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HomeMy WebLinkAboutSDP201200037 Review Comments Road Plan and Comps. 2012-05-14ALg�,�� �'IRGINZ� COUNTY OF ALBEMARLE Department of Community Development 401 McIntire Road Charlottesville, Virginia 22902 -4596 Phone (434) 296 -5832 Fax (434) 972 -4126 Project: District Avenue Extended; SUB - 2012 -00043 and WPO- 2012 -00039 Plan preparer: Mr. Herb White, PE; W & W Associates Owner or rep.: Albemarle Place EAAP LLC Date received: 5 April 2012 Date of Comment: 14 May 2012 Engineer: Phil Custer The ESC and road plans for District Avenue Extended (WPO- 2012 -00039 and SUB - 2012 - 00043), received on 5 April 2012, have been reviewed. The plans can be approved after the following comments have been addressed: A. Road Plan Review Comments (SUB- 2012 - 00043) 1. Revised Proffer 1.13 (3/23/2012) refers to this temporary street stating that the design standards for it must be approved by the Director of Community Development. The use of the rural cross - section for the majority of this street is acceptable. The superelevation of the street is permissible but not recommended by county staff because the slope of the southbound lane would direct drifting vehicles into the northbound lane rather than onto the shoulder as a normal crowned road would. The pedestrian path along the road must be upgraded to at least prime and double seal. Shade trees must also be provided on the south side of the walking path at an interval of no greater than 50ft. Please provide an unstopped through movement for District Avenue and one stop sign on Blackbird or provide traffic data showing that a three way stop is warranted. 2. There is a safety issue at the Route 29 intersection due to the proximity of the retaining wall to the turning movement onto District Avenue from 29 Northbound. Please address this concern. If the beginning of the retaining wall can be shifted west, there will still be a safety concern associated with the start of the wall since it is inside the clearzone. To start, obtaining an offsite easement appears critical. 3. Please provide traffic data supporting that the stacking distances at the intersection with Route 29 will be acceptable for this phase of construction. 4. Please provide a gradual transition from the rural section to the urban section by tapering the edge of the shoulder. Please also gradually increase the height of the curb from 0" to 6" over at least 20ft. 5. Please provide a speed limit sign for the northbound traffic at approximately Sta. 28 +00. The speed limit sign for southbound traffic appears too close to the intersection. 6. Please clearly show in the grading plan and profile an adequate sump at Structures 139 and 140. 7. Please show the existing and proposed grade lines for the centerline of each roadside ditch. 8. In addition to the existing road grade shown, please provide the existing grade before mass grading so the areas of actual fill can be more clearly determined. This new existing grade line will influence where the correct locations for the CD -1's are. 9. Please provide Inlet Shaping (IS -1) on all structures. 10. Please show in the plan all easements necessary for the road, sidewalks, and drainage channels and pipes. 11. This comment is only advisory. The final plan for the first several hundred feet of Fourth Street from Route 29 will be expected to provide shade trees between the back of curb and retaining wall as shown in the approved preliminary plan. It is recommended that the design of this plan account for the expectations of the final construction plan. 12. VDOT approval must be provided. County Engineering supports VDOT's comment requiring a continuation of the Route 29 cross slope into District Avenue Extended and providing a low point west of the Route 29 gutterline. B. Erosion and Sediment Control Plan Review Comments (WPO- 2012 - 00039) 1. This plan relies on the downstream sediment basin for the majority of its effectiveness. However, the extension to the 9 -month stabilization deadline granted by the County Engineer expires on July 26th. If this plan continues to rely on the sediment basin, it will be invalidated if construction is not completed by July 26`h and the Board of Supervisors does not grant an extension to the plan. In order for the Board to consider granting an extension of the stabilization requirement, the request must be received by the Clerk of the Board of Supervisors by May 26th. My recommendation is to make this request to the Board AND design this plan so that it can be considered independent of the mass grading plan /sediment basin. This can be done by providing a sediment trap below structure 135 and replacing the silt fence west of this outlet with a diversion to Sta. 33 +75. 2. Between steps 2 and 3 in the construction sequence, please add a step to construct all perimeter measures. 3. It is critical to this plan to get the clean water to bypass the construction area so that the silt fence is not blown out. Please state in the construction sequence (see above comment) that structures 141, 142, 143, 144, and 145 as well as SCC -1 and SCC -3 must be completed and stabilized before road construction can begin. 4. The construction entrance must drain to a sediment trapping measure. 5. Please provide riprap or sod stabilization on all channels upstream of the stormwater pond and downstream of the ESC measures in this plan. 6. Please provide a RWD across the entrance at 29 to direct runoff towards the sediment basin /trap downstream of structure 135. (The VDOT comment regarding the vertical profile at this entrance seems to make this change unnecessary, however.) 7. Please provide a completed Bond Estimate Request Form to the county engineer to receive an ESC bond. A grading permit cannot be issued until a bond is posted. C. Stormwater Management Plan Review Comments (WPO- 2012 - 00039) The update to stormwater calculations for the intermittent pond BMP is acceptable. No modification to the existing SWM plan (WPO- 2010 - 00023) is warranted with this application. At the time of this plan's approval, two additional copies of Sheet C -18 will be necessary for me to include in the file. File: E1_rp ecp_PBC _ wpo- 2012 -00039 sub - 2012 -00043 District Ave Extended.doc