Loading...
HomeMy WebLinkAboutWPO201300016 Review Comments 2013-03-01 Michael Koslow From: Michael Koslow Sent: Tuesday, January 07, 2014 4:27 PM To: 'Scott Collins' Cc: 'josh @collins-engineering.com' Subject: Planning Application Review for WPO201300016 Westlake Hills- Phase 1. The Review for the following application has been completed: Application Number= WPO201300016 (ESC only) Reviewer = Michael Koslow Review Status =Approved Completed Date =01/07/2014 O1 ALBS COUNTY OF ALBEMARLE Department of Community Development I 401 McIntire Road RC�iP Charlottesville, Virginia 22902 WPO Plan Review Proj ect: t 6, 0. Wk T�`g"V_ Number: WP020 t 3 - © o ® 1 Date: 0i Reviewer: Michael Koslow Phone: (434) 296 -5832 ext 3297 This is an abbreviated review comment notice. County engineering staff is available every Thursday afternoon to discuss details of review. To schedule, please call your reviewer for an appointment Erosion .& Sediment Control: Adequate (Code Chapter 17, Article II) Not Adequate Y N State standards followed, and Design Standards Manual notes and details �.� Adequate limits and perimeter measures out of work areas All stages protected adequately t Adequate channels Stormwater Management: Adequate (Code Chapter 17, Article III) Not Adequate Y N i Enough capture and treatment for on -site areas U c Pw,, 6(e� U<&1 z -) 4ne t� � i Enough detention storage for on -site areas Sealed hydrologic and hydraulic computations provided 6Aeiuk play's I Of eX, Mitigation: (Code Chapter 17, Article III) Adequate Not Adequate Y N Buffers and disturbed areas adequately shown s/ Adequate plantings at,2:1, qr other mitigon provided ,f 1 l VC9 ®1e A lei 2- 9 1 [,A 0 �; c c �1 130 J'r g This review attempts to encompass the larger compliance questions. County staff does not assume responsibility for any calculation or plan details, and cannot cover the intricacies of every plan submitted. Each plan and calculation must have a professional seal and signature to assume these responsibilities. This plan is Approved (please see attached Approval Fact Sheet) Not Approved COUNTY OF ALBEMARLE Department of Community Development 401 McIntire Road ��RCirnP Charlottesville, Virginia 22902 WPO Plan Review Project:��- �2 Number: WP020 Date: --7 ) l t 113 Reviewer: Michael Koslow Phone: (434) 296 -5832 ext 3297 This is an abbreviated review comment notice. County engineering staff is available every Thursday afternoon to discuss details of review. To schedule, please call your reviewer for an appointment. Erosion & Sediment Control: Adequate (Code Chapter 17, Article II) Not Adequate Y N State standards followed, and Design Standards Manual notes and details Adequate limits and perimeter measures out of work areas All stages protected adequately Adequate channels M Stormwater Management: Adequate (Code Chapter 17, Article IIi) Not Adequate Y N ✓' Enough capture and treatment for on -site areas Enough detention storage for on -site areas Sealed hydrologic and hydraulic computations provided f Le'.�"r w� G Q�+s �Y���C' � ��s G;�.6 Mfigation' Adequate (Code Chapter 17, Article M) Not Adequate Y N Buffers and disturbed areas adequately shown ✓ I Adequate plantings at 2:1, or other mitigation provided �Uf�2✓ Ai'_+vf brn,Vlcz cLr -eo"s Wt It -1,aA' This review -attempts -to- encompass -the larger- compliance-questions.-County staff- does- not- assume -- - - responsibility for any calculation or plan details, and cannot cover the intricacies of every plan submitted. Each plan and calculation must -have a professional seal and signature to assume these responsibilities. This plan is Approved (please see attached Approval Fact Sheet) Not Approved Michael Koslow From: Michael Koslow Sent: Tuesday, April 16, 2013 11:42 AM To: 'Scott Collins' Cc: 'Graham Murray' Subject: RE: Westlake Hills - Phase 1 WPO (WP02013-00016); preliminary comment Attachments: CDDE1 ESC SWM MAK Westlake Hills Phase1 WP0201300016.doc Good morning Scott, Please see attached comment letter for the Westlake Hills. I went on a field check yesterday and noted an additional unnamed tributary to Lickinghole Creek which wasn't showing on our county GIS system. Addressing this stream's buffer will be integral to development of the plan, so I wanted to mention this specifically. Also, although the GIS section might not introduce this into our county mapping, I would be happy to meet someone from your office in the field to clarify the location I mention in attached. Cordially, Michael Michael Koslow, PE County of Albemarle Community Development Department 401 McIntire Road Charlottesville,VA 22902 434-296-5832 ext. 3297 434-972-4126(fax) mkoslowPalbemarle.org From: Michael Koslow Sent: Thursday, April 11, 2013 9:53 AM To: 'Scott Collins' Cc: 'Graham Murray' Subject: Westlake Hills - Phase 1 WPO (WP02013-00016); preliminary comment Scott, I'm in the process of reviewing the Westlake Hills Phase I WPO plan. The plan is not approved; based on the road plan I have 1 preliminary comment at this time: 1. Pipe 2 appears to have excessive velocity. Please reduce slope or otherwise change drainage design to ensure flow velocity is< 15 fps. I'll send a full comment letter within a week. I apologize for the delay;we're slowly coming out from the annual spring submittal rush and I don't anticipate any further reviews going beyond 45 days of submittal. Cordially, Michael Michael Koslow, PE County of Albemarle Community Development Department 401 McIntire Road Charlottesville,VA 22902 1 COUNTY OF ALBEMARLE Department of Community Development 401 McIntire Road, Room 227 Charlottesville, Virginia 22902-4596 Phone (434) 296-5832 Fax (434) 972-4126 Project: Westlake Hills – Phase 1 (WPO2013-00016) Plan preparer: Collins Engineering [tel 434-293-3719] Owner or rep.: Lickinghole Creek, LLC Plan received date: 5 March 2013 Date of comments: 16 April 2013 Reviewer: Michael Koslow The first erosion and sediment control and stormwater management plan (WPO201300016) submitted 28 February 2013 has received Engineering Review and does not appear to meet Albemarle County minimum checklist items for approval. Please adequately address the following comments for final approval: A. Application Information 1) After plan approval but prior to grading permit issuance, a stormwater management maintenance agreement will be required. 