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HomeMy WebLinkAboutSDP200500094 Review Comments 2006-11-15iyPr8 ®®=: V COUNTY OF ALBEMARLE Department of Community Development 401 McIntire Road, Room 227 Charlottesville, Virginia 22902 -4596 Phone (434) 296 -5832 Fax (434) 972 - 4126 Project:University Village, Phase 111, Final Site Plan, E &SC Plan and SWM Plan Plan preparer:Mr. Eric Woolley, PE, The Cox Company fax 434.295.7540) Owner or rep.:Mr. David Turner, MD Development, LLC fax 434.972.7769) Date received:19 Sep 2005 (fsp), 20 Sep (ecp), 14 Sep (swm) Rev. 1: 7 Feb 2006 (fsp,ecp,swm) Rev.2: 10 August 2006 REV. 3: 27 October 2006 Date of Comment: 28 Sep 2005 (fsp), 30 Sep (ecp), 6 Oct (swm) Rev. 1: 16 Mar 2006 Rev.2: 13 September 2006 REV. 3: 15 November 2006 Engineer:Allan Schuck Rev.1: Glenn Brooks Rev.2: Allan Schuck REV. 3: Allan Schuck The following items that are highlighted still need to be addressed by the applicant. A. Final site plan comments: (SDP200500094) 1. Please provide a signed and dated professional seal on the computations. [18-32.6.1] Rev. 1: comment addressed. 2. Please revise Note J on Sheet C -1.0. The pavement width is not specified in typical section. Rev.1: comment addressed. 3. There are two Sheets numbered C -5.0. Please revise these sheets with the next submittal. Rev.1: comment addressed. 4. Please show and label all applicable traffic control signage. [18- 4.12.15f] Rev.1: comment addressed. 5. The invert elevations at STR -5 on the profiles do not match the elevations on plan sheet C -4.0. Rev.1: comment addressed. 6. Please show the outfall elevations for STR -1 outfall on plan sheet C -4.0. [18- 32.6.6d3] Rev.1: comment not adequately addressed. Not, found. Rev.2: This comment has been adequately addressed with this plan submittal. 7. The outfall area at Point 1 cannot be approved as shown. The water velocity exceeds 10 ft /sec and comes out of the pipe onto a 2:1 riprap slope. The designer will provide the type of velocity dissipation appropriate for velocity, pipe size, and discharge and site conditions. [DM505E7 &8] Rev.1: comment not adequately addressed. The velocity could not he found in the lengthy computer printouts submitted as computations. I computed 6cfs at 9fps. Using plate 3.18 -3 from the Erosion Control Handbook, 9 feet of class Al rip -rip is acceptable. Rev.2: This comment has been adequately addressed with plan submittal. 8. Please show the entire pipe drainage system and computations for the eastern reach. The system needs Albemarle County Community Development Engineering review comments Page 2 of 5 to handle the 10 -year storm and address MS -19 concerns. [18- 32.6.6d1, 32- 6.6d3] Rev.1: comment not adequately addressed. Existing inlet 3 appears not to be considered on sheet 7 or in the computations. The outlet pipe appears to be in a different location in the field. It is completely blocked, and without a receiving channel. MS -19 considerations are not addressed. The drainage area labeled "Ex. DI 11" (not to be confused with VDOT DI designations) could not be found in the computations. This drainage area looks incorrect in the field. Rev.2: This comment has NOT been adequately addressed with this plan submittal. The existing 15" pipe does NOT outlet into an existing channel. The applicant can either provide a ditch channel or pipe system to the existing basin located at the entrance to Crestwood Drive. Please provide drainage area maps and corresponding computations to satisfy the requirements of MS -19. REV. 3: This comment has been adequately addressed with this Ilan submittal. dF r r a Iy ZY f N R '" P•._P 14Y'b.'Y F'!'.. c ,.,e ' * 'r' yG k r ; ,( n x"` ' ".a r s-a"'r,s w. wf 7 .;. N k 'rH 4 i 44 1 7 w 44 g "''3 4 - ‘1C3"."'' Nt 5 S s'S F' A. x .v "ii t # mis B r M t w vy[ 3i4r a a* e x t . ri' w 9. The drainage computations for the eastern reach do not have correlating drainage areas shown on the plans. [DM909.1 A(1)] The computations were not reviewed for the eastern reach pipes. Rev.1: comment not adequately addressed. See comment 8. Rev.2: Please see review comment # 8. REV. 3: This comment has been adequately addressed with this plan submittal. 10. Structure #8 needs to provide 100% capture to eliminate drainage getting to Crestwood Drive or provide additional information on downstream structures. [DM505G4] Rev.1: comment not adequately addressed. The plans now indicate curb inlet 8 is to be replaced by a manhole, which appears incorrect. Rev.2: This comment has been adequately addressed with this plan submittal. 