SW8060648_COMPLIANCE_20061117

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

STORMWATER DIVISION CODING SHEET
NCS PERMITS
PERMIT NO.
DOC TYPE
❑ FINAL PERMIT
❑ MONITORING REPORTS
❑ APPLICATION
❑ COMPLIANCE
❑ OTHER
DOC DATE
❑
YYYYM M DD

S1� '�K
Permit No, hhV �- N b L',I(�
(to be provided by UtVQ)
State of North Carolina
Department of Environment and Natural Resources
Division of Water Quality
STORMWATER MANAGEMENT PERMIT APPLICATION FORM
UNDERGROUND INFILTRATION TRENCH SUPPLEMENT
This form may be photocopied for use as an original
DWQ Stormwater Management Plan Review:
A complete stormwater management plan submittal includes a stormwater management permit application, an
underground infiltration trench supplement for each system, design calculations, and plans and specifications
showing all stormwater conveyances and system details.
I. PROJECT INFORMATION
Project Name : V 0A
Contact Person: Phone Number: (74" 000
For projects with multiple infiltration systems, a supplement form must be completed for each system. This
workshect applies to: Trench
(from plans)
in Drainage Area
(from Form S PYU--101)
II. DESIGN INFORMATION (attach supporting calculations/documentation):
5
Soils Report Summary (based upon an actual field investigation and soil borings)
Soil Type K.nP-c. \`.1"+<n ♦ Swn�+
Infiltration Rate 1-i0 e% r in/hr or cf/hr/sf (circle appropriate units)
SI-1 WT Elevation , O fmsl (Seasonal High Water Table elevation)
Trench Design Parameters
Design Volume
Design Storm
Drawdown Time
Perforated Pipe Size
Perforated Pipe Length
No. Observation Wells
Zti "-ko c. f.
inch event (1.5 inch event for SA waters, I inch event for others)
days
g inch diameter
ft.
Stone Type (if used) -il 5 7
Stone Void Ratio 40 `70
(may be required on a case -by -case basis)
Trench Elevations (in feet mean sea level)
Bottom Elevation fmsl
Storage/Overflow Elevation fmsl < - b
Form SWU-107 Rev 3.99 Page 1 of 4

Trench Dimensions
Height
Width
►-� ft. Length "?'440 ft.
ft. Volume Provided 7,7,A . 4 cu.ft.
Ill. REQUIRED ITEMS CHECKLIST
The following checklist outlines design requirements per the Stormwater Best Management Practices manual (N.C.
Department of Environment, Health and Natural Resources, November 1995) and Administrative Code Section: 15
A NCAC 2H .1008.
Initial in the space provided to indicate that the following design requirements have been met and supporting
documentation is attached. If the applicant has designated an agent in the Stormwater Management Permit
Application Form, the agent may initial below. Attach justification if a requirement has not been met.
Applicants Initials
&N �( a.
System is located 50 feet from class SA waters and 30 feet from other surface waters.
f b.
System is located at least 100 feet from water supply wells.
I c.
Bottom of system is at least 2 feet above the seasonal high water table.
f d.
Bottom of the system is 3 feet above any bedrock or, impervious soil horizon.
e.
Off-line system, runoff in excess of the design volume bypasses the system (bypass detail
provided).
+� f.
System is designed to draw down the design storage volume to the proposed bottom
elevation under seasonal high water conditions within five days based upon infiltration
through the bottom only (a hydrogeologic evaluation may be required).
g.
Soils have a minimum hydraulic conductivity of 0.52 inches per hour.
h.
System is not sited on or in fill material or DWQ approval has been obtained.
�c, f i.
Plans ensure that the installed system will meet design specifications (constricted or
restored) upon initial operation once the project is complete and the entire drainage area is
stabilized.
6C,N& f J.
System is sized to take into account the runoff at the ultimate built -out potential from all
surfaces draining to the system, including any off -site drainage.
'h(,6L 'r k.
System is located in a recorded drainage casement for the purposes of operation and
maintenance and has recorded access easements to the nearest public right-of-way.
Glv 1.
System captures and infiltrates the runoff from the first 1.0 inch of rainfall (1.5 inch event
for areas draining to SA waters ).
�c. ✓ m.
Drainage area for the device is less than 5 acres.
!&i�c �_ n.
A pretreatment device ( filter strip, grassed swale, sediment trap, etc.) is provided.
o.
Trench bottom is covered with a layer of clean sand to an average depth of 4 inches.
C"N6 p. Sides of the infiltration trench are lined with geotextile fabric.
q. Rock used is free of fines (washed stone) and has a large void ratio.
r. Side to bottom area ratio is less than 4:1.
Form SWU-107 Rev 3.99 Page 2 of 4