2) After plan approval but prior to grading permit issuance, a pro-rated share payment to Lickinghole Basin will be required. B. Title Information 1) Each sheet of final plans will require a date and professional engineer signature prior to approval. C. Existing Conditions Information 1) Per a field check of the project on 4/15/2013, there is an existing unnamed tributary flowing south to Lickinghole Creek which was not identified by existing topography. This unnamed tributary is identified by a dark blue line in an exhibit attached to this letter. Please include WPO buffer designations to protect this stream with future plan submittals. D. Erosion and Sediment Control (ESC) Plan 1) Please label proposed contour elevations adjacent to Guadalupe Drive and for sediment basin 1. 2) ESC narrative refers to sheets ESC-1 and ESC-2 for existing soils information. Please update sheet reference. 3) Western limits of proposed grading appear to be missing on sheet 22. Please include entire proposed grading area with ESC plan (could use match lines). 4) Permanent seeding appears to be missing on sheet 23. Please include permanent seeding for denuded areas with ESC plan. Engineering Review Comments Page 2 of 4 5) Silt fence appears to be proposed crossing contour lines at several locations on sheet 22. Please indicate diversion dikes instead in these areas. Silt fence is limited to areas of sheet flow with ¼ acre per 100 ft of level on-grade silt fence. 6) It appears another sediment trap is needed at the northern limit of disturbance just NE of ST2. 7) Please update General Notes 1 and 2 on sheet 21 regarding project owner and developer names and addresses. 8) Please provide an adequate channel analysis for runoff from proposed construction. Analysis needs to be carried further downstream compared with submitted MS-19 computations shown on p. 28 of SWM Report dated 10/31/2012. Analysis could be proven given: a) adherence to VESCH MS-19 requirements (see 4VAC50-30-40, MS-19 sec. b (1)): The applicant shall demonstrate that total drainage area to the point of analysis within the channel is one hundred times greater than the contributing drainage areas of the project in question. A report or plan depiction with analysis to this point could prove channel adequacy. b) adherence to VA code 10.1-603.4(7): essentially, the required condition for an on-site solution without looking downstream for a 24 hour 1.5, 2, and 10-year intensity event - (post-development) Peak flow rate <= Pf*Vf/Vp Where Pf = peak flow rate in a forested condition Vf = runoff volume in a forested condition Vp = runoff volume proposed If a proposed outfall drains directly to Lickinghole Creek, a statement as much for this outfall is acceptable for adequate channel analysis for this project. 9) Sediment traps are required to have minimum 2:1 length to width ratio (measured from point of maximum runoff introduction to outlet). Please provide calculations to ensure ST1 and ST2 have a layout with this minimum ratio. 10) Please label existing contour elevations for sediment trap and sediment basin details on sheet 24. 11) Please revise label for sediment basin 1’s watershed on sheet 22. Phase 1I appears to refer to phase 1. 12) Sediment basin 1 calculations on sheet 24 do not appear to be consistent with plan view depictions for watershed for sediment basin 1 on sheets 22 and 23. Per sheet 23, it appears the maximum contributing watershed area for sediment basin 1 is 19.47 Ac. However, sediment basin 1 calculations on sheet 24 indicate this area is 20.1 Ac. Runoff calculations using a “c” value of 0.6 for sizing the principal spillway do not appear to be calculated based on 19.47 or 20.1 Ac. Please confirm that the assumed “c” value is 0.6 for sediment basin 1. Please clarify proposed maximum contributing watershed and revise calculations appropriately. Engineering Review Comments Page 3 of 4 13) It appears that the riser diameter should be 48” per VESCH Plate 3.14-8. Please clarify. 14) It appears that the trash rack diameter should be 72” for a 48” diameter riser per VESCH Table 3.14-D. Please clarify. E. Stormwater Management Plan 1) Bottom of retention basin elevation of 387’ as proposed on sheet 20 appears to be incorrect. Please revise. 2) Please provide a flow path > 2:1 for Retention Basin 1 without the use of baffles. 3) Please provide riser base size and dimensions for Retention Basin 1. 4) Please provide dimensions and label linings proposed for permanent proposed emergency spillway for Retention Basin 1. 5) Please propose gravel surface or better for portions of SWM access road with grades steeper than 10%. 6) Please provide channel computations for erosion and capacity for the emergency spillway channel proposed for Retention Basin 1. Current Development Engineering is available from 2:30-4 PM on Thursdays to discuss these review comments. Please contact Michael Koslow at 434-296-5832 ext. 3297 or email mkoslow@albemarle.org to schedule an appointment. [17-204.f] An application for an erosion and sediment control plan that requires modifications, terms, or conditions to be included in order for it to be approved shall be deemed to be withdrawn if the owner fails to submit a revised plan addressing the omitted modifications, terms or conditions within six (6) months after the owner is informed of the omitted information as provided under paragraph (B). File: C:\Users\mkoslow\Documents\CurrentReviews\WPO201300016 Westlake Hills - Phase 1\CDDE1_ESC_SWM_MAK_Westlake_Hills_Phase1_WPO201300016.doc Engineering Review Comments Page 4 of 4