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HomeMy WebLinkAboutWPO200800011 Review Comments Erosion Control Plan 2008-04-18� 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: ACSA Red hill Water System [WP0200800011] Primary Contact: Jeremy Lynn, ACSA jlynn @serviceauthority.org (434) 979 -0698 Applicant: Jennifer Whitaker, RWSA jhitaker @rivanna.org (434) 293 -8858 Plan Preparer: O'Brien & Giere Engineers bellre@obg.com (804) 270 -5808 Plan received date: (Rev. #1) 17 April 2008 19 February 2008 Date of comments: (Rev. #1) 18 April 2008 14 March 2008 Reviewer: Max Greene The Erosion and sediment Control plan submitted 17 April 2008 has received Engineering review. This E &SC submittal appears incomplete and requires the following changes /corrections: 1. Silt fence outlet protection is not an approved perimeter control measure. A modification of the standard E &SC measures requires County Engineer/Program administrator approval. (Rev. #1) This Item appears adequately addressed at the time of this review. 2. Drainage area #1 does not appear to meet the minimum State requirements for Silt fence. [Std. & Spec. 3.05] Drainage areas #1 might be protected by showing a 50' section of the silt fence that is level on grade so water will filter through equally for the 50' length of silt fence. This office recommends wire - supported silt fence for the 50' level section incase of hydraulic backpressure during a runoff producing storm event. (Rev. #1) Plan appears to show modified E &SC measures and will require County Engineer/Program administrator approval. Please make a formal request to the County Engineer for the modification as shown on the submittal. The modifications are the 2' stone outlets. 3. Drainage area #2 does not appear to meet the minimum State requirements for silt fence. [Std. & Spec. 3.05] Drainage area #2 might be protected by showing a 120' section of the silt fence that is level on grade so water will filter through equally for the length of silt fence. This office recommends wire - supported silt fence for the 120' level section incase of hydraulic backpressure during a runoff producing storm event. Otherwise, a sediment trap will be required. (Rev. #1) Plan appears to show a sediment trap but is not labeled as such and no Albemarle County Community Development Engineering Review Comments Page 2 of 2 Computations have been attached. Please show the proposed grading, bottom dimensions for the trap, and include the computation design information for review. The Sediment trap will be moved out of the proposed fill area. Perimeter control structures are required until the site is deemed stabilized by the County Erosion Control Officer. In addition, the wire supported silt fence could be replaced with a diversion into the sediment trap to reduce the cost of E &SC protection. 4. Culvert inlet protection does not appear required and cannot be utilized if the total drainage area is over 3 acres. [ Std. & Spec. 3.081 (Rev. #1) This Item appears adequately addressed at the time of this review. 5. County GIS mapping shows an unnamed intermittent stream and water protection buffer adjacent to the property. Please changelcorrect the narrative to state this fact and how it will be protected from sediment loads during the development of this site. (Rev. #1) This Item appears adequately addressed at the time of this review. 6. Please add a vicinity map to the plan sheet. (Rev. #1) This Item appears adequately addressed at the time of this review. 7. Please add the following note: `Standard & Spec. 3.02 is adequate due to the lacy of available water to the site. Should the temporary construction entrance not be maintained properly or an excessive amount of soil found tracked onto the public roadway, then a paved construction entrance, water tanker truck with 2 pressure washers and a settling area may be required b -, the eros} "n and sediment control program administrator." (Rev. #1) This Item appears adequately addressed at the time of this review. 8. Please add minimum standards #4, #5, #17, #18 and any other minimum standards that will be required by the contractor. (Rev. #1) This Item appears adequately addressed at the time of this review. Just a reminder, DCR is enforcing the VSMP General Permit Registration Statement. Please contact Mr. Matthew Grant, DCR, at 804.225.3068 for more information. This does not affect your review /approval of this plan. Additional comments and/or conditions may be forthcoming, on the review of future submittals, due to the changes required for this plan submittal. Engineering staff is available on Thursdays from 2 -4 PM to discuss these review comments. Please contact a Plan reviewer at 434.296.5832 to schedule a time to meet. File: E2_ESC_MRG_Red hill Water System.doc