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Home My WebLink AboutSW6120401_401 Certification Application_20120524Permit No. 5tt/ b %ZOLto ) (b be pooMed by DWQ) �app+NATER G n 9~ STORMWATER MANAGEMENT PERMIT APPLICATION FORM o ,� IMEM 401 CERTIFICATION APPLICATION FORM INFILTRATION BASIN SUPPLEMENT This form must be filled out, panted and submitted. The Required Kerns Checklist (Part )ll) must be prirded, tilted out and submitted along ttrithh all of the required irdormation. i. PROJECT INFORMATION Project Name Cumberland Park Contact Person Scod Brown Phone Number 010426-6M md-102 Date 23.*-12 Drainage Area Number 1 II DESIGN INFORMATION,>=r�- Site Characteristics Drainage area 154,890.00 Impervious area Percent impervious Design rainfall depth 56,112.00 36.23 % 1.00 in :i!t' N ''•. •' ►4 •,� Peak Flow Calculations ' 1-yr, 24-hr rainfall deplfi 1.00 in • = SEAL 1-yr, 24-hr intensity 0.13 inlhr 027452 Pre -development 1-yr, 24-hr discharge 5.65 ft'lsec Postdevelopmentl-yr,24-hrdischarge 10.17 ft'lsec �' '•' Q. - • ''. •G HQ II iE � PrOost 1-yr, 24-hr peak flow control 4.52 il'Isec •eP',�� '''�SC�T Storage volume: Non -&A Waters Y Minimum design vome urequired 4,887.00 fe1Z � 3- Design volume provided 16,930.00 fe OK for non -SA waters Storage Volume: SA Waters 1.5' runoff volume f Pre -development 1-yr, 24-hr runoff volume fe Post -development 1-yr, 24-hr runoff volume ft Minimum required volume Volume provided Sob Report Summary Sod type IbB Infiltration rate 3.75 Mr SHWT elevation 239.73 frrtsl Basin Design Parsmetes Drawdown time 4.00 days OK Basin side slopes 3.00 : i OK Basin bottom elevation 247.65 imsl OK Storage elevation 249.65 fmsl Storage Surface Area 12,819.0D fe Top elevation 250.65 frrrsl Basin Bottom Dimensions Basin length 2,129.00 ft Basin width 2.00 ft Bottom Surface Area 4,258.00 ft Form SW401-Infiltration Basin-Rev.6 itApr2011 Parts I. & Ir. Design Summary, Pepe f of r ' Permit No. (to be RMvided by DWQ) Additlanal Information Maxftm runoff to each inlet to the basin? 1.40 ao4n OK Length of vegetative filter for overflow 0.00 ft Filler is too short, must be > 30-ft Distance to structure 5.60 ft Too dose to structure, mast be minimum of 15-ft downgradieni Distance from surface waters 100.00 ft OK Distance from water supply well(s) 100.00 ft OK Separation from impervious soil layer 11.33 ft OK Naturally occudng soil above shwt 11,33 ft OK Bottom covered with 4-in of clean sand? Y (Y or N) OK Proposed drainage easement provided? Y (Y or N) OK Capures all runoff at ultimate build -out? Y (Y or N) OK Bypass provided for larger stomis? Y (Y or N) OK Pretreatment device provided Grass Strip Form SWQI-Infiltration Besin-Rev.5 11Apr2ol l Parts 1. & 11. Design Summary, Page 2 of 2 Permit No. OJ (to be provided by DW4) � of Wa7�A STORMWATER MANAGEMENT PERMIT APPLICATION FORM p -c NCDENR 401 CERTIFICATION APPLICATION FORM INFILTRATION BASIN SUPPLEMENT This form must be filled out, printed and submitted. The Required Items Checklist (Part 111) must be printed, filled out and submitted along with all of the required information. I. PROJECT INFORMATION Project Name Cumberland Park Contact Person Scott Brown Phone Number 910-426-6777 ext.102 Date 19-Mar-12 Drainage Area Number 1 II- DESIGN INFORMATION Site Characteristics Drainage area 154,890.00 ftz Impervious area 56,112.00 ftz �r•, Percent impervious Design rainfall depth 36,23 % 1.00 in ,��„,r ` •(Irl. �'••, . •'' �';., Peak Flow Calculations :Q 1-yr, 24-hr rainfall depth 1.00 in = SEAL 1-yr,24-hrintensity 0.13 infhr = '027452 Pre -development 1-yr, 24-hr discharge 5.65 0sec " Post -development 1-yr, 24-hr discharge 10,17 ft3lsec : L1�'•.lC P. • Pre/Post 1-yr, 24-hr peak flow control 4.52 ft3lsec •!VINEE• G mil' �•.