11. Please show the pipe and structure on the plan sheets that correlate to Pipe 1 on Page 1 of the eastern reach computations. Rev.1: comment addressed. However, see comment 8. Rev.2: This comment has been adequately addressed; however please see comment #8. REV. 3: This comment has been adequately addressed with this plan submittal. 12. Please show inlet shaping for most of the structures because the flow drop exceeds 4 feet. Please refer to VDOT standard, IS -1, Road & Bridge Standards, Volume 1. [DM505E9] Rev.1: comment addressed. 13. The pavement detail, shown on Sheet C -7.0, needs to be referenced on Sheets C -4.0, C -5.0, C -6.0. Rev.1: comment addressed. 14. Additional comments and /or conditions may be forthcoming, on the review of future submittals, due to the changes required for this plan submittal. Rev.1: see comment 15. 15. Rev.1: It is recommended that the summary tables provided in the Design Manual WR -18 to WR -22, and in the VDOT Drainage Manual, for pipe and inlet computations he used. While the computer Albemarle County Community Development Engineering review comments Page 3 of 5 printouts are impressively weighty, they are difficult to decipher, the review takes much longer, and information cannot always be found. Rev.2: This comment has been adequately addressed with this plan submittal. A bond amount will be computed when plans are approved. B. Stormwater management plan comments: (WPO200500074) 1. The SWM plan showing the filterras needs to be reviewed by Americast. Rev.1: comment addressed. 2. Please provide 2 copies of the signed, dated, and sealed computations. [18-32.6.1] Rev.1: comment addressed. 3. Please provide the computations and drainage areas used to determine flows from the pre- developed areas to the biofilter. [ 17 -314E] Rev.1: comment not adequately addressed. No drainage area maps were found for pre- development areas. No comparison ofpre- and post - development flows was found. Rev.2: The applicant 's response will be adequate to address this comment. 4. The surface area of the biofilter at elevation 641.50 needs to be at least 5.0% of the total impervious area draining to the biofilter. Currently, with 250 SF, the biofilter's surface area is too small. [DM 503.1F, VSMH Section 3.1 1 ] Rev.1: comment addressed. 5. The design of the biofilter needs to allow a maximum water depth of one foot above the surface of the biofilter. [DM 503.1F-1&4] Rev.1: comment not adequately addressed. The biofilter appears to be 2 feet deep at the berm, and the spillway is shown 3' deep, without rip -rap sized, or a fabric liner. It is unlikely rip -rap can he used effectively in this case, as the vertical allowances do not leave room for the stone size. Rev.2: This comment has been adequately addressed with this plan submittal. 6. Please provide the following notes on the biofilter plan sheet: [DM 503.1F-10&11] i. Biofilters must not be installed until the site is determined to be adequately stabilized by the erosion control and water resources inspectors. ii. Contractor shall contact the water resources inspector 24 hours prior to backfilling the biofilter and request an inspection and approval of the under -drain installation and the soil mix. Rev.1: comment not adequately addressed. These notes were not found on the stormwater management plan. Rev.2: This comment has been adequately addressed with this plan submittal. 7. Please label the 6" outlet pipe of the biofilter and describe layout of rock outfall in this area. Rev. 1: comment not adequately addressed. Not found on plans. Rev.2: This comment has been adequately addressed with this plan submittal. 8. Please provide a detail of the filterras, along with showing the size of the filterras on Sheet 5.0. Rev.1: comment not adequately addressed. Not found on stormwater management plan sheet. Rev.2: This comment has been adequately addressed with this plan submittal. 9. Please provide information that shows the eastern section is capable of handling the 2 & 10 year storms. [17 -314 A &B] Rev.1: comment not adequately addressed. Nothing was found in the package verifying detention or adequate channels for the eastern side. See also comment A8. A field inspection revealed that the basin at the entrance to the development is in need of cleaning and erosion repair. Rev.2: This comment has NOT been adequately addressed. Please refer to review comment A8. REV. 3: This comment has been adequately addressed with this plan submittal. 10. The applicant needs to submit a completed stormwater management facilities maintenance agreement and fee to the County for review. [17 -323] Rev. 1: comment not adequately addressed. Our tracking system does not indicate we have received Albemarle County Community Development Engineering review comments Page 4 of 5 an agreement. Rev.2: This comment has been adequately addressed. 