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HomeMy WebLinkAboutWPO200600066 Review Comments Erosion Control Plan 2010-11-29� 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: Briarwood Phases IA, 113, 4, and 8 Site Plan Amendment (SDP- 2010 - 00084), Road Plan Amendment (SDP- 2006 - 00041), and ESC Plan Amendment (WPO- 2006- 00066) Plan preparer: Mr. John Matusik, PE; The Engineering Groupe Owner or rep.: Woodbriar Associates Plan received date: 19 October 2010 Date of comments: 29 November 2010 Reviewer: Phil Custer The amendments to the road, esc, and site plans for Briarwood Phases IA, 1B, 4, and 8, submitted 19 October 2010, have been received and reviewed by County Engineering. The minor site plan amendment has been provided a new number. Engineering will track this revision to the ESC and Road plans under the previously approved application numbers. When the road plans are approved, the updated sheets will replace the outdated versions in the construction set used by the county inspector. The following comments must be addressed prior to plan approval. A. Site, Road, and Drainage Plan Review (SDP- 2010 -00084 and SDP - 2006 - 00041) 1. I recommend processing a variation to straighten out the phasing lines with the Planning Department as soon as possible. 2. Please remove any reference to the future lots south of Lot 111. Please also correct the grading in this area so that the proposed contours meet. 3. On commercially zoned properties, there is a 20ft undisturbed buffer adjacent to all residential and rural zoning districts. Please revise the grading plan so as to not disturb this buffer or please provide a request to allow for construction activity to clear this area per 18- 21.7.c. The Planning Commission will likely need to consider this waiver request. 4. The current proposed amendment replaces several large 3:1 slopes with 2:1 grades. This modification requires a low- maintenance, non - grassed groundcover. Please note on each revised grading sheet this requirement in the general area of the slope. 5. Engineering review notes that there are several areas where parking and driveways are shown at greater than 5%. However, since the plan has always seemed to have these steep driveways throughout the life of the project, engineering review will not require a revision to the grading plan to make these corrections. I recommend re- evaluating the grading plan to provide more reasonable driveways and parking spaces. 6. The storm sewer system 15 -14 must capture the rear of units 112 -119 to satisfy the County's Water Protection Ordinance. [17- 312.C] This can either be done with a revision to the grading or providing roofdrain collectors for the rear of the buildings and directing the pipe into structure 14. 7. The drainage profile for structures 14 -15 does not appear to be updated after the revised grading. It appears the entire drainage system will need to be lowered at least until structure 10. Please update the drainage profile and calculations accordingly. Please note that an increased depth to the drainage system will require a wider easement per the formula on page 12 of the design manual, available online. 8. On sheet 13, structure 5 looks to be labeled with a top elevation of 20, with a freeboard of 1 ft. However, the profile does not show this. Also, the top elevation of structure 4 does not appear to Albemarle County Community Development Engineering Review Comments Page 2 of 2 match the grading on sheet 13. 9. The profile for structures 31B through 27 looks different from the approved version. Please clarify. 10. It looks as though structures 119A and 119B should have the same top elevation. 11. The drainage profiles for 20B -21 and 23 -19 do not appear to have been updated. Please adjust the calculations and profiles accordingly. Because of the sharp angle in structure 21, the invert for the pipe from 20B must enter the structure no shallower than the center of the invert out pipe. 12. The Townhouse Schedule on the cover sheet appears to need to be updated. B. ESC Plan Review (WPO- 2006 - 00066) 1. Please update the county's general ESC notes on the cover sheet. The latest edition of the notes can be found within the design manual, available online. 2. An area of the property on sheets 3 and 7 are shown as being amended. However, the only difference between the submitted set and what was approved appears to be the expansion of the limits of disturbance. Are any of the ESC methods being modified? 3. On sheets 3, 4, 7, and 8, the limits of construction have expanded into an undisturbed buffer area on the offsite property. Please either modify the limits of disturbance in these areas to the previously approved limits or request a waiver of this requirement per 18- 21.7.c. The Planning Commission will likely need to consider this waiver request. 4. On sheet 6, please show the riprap on the spillway of SB -5 and within the downstream channel. 5. An update to the existing ESC bond will not be necessary due to the minor alterations to the plan.