Note(s). Either select note a or b and select notes c and d as applicable.
a. There is no floodplain on this property from a water course with a drainage area exceeding 100 acres or
floodplain per FIRM Panel _________ dated ____________.
b. Floodplain on this property from all water courses with a drainage area exceeding 100 acres is shown.
c. Floodplain shown is from FIRM panel _______ dated ________.
d. Floodplain shown is from Floodplain study titled ____________ by _______________ dated _______.
Study was done as a part of project number XXX xxxx-xxxxx.
2. ... Select appropriate wetlands note(s). Select either a or b, if wetlands are being disturbed on the site select note c.
a. There are no wetlands being disturbed on this site.
b. All wetlands to be disturbed are delineated on this site.
c. The wetlands are being disturbed in accordance with permit ___________.
3. ... Select the appropriate SWM note.
a. Storm Water Management for this project is provided on-site.
b. Storm Water Management for this site is provided off-site in project named _________ with case number
4. ... Select appropriate state waters note(s). Select either a or b and if a state waters buffer is being disturbed on the
site select note c.
a. There are no stream buffers on this property.
GWINNETT COUNTY SWM – REVIEW CHECKLIST – PLANS Page 2 of 13
b. A 50-foot undisturbed buffer and a 75-foot impervious setback shall be maintained adjacent to all streams.
c. Stream buffer variance number ____________ was obtained to work in buffer as shown.
5. ... Wetland certification: The design professional, whose seal appears hereon, certifies the following: 1) the
National Wetland Inventory maps have been consulted; and, 2) the appropriate plan sheet [ ] does / [ ] does not (circle
appropriate box) indicate areas of united states army corps of engineers jurisdictional wetlands as shown on the maps;
and, 3) if wetlands are indicated, the land owner or developer has been advised that land disturbance of protected
wetlands shall not occur unless the appropriate federal wetlands alteration (“section 404”) permit has been obtained.__
6. ... Select appropriate easement note.
a. Residential - Gwinnett County assumes no responsibility for overflow or erosion of natural or artificial drains
beyond the extent of the street right-of-way, or for the extension of culverts beyond the point shown on the
approved and recorded subdivision plat.
b. Commercial - Gwinnett County assumes no responsibility for overflow or erosion of natural or artificial
drains beyond the extent of the street right-of-way, or for the extension of culverts beyond the point shown on
the approved and recorded plan. Gwinnett County does not assume the responsibility for the maintenance of
pipes in drainage easements beyond the county right-of-way.
7. ... An approved Residential Drainage Plan (RDP) is required prior to issuance of a building permit on those lots
labeled "RDP". An approved Hold and Release Affidavit is required on those lots labeled “RDP” or Residential
Drainage Study (RDS). An elevation certificate is required on lots labeled “RDP-E” or RDS-E”.
8. ... It is the responsibility of the property owners of the storm water management facility to keep the access drive
free of obstructions and to maintain the facility free of obstructions, silt and debris, and operational pursuant to County
9. ... Source of topography is ____________ and reference datum is (i.e. NGVD 1929, Mean Sea Level, etc.)
10. ... Maximum slope for cut or fill is 2H:1V except earthen dam embankments shall be 3H:1V.
11. ... Detention pond, detention outlet structures and temporary sediment pond features are to be constructed and fully
operational prior to any other construction or grading.
12. ... Developer is to clean out accumulated silt in detention pond at end of construction when disturbed areas have
13. ... Provide detention pond post-construction (record) drawings with the submittal of the final plat at least two
weeks prior to requesting a certificate of occupancy so that the post-construction conditions may be verified and
approved. Certified record drawings shall include topography of pond and outlet structure detail using post-
construction survey data. Using record drawings, provide a certified hydrology report verifying pond volumes and
peak outflows from regulated storm events.
14. ... Access easement to be cleared and grubbed.
15. ... If using HDPE pipe, add following note to plans:
HDPE pipe shall conform to the requirements of AASHTO M-294 and AASHTO MP7, Type S & D.
Connections shall use a rubber gasket, which conforms to ASTM F-477. Installation shall be in accordance
with ASTM Recommended Practice D-2321, AASHTO Section 30, or with Section 550 of the Georgia DOT
Standard Specifications, Construction of Roads and Bridges.