11. Please show a graded SWM maintenance road along with easement on SWM plans. [503.1D] Rev.1: comment addressed. 12. Additional comments and /or conditions may be forthcoming due to the changes required. The SWM bond amount has not been computed at this time. Rev.1: See comment 13 -17 below. 13. Rev.1: The biofilter section and planting plan are incorrect. The areas do not agree with the computation package, and the grades on the section do not match the plan. Rev.2: This comment has been adequately addressed with this plan submittal. 14. Rev.1: The drainage areas used in the computations package could not be found on the drainage maps. There appear to be errors and omissions. Rev.2: This comment has been adequately addressed with this plan submittal. 15. Rev. l: The outlet structure used in the routing model could not be found in the computer printouts. Please provide this information and ensure it matches the plans. Rev.2: This comment has been adequately addressed with this plan submittal. 16. Rev.1: It does not appear that the modified rational method has been completed. A peak intensity storm should be run, and the storm with the controlling duration which results in the maximum storage volume. Rev.2: This comment has been adequately addressed with this plan submittal. 17. Rev.1: The requirements of 17-314 must be met. Please provide a computation summary which demonstrates that the requirements of 1 7-31 4 have been met. This information could not be gleaned from the computer printouts provided. Rev.2: This comment has been adequately addressed with this plan submittal. 18. REV. 3: The SWM portion of the Water Protection Bond amount is $56,000.00. Please contact Ms. Pam Shifflett at 434.296.5861 Ext. 3246 for information about posting this bond. 19. REV. 3: Please submit two (2) sets of the SWM plans to this office. C. Erosion and sediment control plan comments: (WPO200500074) Narrative: 1. Please add the following verbiage under the Maintenance section of the E &SC narrative: a. Sediment basins and /or traps will be cleaned and maintained in accordance with the Virginia Erosion & Sediment Control Handbook. b. All gravel outlets will be checked regularly for sediment buildup that will prevent proper drainage. If the gravel is clogged by sediment, the gravel will be removed and cleaned, or it will be replaced. Rev.1: comment addressed. Plans: 2. On the next submittal, please provide only the sheets associated with the E &SC plans. Rev.1: comment addressed. 3. Please show the limits of clearing and grading on the E &SC plan, Sheet C -9.1. Rev.1: comment addressed. 4. The entire area of the sediment trap is wooded; please clearly define the TP limits. Please show the existing tree lines on Sheet C -9.1. Please coordinate the limits of clearing with the proposed Tree Protection measures. The TP limits need to be shown outside of the drip lines of the trees. Rev.1: comment addressed. 5. On the E &SC plan sheet, please show and label the dividing lines and the direction of flow for the different drainage areas (including the areas for each inlet, ST, and E &SC measure). Rev.1: comment addressed. Albemarle County Community Development Engineering review comments Page 5 of 5 6. The eastern section of E &SC plan needs a trapping measure. The proposed SF has more than 100' of slope length to it and the SF cannot be used as a diversion. [VESCH 3.05] Rev.1: comment not adequately addressed. The trap is short in dry volume, and silt fence needs to be placed below the berm. Rev.2: This comment has been adequately addressed with this plan submittal. 7. Please include the following note on the E &SC plan sheets: "The developer shall reserve the right to install, maintain, remove and /or convert to permanent stormwater management facilities (where applicable) all erosion control measures required by this plan regardless of the sale of any lot." Rev.1: comment addressed. 8. Please extend the diversion dikes (DD) towards STR -3 & 4 to encompass the disturbed area. Rev.1: comment addressed. 9. The CE detail on Sheet 9 -0 needs to be labeled as a paved CE not a stone CE. Rev.1: comment addressed. 10. Please provide the following note for the CE on the E &SC plans: "A minimum water tap of 1 inch must be installed with a minimum 1 inch ballcock shutoff valve supplying a wash hose with a diameter of 1.5 inches for adequate constant pressure. Wash water must be carried away from the entrance to an approved settling area to remove sediment. All sediment shall be prevented from entering storm drains, ditches or water courses." Rev.1: comment addressed. 