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Home My WebLink About20050588 Ver 2_Stormwater Info_201204274 X1005 - 0� % 8 TO Annette Lucas PE NCDENR /DWQ /Wetlands and Stormwater Branch 1650 Mail Service Center (mail) Raleigh NC 27699 -1650 LAPR FROM Carlton Hunt 2012 Stewart - Proctor PLLC 319 Chapanoke Road Suite 106 Mrs Lucas This is the submittal I called you about We are proposing to redesign 3 of the level spreaders for Ferrell Meadows Project # 050588 This site plan s a whole will not be changed only the level spreaders The level spreaders as previously approved they are not really buildable With this submittal are the flow calculations for the li.n per hour storm the level spreader supplement forms and the details for the spreaders and the splatter boxes FERRELL MEADOWS LEVEL SPREADER CONVERSION TO NEW 1001211111= THE PURPOSE OF THIS CHANGE IS TO SHORTEN THE LENGTH OF THE PROPOSED LEVEL SPREADERS AND INSTALL BYPASSES FOR FLOW EXCEEDING THE DESIGN STORM LEVEL SPREADER #1 DRAINAGE AREA - 4 9 ACRES DESIGN STORM -1 IN /HOUR C VALUE 0 40 DESIGN STORM Q -196 CFS DESIGN LENGTH - 98 FEET LEVEL SPREADER #2 DRAINAGE AREA -16 ACRES DESIGN STORM -1 IN /HOUR C VALUE 0 40 DESIGN STORM Q -0 64 CFS DESIGN LENGTH - 32 FEET LEVEL SPREADER #3 DRAINAGE AREA - 3 8 ACRES DESIGN STORM -1 IN /HOUR C VALUE 0 40 DESIGN STORM Q -152 CFS DESIGN LENGTH - 76 FEET SPUTTER BOX DETAILS ATTACHED oa�F W ATEgOG y f _ _ > HCDENR ° STORMWATER MANAGEMENT PERMIT APPLICATION FORM 401 CERTIFICATION APPLICATION FORM LEVEL SPREADER VEGETATED FILTER STRIP (LS VFS) SUPPLEMENT This form must be completely rifted out printed initialed and submitted 1 PROJECT INFORMATION sq It Forebay is adequately sized Project name Ferrell Meadows Contact name Michael Stewart Phone number 919 7791855 Date April 17 2012 Drainage area number 1 II DESIGN INFORMATION it The purpose of the LS-VFS Buffer Rule Diffuse Flow Stormwater enters LS-VFS from The drainage area Type of VFS Protected riparian buffer (slope < 5 %) Explanation of any Other" responses above If Stonnwater 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 LS VFS Design Forebay surface area Depth of forebay at stormwater entry point Depth of forebay at stormwater exit point Feet of level lip needed per cis Computed minimum length of the level lip needed Length of level lip provided Width of VFS Elevation at downslope base of level lip Elevation at the end of the VFS that is farthest from the LS 213 444 fe 25 613 fe 1200 % U 4U 196 c(s 500 min 722 in/hr 1415 cfs 10 year storm 196 cis y (Y or N) Do not complete this section of the form cfs cis Do not complete this section of the form 2 cfs CIS Do not complete this section of the form (Y or N) 52 sq It Forebay is adequately sized 12 in 12 in Depth is appropriate 50 ft/cfs 98 ft 98 ft 50 it 34000 fmsl 33900 fmsl Forrn SW401 LS-VFS 27Ju12011 Rev 9 page 1 of 3 Slope (from level lip to the end of the VFS) 200 %, Are any draws present in the VFS? N (Y or N) OK Is there a collector swale at the end of the VFS9 N (Y or N) Bypass System Design (if applicable) Is a bypass system provided? Is there an engineered flow splitting device? Dimensions of the channel (see diagram below) M B W y (flow depth for 10 year stone) freeboard (during the 10 year storm) Peak velocity in the channel during the 10 yr stone Channel lining material Does the bypass discharge through a wetland? Does the channel enter the stream at an angle? Explanation of any Other" responses above Y (Y or N) Y (Y or N) 300 ft 300 It 900 It 073 It 100 It 376 ft /sec Pick one N (Y or N) Y (Y or N) Please provide plan details of flow splitter & supporting caics W g w .0 L B 1 III REQUIRED ITEMS CHECKLIST EDIT Please indicate the page or plan sheet numbers where the supporting documentation can be found M 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 Na requirement has not been met, attach jusbficabon Requrled 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 (d 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 Initials Page or plan sheet number and any notes Form SW401 LS-VFS Mul2011 Rev 9 