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HomeMy WebLinkAboutSUB201000119 Review Comments Preliminary Plat 2010-10-05 (8)�'IRGINZ� COUNTY OF ALBEMARLE Department of Community Development 401 McIntire Road Charlottesville, Virginia 22902 -4596 Phone (434) 296 -5832 Fax (434) 972 -4126 Project: SUB - 2010 - 00119, Granger Property - Preliminary Plat Plan preparer: Mr. Scott Collins, PE; Collins Engineering Owner: Stribling Holdings LLC Date received: 13 September 2010 Date of Comment: 5 October 2010 Engineer: Phil Custer The preliminary plat for The Granger Property (SUB- 2010 - 00119), received on 13 September 2010, has been reviewed. The plans cannot be approved as submitted and will require the following corrections before approval can be granted: 1. This proposed preliminary plat shows significant disturbance to critical slopes. The applicant has included in his submittal package a waiver request to disturb these critical slopes. Engineering analysis of this waiver request will be provided in a separate document. 2. The plan shows fill in the floodplain as being required. Since permission to fill in the floodplain can only be granted by the Board of Supervisors, the preliminary plat cannot be approved until the Special Use Permit(s) has been approved. The applicant should defer the preliminary plat until the fill in the floodplain has been authorized. 3. The Albemarle County Subdivision Ordinance requires that the public streets within a subdivision be coordinated "with existing or future planned streets within the general area of the subdivision" and "extended and constructed to the abutting property lines to provide vehicular and pedestrian interconnections to future development on adjoining lands." In the Comprehensive Plan, an Urban Collector Road is slated to connect Fontaine Avenue and Sunset Avenue Extended. The exact alignment of this collector road had not been determined by the Comprehensive Plan and had considered 4 options. However, the recently approved Zoning Map Amendment application for the Fontaine Research Park (ZMA- 2007 - 00013) has eliminated many of the anticipated routes. The University of Virginia Foundation proffered to eventually construct their portion of the Fontaine /Sunset Connector along the southern and eastern boundaries of their properties (see Exhibit D1 from ZMA- 2007 - 00013). In light of the general alignment of the northern section of this connector implicitly approved by the Board of Supervisors, Road A in the Granger Preliminary Plat must be extended to the existing Stribling Avenue railroad underpass to meet County Subdivision Requirements. [14- 409.A, 14- 409.13, 14 -429] 4. Because Road A is a portion of the Sunset - Fontaine Connector, its intersection with Sunset Avenue Extended cannot be perpendicular but must establish a through movement with a horizontal curve. The remainder of Sunset Avenue Extended (road to Eagle's Landing) must be modified to provide a perpendicular intersection with the Connector Road. Below is a screenshot of Alignment 4 (the most likely alignment) taken from the connector road study. The concept of the intersection of existing Sunset Avenue Extended should be mimicked, though the current location is acceptable. (Also, sight distance to the east appears to be an issue in the current proposed intersection configuration.) [14- 409.A, 14- 409.13, 14 -429] 5. Based on the existing comprehensive plan, the Sunset - Fontaine collector should be classified as an Urban Collector and must meet the VDOT standards for such. 6. Sidewalks and plantings strips are required on both sides of each new street within a subdivision of single family attached or detached dwellings within the development area. Please modify the plans to meet this requirement or request a waiver to the Planning Commission per 14 -422.E and 14- 422.F. Also, because Road A will be classified as an Urban Collector, VDOT clear zone requirements may be problematic. Five foot wide bicycle lanes and eight foot wide plantings strips were a solution to this issue with another development with an Urban Collector. [14 -422] 7. Please correctly label the deedbook and page number for the property each time it is referenced. 8. The topography within the survey must use the same vertical datum of the FEMA maps. The flood elevations shown within the FEMA study are based on the North American Vertical Datum 1988 (NAVD 1988) and the site survey is said to have used the North American Datum 1983 (NAD83), which is defined as a horizontal datum by NOAA. The vertical datum for the site survey appears to use a benchmark that is a nail in a tree deep within the site. The site survey must be converted to NAVD 1988 to match the datum of the floodplain study, if it is not already. Additionally, the floodplain limits should be revised as necessary to relate the elevations within the study to the site topography. In other words, at the locations shown on the FEMA study, match the 408, 410, 413, 414, 418, and 422 elevations to the contour lines of the site - specific survey and interpolate where appropriate. 