11. Please show an area for soil stockpiling on the E &SC plan. Show SF around stockpile [MS -2] Rev.1: comment addressed. 12. Please provide required computations for sediment trap and show drainage area to the sediment trap on the E &SC plan sheet. [MS -6] Rev.1: comment addressed. 13. Please show and label the required weir length, minimum bottom, dimensions, slopes noted on plans per computations for volume. Label detail with elevations, slopes, weir length, etc... Rev.1: comment addressed. 14. Please label the bottom elevations of the sediment traps on the E &SC plan sheet. Rev.1: comment addressed. 15. Additional comments and /or conditions may be forthcoming due to the changes required. The E &SC bond amount has not been computed at this time. It shall become a part of the whole Water Protection bond amount. Rev.1: See comment 16. The bond amount for erosion control is $19,000. 16. Rev.1: The safety fence around the western trap must encircle the facility, and silt fence needs to be placed below the berm. Rev.2: This comment has been adequately addressed with this plan submittal. 17. Rev.2: Please submit four (4) copies of the E &SC plan and narrative to this office. pF ALB 1411111 8 111, IRGINV" COUNTY OF ALBEMARLE Department of Community Development 401 McIntire Road, Room 227 Charlottesville, Virginia 22902 -4596 Phone (434) 296 -5832 Fax (434) 972 - 4126 Project:University Village, Phase III, Final Site Plan, E &SC Plan and SWM Plan Plan preparer:Mr. Eric Woolley, PE, The Cox Company fax 434.295.7540) Owner or rep.:Mr. David Turner, MD Development, LLC fax 434.972.7769) Date received:19 Sep 2005 (fsp), 20 Sep (ecp), 14 Sep (swm) Rev.1: 7 Feb 2006 (fsp,ecp,swm) Rev.2: 10 August 2006 Date of Comment: 28 Sep 2005 (fsp), 30 Sep (ecp), 6 Oct (swm) Rev.1: 16 Mar 2006 Rev.2: 13 September 2006 Engineer:Allan Schuck Rev.1: Glenn Brooks Rev.2: Allan Schuck A. Final site plan comments: (SDP200500094) 1. Please provide a signed and dated professional seal on the computations. [18-32.6.1] Rev.1: comment addressed. 2. Please revise Note J on Sheet C -1.0. The pavement width is not specified in typical section. Rev.1: comment addressed. 3. There are two Sheets numbered C -5.0. Please revise these sheets with the next submittal. Rev.1: comment addressed. 4. Please show and label all applicable traffic control signage. [18- 4.12.15f] Rev.1: comment addressed. 5. The invert elevations at STR -5 on the profiles do not match the elevations on plan sheet C -4.0. Rev.1: comment addressed. 6. Please show the outfall elevations for STR -1 outfall on plan sheet C -4.0. [18- 32.6.6d3] Rev.1: comment not adequately addressed. Not found. Rev.2: This comment has been adequately addressed with this plan submittal. 7. The outfall area at Point 1 cannot be approved as shown. The water velocity exceeds 10 ft /sec and comes out of the pipe onto a 2:1 riprap slope. The designer will provide the type of velocity dissipation appropriate for velocity, pipe size, and discharge and site conditions. [DM505E7 &8] Rev.1: comment not adequately addressed. The velocity could not be found in the lengthy computer printouts submitted as computations. I computed 6cfs at 9fps. Using plate 3.18 -3 from the Erosion Control Handbook, 9 feet of class A 1 rip -rip is acceptable. Rev.2: This comment has been adequately addressed with plan submittal. 8. Please show the entire pipe drainage system and computations for the eastern reach. The system needs to handle the 10 -year storm and address MS -19 concerns. [18- 32.6.6d1, 32- 6.6d3] Rev.]: comment not adequately addressed. Existing inlet 3 appears not to be considered on sheet 7 or in the computations. The outlet pipe appears to be in a different location in the field. It is completely blocked, and without a receiving channel. MS -19 considerations are not addressed. The drainage area labeled "Ex. DI 11" (not to be confused with VDOT DI designations) could not be found in the Albemarle County Community Development Engineering review comments Page 2 of 5 computations. This drainage area looks incorrect in the field. Rev.2: This comment has NOT been adequately addressed with this plan submittal. The existing 15" pipe does NOT outlet into an existing channel. The applicant can either provide a ditch channel or pipe system to the existing basin located at the entrance to Crestwood Drive. Please provide drainage area maps and corresponding computations to satisfy the requirements of MS -19. tii \d S at e „a r,w, /.j1,0 *., 0 d , ni at r 3 5 :' nT" t ;f' It' ' .