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Home My WebLink AboutWPO202200002 Correspondence 2022-05-19�r County of Albemarle COMMUNITY DEVELOPMENT DEPARTMENT VSMP Permit Plan Review 401 McIntire Road, North Wing Charlottesville, VA 22902-4579 Telephone: 434-296-5832 Engineering Review Comments Page 2 of 3 Project title: North Pointe Subdivision Section 2 Project file number: WPO-2022-00002 Plan preparer: Townes Site Engineering [Inugent@cctownes.comj Owner or rep.: CWH Properties [david@southern-classic.com] Plan received date: 1 February 2022 Date of comments: 17 March 2022 Reviewer: Matt Wentland 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 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. The on -site SWPPP will need to be updated with this plan after approval. Understood B. Pollution Prevention Plan (PPP) The PPP content requirements can be found in County Code section 17-404. 1. Provide a PPP with the next submittal. This will need to be included with the on -site PPP after approval. PPP has been provided on sheet C-13 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. 1. A SWIM maintenance agreement will be required. Please contact Ana Kilmer to begin this process. Understood 2. The analysis points shall be at each point of discharge and each pipe shall discharge into an adequate channel (9VAC25-870-95A,G, 9VAC25-840-40(19)). Provide calculations showing that each proposed pipe outfall discharges into an adequate channel and that the channel is adequate to the 1 % analysis limits. Entering a flood plain does not relieve the channel erosion analysis requirement. Provide additional measures as necessary. Channel analysis has been provided on sheet C-9a to the 1 % limits. Drainage areas for the channels has been provided on sheet C-8. 3. The concentrated flow from the bioretention spillways will also need to outlet into an adequate channel. Inlet structures have been provided in the bioretention facilitys in lieu of the concrete weir structures. 4. Include the calculations for the C numbers. It is not clear from the table that the future homes are included. C of 0.4 is assumed for the areas in lots. Equation in speadsheet is (0.9*impervious area + 0.4* (drainage area -impervious area))/ drainage area 5. Provide VDOT pipe worksheets for the proposed pipes. Engineering Review Comments Page 3 of 3 Drainage Structure Summary has been provide on sheet C-06D 6. Show and label the access to the proposed facilities. Also label the max slope of the ccess. 12' access drive to bio-retention areas, with a max slope of 6:1, has been provided on plans. 7. Show and label all required easements on the plans, including access easements to proposed facilities. 16' Access Easement has been provided on the plans and all drainage easements have been labelled. 8. Include the Albemarle County as -built requirements on the plans. Added on C 11 a. 9. Include the bioretention maintenance schedule on the plans. Added on C-12a. 10. Provide elevation labels for the existing and proposed contours. All slopes will need to meet the grading standards of County Code section 18.4.3.3 (this includes slope benches/surface water diversions for steep slopes). If possible, use different line weights for major and minor contours. Existing and proposed contour labels have been provided and Iineweights have been adjusted. 11. Include a note that all slopes steeper than 3:1 will require a low -maintenance ground cover. Note has been provided on the Cover Sheet. 12. Label retaining walls, including the max height and bottom/top spot elevations. Max height for retaining walls is 10' (18.4.3.3). Retaining walls crossing lots should have a maintenance easement. Grading has been adjusted so that no retaining wall is greater than 10' in height. Spot elevations and maintenance easements have been provided. 13. Grading and retaining walls located on managed and preserved (to be treated like managed per the ZMA) slopes will need to follow the design standards of 18.30.7.5. Understood. Revisions have been made to meet design standards. 14. Show outlet protection on all pipes. Include the design calculations. Outlet protection has been provided. Chart below was used for sizing. 15. Include sheets showing the post conditions in better detail, at 30 or 50 scale. Several items were difficult to review due to lack of detail and labelling. Grading plans at 50 Scale have been provided to show post conditions in a more readable scale. Engineering Review Comments Page 4 of 3 16. Include a note that all houses will require splash blocks for downspouts and provide a detail. Note has been added to the Cover Sheet and details provided on sheet C-05A 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. The max allowable slope behind silt fence is 100' and silt fence is only allowed in swales when the drainage area is 1 acre or less and the flow is 1 cfs or less (VESCH 3.05). Check dams are also not a substitute for trapping measures (VESCH 3.20). The breaks in the silt fence with check dams will need to be replaced with sediment traps and sediments basins and the silt fence will need to be replaced with diversion dikes where the above requirements are not met. Notation has been revised to read "Stone Outlet" and a detail has been provided on sheet C-05A. Additional Silt Traps have been provided and calculations have been provided on sheet C-0513. 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, erosion and sediment control and stormwater management improvements must be bonded. The bonding process begins when the plan is approved, and the applicant submits a bond estimate request form and fee to the Department of Community Development. A plan reviewer will prepare estimates and check parcel and easement information based on the approved plans. 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 to the County, who will record the agreement. After bonding and agreements are complete, county staff enters project information in a DEQ database for state application processing, if a DEQ permit is required. DEQ reviews 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 Engineering Review Comments Page 5 of 3 instructions on how to pay fees. When DEQ approves the application, they will issue a permit coverage letter, which must be posted at the construction site. After DEQ coverage is issued, via the coverage letter, the County can hold a pre -construction conference. Applicants must 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. County forms can be found on the county website forms center under engineering; https://www.albemarle.org/govern ment/community-development/apply-for/engineering-applications