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Home My WebLink AboutWPO202200049 Review Comments WPO VSMP 2022-12-28 (2)a$ County of Albemarle m COMMUNITY DEVELOPMENT DEPARTMENT VSMP Permit Plan Review Project title: Maplewood Development— VSMP Project file number: WP02022-00049 Plan preparer: Scott Collins, PE, Collins Engineering 200 Garrett Street, Suite K, Charlottesville, VA 22902 scott(&,,collins-engineering. com Owner or rep.: Maplewood Investments LLC 455 Second Street SE, Suite 201 Charlottesville, VA 22902 alan(a),,riverbenddev. com Plan received date: 22 Nov 2022 Date of comments: 28 Dec 2022 Reviewer: John Anderson, PE 401 McIntire Road, North Wing Charlottesville, VA 22902-4579 Telephone: 434-296-5832 WWW.ALBEMARLE.ORG 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 disapproved for reasons listed 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. Revise title pg. to include ref. to WPO2022-00049. 2. Once revisions complete, include I F x l7 plan inserts, Sec 4 /5 (ESC /SWM plans). 3. Sec. 1 /Registration Statement: a. Sec. II.F. —List `Albemarle County' since project located in Albemarle County MS4. b. Sec. V — Please provide (Alan Taylor) signature /date with next submittal. 4. Sec. 9, Certification: Add signature — title, with next submittal. B. Pollution Prevention Plan (PPP) — See above. The PPP content requirements can be found in County Code section 17-404. 1. Sec. A: Revise I I" x 17" PPP exhibits to show initial locations of rain gauge, and solvent /paint storage. 2. Sec. E: List named individual responsible for PPP (required for Grading permit, not plan approval). C. Stormwater Management Plan (SWMP) VSMP Regulation 9VAC25-870-108 requires the VSMP authority to approve or disapprove a SWMP. This plan is disapproved for reasons listed below. The stormwater management plan content requirements can be found in County Code section 17-403. 1. Revise plan title and Calc. packet title to include reference to WPO2022-00049. 2. Check Mid -flow orifice dimension (13" DIA), p. 50 calc. packet, against detail, sheet 12, which shows 12" mid -flow orifice diameter. If mid -flow orifice DIA =12", please revise routings and post-dev Ql, Q2, Q10 values, if mid -flow orifice DIA=13", please revise detail, sheet 12. Engineering Review Comments Page 2 of 3 3. Sheet 9 proposes purchase of 4.57 lb. nutrient credits to meet 9VAC25-870-65 requirements. Incl. letter of nutrient credit availability for project from Ivy Creek Nutrient bank on the plan. Project discharges to Powell's Creek /S. Fork Rivanna River, impaired streams. Ivy Creek is the only nutrient bank that meets DEQ eligibility criteria for impaired streams in project HUC. Please coordinate with Ana Kilmer, 434.296- 5832 -x3246 ( akilmer(a),,albemarle.org) prior to purchase to ensure bill of sale /Affidavit include requisite project data. Nutrient purchase not required for plan approval but is required to receive a Grading Permit. 4. Check /ensure proposed SWM facility easement width is at least 77'6" with at least 14' of easement on one side extending beyond face of detention pipe, to provide a 10' equipment landing. 5. Provide separate easement plat application for SWM /public drainage easement. Application is at this link (or Camino . Easement plat review requires separate review /approval process. Please submit plat at earliest convenience. WPO plan may not be approved until SWM easement plat is recorded. 6. Include storm pipe and UGD detention profiles presently part of final site plan with WPO plan, as well. Profiles are useful to both plans. ESC inspectors do not inspect using ESP, only an approved WPO plan. 7. Revise WPO consistent with final site plan drainage (inlet /pipe/structure) review comments. 8. Increase Str. 16 DI throat length to 10'. Inlet is located on Drexel Lane, a principal access. Final site plan inlet design table (VDOT LD-204), sheet 8A, SDP202200067, indicates Lt, this inlet=10.68' but inlet length provided is 6', causing inlet carryover during 65 /hr. storm intensity event. 