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HomeMy WebLinkAboutWPO201100088 Review Comments Erosion Control Plan 2012-03-14� 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: Stonewater; WPO- 2011 -00088 Plan preparer: Mr. Scott Collins, PE; Collins Engineering Owner or rep.: Rio Road Holdings, LLC Plan received date: 15 December 2011 20 January 2012 Date of comments: 12 January 2012 14 March 2012 Reviewer: Michael Koslow The third submittal of the ESC plan for Stonewater (WPO- 20 1 1 - 0008 8), received on 20 January 2012, has been reviewed. The plan is conditionally approved. The following comments must be addressed to receive unconditional county approval: A. General Review Comments 1. Please identify the date and source of topography. (Rev2) Comment has been addressed. B. Erosion and Sediment Control Review Comments 1. Except for the eastern roadwork where updated survey information appears to take into account the work already performed by the Treesdale contractor, these sheets match those approved in WPO -2010- 00011. The only purpose for this submittal appears to be to separate two projects, Treesdale and Stonewater, that were fused together for a short term convenience one or two years ago. The county has reviewed and approved previous plans with the assumption that these two projects were to be developed in harmony. The previous application, WPO- 2010 -00011 contained all of the measures necessary to construct everything needed for both developments. From October of 2010 til the date of this letter, work could have begun on the Stonewater subdivision without any step other than the paper work necessary to link Rio Road Holdings, LLC to the bond that had been posted by Treesdale. With one project ready to convert the facility to a permanent stormwater BMP and one project wanting to prolong the utilization of the basin, the county is in the middle of two property owners that are now on different timelines. But because county engineering is tasked with reducing overall construction times to as close to nine months as possible [17- 207.B.2], we cannot allow the use of this basin for ESC purposes by the Stonewater Subdivision unless the Board of Supervisors grants approval of the extension to the construction timeline. If the Board of Supervisors grants this approval, the maintenance and bonding of this basin will need to be worked out at that time. However, it is anticipated that the Treesdale development will be ready to convert the facility at that time and demobilize so Rio Road Holdings, LLC will then be responsible for the conversion of the facility. If the applicant chooses to modify the ESC plan for the Stonewater development so the basin is not utilized, Treesdale will be free to convert the facility to the Albemarle County Community Development Engineering Review Comments Page 2 of 3 extended detention facility, as designed, and a small SWM bond will be required of the Stonewater development for repair of the BMP in the event damage to it occurs from siltation. (Rev2) Engineering staff has yet to hear from the two property owners since the meeting held at the county office building on the 15`h of December. One solution that was discussed was Rio Road Holdings, LLC taking over the full bonding and responsibility of the basin. Our office recalls no other solution that was discussed in depth. This comment still stands until a resolution between the two property owners is achieved that also alleviates the county concerns detailed above. (Rev3) Engineering staff has not yet received an agreement letter from Rio Road Holdings which includes their acceptance of full bonding and responsibility for the basin. Please provide this letter once finalized. 2. Please move the limits of disturbance and the construction entrance out of the areas of the site that are about to be completed by the Treesdale development. Traffic to /from Treesdale must not travel through an active construction area. Please move the limits of construction, including staging and parking areas, west of the soon -to -be completed roads. (Rev2) Comment has been addressed. 3. Please update all county construction notes. The current set in this application is several years old. (Rev2) Comment has been addressed. 4. Please identify how the sanitary sewer line is to be constructed across the stream. It will be necessary for construction equipment to access the northside of the stream. This must also be identified. Please also provide an approval letter from the Army Corps of Engineers. (Rev2) Please provide an approval letter from the Army Corps of Engineers for the sanitary sewer line crossing the stream. Please revise "Diversion Channel Crossing" detail on sheet ESC -3 [VESCH Plate 3.25-1] to show the "Flume Pipe Crossing Detail" [VESCH Plate 3.25 -3] for the Utility Stream Crossing. 30" pipe corresponds with [VESH Table 3 -24A]; however this table assumes a drainage area density less than the current watershed. Additional capacity is necessary. County engineer calculations show that two 30" RCP pipes will provide more than adequate capacity for a 2 year storm event. (Rev3) Engineering staff has yet to receive an approval letter from the Army Corps of Engineers. "Diversion Channel Crossing" detail revision addresses above partial comment. Please provide this letter once finalized. Dual 30" RCP pipes specified for the utility crossing addresses above partial comment. 5. Why doesn't the drainage area used for the sediment basin calculations match t, stormwater drainage area on Sheet SWM -1? I would expect the drainage areas to be �. same. (Rev2) The plan now calls for a dewatering orifice at an elevation different th what was approved with the Treesdale application. If the contractor must adjust the elevation of the dewatering orifice, please add to the note on sheets ESC -2 and ESC -_ in reference to the three 9" orifices directing the contractor to install an new orifice and seal the previous one. (Rev3) Comment has been addressed. 6. The construction sequence references sheet SWM -3 which has not been included in this set. (Rev2) Comment has been addressed. Note #I on sheet ESC-1 has been updated. 7. In the field, the three 9" orifices are currently opened. Is there enough dry storage to the 387.2 elevation for this to be the case or must these openings be sealed until conversion? (Rev2) Comment has been addressed. 8. Please show and label the easement needed to construct the work shown on the Stonehenge property. (Rev2) Comment has been addressed. 9. This work will need to be bonded by Rio Road Holdings, LLC. The bonding procedure Albemarle County Community Development Engineering Review Comments Page 3 of 3 will be dependent on how the applicant wishes to address Comment B.1. (Rev2) Comment has been acknowledged by the applicant. (Rev3) Comment has been acknowledged by the applicant. 10. IL n General (Rev3) Comment has been addressed. C. Stormwater Management Review Comments 1. A fee was provided for the review a Stormwater Management Plan. But all sheets in this set appear to be exactly those incorporated in WPO -2010- 00011. Since nothing was modified, a review was not performed. Therefore, there is a $300 credit in this application. Please let me know if you want this refunded now or want to save it for the next ESC submittal. That SWM plan, WPO- 2010 - 00011, is still valid and may be used by the Stonewater Development after successful stabilization. Please remove all SWM sheets from this set to avoid confusion. (Rev2) Comment has been addressed. 2. The applicant must sign a Stormwater Management Facility Maintenance Agreement. Please submit this completed agreement to Ana Kilmer with $17 recordation fee after reviewing the instructions online. The agreement must refer to the original SWM application, WPO- 20 1 0 - 000 1 1. (Rev2) Comment open until acceptance of Stormwater Management Facility Maintenance Agreement. (Rev3) Comment open until acceptance of Stormwater Management Facility Maintenance Agreement. 3. A portion of this work will need to be bonded by Rio Road Holdings, LLC. The bonding procedure will be dependent on how the applicant wishes to address Comment B.1. As mentioned in Comment B.1, a modest SWM bond will be held by the county if construction of Stonewater development occurs after conversion of the enhanced, extended detention facility. (Rev2) Comment open until Comment BI is addressed. (Rev3) Comment open until Comment BI is addressed.