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HomeMy WebLinkAboutSW6240803_Supplement-EZ Form_20240916 Red triangles at the upper right hand corner indicate design comments Please complete the yellow shaded items. OFWATF9 NCDENR STORMWATER MANAGEMENT PERMIT APPLICATION FORM 401 CERTIFICATION APPLICATION FORM WETLAND SUPPLEMENT This form must be filled out,printed and submitted. The Required Items Checklist(Part Ill)must be printed,filled out and submitted along with all the required information. I. PROJECT INFORMATION Project name HIES EASTOVER Contact name WILLIAM CLAYTON,PE Phone number 828-455-3456 Date Drainage area number 1 II. DESIGN INFORMATION Site Characteristics Drainage area 187,582.00 ft2 Impervious area 174,894.00 ft2 Percent impervious 93.2% % Design rainfall depth 1.00 inch Peak Flow Calculations 1-yr,24-hr rainfall depth 3.02 in 1-yr,24-hr intensity 0.13 in/hr Pre-development 1-yr,24-hr runoff 0.39 ft3/sec Post-development 1-yr,24-hr runoff 0.53 ft3/sec Pre/Post 1-yr,24-hr peak control 0.14 ft3/sec Storage Volume: Non-SA Waters Minimum required volume 13,114.00 ft3 Volume provided(temporary pool volume) 15,000.00 ft3 OK Storage Volume: SA Waters Parameters 1.5"runoff volume ft3 Pre-development 1-yr,24-hr runoff volume ft3 Post-development 1-yr,24-hr runoff volume ft3 Minimum volume required ft3 Volume provided ft3 Outlet Design Depth of temporary pool/ponding depth(DPlants) 12.00 in OK Drawdown time 2.70 days OK Diameter of orifice 2.00 in OK Coefficient of discharge(CD)used in orifice diameter calculation 0.60(unitless) Driving head(Ho)used in the orifice diameter calculation 0.33 ft Provide calculations to support this driving head. Form SW401-Wetland-Rev.6-1 1/16/09 Parts I and II.Project Design Summary,Page 1 of 3 Surface Areas of Wetland Zones Surface Area of Entire Wetland 15,000.00 ft2 OK Shallow Land 5,000.00 ft2 OK The shallow land percentage is: 33% % Shallow Water 6,000.00 ft2 OK The shallow water percentage is: 40% % Deep Pool Forebay portion of deep pool(pretreatment) 1,500.00 ft2 OK The forebay surface area percentage is: 10% % Non-forebay portion of deep pool 1,500.00 ft2 OK The non-forebay deep pool surface area percentage is: 10% % Total of wetland zone areas 14,000.00 ft2 Enter data into the shaded cells in this section. Add or subtract the following area from the zones -1,000.00 ft2 Topographic Zone Elevations Temporary Pool Elevation(TPE) Shallow Land(top) 127.50 ft amsl Permanent Pool Elevation(PPE) Shallow Water/Deep Pool(top) 127.50 ft amsl Shallow Water bottom 127.00 ft amsl Most shallow point of deep pool's bottom 125.00 ft amsl Deepest point of deep pool's bottom 125.00 ft amsl Design must meet one of the following two options: This design meets Option#1, Top of PPE is within 6"of SHWT,If yes: (Y or N) SHWT(Seasonally High Water Table) 124.80 ft amsl OK This design meets Option#2, (Y or N) Wetland has liner with permeability<0.01 in/hr,If yes: Depth of topsoil above impermeable liner in Topographic Zone Depths Temporary Pool Shallow Land 0.00 in Permanent Pool Shallow Water 6.00 in OK Deep Pool(shallowest) 30.00 in OK Deep Pool(deepest) 30.00 in OK Planting Plan Are cattails included in the planting plan? N (Y or N) OK Number of Plants recommended in Shallow Water Area: Herbaceous(4+cubic-inch container) 1,500 Number of Plants recommended in Shallow Land Area: Herbaceous(4+cubic-inch container),OR 1,250 Shrubs(1 gallon or larger),OR 200 Trees(3 gallon or larger)and Herbaceous(4+cubic-inch) 25 and 1,000 Number of Plants provided in Shallow Water Area: Herbaceous(4+cubic-inch container) Number of Plants provided in Shallow Land Area: Herbaceous(4+cubic-inch container) Shrubs(1 gallon or larger) Trees(3 gallon or larger)and Grass-like Herbaceous(4+cubic-inch) Form SW401-Wetland-Rev.6-11/16/09 Parts I and II.Project Design Summary,Page 2 of 3 Additional Information Can the design volume be contained? Y (Y or N) OK Does project drain to SA waters? If yes, N (Y or N) Excess volume must pass through filter. What is the length of the vegetated filter? ft Are calculations for supporting the design volume provided in the (Y or N) OK application? Is BMP sized to handle all runoff from ultimate build-out? Y (Y or N) OK Is the BMP located in a recorded drainage easement with a (Y or N) OK recorded access easement to a public Right of Way(ROW)? The length to width ratio is: 1.78 :1 OK Approximate wetland length 160.00 ft Approximate wetland width 90.00 ft z This approx.surface area is within this number of square feet Approximate surface area using length and width provided 14,400.00 ft of the entire wetland surface area reported above: Will the wetland be stabilized within 14 days of construction? Y (Y or N) OK Form SW401-Wetland-Rev.6-11/16/09 Parts I and II.Project Design Summary,Page 3 of 3