16. ... If using Aluminum coated Type 2 steel pipe or aluminum alloy pipe, add following note to plans:
All aluminum coated Type 2 steel pipe or aluminum alloy pipe, which will carry a live stream, shall have
paved inverts in accordance with AASHTO M-190, type C, except that the pipe need not be fully coated.
Installation shall be in accordance with Section 550 of the Georgia DOT Standard Specifications,
Construction of Roads and Bridges.
17. ... If using RCP pipe, add following note to plans:
All RCP pipe joints shall be bell & spigot types with a rubber gasket conforming to ASTM C-443. The pipe
shall be manufactured in accordance with AASHTO M-170 and/or ASTM C-76. Class of pipe and wall
thickness shall be in accordance with 1030-D, Georgia DOT specification, Table No. 1. Installation shall be
in accordance with Section 550 of the Georgia DOT Standard Specifications, Construction of Roads and
GWINNETT COUNTY SWM – REVIEW CHECKLIST – PLANS Page 3 of 13
18. ... A separate building permit shall be obtained prior to construction for each site retaining wall (which either
exceeds 4 feet in height or which has a backfill slope greater than 1 foot rise in 3 feet horizontal) and for each
detention pond wall (dam) in accordance with Gwinnett County Construction Code section 103.1.1. A
Certificate of Completion shall be issued by Gwinnett County Building Inspections Section for all walls
pertinent to the project prior to issuance of a Certificate of Occupancy for any usable structure on the site or
prior to approval of the Final Subdivision Plat as applicable.
11) ... Indicate minimum floor elevation of building on plan for lots . (FPMO 1.5)
12) ... Indicate Residential Drainage Plan (RDP) required on the following lots: .
Note that an RDP is required on a residential lot with a SWM BMP located on the lot. (DR 9.2.1b)
13) ... Indicate Residential Drainage Study (RDS) required on the following lots: . (DR 9.2.1b)
14) ... Storm sewer pipe that do not carry live streams must extend at least 50 feet past the front building setback
line. (SSFISS 18.104.22.168)
15) ... Standard landscaping and landscaping requirements that are part of zoning conditions are not permitted within
designated drainage or BMP easements. Provide Landscape Plan. (BLTO 3.2.5a.)
16) ... For residential subdivisions, the detention pond must be located on a storm water management facility lot (as
defined in the January 25, 2000 amendment to the Zoning Resolution) and be owned by a property
17) ... Provide a drainage easement located a minimum of 10-feet outside the 100-year ponding limits of the
18) ... For residential projects, provide a cleared access easement 30’ wide to the detention pond (DR 8.2.5.b).
19) ... For commercial projects, provide a cleared access easement 20’ wide to the detention pond from a public
street. (DR 8.2.5).
20) ... Within the access easement, a 15-foot wide road shall be graded at a maximum 20% grade to provide access
to the facility. Show grading on plans. The road shall be grassed or paved. The road shall extend to the
bottom of the pond when the pond is greater than 10 feet deep or 50 feet wide. (DR 8.2.5c)
21) ... Discuss location of pond(s) # outlet with this office.
22) ... In residential subdivisions, no more than 50% of the basin perimeter may be a wall of any type unless a drive
is provided to the bottom of the facility. The drive shall be a minimum of 15 feet wide with a maximum slope
of 20%. (DR 8.2.3.l)
23) ... Show the detention pond 100-year ponding contour and elevation on plan.
23) ... When depth of normal pool or water quality ponding is over four feet, a 10’ wide bench shall be provided and
provide standard detail 622 for a dry facility or 623 for a wet facility. (SSFISS 22.214.171.124)
24) ... Bottom of dry facility shall have positive drainage. Provide standard detail 622. (SSFISS 126.96.36.199)
GWINNETT COUNTY SWM – REVIEW CHECKLIST – PLANS Page 4 of 13
25) ... Discharge pipe must be no closer to the project site's property line than the greater of the distance
necessary to construct any velocity protection or a flow distance equal to six (6) pipe diameters.(DR
26) ... Show locations for temporary detention ponds if permanent ponds will not be constructed in this phase.
Provide design data in storm water management report.
27) ... Minimum top width of detention pond, earthen dam to be 8’-0”. (DR 9.8.2d(5))
28) ... Show grading associated with roadway deceleration lane.
