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Home My WebLink About20201217 Ver 1_09_Level Spreader Supplement Form_20201029o��F WATF9Qv y � r NCDENR STORMWATER MANAGEMENT PERMIT APPLICATION FORM 401 CERTIFICATION APPLICATION FORM LEVEL SPREADER - VEGETATED FILTER STRIP (LS-VFS) SUPPLEMENT This form must be completely filled out, printed, initialed, and submitted. Project name Project Walter Contact name David Starkel Phone number 704.909.3513 Date 10.19.2020 Drainage area number II. DESIGN INFORMATION The purpose of the LS-VFS Buffer Rule: Diffuse Flow Stormwater enters LS-VFS from The drainage area Type of VFS Engineered filter strip (graded & sodded, slope < 8%) Explanation of any "Other" responses above If Stormwater Enters the LS-VFS from the Drainage Area Drainage area Impervious surface area Percent impervious Rational C coefficient Peak flow from the 1 in/hr storm Time of concentration Rainfall intensity, 10-yr storm Peak flow from the 10-yr storm Design storm Maximum amount of flow directed to the LS-VFS Is a flow bypass system going to be used? Explanation of any "Other" responses above If Stormwater Enters the LS-VFS from a BMP Type of BMP Peak discharge from the BMP during the design storm Peak discharge from the BMP during the 10-year storm Maximum capacity of a 100-foot long LS-VFS Peak flow directed to the LS-VFS Is a flow bypass system going to be used? Explanation of any "Other" responses above 1,007,422 ft2 409,699 ft2 40.67 % n 5fi 13.05 cfs 5.00 min 7.22 in/hr 94.23 cfs Other: Explained below 9.79 cfs Y (Y or N) 0.75 in/hr intensity per 15A NCAC 02H .1059 Do not complete this section of the form. Pick one: cfs cfs Do not complete this section of the form. 10 cfs cfs Do not complete this section of the form. (Y or N) Form SW401 - LS-VFS - 29June2012 - Rev.10 page 1 of 3 LS-VFS Design Forebay surface area 820 sq It Forebay is adequately sized. Depth of forebay at stormwater entry point 36 in Depth of forebay at stormwater exit point 12 in Depth is appropriate. Feet of level lip needed per cfs 10 ft/cfs Computed minimum length of the level lip needed 98 ft Length of level lip provided 100 ft Width ofVFS 50 ft Elevation at downslope base of level lip 210.50 fmsl Elevation at the end of the VFS that is farthest from the LS 209.50 fmsl Slope (from level lip to the end of the VFS) 2.00 % Are any draws present in the VFS? N (Y or N) OK Is there a collector swale at the end of the VFS? N (Y or N) Bypass System Design (if applicable) Is a bypass system provided? Y (Y or N) Is there an engineered flow splitting device? Y (Y or N) Please provide plan details of flow splitter & supporting calcs. Dimensions of the channel (see diagram below): M ft B ft W ft y (flow depth for 10-year storm) ft freeboard (during the 10-year storm) ft Peak velocity in the channel during the 10-yr storm ft/sec Channel lining material Other: Explained below Does the bypass discharge through a wetland? N (Y or N) Does the channel enter the stream at an angle? Y (Y or N) Explanation of any "Other" responses above Bypass outfalls through 42" pipe. W i B 1 Form SW401 - LS-VFS - 29June2012 - Rev.10 page 2 of 3 III. REQUIRED ITEMS CHECKLIST EDIT 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. Requried Item: 1. Plans (1"- 50' or larger) of the entire site showing: - Design at ultimate build -out, Off -site drainage (if applicable), Delineated drainage basins (include Rational C coefficient per basin), Forebay (if applicable), High flow bypass system, Maintenance access, Proposed drainage easement and public right of way (ROW), and Boundaries of drainage easement. 2. Plan details (1" = 30' or larger) for the level spreader showing: - Forebay (if applicable), High flow bypass system, One foot topo lines between the level lip and top of stream bank, Proposed drainage easement, and Design at ultimate build -out. 3. Section view of the level spreader (1" = 20' or larger) showing: - Underdrain system (if applicable), Level lip, Upslope channel, and Downslope filter fabric. 4. Plan details of the flow splitting device and supporting calculations (if applicable). 5. A construction sequence that shows how the level spreader will be protected from sediment until the entire drainage area is stabilized. 6. If a non -engineered VFS is being used, then provide a photograph of the VFS showing that no draws are present. 7. The supporting calculations. 8. A copy of the signed and notarized operation and maintenance (0&M) agreement. Initials Page or plan sheet number and any notes: Form SW401 - LS-VFS - 29June2012 - Rev.10 page 3 of 3