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HomeMy WebLinkAboutWPO201700049 Review Comments WPO VSMP 2017-07-20COUNTY OF ALBEMARLE Department of Community Development 401 McIntire Road, Room 227 Charlottesville, Virginia 22902-4596 Phone (434) 296-5832 Fax (434) 972-4126 VSMP Permit plan review Project title: Field School of Charlottesville, Phase 1 Project file number: WP0201700049 Plan preparer: Shimp Engineering [Justin@shimp-engineering.com] Owner or rep.: Jay Fennell, Aguilera LLC Usgfennell@gmail.com] Date of comments: 22"d July 2017 Reviewers: Bobby Jocz County Code section 17-410 and Virginia Code §62.1-44.15:34 requires the VSMP authority to act on any VSMP permit by issuing a project approval or denial. This project is denied. The rationale is given in the comments below. The application may be resubmitted for approval if all of the items below are satisfactorily addressed. The VSMP application content requirements can be found in County Code section 17-401. A. Stormwater Pollution Prevention Plan (SWPPP) The SWPPP content requirements can be found in County Code section 17-405. A SWPPP must contain (1) a PPP, (2) an ESCP, (3) a SWMP, and (4) any TMDL measures necessary. 1. [Registration Statement] Provide the mailing address and email address of the CAO, indicate if DEQ electronic correspondence can be used, and indicate the status of construction activity (federal, state, private, public). 2. [Pre -Development SWM map] Open space area value is incorrect. Includes Forest and open space which is not indicated to be in that area. 3. [General] Provide overall phase 1 site development and grading plan. Initial site plan shows phase 1 structures that would add to impervious area on site, but are not accounted for in the SWM analysis. 1. [General] Per County Code section 18-30.7.5.c, reverse slope benches or surface water diversions are required in critical slopes overlay districts when (ii) the vertical height of any 3:1 slope exceeds 30 feet. This regulation applies to the slope to the north of the property adjacent to the entrance roadway. Please address. 4. [C1] Provide WPO number [WP0201700049] on the cover sheet and SWPPP booklet. 5. [All] Specify that slopes greater than 3:1 slope will be covered with low maintenance, not grass, vegetation. 6. [All] Identify critical slopes on all sheets. B. Pollution Prevention Plan (PPP) The PPP content requirements can be found in County Code section 17-404. 1. Adequately Addressed. Engineering Review Comments Page 2 of 3 C. Stormwater Management Plan (SWMP) VSMP Regulation 9VAC25-870-108 requires the VSMP authority to approve or disapprove a SWMP. This plan is disapproved, and the reasons are provided in the comments below. The stormwater management plan content requirements can be found in County Code section 17-403. 2. Provide SWM maintenance easement for proposed extended detention pond and dry swale. 3. 24,000 sq-ft "preservation area" will need to be placed in conservation easement identified as "SWM conserved forest and open space". A SWM agreement as well as plat and deed of dedication will need to be recorded prior to VSMP approval. 4. Please use most recent version of VRRM spreadsheet (3.0) for water quality calculations. 5. Gravel diaphragm must maintain 5:1 max slope within a 2 ft minimum from end of washed gravel section per DEQ SWM design spec. # 2 figure 2.5. Current max slope is identified as 4:1. Please address. 6. Provide sizing calculations for dry swale. Engineered soil mixture must be min 18" deep per DEQ SWM Design spec. #10 for level 1 dry swale. Subsoil testing for dry swale will need to be provided if underdrain is not included in design. 7. Update dry swale material table to most current version (version 1.9 table 10.4). Version presented is outdated. 8. Calculations packet uses incorrect invert elevations for dry swale calculations (approx. 100' off). In addition depths for each media are inconsistent compared to design detail. Please correct. 9. Provide sizing calculations for extended detention facility. Provide stage storage curves for extended detention facility. Extended detention facility design does not meet standards for Level 1 design. In addition, detail states facility is a permanent detention facility, which is incorrect. Please address. 10. Provide SWM maintenance notes for all facilities (dry swale, forest and open space, extended detention. D. Erosion and Sediment Control Plan (ESCP) Virginia Code §62.1-44.15:55 requires the VESCP authority to approve or disapprove an ESCP. This plan is disapproved, and the reasons are provided in the comments below. The erosion control plan content requirements can be found in County Code section 17-402. 1. [C4] Extend diversion dike conveying draining from the south-east of the property to ST1 all the way to the LOD so that it captures drainage from the total area where trees are to be removed. 2. [C4] Extend the diversion dike conveying drainage from the south-west portion of the property to ST2 to connect to the end of adjacent silt fencing. 3. [C4] Designs presented in detail for ST2 do not match those presented in plan view. Please correct. 4. [C5] Smooth out the curve from the drainage dike that follows along the proposed dry swale pathway as it enters ST2. As currently presented it is too steep of a curve to function properly. 5. [C5] Steep slopes greater than 3:1, especially those on the north east of the property along the conveyance channel and roadway entrance, will need to be stabilized with blanket matting. 6. [C6] Steep slopes greater than 3:1, such as those downhill from the proposed retaining wall at the north end of the property, will need to be stabilized with blanket matting. 7. [C6 & C7] silt fence downhill from steep slopes must be placed 5-7 feet from the base of the disturbed slopes. Wire backed super -silt fence should be used in replacement of conventional silt fence. Provide engineering detail for super silt fence. Engineering Review Comments Page 3 of 3 8. [C6 & C7] extend ST1 outfall further down slope to prevent erosion. 9. [C7] Provide paved construction entrance detail per County DSM Chapter 3 section F. 10. [All] Ensure LOD does not extend into stream buffer areas. 11. [All] Indicate where dust control will be applied on site. Provide detail. The VSMP permit application and all plans may be resubmitted for approval when all comments have been satisfactorily addressed. For re -submittals please provide 2 copies of the complete permit package with a completed application form. Engineering plan review staff are available from 2-4 PM on Thursdays, should you require a meeting to discuss this review. Process; After approval, plans will need to be bonded. The bonding process is begun by submitting a bond estimate request form and fee to the Department of Community Development. The County's Management Analyst will prepare bond agreement forms, which will need to be completed by the owner and submitted along with cash, certificates or sureties for the amounts specified. The agreements will need to be approved and signed by the County Attorney and County Engineer. This may take 2-4 weeks to obtain all the correct signatures and forms. Stormwater Management Facilities Maintenance agreements will also need to be completed and recorded. The County's Management Analyst or other staff will prepare the forms and check for ownership and signature information. The completed forms will need to be submitted along with court recording fees. After bonding and agreements are complete, county staff will need to enter project information in a DEQ database for state application processing. DEQ will review the application information based on local VSMP authority approval. At this time, the DEQ portion of the application fees will need to be paid directly to the state. For fastest processing, this is done electronically with the emails provided on the application. DEQ should notify applicants with instructions on how to pay fees. When DEQ approves the application, they will issue a permit coverage letter. This should be copied to the county. After DEQ coverage is issued, via the coverage letter, the County can hold a pre -construction conference. Applicants will need to complete the request for a pre -construction conference form, and pay the remainder of the application fee. The form identifies the contractor and responsible land disturber, and the fee remaining to be paid. This will be checked by county staff, and upon approval, a pre -construction conference will be scheduled with the County inspector. At the pre -construction conference, should everything proceed satisfactorily, a joint VSMP and grading permit will be issued by the County so that work may begin. Bobby Jocz, EIT Civil Engineer I (434) 296-5832 ext: 3283 County of Albemarle Department of Community Development 401 McIntire Rd. Charlottesville, VA 22902 www.Albemarle.org