29) ... Extend storm sewer cross drains due to widening of collector road.
30) ... Provide a flume and riprap at end of the widened collector road or deceleration lane section. Provide
flume detail on detail sheet.
PIPE & OPEN CHANNEL PROFILE SHEET
31) ... Galvanized corrugated steel pipe may not be used in drainage easements or county rights-of-way.
32) ... Only Reinforced Concrete Pipe may be used under non-local roads. Specifically, .
33) ... Specify which pipe material type (Aluminized Steel Type 2 pipe, Corrugated Aluminum Alloy pipe,
smooth lined corrugated Polyethylene pipe, or reinforced concrete pipe) is to be used.
34) ... All pipes carrying a live stream shall have paved inverts. Note which pipes need paved inverts in the pipe
chart. (SSFISS 3.9.5)
35) ... Provide pipe profiles. Show existing and proposed ground surface profiles, pipe lengths, slopes, inverts,
and 25-year hydraulic grade lines. (DR 10.2.7c and SSFISS 188.8.131.52)
36) ... Provide channel profiles. Show existing and proposed ground surface profiles, channel lengths, 25-year
normal flow depth and slopes. Minimum freeboard to be 20% of the flow depth. (SSFISS 5.2.1)
37) ... 25-year hydraulic grade line must be at least 1 foot below the gutter line or top of grate.
38) ... Specify gage and corrugation for all CMP pipes . (SSFISS 3.9.5)
39) ... Minimum pipe size shall be 15” diameter for public piped collection systems. Refer to pipe # .
40) ... Minimum culvert size shall be 18” diameter. (SSFISS 4.3)
41) ... Channel velocities for the fully developed 25-year flow shall not exceed the non-erosive velocity as shown
in 5.2.3 of the Gwinnett County Stormwater System and Facilities Installation Standards and
Specifications Refer to open channel # . (SSFISS 5.2.1)
42) ... Velocity in pipe system or corrugated metal pipe culvert(s) # exceed(s) 15 fps maximum. (SSFISS
3.4.1 and SSFISS 4.3).
GWINNETT COUNTY SWM – REVIEW CHECKLIST – PLANS Page 5 of 13
43) ... Slope of CMP or HDPE pipe(s) # exceed(s) 14% maximum. Provide anchors per manufacture’s
recommendations. (DR 9.9.2c and SSFISS 3.4.1)
44) ... Slope of RCP pipe(s) # exceed(s) 10% maximum. Provide anchors per manufacture’s
recommendations. (DR 9.9.2c and SSFISS 3.4.1)
45) ... Show minimum ground cover of 1’-0” for pipe(s) # .(SSFISS 184.108.40.206)
46) ... Anchor collars may be required on CMP pipes exceeding 10% slope. Specifically pipe(s) # .
47) ... Show 100-year ponding limit and elevation above inlet # . (SSFISS 4.3)
48) ... Show 100-year hydraulic grade line in all culverts. Specifically pipe(s) # . Use USGS regression
equations where applicable to check the magnitude of peak flows when other hydrologic methods
recommended in the manual are used (SSFISS 4.3)
49) ... Provide transition channel profiles from inlet and outlet ends of all pipes to natural drainage swales.
Specifically, at inlet / outlet of pipe(s) # . (SSFISS 3.4.1 and SSFISS4.3)
50) ... Maximum spacing of structures that can be used for access shall be 300’. Specifically, pipe(s) # .
51) ... Provide complete pipe chart indicating the following (including OCS outlet pipe):: (DR 10.6.7c2)
1. ... Upstream Structure Type (DWCB, SWCB, DI, etc.)
2. ... Pipe numbers/Pipe Structures
3. ... Pipe size
4. ... Pipe length
5. ... Pipe slope
6. ... Contributing drainage area
7. ... Design discharge (Q25 for piped drainage; Q100 for culverts)
8. ... Design storm frequency (25 year for piped drainage; 100 year for culverts)
9. ... Runoff coefficient (per future land use plan and assuming no detention – SSFISS 2.5)
10. ... Pipe material/coating
11. ... Velocity (V25 may not exceed non-erosive velocity at outlet headwall, unless energy dissipation is
52) ... Provide complete channel chart indicating the following: (DR 10.6.7c2)
12. ... Open channel numbers
13. ... Contributing drainage area
14. ... Runoff coefficient (per future land use plan and assuming no detention – SSFISS 2.5)
15. ... Conveyance size
16. ... Lining material (riprap, grouted riprap, sod, or erosion control blanket.)
