Loading...
HomeMy WebLinkAboutWPO200800020 Review Comments Stormwater Management Plan 2008-04-24� OF AL ,. vIRGI1`IZP 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: Flow Automotive - Final [SDP200800038] Plan preparer: Collins Engineering [email: scott@collins-enaineerin,-.co m] Plan received date: 11 Mar 2008 16 Apr 2008 (Revl) Date of comments: 31 Mar 2008 24 Apr 2008 (Revl) Reviewer: Amy Pflaum, Jonathan Sharp (Rev I) The final site plan for Flow Automotive has been reviewed. Before engineering can recommend approval the following items must be addressed: A. Final Site Plan comments 1. It does not appear that the fill in the southwest corner of the site (near existing STM manhole 5) can tie to existing grading without exceeding a 2:1 slope. [ 18- 32.6.6] Rev]: comments addressed. 2. The disturbance of existing areas of critical slope will require a waiver by the Planning Commission. [18 -4.2, 14 -304] Rev]: This item is scheduled to go to the Planning Commission. 3. One hundred feet on -site sight distance must be maintained by use of curbed islands a minimum 6' off building corners or other obstructions. Please provide curbed islands (minimum 3'x6') at the northeast and southeast corners of the existing portion of the building. Rev]: comments addressed. 4. All parking rows must be protected by curbed islands. The proposed parallel parking along the eastern property line of the site must be flanked by curbed islands. [18 -4.12] Rev]: comments addressed. 5. Curbing is required on all parking areas, please show curbing along the proposed parallel parking on the eastern property line of the site. Rev]: comments addressed. 6. Proposed parking areas may not exceed 5% grade in any direction. All new parking spaces must meet this criteria, including those proposed on existing pavement. Rev]: An administrative waiver request for this item is being reviewed by Engineering and Zoning Staff. 7. Proposed sidewalks must be a minimum of 5' wide, exclusive of the curb. Those shown around the proposed showroom appear to scale less than this. As this is a very "tight" site, please verify the dimension. Rev1: comments not addressed. 8. Please revise the Sight Distance Exhibit to state proper scale, show lane lines on Route 250, and shade the site triangles. Please see VDOT Road Design Manual Appendix B, Page B -11. Rev]: comments addressed. 9. Please revise the Easement Exhibit to include information pertaining to the parties easements will be dedicated to and from. Rev]: All offsite drainage easements and any necessary construction easements will need to be Current Development Engineering Review Comments Page 2 of 3 recorded prior to final site plan approval. 10. An easement is not required on the portion of the 4" sanitary sewer service lateral that is on the parcel under review. Where the lateral leaves this parcel and enters another, an easement is required there. [ 18- 32.7.4] Rev]: comments addressed. 11. Please label the two round symbols found in the center of TMP 78 -15E on the Site Plan, they do not show up on the Existing Conditions Plan. Rev]: comments addressed. 12. There is an existing retaining wall shown on TMP 78 -15 in the area of proposed grading. Is this wall to be removed? Rev]: comments addressed. 13. The labeling of the storm sewer system is confusing. For example, the existing STM manhole near the southwest corner of the site is labeled as both "EX1" and "5 ". On the Profile sheet it is labeled as "EX STR 1" in one profile and "EX STR 5" in another. Please clarify this labeling. It is also unclear which portions of the storm sewer pipes are to be abandoned and which are to remain. Please clarify by shading the existing pipes and labeling the proposed pipes with sizes and lengths. Rev]: comments not addressed. 14. On the border of the two sheets pertaining to erosion & sediment control, "erosion" is spelled incorrectly in the title block. Rev]: comments addressed. 15. Comments on the Drainage Areas and Computations, Stormwater Management Plan, and Erosion & Sediment Control Plan will be forthcoming with the review of the previously submitted WPO application (WPO200800020). 16. VDOT approval is required for any work affecting the public right -of -way. Rev]: A copy of the plans has been forwarded to VDOT for review. 17. More comments may be necessary upon resubmittal. Additional comments: 18. All slopes steeper than 3:1 require non grass low maintenance ground cover. 19. Parking spaces adjacent 20 feet wide travelways must be 10 feet in width. 20. The note for pipe profile Ex. Str. 5 to Ex. Str. 15 is confusing. It states that the existing storm sewer will be abandoned when it appears that it is to remain. 21. For the pipe profile Ex. Str. 5 to ex. Str. 15, the revised Ex. Str. 3 length is not provided. 22. On DP -1, the match -line refers to sheet S -2 when it should refer to the insert at the bottom of the sheet. 23. Please provide pipe calculations for Ex. Str. 4 to Structure 18. 24. Please provide pipe profiles for Str. 17 to Ex. Str. 4. 25. For the pipe profile Str. 6 to Proposed Raintanks, the invert in for pipe 7 at Str. 10 is shown incorrectly. 26. Please include the following on the pipe profiles: a. A VDOT designation for each structure b. A throat length or grate type for each inlet. c. Inlet shaping (IS -1) in all structures d. Safety slabs (SL -1) in any structures taller than 12 feet. 27. Drainage area maps are incorrect, causing inlet and pipe calculations to be incorrect. For the drainage plans, drainage going to Filterras should assume overflow for the 2 and 10 year storm, and the drainage areas should be included with the downstream inlets. For example, there should be 1.27 acres draining to Structure 6. 28. Drainage area maps should have the destination structure labeled for each drainage area. Current Development Engineering Review Comments Page 3 of 3 29. All spreads must be less than 10 feet. B. Stormwater Management comments 30. Please provide a Stormwater Maintenance Agreement signed by the land owners of TMP 78 -14D, 15D, and 15E. Please include the appropriate $17 fee. Please send to Pam Shifflett. 31. Please provide a Filterra approval letter. 32. The proposed drainage area map appears to be missing the 0.10 acres draining to Structure 16. 33. Please label the elevations of the orifice and weir, and label the weir length and location in the manhole (is it centered in the manhole ?). 34. Please specify a trash rack over the orifice. 35. Please label the length and width of the raintank facility, as well as indicate the number of milk crates used per length, width, and height. 36. Please provide the routing model and results for the detention facility, as well as graphs of routings for the 2, 10, and 100 year storm. 37. Please indicate the critical duration used for each storm event. 38. Please provide computations for composite land use coefficients. 39. Times of concentration should generally decrease with development. 40. Please provide contour areas and elevations used for storage, matching the plans. 41. Please provide the hydraulic dimensions and coefficients for each weir, orifice, culvert or other control structure used in the routing model, matching the plans. 42. A SWM bond will be computed by the County once the plans have been approved. C. Erosion Control Plans 43. Please show existing vegetation on the plans. 44. Please identify the SW corner of the site as a critical erosion area, as a small portion drainage will pocket in the corner as there is a low point in the silt fence. This area will need to be cleaned regularly. 45. The temporary slope drain (TSD) is shown in a sump location running uphill and is very close to a 15" CM pipe to be removed. Please show the grading required to install the TSD. 46. Please remove Inlet Protection from the manhole. 47. Please clearly show details of how the TSD will tie into a manhole. Safety is a concern. The manhole will be upwards of 15 feet deep and is very close to pedestrian areas. 48. The TSD must be 21 inches in diameter to meet VESCH standards. 49. Please provide calculations to show that the downstream drainage system is adequate. [MS -19] 50. An ESC bond will be computed by the County once the plans have been approved.