-, .' x r 4" s t d4 ` n. ' +." I"'.. w , , 3 t uE A31) 7': Pt' : s. w . , c „.' ! i 's °a: 4 t r :r.t; a- ... rt" S' :: , . 9. The drainage computations for the eastern reach do not have correlating drainage areas shown on the plans. [DM909.1 A(1)] The computations were not reviewed for the eastern reach pipes. Rev.1: comment not adequately addressed. See comment 8. Rev.2: Please see review comment # 8. 10. Structure #8 needs to provide 100% capture to eliminate drainage getting to Crestwood Drive or provide additional information on downstream structures. [DM505G4] Rev. 1: comment not adequately addressed. The plans now indicate curb inlet 8 is to be replaced by a manhole, which appears incorrect. Rev.2: This comment has been adequately addressed with this plan submittal. 11. Please show the pipe and structure on the plan sheets that correlate to Pipe 1 on Page 1 of the eastern reach computations. Rev.1: comment addressed. However, see comment 8. Rev.2: This comment has been adequately addressed; however please see comment #8. 12. Please show inlet shaping for most of the structures because the flow drop exceeds 4 feet. Please refer to VDOT standard, IS -1, Road & Bridge Standards, Volume 1. [DM505E9] Rev. 1: comment addressed. 13. The pavement detail, shown on Sheet C -7.0, needs to be referenced on Sheets C -4.0, C -5.0, C -6.0. Rev.1: comment addressed. 14. Additional comments and /or conditions may be forthcoming, on the review of future submittals, due to the changes required for this plan submittal. Rev. 1: see comment 15. 15. Rev. 1: It is recommended that the summary tables provided in the Design Manual WR -18 to WR -22, and in the VDOT Drainage Manual, for pipe and inlet computations he used. While the computer printouts are impressively weighty, they are difficult to decipher, the review takes much longer, and information cannot always be found. Rev.2: This comment has been adequately addressed with this plan submittal. A bond amount will be computed when plans are approved. B. Stormwater management plan comments: (WPO200500074) 1. The SWM plan showing the filterras needs to be reviewed by Americast. Rev.1: comment addressed. Albemarle County Community Development Engineering review comments Page 3 of 5 2. Please provide 2 copies of the signed, dated, and sealed computations. [18-32.6.1] Rev. l: comment addressed. 3. Please provide the computations and drainage areas used to determine flows from the pre - developed areas to the biofilter. [17 -314E] Rev. 1: comment not adequately addressed. No drainage area maps were found for pre - development areas. No comparison ofpre- and post - development flows was found. Rev.2: The applicant's response will be adequate to address this comment. 4. The surface area of the biofilter at elevation 641.50 needs to be at least 5.0% of the total impervious area draining to the biofilter. Currently, with 250 SF, the biofilter's surface area is too small. [DM 503.1F, VSMH Section 3.11] Rev. 1: comment addressed. 5. The design of the biofilter needs to allow a maximum water depth of one foot above the surface of the biofilter. [DM 503.1F -1 &4] Rev. 1: comment not adequately addressed. The biofilter appears to be 2 feet deep at the berm, and the spillway is shown 3 ' deep, without rip -rap sized, or a fabric liner. It is unlikely rip -rap can be used effectively in this case, as the vertical allowances do not leave room for the stone size. Rev.2: This comment has been adequately addressed with this plan submittal. 6. Please provide the following notes on the biofilter plan sheet: [DM 503.1F-10&11] i. F3iofilters must not be installed until the site is determined to be adequately stabilized by the erosion control and water resources inspectors. ii. Contractor shall contact the water resources inspector 24 hours prior to backfilling the biofilter and request an inspection and approval of the under -drain installation and the soil mix. Rev.1: comment not adequately addressed. These notes were not found on the stormwater management plan. Rev.2: This comment has been adequately addressed with this plan submittal. 7. Please label the 6" outlet pipe of the biofilter and describe layout of rock outfall in this area. Rev.1: comment not adequately addressed. Not found on plans. Rev.2: This comment has been adequately addressed with this plan submittal. 8. Please provide a detail of the filterras, along with showing the size of the filterras on Sheet 5.0. Rev.1: comment not adequately addressed. Not found on stormwater management plan sheet. Rev.2: This comment has been adequately addressed with this plan submittal. 