17. ... Channel length
18. ... Channel slope (for min and max values – see SSFISS 5.2.1. Maximum 10%.)
19. ... Velocity (V25 may not exceed non-erosive velocity – SSFISS 5.2.3. Max 4 fps for sod.)
20. ... Design storm frequency (25 year)
21. ... Design discharge (25 year)
22. ... Normal flow depth (25 year)
53) ... Development plans must be sealed by Professional Engineer or Landscape Architect: (DR 11.1.3.a)
GWINNETT COUNTY SWM – REVIEW CHECKLIST – PLANS Page 6 of 13
EROSION AND SEDIMENT CONTROL PLAN
54) ... Provide note(s) indicated below in a notes section on Erosion and Sediment Control Plan.
1. Description of existing land use including landlot and district number at the project site and description of
proposed project ____________.
2. Name, address, and phone number of the property owner is _____________.
3. Name and phone number of the 24-hour local contact person responsible for erosion control emergencies is
4. Total project acres _________.
5. Total disturbed acres _______.
6. THE ESCAPE OF SEDIMENT FROM THE SITE SHALL BE PREVENTED BY THE INSTALLATION
OF EROSION AND SEDIMENT CONTROL MEASURES AND PRACTICES PRIOR TO, OR
CONCURRENT WITH, LAND DISTURBING ACTIVITIES.
7. Erosion and sedimentation control measures and practices shall be maintained at all times. If full implementation
of the approved plan does not provide for effective erosion and sediment control, additional erosion and sediment
control measures shall be implemented to control or treat the sediment source.
8. Sediment storage maintenance indicators must be installed in sediment storage structures, indicating the 1/3 full
9. Maintenance of all soil erosion and sedimentation control measures and practices, whether temporary or
permanent, shall be at all times the responsibility of the property owner.
10. A 50-foot undisturbed buffer and a 75-foot impervious setback is to be maintained adjacent to all streams.
11. Detention pond, detention outlet structures and temporary sediment pond features are to be constructed and fully
operational prior to any other construction or grading.
12. Disturbed areas shall be stabilized with temporary vegetation or mulch if land-disturbing activities cease for more
than 14 calendar days.
13. All fill slopes shall have silt fence placed at the slope’s toe.
14. Concentrated flow areas and all slopes steeper than 2.5:1 with a height of ten feet or greater shall be stabilized
with the appropriate erosion control matting or blanket.
15. The professional who seals this plan certifies under penalty of law that this plan was prepared after a site visit to
the locations described herein by the professional or the professional’s authorized agent, under the professional’s
16. Upon notification and authorization of the owner, the design professional who prepared the ES&PC Plan is
responsible for inspecting the installation of the BMP’s within 7 days after initial construction activities begins.
17. GaSWCC Level II Design Professional Certification number ________________ and signature______________ .
18. The receiving water(s) is ________________ .
19. Total wetland acres on site are _____________
57) ... Identify and delineate topographic features such as state waters on and w/i 200’ of the project site, stream
buffers, wetlands, soil series, and storm water discharge points on-site.
58) ... Provide activity schedule indicating the anticipated starting and completion dates for the project. (ESCO
5.3.2f) (NPDES D.1.b)
GWINNETT COUNTY SWM – REVIEW CHECKLIST – PLANS Page 7 of 13
59) ... Provide vegetative plan for temporary and permanent vegetative practices, including species, planting dates
and seeding, fertilizer, and lime and mulching rates. The vegetation plan shall show options for
year round seeding. (ESCO 5.3.2h)
60) ... Show detail drawings for all structural practices. Specifications shall follow the guidelines set forth in the
Manual for Erosion and Sediment Control in Georgia. (ESCO 5.3.2i)
61) ... Provide temporary berms along the top of fill slopes to prevent the formation of rills and gullies. Grade
berms and top-of-slope to drain laterally to collection points. Install appropriately sized sediment trap and
somewhere in each basin system to trap sediment. Install down drainpipe to drain diverted runoff down each
slope. Locate down-drain discharge point to prevent additional erosion or sedimentation.
