The URL can be used to link to this page

Home My WebLink AboutSW6110406_HISTORICAL FILE_20110621STORMWATER DIVISION CODING SHEET POST -CONSTRUCTION PERMITS PERMIT NO. SWlB/�DiO DOC TYPE ❑ CURRENT PERMIT ❑ APPROVED PLANS HISTORICAL FILE COMPLIANCE EVALUATION INSPECTION DOC DATE �OG�DI�I YYYYMMDD Architecture & Engineering 4000 Westchase Boulevard, Suite 280 Raleigh, NC 27607 P. 919.828.1876 F. 919.828.1877 www.clarknexsen.com transmittal JUN 2 1 2011 ME APR % 6 2011 DENR- WATER QUALITY WEXMDS AND STORMWATER BRANCH DATE: We transmit the following: April 25, 2011 PROJECT: ® Drawings ❑ Specifications Code T Adapt Build for Vehicle ❑ Change Order ❑ Shop Drawings Maintenance Shop TO: ❑ Computer File(s) ❑ Samples Stormwater Permitting Unit Division of Water Quality ❑ Product Literature ® Calculations NC Department of Environment and Natural Resources 512 N. Salisbury Street, Copies Description 9°M1 Floor, Raleigh, North Carolina 27604 1 Stormwater Calculations 919/807-6300 2 Construction Plans FROM: K. Joshua Hurst, PE 2 Stormwater Permit Application SUBJECT: Post -construction Stormwater 1 Infiltration Trench Supplement Permit Application 1 Infiltration Trench O&M Agreement COMMISSION NUMBER: 3417 1 Stormwater Permit Application Fee ($505) VIA: Remarks: Attached are the Stormwater Calculations, Plans, Application, Supplement, O&M Agreement, and Application Fee for the Code T Adapt Build Vehicle Maintenance Shop project (PN 73947) at Fort Bragg, for review. Please contact me via email (ihurst(&clarknexsen.com) or at 919/576- 2120 if you have questions or need anything else regarding this submittal. CC: Page 1 of 1 Architecture & Engineering 4000 Westchase Boulevard, Suite 280 Raleigh, NC 27607 P. 919.828.1876 F. 919.828.1877 www.clarknexsen.com transmittal DATE: We transmit the following: May 18, 2011 PROJECT: ® Drawings' NCDENR DWQ #SW6110406 ❑ Change Order Code T Adapt Build for Vehicle Maintenance Shop ❑ Computer File(s) TO: Mr. Robert Patterson, PE ❑ Product Literature Stormwater Permitting Unit Division of Water Quality NC Department of Environment and Natural Resources ❑ Specifications ❑ Shop Drawings ❑ Samples ® Calculations,._ MAY t 9 2011 512 N. Salisbury Street,Copies Description NR831 �w UAI 91h Floor, 1 Revised Stormwater Calculations mer Branch Raleigh, North Carolina 27604 919/807-6300 2 Construction Plans FROM: K. Joshua Hurst, PE 1 Revised Infiltration Trench Supplement SUBJECT: 1 Response to Comments Letter Post -Construction Stormwater Permit - Response to Comments COMMISSION NUMBER: 3417 Remarks: VIA: Attached are the revised Stormwater Calculations, Plans, and Supplement for the Code T Adapt Build Vehicle Maintenance Shop project (DWQ Project SW6110406) at Fort Bragg. A Response to Comments letter is also attached, providing responses to comments from DWQ. ROUTE TO: CC: Please contact me via email (jhurst(cbclarknexsen.com) or at 919/576- 2120 if you have questions or need anything else regarding this submittal. Page 1 of 1 Architecture & Engineering May 18, 2011 Mr. Robert D. Patterson, PE Environmental Engineer NCDENR I DWQ I Stonnwater Permitting 512 N. Salisbury Street, 9°i Floor Raleigh, NC 27604 RE: NCDENR DWQ Project Number SW61 10406 Fort Bragg PN 73947 1" TSC VMS - Response to Comments Clark Nexsen Project 3417 Dear Mr. Patterson, Below are the NCDENR DWQ continents on the l" TSC Vehicle Maintenace Shop (DWQ Project SW6110406), followed by Clark Nexsen's responses in bold and italics. 1) Supporting calculations need to be provided for showing the minimum required treatment volume using the Simple Method; and the infiltration trench volume provided and drawdown time. RESPONSE: The Simple Method is used to calculate the required infiltration trench volume and can be seen, along with the drawdown time, on the Drainage Area Design Sheet- Infiltration Basin- Post Development Drainage Area. 2) The existing vs. proposed BUA is confusing as presented. Please provide a table showing existing BUA, existing BUA to be removed, existing BUA to remain, new BUA added, and the total post -construction BUA. Also, the table in Section 1V.10 of SWU-101 appears to incorrectly show that there is zero existing BUA. RESPONSE: The existing BUA is provided on the Drainage Area Design Sheet - Infiltration Basin- Pre Development Drainage Area. The existing BUA is 1.68 acres impervious. All 2.68 acres of the existing BUA is to be removed, with zero acres BUA remaining. The new added BUA is provided on the Drainage Area Design Sheet- Infiltration Basin- Post Development Drainage Area, which is 5.16 acres. Per the footnote on Section IV 10 of SWU-101, there is zero existing BUA to remain. 3) The narrative states the volume provided in the infiltration trench is 18,541cf, but the supplement form states it is 17,141cf. Please make these consistent. RESPONSE: The supplement has been revised to show a provided volume of 18,541. 4000 Westchase Blvd, Suite 280, Raleigh, NC 27007 9191828-1876 Fax 9191828-1877 Gttp:llwww clarknexsen. coin A Professional Corporation Offices in Norfolk, Richmond, Alexandria, Roanoke, Washington, D.C, Chandotte and Raleigh Architecture & Engineering Robert Patterson NCDENR DWQ Stormwater Permitting May 18, 2011 Page 2 of 2 4) The overflow elevation is shown on the plans and calculations to be 319.5. However, this elevation appears to be incorrectly stated as 319.0 on the supplement form. RESPONSE: The supplement has been revised to show an elevation of 319.50. 