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HomeMy WebLinkAboutWPO201000041 Review Comments Erosion Control Plan 2011-01-04� 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: Old Trail Village Block 4 (WPO- 2010 - 00041) Plan preparer: Mr. Scott Collins, PE; Collins Engineering Owner or rep.: March Mountain Properties I, LLC Plan received date: 16 August 2010 (Rev. 1) 23 November 2010 Date of comments: 24 September 2010 (Rev. 1) 4 January 2011 Reviewer: Phil Custer The first resubmittal of the Old Trail Block 4 site ESC plan (WPO- 2010 - 00041), received 23 November 2010, has been reviewed. Engineering can approve the plan after the following comments have been addressed. 1. A detail for a clearwater diversion has been provided on sheets ESC -1 and ESC -4 but does not appear to be shown on the plan. A cleanwater diversion is not a state approved standard and must be given a variance by the County Engineer. Please either remove this detail from the set or request a variance from the County Engineer to allow this method and show how the cleanwater diversion is to be utilized. (Rev. 1) Comment has been addressed. 2. This ESC plan is currently reliant on at least two other active ESC plans (three if the Block 2 plan is approved and a grading permit is given for it). On all plan view ESC sheets and the cover sheet, please provide the following note: This ESC plan relies on sediment trapping measures of other Old Trail ESC plans. In phase I of the ESC plan, disturbed area will drain to the sediment basin approved in WPO- 2008 - 00106. When the stormsewer structures are installed in phase 2, construction runoff will be directed to Sediment Basin 1 approved in WPO- 2008 - 00014. These plans must remain active until the grading permit for Block 4 is terminated. Please also identify these two plans in the first step of the construction sequence. (Rev. 1) Because adjacent development plans have been approved and given grading permits since the last review of the Block 4 application, please update the above note and the construction sequence accordingly. Please also show the limits and measures of WPO -2010- 000361WPO- 2010 - 00075. The drainage area to ST1 does not correlate to the existing topography as drawn and the resulting acreage is likely over the 3 acre maximum for a sediment trap. Also, the elevations used in the trap calculations do not match the topography shown on the ESC plan. It appears trap 1 of WPO- 2008 -00106 was simply relocated 140ft south. Please update the drainage area and calculations accordingly. (Rev. 1) The drainage area has been modified and appears to be correctly labeled. However, the drainage area is larger than the 3 acre maximum allowed by Virginia DCR for sediment traps. Please modify the plan so that this rule is not violated. Albemarle County Community Development Engineering Review Comments Page 2 of 2 4. There is a tract of land south of the sewer line 8 -6 -5 where no ESC measures are provided. Please move the limits of construction to loft off this sewer line and provide silt fence on the downhill side until the construction of the sewer line is within the drainage area to the sediment basin of WPO- 2008 - 00106. (Rev. 1) Comment has been addressed. 5. Please extend the silt fence downhill of the sewer line 2 -2A to the top of the Sediment basin embankment. (Rev. 1) Comment has been addressed. 6. Please show the northern diversion of WPO- 2008 -00106 and demonstrate how the sewer line is to be constructed in the vicinity. (Rev. 1) Comment has not been addressed. Please also show the diversions and sediment basin in the general vicinity that were approved recently in WPO- 2010 -00036 and WPO- 2010 - 00053, after the last review of the Block 4 plan. 7. In phase 2, please provide silt fence on the north and west sides of the block at the edge of the sidewalk. (Rev. 1) Comment has been addressed. 8. Please include the updated County ESC notes from the latest edition of the design manual, available online. (Rev. 1) Comment has been addressed. 9. A bond amount will be computed by the County when the plans have been approved. (Rev. 1) When the plans are approved, the applicant must request that a bond amount be computed by submitting the Bond Estimate Request Form to the County Engineer.