62) ... If using existing detention pond as a sediment trap or basin, volume must be provided below the outlet control
invert. Existing lakes that will not be modified under this permit may not be used as sediment trap or basin.
63) ... Erosion control maps, drawings, and supportive computations shall bear the signature, date of signature, and
seal of a registered or certified professional in engineering, architecture, landscape architecture, land
surveying, or erosion and sediment control. (ESCO 5.3.3)
64) ... Provide graphic scale and north point or arrow indicating magnetic north. (ESCO 5.3.3a)
65) ... Provide vicinity map indicating the location of the project and existing streets. (ESCO 5.3.3b)
66) ... Provide boundary line survey information. (ESCO 5.3.3c)
67) ... Show delineation of disturbed areas within project boundary. (ESCO 5.3.3d)
68) ... Existing and planned contours, with contour lines drawn with an interval in accordance with the following
table: (ESCO 5.3.3e)
Map Scale Ground slope Contour interval (ft)
Flat: 0-2% 0.5 or 1
1”=100’, or larger Rolling: 2-8% 1 or 2
Steep: 8%+ 2, 5, or 10
69) ... Indicate on the plans adjacent areas and features such as streams, lakes, residential areas, etc., which might be
affected by project work. (ESCO 5.3.3f)
70) ... Show all proposed structures or additions to existing structures. (ESCO 5.3.3g)
71) ... Inside the 2000’ River Corridor, a 50-foot undisturbed buffer adjacent to the Chattahoochee River and a 35-
foot undisturbed buffer adjacent to perennial streams shown on the USGS quad maps is required by the
Metropolitan River Protection Act. No variance is allowed. (ESCO 5.3.3h)
72) ... For projects in Big Haynes Creek watershed inside the 7 mile radius to Black Shoals Reservoir, on perennial
streams shown on the USGS quad maps, show a minimum 100 foot buffer and 150 foot no-impervious
surface setback. See the zoning resolution for exempt activities. (Zoning Resolution 1314.2)
73) ... For Alcovy River watershed and Big Haynes Creek watershed outside the 7 mile radius to Black Shoals
Reservoir, on perennial streams shown on the USGS quad maps, show a minimum stream buffer of 50 feet
and a no-impervious surface setback of 75 feet. See the zoning resolution for exempt activities.
74) ... Outside the 2000’ corridor, for perennial streams tributary to the Chattahoochee River shown on the USGS
GWINNETT COUNTY SWM – REVIEW CHECKLIST – PLANS Page 8 of 13
quad maps, a 15-foot no-encroachment buffer and a 35-foot accessory building setback from the banks of the
stream exist. No variance is allowed.
75) ... Obtain a variance from EPD for proposed encroachment into the 25’ buffer.
76) ... Locate the erosion and sediment control measures on the plan using the uniform coding symbols from chapter
6 of the Manual for Erosion and Sediment Control in Georgia.
77) ... Provide sediment basins with 67 CY/Acre of drainage area storage capacity (per Manual for Erosion and
Sediment Control in Georgia). Note proposed length, width and depth. Show on plan and provide detail.
Include a written rationale if sediment storage basin is not to be provided .
78) ... Provide checkdams or grade stabilization structures in proposed channel(s) # to prevent gulleying.
Provide checkdam/structure detail.
79) ... Provide energy dissipation structures (riprap apron, riprap basin or baffled outlet details) at outlets of
headwalls where the discharge velocity (V25) is greater than the non-erosive velocity of the receiving channel.
Design them using the procedures in the Gwinnett County Stormwater Systems and Facilities Installation
Standards and Specifications. Provide supporting calculations in the Storm Water Management Report.
80) ... If detention pond is located on a live stream, sediment ponds must be installed above detention area.
81) ... Specify type ‘C’ silt fence (steel posts with wire reinforcement) in these areas:
82) ... Each Plan shall contain a description of appropriate controls and measures that will be implemented at the
construction site including; (1) initial perimeter control BMPs, (2) intermediate grading and drainage BMPs,
and (3) final BMPs. Common developments must provide typical or situational lot ES&PC plan (NPDES
83) ... The description and implementation of controls shall address waste disposal. Solid materials, including
building materials, shall not be discharged to water of the State, except as authorized by a section 404 permit.
