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HomeMy WebLinkAboutWPO200900043 Review Comments Mitigation Plan 2009-08-28COUNTY OF ALBEMARLE Department of Community Development 401 McIntire Road Charlottesville, Virginia 22902 -4596 Phone (434) 296 -5832 Fax (434) 972 -4126 Project: Profit Ridge Lot 3; WPO- 2009 -00043 Plan preparer: Brian Smith, PE Owner or rep.: John Kerber Plan received date: 10 August 2009 Date of comments: 28 August 2009 Reviewer: Phil Custer Stream Determination On the morning of Friday August 21", I visited the site to review the applicant's request to reduce the stream buffer on Lot 3 based on a field determination that located the start of the stream near the boundary line with Lot 4. The temperature was in the upper 80's with high humidity. The last recorded rainfall by the weather station at the airport was 0.25" on Wednesday August 19th. I began the site inspection from the western property line and walked to the east in the valley. A short distance down from the western property line I came across a ravine with steep banks that was approximately 8 -10ft deep. Once in the ravine, looking back uphill I found what appeared to be the headcut of the channel (photo A). Approximately 20ft downstream of this eroded bank I discovered a weak flow of water that ran for close to 60ft before infiltrating back into the ground (photos C and D). From the point of infiltration to the property line with Lot 4 an eroded channel devoid of water approximately lft deep was encountered (photo D). Considering the upstream conditions, it is reasonable to anticipate that this channel will run with a live flow at other times of the year. Therefore, it is my opinion that the intermittent stream begins in close proximity to the point depicted in the County's GIS system. It is difficult to locate the exact starting point of the stream graphically because the deep ravine does not appear to be clearly represented in the county 4ft contours. For the purposes of the building plan for Lot 3 any possible reduction of the buffer would not affect the development possibilities. Comments regarding the Critical Resource Plan The disturbance as shown through the stream buffer and over critical slopes is acceptable to county engineering as long as the first 50ft of stream buffer is not disturbed (with the exception of the driveway as it crosses over the low point of the lot). The mitigation required to disturb the buffer as proposed will be the replanting of any slope downhill of the driveway with landscape found in the CBLAD manual and reconstructing the headcut so that it no longer erodes. This may entail grading a slope into the headcut and providing armoring down to the bottom of the channel. It should be noted that a grading permit can only be given for this site with either an approved building permit with an approved CRP or an approved erosion and sediment control plan absent of a building permit. If the applicant still intends to prepare the lot for a building without a building permit, a full ESC plan must be submitted. In either plan, the area to be planted must be determined so that the landscaping Albemarle County Community Development Engineering Review Comments Page 2 of 4 can be bonded before a grading permit is given. Even if the CRP plan is chosen by the applicant, an exhibit showing the grading of the driveway to the house site should be provided with a planting plan for the downhill fill slopes. Exhibits Lot 3 Albemarle County Community Development Engineering Review Comments Page 3 of 4 Photo B: Looking downstream from inside the ravine Albemarle County Community Development Engineering Review Comments Page 4 of 4 Photo D: Looking upstream from 20ft within Lot 4