9. Please provide information that shows the eastern section is capable of handling the 2 & 10 year storms. [17 -314 A&131 Rev. 1: comment not adequately addressed. Nothing was found in the package verifying detention or adequate channels for the eastern side. See also comment A8. A field inspection revealed that the basin at the entrance to the development is in need of cleaning and erosion repair. Rev.2: This comment has NOT heen adequately addressed. Please refer to review comment A8. 10. The applicant needs to submit a completed stormwater management facilities maintenance agreement and fee to the County for review. [17 -323] Rev.1: comment not adequately addressed. Our tracking system does not indicate we have received an agreement. Rev.2: This comment has been adequately addressed. 11. Please show a graded SWM maintenance road along with easement on SWM plans. [503.1D] Rev.1: comment addressed. 12. Additional comments and /or conditions may be forthcoming due to the changes required. The SWM bond amount has not been computed at this time. Rev. 1: See comment 13 -17 below. 13. Rev.1: The biofilter section and planting plan are incorrect. The areas do not agree with the computation package, and the grades on the section do not match the plan. Albemarle County Community Development Engineering review comments Page 4 of 5 Rev.2: This comment has been adequately addressed with this plan submittal. 14. Rev. 1: The drainage areas used in the computations package could not be found on the drainage maps. There appear to be errors and omissions. Rev.2: This comment has been adequately addressed with this plan submittal. 15. Rev.1: The outlet structure used in the routing model could not be found in the computer printouts. Please provide this information and ensure it matches the plans. Rev.2: This comment has been adequately addressed with this plan submittal. 16. Rev.1: It does not appear that the modified rational method has been completed. A peak intensity storms should he run, and the storm with the controlling duration which results in the maximurn storage volume. Rev.2: This comment has been adequately addressed with this plan submittal. 17. Rev.1: The requirements of 17 -314 must be met. Please provide a computation summary which demonstrates that the requirements of 17 -314 have been met. This information could not be gleaned from the computer printouts provided. Rev.2: This comment has been adequately addressed with this plan submittal. C. Erosion and sediment control plan comments: (WPO200500074) Narrative: 1. Please add the following verbiage under the Maintenance section of the E &SC narrative: a. Sediment basins and /or traps will be cleaned and maintained in accordance with the Virginia Erosion & Sediment Control Handbook. b. All gravel outlets will be checked regularly for sediment buildup that will prevent proper drainage. If the gravel is clogged by sediment, the gravel will be removed and cleaned, or it will be replaced. Revd : comment addressed. Plans: 2. On the next submittal, please provide only the sheets associated with the E &SC plans. Rev.1: comment addressed. 3. Please show the limits of clearing and grading on the E &SC plan, Sheet C -9.1. Rev.1: comment addressed. 4. The entire area of the sediment trap is wooded; please clearly define the TP limits. Please show the existing tree lines on Sheet C -9.1. Please coordinate the limits of clearing with the proposed Tree Protection measures. The TP limits need to be shown outside of the drip lines of the trees. Rev. 1: comment addressed. 5. On the E &SC plan sheet, please show and label the dividing lines and the direction of flow for the different drainage areas (including the areas for each inlet, ST, and E &SC measure). Rev.1: comment addressed. 6. The eastern section of E &SC plan needs a trapping measure. The proposed SF has more than 100' of slope length to it and the SF cannot be used as a diversion. [VESCH 3.05] Rev. 1: comnnent not adequately addressed. The trap is short in dry volume, and silt fence needs to he placed below the berm. Rev.2: This comment has been adequately addressed with this plan submittal. 7. Please include the following note on the E &SC plan sheets: "The developer shall reserve the right to install, maintain, remove and /or convert to permanent stormwater management facilities (where applicable) all erosion control measures required by this plan regardless of the sale of any lot." Rev.1: comment addressed. 8. Please extend the diversion dikes (DD) towards STR -3 & 4 to encompass the disturbed area. Rev.1: comment addressed. 9. The CE detail on Sheet 9 -0 needs to be labeled as a paved CE not a stone CE. Albemarle County Community Development Engineering review comments Page 5 of 5 Rev.1: comment addressed. 