page 2 of 3 3 Section view of the level spreader (1 - 20 or larger) showing Underdram system (d 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 Form SW401 LS-VFS 27M2011 Rev 9 page 3 of 3 SPUTTER BOX DESIGN DETAIL FOR LEVEL SPREADER #1 6 5 FES OUT FBfJ,:$j="ft,3 X 6 DISSIPATER WEIR TO BE 0 2 OVER THE 12 OPENING SPLITTER BOX FLOW OVER THE lm/hr EVENT TO WEIR FLOW OUT SIDE OF BOX INTO CHANNEL �R DIS SIPqPAP CNgNNEC lN REINFORCED VEGETATED CH NEL TO DRAIN TO STREAM BUFFER 6 PIPE OUT /W FES INTO LEVEL SPREADER If Stormvater Enters the LS•VFS from the Drainage Area Drainage area 69 696 TA y r HCDEHR y < STORMWATER MANAGEMENT PERMIT APPLICATION FORM 1200 401 CERTIFICATION APPLICATION FORM LEVEL SPREADER VEGETATED FILTER STRIP (LS VFS) SUPPLEMENT This form must be completely filled out printed Initialed and submitted 1 PROJECT INFORMATION 064 Project name Ferrell Meadows Contact name Michael Stewart Phone number 919- 7791855 Date Apnl 17 2012 Drainage area number 2 11 DESIGN INFORMATION 10 year storm The purpose of the LS-VFS Buffer Rule Diffuse Flow Stormwater enters LS-VFS from The drainage area Type of VFS Protected riparian buffer (slope < 5 %) Explanation of any Other" responses above Explanation of any Other" responses above If Stormvater Enters the LS•VFS from the Drainage Area Drainage area 69 696 fe Impervious surface area 8 364 fe Percent Impervious 1200 A Rational C coefficient 040 ff/efs Peak flow from the 1 in/hr storm 064 cis Time of concentration 500 min Rainfall intensity 10 yr storm 722 in/hr Peak flow from the 10 yr storm 462 cis Design storm 10 year storm fmsl Maximum amount of flow directed to the LS VFS 152 cis Is a flow bypass system going to be used9 Y (Y or N) 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 LS-VFS Design Do not complete this section of the form cis cis Do not complete this section of the form 2 cis cis Do not complete this section of the form (Y or N) Forebay surface area 18 sq ft Depth of forebay at stormwater entry point 12 in Depth of forebay at stormwater exit point 12 in Feet of level hp needed per cis 50 ff/efs Computed minimum length of the level lip needed 76 ft Length of level lip provided 76 ft Width of VFS 50 ft Elevation at downslope base of level hp 34200 frisl Elevation at the end of the VFS that is farthest from the LS 34100 fmsl Forebay is adequately sized Depth is appropriate Form SW401 LS-VFS 27Ju12011 Rev 9 page 1 of 3 Slope (from level lip to the end of the VFS) Are any draws present in the VFS? Is there a collector swale at the end of the VFS? Bypass System Design (if applicable) Is a bypass system provided? Is there an engineered flow splitting device? Dimensions of the channel (see diagram below) M W y (flow depth for 10 -year storm) freeboard (during the 10 year storm) Peak velocity in the channel during the 10-yr storm Channel lining material Does the bypass discharge through a wetland? Does the channel enter the stream at an angle? Explanation of any Other" responses above 200 % N (Y or N) N (Y or N) Y (Y or N) Y (Y or N) 300 ft 300 ft 900 ft 040 It 100 It 272 ft/sec Pick one N (Y or N) Y (Y or N) W oil OK Please provide plan details of flow sputter & supporting calcs ." W L B 1 Ill REQUIRED ITEMS CHECKLIST EDIT Please indicate the page or plan sheet numbers where the supporting documentation can be found M 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 N a requirement has not been met, attach justdication Requned Item 1 Plans (1 50 or larger) of the entire site showing Design at ultimate build-out, Off -sde drainage (d 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 Initials Page or plan sheet number and any notes Form SW401 LS-VFS 27M2011 Rev 9 page 2 of 3 3 Section view of the level spreader (1 20 or larger) showing Underdram system (d applicable) Level lip Upslope channel and Downslope filter fabric 4 Plan detail of the flow splitting device and supporting calculations (d 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 (08M) agreement Form SW401 LS-VFS 27M2011 Rev 9 page 3 of 3 SPUTTER BOX DESIGN DETAIL FOR LEVEL SPREADER #2 4 FES