s. Observation well(s) are provided (case -by -case basis).
N//j t. Vegetated filter is provided for overflow (50 feet for SA waters, 30 feet for other waters)
and detail is shown on plans.
c4y\ u. A benchmark for checking sediment accumulation is provided.
IV. UNDERGROUND INFILTRATION TRENCH OPERATION AND MAINTENANCE AGREEMENT
After every runoff producing rainfall event and at least monthly inspect the bypass/overflow structure for
blockage and deterioration and the infiltration system for erosion, trash accumulation, grass cover, and general
condition.
2. Repair eroded areas immediately, re -seed as necessary to maintain adequate vegetative cover, mow vegetative
cover to maintain a maximum height of six inches, and remove trash and blockages as needed to maintain
system performance.
3. Remove accumulated sediment annually or when depth is reduced to 75% of the original design depth. Restore
depth to original design depth without over -excavating. Over -excavating may cause the required water table
separation to be reduced and may compromise the ability of the system to perform as designed.
4. The water level in any monitoring wells will be recorded after a I inch rainfall event and at least once a month.
Chronic high water table elevations (within 1 foot of the bottom of the system for a period of three months)
shall be reported to DWQ immediately.
If DWQ determines that the system is failing, the system will immediately be repaired or replaced to original
design specifications. If the system cannot be repaired to perform its design function, other stormwater control
devices as allowed by NCAC 2H .1000 must be designed, approved and constructed.
6. Remove accumulated sediment from the infiltration system annually or when depth in the unit is reduced to
75% of the original design depth. The system shall be restored to the original design depth without over -
excavating. Over -excavating may cause the required water table separation to be reduced and may
compromise the ability of the system to perform as designed. Removed sediment shall be disposed of in an
appropriate manner and shall not be handled in a manner that will adversely impact water quality (i.e.
stockpiling near a stormwater treatment device or stream, etc.).
A benchmark shall be established in the infiltration system. The benchmark will document the original
design depth so that accurate sediment accumulation readings can be taken. The measuring device used to
determine the depth at the benchmark shall be such that it will give an accurate depth reading and not
readily penetrate into accumulated sediments.
When the depth at the benchmark reads , the accumulated sediment shall be removed
from the system.
Form SWU-l07 Rev 3.99 Page 3 of 4

I acknowledge and agree by my signature below that t am responsible for maintaining the stormwater
collection system in accordance with the six maintenance procedures listed above. l agree to notify DWQ
of any problems with the system or prior to any changes to the system or responsible party.
Print Name and Title
Address: q"1
Phone: -
Signature:
L�SS-
Z+�v Date:
��
Note: The legally responsible party should not be a homeowners association unless more than 50% of the lots have been sold and a
resident of the subdivision has been named the president.
i / 4 �r J o��v` f` a Notary Public for the State of �'�'t'�"'{ , County of
6eo!�k e 7 — do hereby certify that -' tJN �,A Z.C,..,n personally appeared before me this
day of Z!4,c/ , O 6e;O 6' and acknowledge the due execution of the forgoing infiltration basin maintenance
requirements. Witness my hand and official seal,
SEAL My commission expires 3' Qc °'
r �ry
r
Form SWU-107 Rev 3.99 Page 4 of 4