10. Please provide the following note for the CE on the E &SC plans: "A minimum water tap of 1 inch must be installed with a minimum 1 inch ballcock shutoff valve supplying a wash hose with a diameter of 1.5 inches for adequate constant pressure. Wash water must be carried away from the entrance to an approved settling area to remove sediment. All sediment shall be prevented from entering storm drains, ditches or water courses." Rev.1: comment addressed. 11. Please show an area for soil stockpiling on the E &SC plan. Show SF around stockpile [MS -2I Rev.1: comment addressed. 12. Please provide required computations for sediment trap and show drainage area to the sediment trap on the E &SC plan sheet. [MS -6] Rev.1: comment addressed. 13. Please show and label the required weir length, minimum bottom, dimensions, slopes noted on plans per computations for volume. Label detail with elevations, slopes, weir length, etc... Rev. 1: comment addressed. 14. Please label the bottom elevations of the sediment traps on the E &SC plan sheet. Rev.1: comment addressed. 15. Additional comments and /or conditions may be forthcoming due to the changes required. The E &SC bond amount has not been computed at this time. It shall become a part of the whole Water Protection bond amount. Rev.1: See comment 16. The bond amount Ibr erosion control is $19,000. 16. Rev.1: The safety fence around the western trap Hurst encircle the facility, and silt fence needs to he placed below the berm. Rev.2: This comment has been adequately addressed with this plan submittal. 17. Rev.2: Please submit four (4) copies of the E &SC plan and narrative to this office. A)1 AL &fi t yRG- NAP COUNTY OF ALBEMARLE Department of Community Development 401 McIntire Road, Room 227 Charlottesville, Virginia 22902 -4596 Phone (434) 296 -5832 Fax (434) 972 -4126 Project:University Village, Phase III Plan preparer:Mr. Eric Woolley, PE, The Cox Company fax 434.295.7540) Owner or rep.:Mr. David Turner, MD Development, LLC fax 434.972.7769) Date received:19 Sep 2005 (fsp), 20 Sep (ecp), 14 Sep (swm) Rev.1: 7 Feb 2006 (fsp,ecp,swm) Date of Comment: 28 Sep 2005 (fsp), 30 Sep (ecp), 6 Oct (swm) Rev.1: 16 Mar 2006 Lead Engineer:Allan Schuck, Rev.1: Glenn Brooks A. Final site plan comments: (SDP200500094) 1. Please provide a signed and dated professional seal on the computations. [18-32.6.1] v"2. Please revise Note J on Sheet C -1.0. The pavement width is not specified in typical section. 3. There are two Sheets numbered C -5.0. Please revise these sheets with the next submittal. Please show and label all applicable traffic control signage. [18- 4.12.15f] 5. The invert elevations at STR -5 on the profiles do not match the elevations on plan sheet C -4.0. 6. Please show the outfall elevations for STR -1 outfall on plan sheet C -4.0. [18- 32.6.6d3] 7. The outfall area at Point 1 cannot be approved as shown. The water velocity exceeds 10 ft /sec and comes out of the pipe onto a 2:1 riprap slope. The designer will provide the type of velocity dissipation appropriate for velocity, pipe size, and discharge and site conditions. [DM505E7 &8] 8. Please show the entire pipe drainage system and computations for the eastern reach. The system needs to handle the 10 -year storm and address MS -19 concerns. [18- 32.6.6d1, 32- 6.6d3] 9 The drainage computations for the eastern reach do not have correlating drainage areas shown on the plans. [DM909.1A(1)] The computations were not reviewed for the eastern reach pipes. 10. Structure #8 needs to provide 100% capture to eliminate drainage getting to Crestwood Drive or provide additional information on downstream structures. [DM505G4] 11. Please show the pipe and structure on the plan sheets that correlate to Pipe 1 on Page 1 of the eastern reach computations. 1.12. Please show inlet shaping for most of the structures because the flow drop exceeds 4 feet. Please refer to VDOT standard, IS -1, Road & Bridge Standards, Volume 1. [DM505E9] 13. The pavement detail, shown on Sheet C -7.0, needs to be referenced on Sheets C -4.0, C -5.0, C -6.0. 14. Additional comments and /or conditions may be forthcoming, on the review of future submittals, due to the changes required for this plan submittal. B. Stormwater management plan comments: (WP0200500074) y 1. The SWM plan showing the filterras needs to be reviewed by Americast. 