84) ... Off-site vehicle tracking of dirt, soils, and sediments and the generation of dust shall be minimized or
eliminated to the maximum extent practical. The Plan shall include the best management practice to be
implemented at the site or construction activity. (NPDES IV.D.2.c.(2))
85) ... All permittees shall ensure and demonstrate that their Plan is in compliance with applicable State and local
waste water disposal, sanitary sewer or septic system regulations. (NPDES IV.D.2.c.(3))
86) ... The Plan shall include best management practices for the remediation of all petroleum spills and leaks as
appropriate. (NPDES IV.D.2.c.(4))
87) ... Provide map showing (a) the location of all perennial and intermittent streams and other water bodies into
which the storm water is discharged and (b) the receiving water and/or outfall sampling locations. (NPDES
88) ... Provide a written narrative of site specific analytical methods used to collect, handle and analyze the samples
including quality control/quality assurance procedures. This narrative must include precise sampling
methodology for each sampling location. (NPDES IV.D.5.a.(2))
89) ... When the permittee has determined that some or all outfalls will be monitored, a rationale must be include for
the NTU limit(s) selected from Appendix B of the NPDES General Permit for Storm Water Discharges
Associated with Construction Activity. This rationale must include the size of the facility or stand alone
construction, the calculation of the size of the surface water drainage area, and the type of receiving water(s).
GWINNETT COUNTY SWM – REVIEW CHECKLIST – PLANS Page 9 of 13
(NPDES IV.D.5.a.(3)) :
90) ... The Primary permittee must sample all receiving water(s), or all outfall(s), or a combination of receiving
waters and outfall(s). Receiving waters must have an upstream and a downstream sample location. (NPDES
91) ... Provide details on required inspections and record keeping by the all personnel involved with each phase of
construction. (NPDES IV.C.3.a)
EROSION CONTROL DETAIL / MISC DETAIL SHEET(S)
92) ... Provide a flume detail.
93) ... Specify Gwinnett County detail number 611, manhole casting – non-traffic areas, for all non-traffic bearing
manholes. Include detail on plans. Detail can be downloaded from “Development Review Documents” on
www.gwinnettstormwater.com web page, or a copy of the standard drawings can be obtained on CD-ROM or
paper from Planning and Development. Material suppliers include East Jordan Iron Works and US Foundry.
94) ... Provide typical swale detail.
95) ... Provide detail of proposed retaining wall which does not exceed 4 feet in height nor has backfill slope
greater than 1 foot rise in 3 feet horizontal.
96) ... Indicate on site grading plan the applicable location for each site retaining wall and for each detention pond
wall (dam) and specify elevation at top and bottom of each wall.
97) ... Remove from site plans all structural details and specifications pertinent to construction of retaining walls
(which either exceed 4 feet in height or have backfill slope greater than 1 foot rise in 3 feet horizontal) and
detention pond walls (dams). [Note: Structural construction details and specifications for each retaining
wall and for each detention pond wall shall be submitted to Gwinnett County Building Plan Review for
review and approval for issuance of a separate building permit.]
98) ... Provide Standard Drawing titled “Typical Detention Pond Wall Tie In” sheet 626.
99) ... For walls over 4’, provide Standard Drawing titled “Retaining Wall Safety Treatment” sheet 630.
100) ... Show temporary construction exit pad detail and location. Specify pad size and show maintenance
101) ... Provide ... Sd1 (type ‘C’), ... Sd2, ... Sd3, ... Rt, ... Cd, ... Co detail(s).
102) ... Provide energy dissipation details (riprap apron, riprap basin or baffled outlet details) on plans and include a
table similar to one of the following:
Riprap Apron Summary
(include Fig 7-4 from SSFISS with table)
Headwall ID Pipe diameter Riprap size Apron Length Width of Apron
(Do) (d50) (La) (W=Do+La)
GWINNETT COUNTY SWM – REVIEW CHECKLIST – PLANS Page 10 of 13
Riprap Basin Details
(include Fig 7-5 from SSFISS with table)
Headwall ID Pool Length, ft Basin Length, ft Approach Basin Thickness, ft,
(> of 10 hs or 3W o) (> of 15hs or 4W o) Thickness, ft, 3D50 2D50
Baffled Outlet Details/Dimensions
(include fig 7-11 from SSFISS with table)
Headwall Fr W L f e H a b c
101) ... Provide details of detention pond outlet control structure.
