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HomeMy WebLinkAboutSDP200800098 Review Comments Final Site Plan and Comps. 2008-07-29�pF .AI,g 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: Montessori Community School [SDP200800098, WP0200800065] Plan preparer: Alex Forast6 [email: aforaste @mckeecarson.com] Owner /Applicant: Wendy Fisher [email: wendyfisher@montessoripantops.co received date: 11 June 2008 Date of comments: 29 July 2008 Reviewer: Jonathan Sharp A. Final Site Plan — Phase 1 1. All final site plans and stormwater management plans require a professional seal, signed and dated. [18- 32.6.1] 2. Proposed slopes steeper than 3:1 require low- maintenance (not grass) ground cover specified on the plans. [DM] 3. The proposed guardrail should be extended 40 -50 ft north along the steep slopes for safety. [18- 32.7.2] 4. The following ordinance requirements are not met for the temporary parking area: [18 -4.12, DM] a. proposed parking spaces exceed 5% in slope b. proposed travelways exceed 10% in slope c. proposed parking area does not meet surface material requirements d. curb and gutter is not proposed on all parking /travelway areas e. sidewalks are not concrete, do not maintain 5' in width I understand that the proposed parking area is temporary. However, waivers must be approved in order to approve the site plan as shown. I cannot find any previous waivers addressing these items. Please provide copies of existing waivers addressing the proposed parking layout, if any. Otherwise, please submit a waiver request, or meet all ordinance requirements. If required, the waiver process is administrative (does not require Planning Commission action.) 5. A portion of the parking area drains uncontained down the steep hillside as it bypasses the proposed curbing. Please direct all drainage away from the steep hillside to avoid potential drainage and erosion problems. [ 18- 32.6.6d] 6. Typical sections for proposed channels with locations referenced from plan view sheets are required on the plans. [DM] 7. The Albemarle County general construction notes are required on the plans. [DM] 8. Grate types for drop inlets must be specified on the plans. [DM] 9. Roof drain locations, profiles, and calculations are required. See also comment 12. [DM] 10. Drainage profiles for proposed channels, existing pipes, and proposed pipes must be provided on the plans. [DM] 11. Drainage computations are substantially incomplete. The drainage areas provided for the pipe computations are incorrect. Inlet drainage area maps are required. Drop inlet calculations are required. Culvert calculations are required. Ditch computations are required. Outlet protection calculations are required. [DM] B. Stormwater Management Plan 12. In order to utilize the cistern for detention, details and calculations for the gutter system must be provided to ensure that the system will actually convey the 2 and 10 year storm into the cistern. If Albemarle County Community Development Engineering Review Comments Page 2 of 2 the 2 and 10 year storm does not make it into the cistern, the cistern is not providing any detention. Detention storage and routings must be over and above the assumed initial storage volume and the required stormwater quality volume (i.e., storage and routing begins above assumed volume of 40% and also above the required water quality volume, in this case about 7 cu yds, or about 1500 gallons. [DM] 13. No details of the cistern have been provided. Cistern details are required, matching stormwater compuations. The details should be to scale, provide all invert elevation information, outlet structures, etc. An adequate depth of soil cover should be provided over the facility. [DM] 14. It appears that the overflow pipe for the cistern will be running uphill. [DM] 15. The routing model and results are required for the cistern. No hydrographs have been provided. [DM] 16. The critical duration computations are incorrect. The calculations provided in the VSMH are only for preliminary facility sizing, and are not based on the facility volume or outlet structures. The critical duration storm is also dependent on the areas bypassing the facility (as you are calculating the critical duration storm causing the peak rate of runoff for the entire watershed, not simply the facility). In this case, the area bypassing the facility represents 95% of the drainage area. In cases like this, the critical duration storm that represents the peak rate of runoff over the watershed will almost always be 0 minutes (because almost all of the runoff is unrouted, and the peak rate of runoff for an unrouted watershed always occurs at a critical duration of 0 minutes). [DM] 17. Albemarle County general stormwater notes are required on the plans. [DM] 18. The stormwater maintenance agreement associated with Montessori School may need to be updated. The proposed SWM facility appears to be located on TMP 12A. Please contact Pam Shifflett to verify whether or not the agreement requires to be updated. 19. A SWM bond will be computed by the County once the plans have been approved. Please provide a cost estimate for the proposed cistern. C. Erosion and Sediment Control Plan 20. The limits of clearing and grading must include all proposed demolition. [DM, VESCH] 21. A parking area, staging area, and stockpile location are required. [DM] 22. The embankment for the proposed trap must be flat. [VESCH] 23. An adequate channel analysis [MS -19] must be provided for the site. The existing pipe system from structure OF -3 to the outfall into the Luxor Pond must be analyzed for adequacy. Existing drainage structure information and drainage area maps should be included with the approved Pavilions at Pantops Site Plans and Luxor Road and SWM plans, and can be made available upon request at the County Office Building Department of Community Development. [DM, VESCH] 24. An ESC bond will be computed by the County once the plans have been approved.