5) We typically require the infiltration rate be determined using a method like a double -ring infiltrometer or Amoozemeter. These constant head methods yield more accurate infiltration rates. RESPONSE: Per the Army Corps of Engineers Geotechnical Engineer on this project, all soil infiltration tests were conducted in substantial accordance with the U.S. Bureau of Reclamation "Field Permeability Test in Boreholes ", Designation E-18, (Earth Manual, 1974). The Caps acknowledges that performing these tests at constant heads would provide more accurate infiltration rates. However, based on the very high infiltration rates calculated from these tests, additional accuracy was not necessary to substantiate that these soils are adequate for storm water infiltration purposes. The infiltration rates provided were calculated directly from the head differential over the elapsed time of the test. Using the equation for permeability from E-18, the infiltration rates are calculated as 45 in/hour, 135 in/hour, and 22 in/hour for infiltration tests 1, 2, and 3 respectively. 6) Regarding Al/C-508: The full plan view layout detail of the infiltration trench needs to be provided so that the contractor knows the number of pipes, pipe lengths, and the total length and width. Note 2 needs to be revised or removed. Any modification to the infiltration trench on the plans will require approval by DWQ prior to installation. Also, the note talks about providing the same required volume in any alternative design, but does not state what that volume is on the plans. RESPONSE: Dimensions have been added to C-508, to provide actual quantities and lengths. Note 2 has been revised, to require DWQ approval for all modifications. Note 3 has been added to provide the required volume. Please contact us if you have questions or want to discuss anything on these responses. Sincerely, K. J ua Hurst, P , LEED AP Associate, Civil Engineer lz,F,-r w o 70 go6Ge i i',s-TTzc,2 r o/J A-r"'rf'e-- iz e t id T q K� d �rh c s[7 uP Application Completeness Review W Flrst Submittal ❑ Re -submittal Date Received: Development/Project Name: CODE 7 4nap7-i Receiving stream name C/Q oSQ cRLE,e (E Date Reviewed:42: By Bill Diuguid — W5-a_1(a; CA CRL chpic -,ci For post -construction requirements, a program will be deemed compliant for the areas where it is implementing any of the following programs: WS=I,',WS-ll, WS-III, WS-IV, HQW, ORW, Neuse River Basin NSW, Tar -Pamlico River Basin NSW, and the R'aildjemaii Lake Water Supply Watershed Nutrient Management Strategy. High Density Projects that require a 401/404 within an NSW require 85% TSS, 30% TN and 30% TP removal. T&E Species (Goose Creek, Waxhaw Creek or Six Mile Creek Water Sheds): Latitude and Longitude:36 D8 55 AI —79 A-7 "?,. t✓ Jurisdicton Kopf SR�GG Project Address: ,jrOR�Fpc-/- ce,wc._ dF PLAr-KSheK %T-rArLihir_ Roao ^-(-- Engineer name and firm: K. SosNu,A 1.1 ipya; P.B. etARx nf61[ sBn/' ❑ Low Density (no curb and gutter) ❑ Low Density with curb and gutter outlets i h Deor ❑ Other �}aJ401/404 impacts to surface waters, wetlands, and buffers (add language to cover letter and or addinfo letter) :d UA 9�. zf % r% 5 s Ac¢cs (!o. t/ Ac.-b"Trw+a<i r _Check for $505.00 included �f original signature (not photocopy) on application m/Legal signature (Corporation-VP/higher, Partnership -General Partner/higher, LLC-member/manager, Agent). Check spelling capitalization, punctuation: http://www.secretary.state.nc,us/corporations/thepage,aspx If an agent signs the application, a signed letter of authorization from the applicant must be provided which includes the name title mailing address and phone number of the person signing the letter. ❑ �r subdivided projects, a signed and notarized.;deed Sestriction statement W Sealed, signed & dated calculations all'�Correct supplement and O&M provided for each BMP on site (check all that were provided & number of each) ❑ Bioretention ❑ Dry Detention Basin ❑ Filter Strip ❑ Grass Swale ❑ Infiltration Basin ur� Infiltration Trench ❑ Level Spreader ❑ Permeable Pavement ❑ Restored Riparian Buffer ❑ Rooftop Runoff Management ❑ Sand Filter ❑ Stormwater Wetland ❑ Wet Detention Basin ❑ Low Density ❑ Curb Outlet ❑ Off -Site ❑ NCDOT Linear Road W Two sets of sealed, signed & dated layout & finish grading plans with appropriate details R' Narrative Description of stormwater management provided a9 Soils report provided 2r Wetlands delineated or a note on the plans that none exist on site and/or adjacent property W" Details for the roads, parking area, cul-de-sac radii, sidewalk widths, curb and gutter; e'_ Dimensions & slopes provided H Drainage areas delineated ❑ Pervious and impervious reported for each ❑ Areas of high density Inspection and maintenance agreements provided Application complete ❑ Application, Incomplete a urned: (Date) ;i,;, • �e-neV�c oPrn¢aT tmPFlcVtows VY S 3- Comments 96 It°U .4 aYLeetu s Oro i-� February 9, 2009 Revision ¢ A`� ✓� 'T'3 /d