9. Sheet 12: Show pipe 41 (elevated 15" DIA bypass emergency overflow) in UGD System #1 profile, label INV IN (524.75'). Pipe 41 INV IN is well below 10-yr peak WSE 526.30'. At this lower elevation, routings may be inaccurate. UGD system should not bypass the 10-yr event unless Q10-peak calculations accurately account for 15" DIA bypass pipe 41 INV IN elevation. Please confirm routings account for pipe 41 INV elevation (524.75'). Typical design for UGD accommodates Q10-yr peak Vol. without bypass, with Q 10-yr peak WSE < top of UGD interior pipe elevation. Please clarify UGD system accurately routes (pipe 41) and is sized to contain Q10-yr peak in anon -pressurized condition. Engineering is inclined to require a more conservative design given that bypass /upset affecting upstream Walgreens or Advance Auto Parts detention systems may cause higher Q10 volumes to discharge to Maplewood Development than anticipated under normal conditions. Performance of Maplewood UGD depends to a degree on performance of off -site SWM systems installed perhaps long ago that may be relatively more susceptible to upset conditions than more recent developments /UG SWM detention systems installed more recently. 10. Sheet 12: Revise UGD System # 1 profile to show UGD installed 1' below floor of sediment basin, or revise sediment basin floor elevation to 1' higher than base elevation of compacted #57 stone bedding for UGD system. Sediment basin floor needs to be 1' higher than lowest element of UGD system (base elevation of 6" bedding). Saturation of basin floor may compromise UGD system soil bearing without this 1' elevation difference. UDG installation low -point excavation should undercut basin floor elevation by at least 1'. 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 approved. 'Next Steps' after WPO plan approval Purchase Nutrient Credits (4.57 lb. required) a. PLEASE coordinate with the County reviewer before working with (Ivy Creek) nutrient bank. The reviewer must confirm if your project must follow the DEQ hierarchy requirements (Ivy Creek is only eligible nutrient bank since project discharges to S. Fork Rivanna River, which is impaired). b. Letter of availability must be provided on the WPO approved plans. c. Applicant must contact/coordinate nutrient credit purchase with Ana Kilmer, akilmer(-a)Abemarle. org. d. Affidavit of Purchase must be provided to Ana Kilmer before a grading permit can be issued. 2. Post WPO Bond a. Applicant must submit a 'Request to Establish a Bond' form and fee to CDD. Engineering Review Comments Page 3 of 3 i.Complete the form and email it to akilmer(awbemarle.org, along with proof of payment (see below). b. Payment can be made either online or with a check. i.If paying online: 1. Go to the online payment portal. a. Select WPONSMP as the application `type.' b. Type in the WPO number and project name in the Notes/Details section of the form. C. Type in the `payment amount' as $294.34. d. Click "Proceed to Secure Checkout" link to make payment. 2. You will receive a receipt in an email. ii.Emad a copy of the receipt to akilmer(a),albemarle.org. c. Once the bond request and payment are received, the applicant can provide the bond estimate (completed on the County worksheet), or Engineering staff will complete the estimate. Once the estimate is approved, Ana Kilmer will contact and work with the applicant to post the bond. Obtain DEQ Permit (if required, required since LOD =4.09 Ac.) After nutrient credits have been purchased and the bond has been posted: a. County staff will register the project with DEQ. b. Applicantloperator listed on the Registration Statement will receive an email with instructions on how to pay the DEQ permit fee. c. Applicant must email a copy of the DEQ receipt of payment to charris@albemarle.org. albemarle.org, d. DEQ typically will issue a permit within 2 weeks of receiving payment. 4. Request pre -construction meeting: a. Complete and email the Request for a Preconstruction Meeting and Grading Permit to charris(2,,albemarle.org. b. Pay the fee via the online pavment portal or a check at the pre -construction meeting. If paid online, email a copy of the receipt to charris(o),albemarle.org. All steps must be completed before the grading permit can be issued. County forms can be found on the county website forms center under Engineering Applications: htti)s: //www. albemarle. org/government/community-develol)ment/ai)ply-for/engineering-applications Thank you. Please call if any questions — tel. 434.296-5832-x3069, or email 4anderson2&aibemarle.org. WP0202200049_Maplewood Devp_122822.docx