9. The Subdivision Ordinance requires that the contour interval for the topographic data in the survey and proposed contours be at an interval no greater than the county supplied data. The current county supplied data is at an interval of 4ft. The topographic information within the plat (existing and proposed) must be converted to 4ft contour intervals. [14- 302A.12] 10. I have evaluated the stream along the southern boundary of the property using an abbreviated version of CBLAD's "Determination of Water Bodies with Perennial Flow" and determined that it is perennial. This stream requires a 100ft buffer from each bank from the existing Moore's Creek buffer to the interstate culvert. If the applicant wishes to dispute this determination, a full assessment must be made following Fairfax County's "Perennial Stream Field Identification Protocol, May 2003." [17- 104, 17 -317, 14- 302.13.101 11. Outside of the Rural Areas and Water Protection Watersheds, the stream buffer is 100ft from the edge of the stream irrespective of the 100 -year floodplain. [17 -317] 12. Per 17- 320.D.6, one stream buffer crossing is allowed for each parcel by -right. Due to the interconnectivity requirements for this parcel, the Program Authority will authorize two crossings in addition to the by -right crossing: one for crossing the stream running parallel to Sunset Avenue Extended, one for the current proposed Road B crossing, and one for the crossing required by comment 3. The Program Authority will also allow the discretionary 50ft of landward buffer disturbance shown on lots 75 and 76. Other disturbances of the landward 50ft of stream buffers will be considered during the more detailed review of the ESC, Road, and SWM plans. Mitigation will be required for all stream buffer disturbances (private laterals, roads, grading, ESC measures, etc.) allowed within the buffer. The placement of stormwater facilities and publicly maintained utilities are exempt from stream buffer mitigation requirements, though engineering review maintains the authority to modify the footprint and alignment of these items to minimize disturbance within the buffer as much as practical. [17 -319, 17 -320, 17 -321] 13. For the local subdivision streets, a curb to curb width of 29ft is needed for parking on both sides of the street. The current proposed 28ft wide road is acceptable for Roads B, C, D, and E, but parking on both sides may not be allowed by VDOT. 14. It appears that a fire truck will not have access from the public streets to most buildings on lots served by the alley. The alley may need to be designed to accommodate a fire truck. The final determination and the necessary standards should be discussed at the site review meeting with the Assistant Chief, James Barber. [14- 410.D] 15. Please provide a letter of intent showing that the owner of TMP 76B -1 and 76B -2 will grant the necessary ROW and easements to complete this project. 16. Please provide a letter from Dominion Virginia Power that indicates they will permit the proposed roads, grading, and pole reconstruction shown in the current plan. 17. Please provide the County's modified simple spreadsheet for each BMP. [14- 302.A.13] 18. A Stormwater facility is needed at the rear of lots 27 and 28. The current SWM concept plan proposes the installation of a drainage pipe 40ft below existing grade (intersection of roads C and D) which is not practical. BMP's must also be sited to reasonably maintain existing drainage patterns. [17 -312, 14- 302.A.131 19. The location of pond I is not practical. The facility must be placed downhill of the culdesac. [17 -312, 14- 302.A.131 20. A sediment trap or basin will be needed at the rear of lot 13 when the ESC plan is submitted. It is feasible that this facility be converted to a BMP to treat the driveways and lots of 12 -18. Please show this facility on the plan. [I7- 312.C, 14- 302.A.13] 21. Around the stream crossing, please provide a BMP to capture the half of Road B that is currently not treated. [17- 312.C, 14- 302.A.13] 22. Each of the three stormwater facilities are described as ponds which is acceptable for preliminary applications because such facilities can be designed for a broad range of removal rates (35 % -65 %). However, the small drainage areas and placement of the facilities outside of natural drainage ways will make each facility susceptible to dry weather drawdown. When the SWM plan is submitted, drought condition drawdown calculations will be required. File: E1 ppt_PBC_SUB- 2010 -00119 Granger Preliminary Site Plan.doc