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HomeMy WebLinkAboutWPO201500056 Approval - County 2015-12-03pF A vt�r�1Q COUNTY 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: Rocky Hollow / Tuerk Stable (Amends WP0201400075NSMP) Project File Number: WP0201500056 Plan preparer: Rob Cummings, Kirk Hughes & Associates -220 E. High St., Charlottesville, VA 22902 [rob(a)khals.net] ; Tommy Dobson tomWdobson73(a),gmail.com Owner or rep.: Adriana K. Tuerk, Trustee of the Adriana K. Tuerk Living Trust -P.O. Box 85, Isla, FL 33036 Karen Tuerk -2684 Paddock Wood Rd, Keswick, VA 22947 [ktuerkkaol.com] Plan received date: 20 Aug 2015 (Rev. 2/3) 15 Oct / 29 Oct 2015 (10 /29:.PDF e -plan) (Rev. 4) 20 Nov 2015 Date of comments: 10 Sep 2015 (Rev. 2/3) 21 Oct / 9 Nov 2015 — Available in County on -line CV system /imprinted, below (Rev. 4) 3 Dec 2015 — Conditional Ap rp oval (SWPPP required) Reviewer: John Anderson Please ref. email: J. Anderson to Rob Cummings (7/24/2015 1:02 PM; 7/13/2015 6:15 PM) A. Stormwater Pollution Prevention Plan 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. Furnish SWPPP/PPP —17 -p. county template attached to 7/24 email — (Rev. 4) Provide SWPPP. Also, see email: J. Anderson to R. Cummings, 12/3/2015 11:14 AM B. VSMP: SWPPP: Stormwater Management Plan (WP0201500056) improved VSMP Regulation 9VAC25- 870 -108 requires the VSMP authority to approve or disapprove a SWMP. This plan is approved. (Rev. 4) Engineering SWM Plan comments addressed with this or prior revisions. 1. Ref. email / Meetings discussing VSMP Application requirements. 2. Provide stand -alone SWM Plan sheet (or sheets), data, information, to include: a. Pre- / post - development drainage areas. Show drainage divide. Show DA `A' (1.05 Ac) and `B' (1.04 Ac) consistent with VaRRM .xls Site Results print -out that accompanied Application. b. Transfer VaRRM .xls (VA Runoff Reduction Method spreadsheet) site data, DA -A, DA -B, and water quality compliance details to the SWM plan. Alternatively, email VaRRM .xls to reviewer at: janderson2galbemarle.org c. Energy balance equation: show compliance with state stormwater post - developed water quantity requirements [9VAC25- 870- 66.B.3.]. d. Routing calculations, if necessary, to show compliance with 9VAC25- 870 -66. [pre- /post- Q2 /Q101 e. Provide SWM design (bioretention, or other). Sheet C3 shows bioretention basin level II design typical detail from BMP Clearinghouse, but there is no specific bioretention design data with this application. Provide basin surface area dimensions, volume, depth of media, etc. Please ref. BMP Clearinghouse Design Specification No. 9, Table 9.3, bioretention basin and filter design criteria. Engineering Review Comments Page 2 of 3 Although .xls site data tab reports 1.25 total phosphorus load reduction required and site results indicate design exceeds the target by 0.6 lb /yr, we need drainage area tabs for `A' and `B' that quantify impervious and turf areas that receive treatment, and method of treatment (BMP). f. Transfer construction/installation and maintenance specifications from DEQ BMP Clearinghouse to plans to guide construction and inspection. [VA DEQ Stormwater Design Specifications] g. Provide permanent SWM facility easements, to allow county access /inspection in the future. h. Provide permanent access to SWM facility (10' w, min; 20% grade, max). i. If permanent pool is considered with SWM design, consider safety (provide fence or railing for slopes steeper than 3:1). C. VSMP: SWPPP: Erosion Control Plan (WPO201500056) — Approved Virginia Code §62.1- 44.15:55 requires the VESCP authority to approve or disapprove an ESCP. This plan is approved. (Rev. 4) Engineering ESC Plan comments addressed with this or prior revisions. Sheet C2 1. Report Limits of Disturbance, Acres. 2. Label stable drive width/material surface. Label (drive) circle diameter /material surface. 3. Report building SF (impervious area). 4. Report impervious cover areas for driveway and stable; report total impervious area. 5. ST -2 exceeds Max. 4' excavated depth. Revise. 6. Show and avoid critical slopes (brownish orange %w / Rev. 4, image deleted): Note: Impact to critical slopes requires waiver approval. Waivers are coordinated with Planning Division, with provisions specified at Albemarle County Code Section 18- 4.2.5. It appears from C2 that grading and proposed stable driveway would impact critical slopes. ffslopes are proposed to be altered, Applicant should contact Planning to discuss waiver request requirements. 