102) ... Provide a detail for .
NOTE: GWINNETT COUNTY REGULATES DAMS BETWEEN 9 AND 25 FEET IN HEIGHT AND IMPOUNDING
BETWEEN 20 AND 100 ACRE-FEET. DAMS GREATER THAN 25 FEET IN HEIGHT OR IMPOUNDING
GREATER THAN 100 ACRE-FEET ARE REGULATED BY GEORGIA DNR SAFE DAMS PROGRAM.
CONSTRUCTION OF THE LATTER REQUIRES A STATE PERMIT.
103) ... For county regulated dams, if constructing the dam according to the design standards contained in the Rules
for Dam Safety and TR-60, see Dam Design Checklist (DR 8.6.1)
104) ... If not constructing the dam according to the rules for dam safety, submit dam breach analysis using the
“DAMBRK” computer program and obtain dam breach easement from offsite property owners. (DR 8.6.1)
105) ... FYI: Submit dam as-built certification from a registered professional engineer stating that the dam is
constructed in accordance with the provisions of the Development Regulations and the authorized
construction plans prior to recording the final plat. (DR 8.6.1f)
106) ... Dam must be constructed to the design standards contained in the Rules for Dam Safety and TR-60 because
development currently exists in the dam breach zone. (DR 8.6.1b)
107) ... Submit construction plans for new dam. Other comments may follow. (DR 8.6.1c)
108) ... FYI: For residential subdivisions, establish mandatory property owner’s association that is responsible for
maintenance of the dam. (DR 8.6.1f)
109) ... Since a category II dam exists upstream, submit to Gwinnett County the following: (DR 8.6.2)
110) ... Location of Category II dam and the proposed development
111) ... A surveyed cross section of the stream valley at the location of the proposed development including finished
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112) ... A dam breach analysis using the DAMBRK computer model to establish the height of the flood wave in the
downstream floodplain. A qualified Professional Engineer shall complete this in accordance with the Safe
Dams Program Quality Assurance Program.
113) ... FYI: Development is adjacent to an NRCS watershed structure. NRCS must approve the proposed design.
An appropriately graded 25’ access easement must be deeded to Gwinnett County to allow maintenance
activities on the dam. The emergency overflow spillway must be contained in a drainage easement.
114) ... After consulting the National Wetlands Inventory Map, it appears that wetlands exist on the project property.
These wetland areas must be indicated on the site plan. National Wetland Inventory Maps are on file with the
Gwinnett County Department of Public Utilities, and are available at 75 Langley Drive for the design
consultant’s perusal. NWI Maps are also available on the internet at http://wetlands.fws.gov/nwi.htm (DR
115) ... Gwinnett County will not issue a land disturbance permit until we receive documentation from the Corps of
Engineers that an Individual Permit or a Letter of Permission authorizes the proposed encroachment in
wetland areas. If the encroachment is authorized under a Nationwide Permit, we must receive documentation
from the applicant’s engineer about which Nationwide Permit is applicable and why the encroachment meets
the conditions of that Nationwide permit. We also must receive a copy of the approved PCN letter from the
Corps of Engineers, if applicable. The Corps of Engineers can be contacted at the following address: (DR
Gary L. Craig, Project Manager
US Army Corps of Engineers, Savannah District
1590 Adamson Parkway
The Plaza, Suite 130
Morrow, GA 30260
116) ... Show water flow direction line on preliminary plan for each lot.
117) ... Place grouted rip-rap at channel inlets to ponds.
118) ... Provide Water Quality Performance Review Checklist.
119) ... Provide Storm Water Management Report Checklist.
120) ... Provide Flood Study Checklist.
121) Provide Water Quality BMP Checklist.
a. ... Extended Detention Pond Checklist.
b. ... Constructed Wetlands Checklist.
c. ... Infiltration Trench Checklist.
d. ... Grassed Swale Checklist.
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122) ... For CDP or MDP project, provide Site Development Release Affidavit
123) ... FYI: Show date and description of all revisions to original.
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