OUT CHANNEL IN X 6 DISSIPATER WEIR TO BE 0 2 OVER THE 12 OPENING SPLITTER BOX FLOW OVER THE 1 in /hr EVENT TO WEIR FLOW OUT SIDE OF BOX INTO CHANNEL CHgNN f� DISS,Pq RR PAApDP �N REINFORCED VEGETATED CH NEL TO DRAIN TO STREAM BUFFER 4 PIPE OUT /W FES INTO LEVEL SPREADER o�oF warFgoc h r _ - y HCDEHR 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 I PROJECT INFORMATION Project name Ferrell Meadows Contact name Michael Stewart Phone number 919 779 -1855 Date April 17 2012 Drainage area number 3 II DESIGN INFORMATION The purpose of the LS VFS Buffer Rule Diffuse Flow Stormwater enters LS VFS from The drainage area Type of VFS Protected riparian buffer (slope < 5 %) Explanation of any Other" responses above If Stormwater Enters the LS-VFS from the Drainage Area Drainage area 165 528 fe Impervious surface area 19 863 fl Percent impervious 1200 % Rational C coefficient 040 Olds Peak flow from the 1 in/hr stone 152 cfs Time of concentration 500 min Rainfall intensity 10 yr stone 722 inthr Peak flow from the 10 yr storm 1097 CIS Design storm 10 -year storm fmsl Maximum amount of flow directed to the LS VFS 196 CIS Is a flow bypass system going to be used? y (Y or N) 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 used9 Explanation of any Other" responses above LS-VFS Design Do not complete this section of the form cis Cis Do not complete this section of the form 2 cfs CIS Do not complete this section of the form (Y or N) Forebay surface area 52 sq it Depth of forebay at stormwater entry point 12 in Depth of forebay at stormwater exit point 12 in Feet of level lip needed per cis 50 Olds Computed minimum length of the level lip needed 98 It Length of level lip provided 98 it Width of VFS 50 it Elevation at downslope base of level lip 34000 5msl Elevation at the end of the VFS that is farthest from the LS 33900 fmsl Forebay is adequately sized Depth is appropnate Form SW401 LS-VFS 27Ju12011 Rev 9 page 1 of 3 Slope (from level lip to the end of the VFS) 200 % Are any draws present in the VFS? N (Y or N) OK Is there a collector swale at the end of the VFS9 N (Y or N) Bypass System Design (if applicable) Is a bypass system provided? Is there an engineered flow splitting device? Dimensions of the channel (see diagram below) M W y (flow depth for 10 year stone) freeboard (during the 10 year stone) Peak velocity in the channel during the 10 yr storm Channel lining material Does the bypass discharge through a wefland9 Does the channel enter the stream at an angle9 Explanation of any Other" responses above (Y or N) (Y or N) 300 It 300 it 900 ft 073 ft 100 It 376 ftlsec Pick one N (Y or N) Y (Y or N) Please provide plan details of flow splitter t£ supporting calcs W w - - -- — III REQUIRED ITEMS CHECKLIST EDIT Please indicate the page or plan sheet numbers when; the supporting documentation can be found An incomplete submittal package veil result in a request for addibonal 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 ff 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 (d 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 buddout Initials Page or plan sheet number and any notes Form SW401 LS-VFS 27Ju12011 Rev 9 page 2 of 3 3 Section view of the level spreader (1 20' or larger) showing Underdram system (d applicable) Level hp 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 Forth SW401 LS-VFS 27M2011 Rev 9 page 3 of 3 e SPUTTER BOX DESIGN DETAIL FOR LEVEL SPREADER #3 6 FES OUT WEIR TO BE 0 2 OVER THE 12 OPENING SPLITTER BOX3 FLOW OVER THE tin /hr EVENT TO WEIR FLOW OUT SIDE OF BOX INTO CHANNEL CH DISS PATER gf ASP ANNEC �N REINFORCED VEGETATED CH NEL TO DRAIN TO STREAM BUFFER 6 PIPE OUT /W FES INTO LEVEL SPREADER cu D CO) VJ 50 9 'r 9 9z z m r U m r -r- 71 FTI zC n Tr m m r cri �D �v rn 0 m r —0-na zooz CIP w ropm �a xrz x MCI zw L" 0 aou'o -<O— MCA 04gma s I- m m Tr m m r cri �D �v rn 0 m r —0-na zooz doo�r°n aou'o 04gma s I- m N (A OZ C r, m r r �nIr� nOM r .a mZ G m � a r m o � r a � x oT om �INW tart r ='^ w 4:0 M— � "o � r- om m�.-. a om A M o-< W m �' �� o m r r m mrnZ L ~ 00 CA a CA � , °z r*t m m D r,