7. Provided that proposed contours avoid critical slopes, slopes steeper than 3:1 require vegetative stabilization hardier the grass. [ACDSM 8.A.2.] Proposed contours north of drive are 2:1. Propose permanent stabilization other than grass for slopes > 3:1. 8. Provide an adequate number of proposed contour /elevation labels to aid review and construction. D. VSMP: Mitigation Plan -NA The mitigation plan requirements can be found in County Code section 17 -406. Design avoids stream buffer. 21 Oct 2015 (CV comments) 1. Provide (scale) profile views for ST #1 and ST #2 to aid bond estimate. Show existing ground. 2. Provide (scale) plan/profile views for each bioretention facility. Show existing ground. Consider elements required of Level 2 design (Table 9.2/9.3, VA DEQ Design Specification No. 9). Sheet C3 -00 provides non - specific information, while sheet C3 -10 provides a schematic from on -line technical specification. Detail sufficient to review, inspect, and construct is required. 3. Notes and legend on C3 -00 indicate departure from GIS critical slope layer (shapes do not match). Please clarify whether on -site survey exists as basis of `field- verified topo.' If an instrument -based field survey is unavailable, critical slopes should be identical with County GIS. 4. Provide additional VRRM spreadsheet data. Site /water quality compliance tab data is shown with sheet C3 -10, but please supplement with DA `A'. `B', `C' tabs. Confirm that DA `C' runoff is untreated. 5. Existing barn is to be removed, do not show on C3 -00. 6. C3 -00 — Provide existing contour elevation labels. 7. C3 -00 — Provide proposed contours with elevation labels. 8. C3 -00 —Label stream and stream buffers. 9. C3 -00 —Show Stony Point Road (State Route 20) Engineering Review Comments Page 3 of 3 10. C3 -10 — Bioretention schedule (table): check/confirm dimensions against calculations. 11. C3 -10 — Provide bioretention planting schedule for each BMP. 12. Confirm future riding rink (15,000 S.F.) is managed turf in VRRM .xls, and that future post - developed runoff from future riding rink is not collected, or treated. 13. Prepare and record Private Stormwater Management Facility Easements. 14. Provide calculation of water quantity compliance. Ref. 9VAC25- 870 -66. 9 Nov 2015 (CV comments) e- review of series of .PDF attachments to 10/29/2015 5:18 PM email: 1. Review, check bioretention schedule (table) dimensions. Revise as necessary. 2. Proposed floor elevation (base 12" stone sump) of each bioretention filter is higher than proposed floor of each sediment trap. VA DEQ Stormwater Design Spec. No. 9 requires the "maximum excavation depth at the construction stage (sediment trap) must be at least 1 foot above the post - construction installation (bioretention filter) ". As discussed 9 -Nov, please provide narrative that supports deviation/design inconsistent with specification. Provide rationale. Include instruction to excavate at least 1' below floor of each sediment trap prior to conversion to bioretention. Proposed base sump elevation (ea. filter) is well above sediment trap floor elevation. 3. Water Quantity - Demonstrate compliance with 9VAC25- 870 -66. Reviewer anticipates design may elect to show that all runoff from the site (post - development; all drainage areas) is sheet flow (9VAC25 - 870-66.D.); otherwise, please demonstrate compliance with (9VAC25- 870- 66.B.3.a.). Topic discussed JA, Alb. County -R. Cummings, KH &A; 9 -Nov 2015. 4. Revise weir /top of berm elevations, each bioretention facility, as discussed 9 -Nov, to obtain 0.5' (Max.) ponded depth required to claim Level 2 design 1.65' storage depth. 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. One of the plan reviewers 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 along with court recording fees. Project will operate under General VPDES Permit VAR10G570, to be amended. Albemarle County will notify DEQ/Richmond of increased Area estimated to be disturbed. Once bond/Agreement processes are complete, the County can hold a pre - construction conference. Applicants will need to request a pre - construction conference by completing a 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; http://www.albemarle.org/deptforms.asp?departinent--cdengmTo WP0201400056 —Tuerk Stable 120315rev4— conditionalApprov.doc