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HomeMy WebLinkAboutWPO200800033 Review Comments Erosion Control Plan 2008-05-09� OF AL ,. vIRGI1`IZP COUNTY OF ALBEMARLE Department of Community Development 401 McIntire Road Charlottesville, Virginia 22902 -4596 Phone (434) 296 -5832 Fax (434) 972 -4126 Project: Plan preparer: Owner or rep.: Plan received date: Date of comments: Reviewer: Wickham Pond Phase 2 Block 2 The Timmons Group Weather Hill Development, LLC 25 March 2008 9 May 2008 Phil Custer [SDP200800056, WP02008000331 fax 295 -8317 fax 296 -2560 The site, SWM, and ESC plans for Wickham Pond Phase 2 Block 2 have been reviewed. The plans cannot be approved as submitted and will require the following changes. A. Final Site Plan [SDP- 2008 - 00056] 1. Please provide a benchmark on the plan with a set elevation. A benchmark is referred to but is not near the project area and must be shown on the plan. [DM] 2. Please specify a VDOT standard entrance for each site access point onto the roadway. 3. Sight distance does not appear to be shown to the VDOT standard for entrances onto the roadway. One hundred feet of sight distance is required for all internal intersections and not entrances onto VDOT ROW. 4. Please show the necessary walls and pillars from the structural plans for the garage on sheet S -1. The garage configuration and layout must be approved by the Zoning department in order to waive the 100ft internal sight distance requirement specified in our ordinance. 5. Please provide traffic control devices on the site. There appears to be several conflict points in the garage and surrounding drive aisle that may need signage. 6. The dumpster and loading space configurations are not currently acceptable to engineering review. The dump trucks and vehicles using the loading spaces will not be permitted to back out into the roadway. The loading spaces also cannot block the dumpsters. [18- 32.7.2] 7. Please provide greater detail with regards to grading throughout the site, specifically of the garage, courtyard, and access aisles from the roadway to the garage. Entrances cannot exceed 4% for the first 40' from the intersected street. Across the garage there appears to be a vertical drop of loft. 8. Please provide more detail in reference to the "stairs to elevator" specified on sheet S -1. 9. Please provide more information regarding the drainage system around the buildings, in the plaza, and around the parking structure. Will the buildings have roofdrains taking runoff to the biofilter or is there an underground drainage system taking water around the parking structure? How is infiltrated water from the courtyard reaching the biofilter? Please also show the trenchdrains. 10. Please provide a section detail for the replacement of the paved pedestrian path. 11. Please do not provide an entrance from the VDOT ROW for the biofilter maintenance path. The access must be given from another entrance on site. 12. On all slopes steeper than 3:1, please specify a low- maintenance groundcover. [DM] 13. Additional comments may be forthcoming on the next submittal due to the required changes. B. Stormwater Management Plan [WPO- 2008 - 00033] 14. The Lickinghole SWM basin pro -rata fee will be computed once the site plan has been approved. Albemarle County Community Development Engineering Review Comments Page 2 of 2 15. The hydrologic characteristics of Post - Development Drainage area I are not reasonable. I do not see how the time of concentration increases from 16 minutes to 19 minutes. I believe a post - development time of concentration between 5 and 10 minutes would be much more reasonable. Please provide a breakdown of the C coefficient for the DA 1. It is likely that grassed area over the courtyard will be highly compacted and a coefficient of around 0.6, rather than 0.3, should be used. 16. Please submit a modified simple spreadsheet for DA 1. 17. The project area data seems to be incorrect in Table 12. 18. Please provide a detention compliance summary. 19. Please remove any reference to the luckstone mix from the biofilter detail. The county now requires that the biofilter mix meets the approved state standard. 20. Please provide lft freeboard of the 100 -year storm in the biofilter facility. 21. The post - development drainage area does not appear to be accurate. 22. The planting plan for the biofilter should be amended. All required plantings should be provided in the bed area. Based on the bed area of the facility, there should be close to 83 trees /shrubs while maintaining a tree to shrub ratio between 2:1 and 3:1. Please adjust the "R -ARA" typo in the lower right corner of the planting detail for the biofilter. 23. The minimum pipe size out of the facility is 15 ". [DM] 24. A bond amount will be computed by the County when the plans have been approved. 25. Please submit signed copy of the Stormwater Maintenance Agreement and $17 fee to the County. 26. Additional comments may be forthcoming on the next submittal due to the required changes. C. Erosion and Sediment Control Plan [WPO- 2008 - 00033] 27. Please remove the "Silt Trap to Biofilter Conversion detail ". The detail shown in the Stormwater management sheet is acceptable and another detail does not need to be included in the ESC plan. 28. Please provide a soil stockpile area. 29. Please show the outlet to the sediment trap to scale. 30. How is site runoff flowing out of the sediment trap to pass the paved pedestrian path? A method to pass the pedestrian path should be accounted for in the ESC plan. 31. In the construction sequence, please move the biofilter conversion step to the end of the sequence and note the conversion is only authorized by the County Water Protection Inspector. 32. Please do not show tree protection fencing within the dripline of trees. On the northern side of the property, it may be best to put the fencing south of the paved pathway. Please note that ARB requirement for tree protection fencing is 5ft from the dripline of a protected tree. Please coordinate ESC with ARB tree conversation plans. 33. Please move the construction entrance into the watershed of the sediment trap and provide a diversion on the northside of the CE direction water into the trap. 34. Please replace the silt fence on the western portion of the property with a diversion direction water into the sediment trap. 35. A bond amount will be computed by the County when the plans have been approved. 36. Additional comments may be forthcoming on the next submittal due to the required changes.