2. Please provide 2 copies of the signed, dated, and sealed computations. [18-32.6.1] 3. Please provide the computations and drainage areas used to determine flows from the pre - developed areas to the biofilter. [17 -314E] 4. The surface area of the biofilter at elevation 641.50 needs to be at least 5.0% of the total impervious Albemarle County Community Development Engineering review comments Page 2 of 3 area draining to the biofilter. Currently, with 250 SF, the biofilter's surface area is too small. [DM r 503.1F, VSMH Section 3.11] 5. The design of the biofilter needs to allow a maximum water depth of one foot above the surface of the biofilter. [DM 503.1F-1&4] 6. Please provide the following notes on the biofilter plan sheet: [DM 503.1F-10&11] i. Biofilters must not be installed until the site is determined to be adequately stabilized by the erosion control and water resources inspectors. ii. Contractor shall contact the water resources inspector 24 hours prior to backfilling the biofilter and request an inspection and approval of the under -drain installation and the soil mix. 7. Please label the 6" outlet pipe of the biofilter and describe layout of rock outfall in this area. 8. Please provide a detail of the filterras, along with showing the size of the filterras on Sheet 5.0. 9'. Please provide information that shows the eastern section is, capable of handling the 2 & 10 year storms. [ 17 -314 A &B] V1644; to (f0,,./. he applicant needs to submit a completed stormwater management facilities maintenance agreement r u`and fee to the County for review. [ 17 -323] vl 1. Please show a graded SWM maintenance road along with easement on SWM plans. [503.1 D] 12. Additional comments and /or conditions may be forthcoming due to the changes required. The SWM bond amount has not been computed at this time. C. Erosion and sediment control plan comments: (WPO200500074) Narrative: V13. Please add the following verbiage under the Maintenance section of the E &SC narrative: a. Sediment basins and /or traps will be cleaned and maintained in accordance with the Virginia Erosion Sediment Control Handbook. b. All gravel outlets will be checked regularly for sediment buildup that will prevent proper drainage. If the gravel is clogged by sediment, the gravel will be removed and cleaned, or it will be replaced. Plans: 14. On the next submittal, please provide only the sheets associated with the E &SC plans. v Please show the limits of clearing and grading on the E &SC plan, Sheet C -9.1. L 16. The entire area of the sediment trap is wooded; please clearly define the TP limits. Please show the existing tree lines on Sheet C -9.1. Please coordinate the limits of clearing with the proposed Tree Protection measures. The TP limits need to be shown outside of the drip lines of the trees. 17. On the E &SC plan sheet, please show and label the dividing lines and the direction of flow for the different drainage areas (including the areas for each inlet, ST, and E &SC measure). 18. The eastern section of E &SC plan needs a trapping measure. The proposed SF has more than 100' of slope length to it and the SF cannot be used as a diversion. [VESCH 3.05] v19. Please include the following note on the E &SC plan sheets: "The developer shall reserve the right to install, maintain, remove and /or convert to permanent stormwater management facilities (where applicable) all erosion control measures required by this plan regardless of the sale of any lot." 20. Please extend the diversion dikes (DD) towards STR -3 & 4 to encompass the disturbed area. 21. The CE detail on Sheet 9 -0 needs to be labeled as a paved CE not a stone CE. 22. Please provide the following note for the CE on the E &SC plans: "A minimum water tap of 1 inch must be installed with a minimum 1 inch ballcock shutoff valve supplying a wash hose with a diameter of 1.5 inches for adequate constant pressure. Wash water must be carried away from the entrance to an approved settling area to remove sediment. All sediment shall be prevented from entering storm drains, ditches or water courses." 23. Please show an area for soil stockpiling on the E &SC plan. Show SF around stockpile [MS -2] 24. Please provide required computations for sediment trap and show drainage are to the sediment trap on the E &SC plan sheet. [MS -6] Albemarle County Community Development Engineering review comments Page 3 of 3 25. Please show and label the required weir length, minimum bottom, dimensions, slopes noted on plans per computations for volume. Label detail with elevations, slopes, weir length, etc... 26. Please label the bottom elevations of the sediment traps on the E &SC plan sheet. 27. Additional comments and /or conditions may be forthcoming due to the changes required. The E &SC' bond amount has not been computed at this time. It shall become a part of the whole Water Protection bond amount. 17'