�SO,O� 0,'`.�� Storage Volume: Non -SA Waters 8 "" t t t r r ,,,1 yI Minimum design volume required 4.887.00 ft3 �� ` Design volume provided 16,930.00 ft3 OK for non -SA waters Storage Volume: SA Waters 1.5' runoff volume Pre -development 1-yr, 24-hr runoff volume Post -development 1-yr, 24-hr runoff volume Minimum required volume Volume provided Soils Report Summary Soil type Infiltration rate SHWT elevation Basin Design Parameters Drawdown time Basin side slopes Basin bottom elevation Storage elevation Storage Surface Area Top elevation Basin Bottom Dimensions Basin length Basin width Bottom Surface Area uNl ft3 ft3 ft3 ft3 Lb B 3.75 inlhr 239.73 fmsl 4,00 days 3.00 :1 — 4i`- ' fmsl —249-60L fmsl --42-;&� ft' 6 t30 —25fmsl 2,129.00 It 2,00 ft 4,258.00 ft2 OK OK OK Z`t9,6s rzJi 2 5-0, cs Form SW401-Infiltration Basin-Rev.5 11Apr2011 Parts I. & H. Design Summary. Page 1 of 2 Permit No (to be provided by DWQ) Additional Information Maximum runoff to each inlet to the basin? 1.40 ac-in Length of vegetative filter for overflow 0.00 ft Distance to structure 5.60 ft Distance from surface waters 100.00 ft Distance from water supply well(s) 100.00 ft Separation from impervious soil layer 11.33 ft Naturally occuring soil above shwt 11.33 ft Bottom covered with 4-in of clean sand? Y (Y or N) Proposed drainage easement provided? Y (Y or N) Capures all runoff at ultimate build -out? Y (Y or N) Bypass provided for larger storms? Al (Y or N) Pretreatment device provided Grass Strip OK Filter is too short, must be > 30-ft o i+C 1 �' Y k S to- R �r Too close to structure, must be minimum of 15-ft downgradient OK OK OK OK OK OK OK OK k'r'—IR.Z 36LT 'OVO T SY i� 5 Form SW401-Infiltration Basin.Rev,5 11Ap2011 Parts I. & ll. Design Summary, Page 2 of 2 Permit (to be provided by 0WQ) III:. REQUIRED)ITEMS,CHECRUST' - 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. Page/ Plan Initials Sheet No. 513 Z, 0 1. Plans (1" - 50' or larger) of the entire site showing: 3 , Z - Design at ultimate build -out, 3 o Off -site drainage (if applicable), Delineated drainage basins (include Rational C coefficient per basin), Basin dimensions, Pretreatment system, - High flow bypass system, Maintenance access, Proposed drainage easement and public right of way (ROW), - Overflow device, and Boundaries of drainage easement. S� C3' D 2. Partial plan (1" = 30' or larger) and details forthe infiltration basin showing: - Bypass structure, - Maintenance access, - Basin bottom dimensions, - Basin cross-section with benchmark for sediment cleanout, - Flow distribution detail for inflow, -Vegetated filter, and - Pretreatment device. 51� S Z 3. Section view of the infiltration basin (1" = 20' or larger) showing: - Pretreatment and treatment areas, and tt - Inlet and outlet structures. S� o1cS 4. A table of elevations, areas, incremental volumes & accumulated volumes to verify the volume provided. 58 CAA 5. A soils report that is based upon an actual field investigation, soil borings, and infiltration tests. The results of the soils report must be verified in the field by DWQ, by completing & submitting the soils investigation request form. County soil maps are not an acceptable source of soils information. 513 (3,1 6. A construction sequence that shows how the in{itlration basin will be protected from sediment until the entire drainage area is stabilized. Cc� C S 7. The supporting calculations. Sche ` 8. A copy of the signed and notarized operation and maintenance (0&M) agreement. S &AC4 9, A copy of the deed restrictions (if required). Form SW401-Infiltration Basin-Rev.4 Page 1 of 1 Part III. Required Items Checklist, Page 1 of 1