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HomeMy WebLinkAboutsdp201000052 Review Comments 2010-12-08OF ALg,�, G�RGINIP COUNTY OF ALBEMARLE Department of Community Development 401 McIntire Road Charlottesville, Virginia 22902 -4596 Phone (434) 296 -5832 Fax (434) 972 -4126 Project: Saint Anne's Belfield; Minor Site Plan Amendment (SDP- 2010 - 00052) Plan preparer: Mr. Kurt Gloeckner, PE Owner or rep.: Saint Anne's Belfield Plan received date: 30 June 2010 (Rev. I) 8 October 2010 Date of comments: 13 August 2010 (Rev. 1) 8 December 2010 Reviewer: Phil Custer The first revision to the minor site plan amendment for the construction of a practice field and 100 space parking lot for Saint Anne's Belfield Private School, received on 8 October 2010, has been reviewed. The following comments must be addressed before engineering review can recommend approval to the plan: 1. Please update the site plan with the removal of the playing field east of the central athletic field. Instead, show what is to remain in the area after the demolition of the existing buildings and parking lots. (Rev. 1) Comment has not been addressed. 2. An amendment to the Erosion and Sediment Control Plan is required for the area. It appears that construction has been operating out of the limits of the previously approved plan for some time. The ESC plan will be required to prove that adequate channels downstream of the development exist. (Rev. 1) Comment has not been addressed. 3. A stormwater management plan is necessary. The stormwater plan will need to provide water quality treatment and detention for the entire limits of this site plan. When the stormwater management plan is submitted, please include a completed County Modified Simple Spreadsheet for the drainage area. Engineering review recommends sizing the facility as if the parking lot is paved so additional disturbance to increase the size of the facility is not needed in the future if a paved lot is ever desired by the school. (Rev. 1) A stormwater facility and some calculations have been provided but a WPO application and fee had not been submitted with the plan. When the plan is submitted, please add the drainage area limits for the stormwater facility and complete the modified simple spreadsheet using this drainage area. 4. Water conveyance channels will be required on the east and west sides of the development to route runoff to the BMP, likely positioned southwest of the parking lot, to capture and treat as much runoff as practicable. [17- 312.C] Calculations will be needed for each channel to make sure each segment can carry the 10 -year storm and can pass the 2 -year storm without erosion. Engineering review recommends designing the channel as if the parking lot is paved so additional disturbance to increase the size of the channels is not needed in the future if a paved lot is ever desired by the school. (Rev. 1) The applicant has drawn several lines on the site plan indicating a Ift deep, 12ft wide Albemarle County Community Development Engineering Review Comments Page 2 of 3 channel to stormwater basin #2. However, no calculations have been provided as stipulated above. 7. Please provide a detail of the "PT 4.0' x 6.0' wood" that is pinned to the ground with rebar. How reliable can these curbs be and where are the concentrated flows released from the parking lot? The ditches required in comment 4 around the perimeter of the site will be adequate for water conveyance. If the curbs are removed, please provide a bumper block in each parking space. (Rev. 1) A detail for the wood curb construction has been provided. However, there are still engineering concerns about the management of the drainage in, around, and along the travelway and parking lots. At the west end of each of the two southern curbs of the parking lot, water will need to be released into an adequate facility. Please provide channels and culverts as necessary with calculations supporting the size and matting material; A properly - sized and stabilized channel is needed in on the east side of the entrance travelway to the 24ft wide berm/channel specified in the detail: If this cannot be achieved due to the restricted space, I recommend looking at drainage alternatives to a channel such as a trenchdrain or curb and gutter. The seam between the slope and the gravel drive will be perpetual erosion problem if the drainage in this area is not routed more efficiently. [18- 32.6.6.dj 10. Drainage structures 15, 16, and 17 outlet near the graded area at the intersection of the Faulconer and the school travelway. Please show where the outlet of this drainage system is in relation to the new proposed grading and provide an adequate channel for the concentrated discharge, if necessary. Calculations should be provided to confirm the channel is non - erosive for the 2 -year storm and can carry the 10 -year storm within the banks. (Rev. 1) The applicant has opted to route this runoff in a pipe system rather than a channel. However, the design of this system has not been provided in a profile (as required by ordinance). No calculations for this pipe system have been provided either. [18- 32.6.6. d/ 11. Please provide the County's General Construction Notes on the plan. These notes can be found in the latest edition of the design manual, available online. (Rev. 1) Comment has not been addressed. N..r eC Albemarle County Community Development Engineering Review Comments Page 3 of 3 14. (Rev 1) The grading plan has been revised and the parking lot is now shown at a slope greater than the maximum allowed by the ordinance. Please revise the grading so no slope within the parking lot is steeper than 5 %, measured in any direction, or provide a waiver request addressed to the Chief of Current Development. 15. (Rev. 1) The plan no longer appears to be in general accord with the SP application plan with respect to the 8ft gravel pathway from the bleachers to the parking lot on the east side of the property. The realignment of the field has caused a restricted width at the southeast corner of the field that seems to prohibit a travelway of 18ft width, a walkway of 8ft width, and space for a properly -sized drainage channel. The walkway on the west side of the property also appears to have been eliminated. Please modify this area so that at least a 5ft walkway, independent of the 18ft wide travelway, is provided. 16. (Rev. 1) Please label the walkway around the west side from the parking lot to intersection at the northwest corner of this site. Please make sure it is in general accord with the approved SP plan. 17. (Rev. 1) The crosswalk from the UVA parcel to the main campus has been painted in the middle of the vehicular entrance. This crosswalk should be located at the 8ft wide gravel path.