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Home My WebLink AboutWPO201800039 Approval - County 2018-06-29COUNTY 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 -Approved Project title: Hollymead Dam Spillway Improvement — VSMP Project file number: WP0201800039 Plan preparer: Jeremy Young, Schnabel Engineering f i o�ung(a)schanbel-eng.com ] Maria Mutuc, JMT [mmutuc(&Jmt.com ] Owner or rep.: Albemarle County, FES, Environmental Services Division, Water Resources Program / Stavros Calos [scalos(&albemarle.org ; gharper(c albemarle.org ] PMD contact: Walter Harris IV, wharris(a)albemarle.org Plan received date: 5/21/18 Rev. 1 6/29/18 (.PDF) Date of comments: 6/4/18 Rev. 1 6/29/18 —Approved Reviewers: John Anderson 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 approved. 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 ESOP, (3) a SWMP, and (4) any TMDL measures necessary. Engineering Division requests permission to include revised ES sheets in SWPPP booklet —please grant Engineering permission to do this. SWM Plan — (Rev. 1) Prior review comments addressed. A/E contract excludes stormwater management plan required by Albemarle County, but Engineering requests VaRRM .xls summary data (that county provides) be copied from runoff reduction spreadsheet summary prepared by Albemarle County, as well as disclaimer identifying County as source of data. Also, if Schnabel /JMT are able to do this, there will be no need for a pre -application meeting with the county (Department of Community Development). CDD proposes a trade-off. placing SWM -related information on sheet ES -2 in lieu of a pre -application meeting. Please let us know if this works for JMT /Schnabel. If so, please: a. Copy /paste summary information from Attached summary .PDF to sheet ES -2 —entire summary. b. Retitle index, ES -2, to "Erosion and Sediment Control, and SWM General Notes". c. Include SWMdesjpn disclaimer: "SWM -related data, including site impervious area assumptions and summary information from the Virginia Runoff Reduction Method Spreadsheet, version 3.0 (VRRMReDev_ComplianceSpreadsheet v3082017) is included by JMT as a strict courtesy. JMT did not prepare and does not warranty or support analysis, assumptions, or compliance evaluation relating to SWM requirements or design elements of this project, which will be reviewed by local VSMP Authority (Albemarle County), the same entity that prepared and developed SWM -related information, including VRRM .xls. Albemarle County specifically requests a SWM -related design disclaimer appear on project plans." d. Provide SWM Narrative (cut paste Verbatim): i. This (project) land disturbing activity is subject to the VSMP (Sec. 17-302), and is not exempt from the VSMP (Sec. 17-302). Water quality compliance is subject to total e. Engineering Review Comments Page 2 of 3 phosphorus load reduction requirements. ii. Albemarle contends water quanti requirements (9VAC25-870-66) do not apply to or affect portions of project that improve primary spillway riser or repair primary and emergency spillway conduits, including a new outfall structure. These activities `maintain the original line and grade, hydraulic capacity, and original construction of the project' (Sec. 17-303/G.). Remaining portion of this project armors the downslope face of Hollymead Dam with articulating concrete block (ACB), and constructs crest walls to ensure stability and integrity during the PMP event, per state dam safety regulations. iii. Albemarle County chose to use the Re -development spreadsheet. Initial dam construction is considered initial (new) development. iv. Albemarle County accepts 0.0 Ac. pre -redevelopment and 0.0 Ac. post -development impervious values, since new impervious is a new outfall structure designed in-line with outfall at an elevation less than (<) receiving stream normal water elevation. Albemarle views this area as partially submerged, comparable to existing water surface (pervious). Articulating concrete block (ACB) is a pervious embankment armoring system. v. 1.0 Ac. of pre -Redevelopment forest is a conservative estimate. vi. Conversion of forest to turf is required; dam embankment must be clear of vegetation. vii. The VaRRM .xls calculates 0.20 TP Load Reduction (lb./yr.) required. viii. Albemarle intends to purchase 0.20 Nutrient Credits (lb.) from an eligible nutrient bank. ix. Albemarle cannot construct on-site SWM. The site is a dam. The downslope face is a structural surface. Albemarle has acquired offsite temporary construction /permanent drainage easements to construct spillway improvements and perform periodic spillway maintenance, only. x. Albemarle County is source of stormwater management -related assumptions and compliance evaluation with respect to ordinance. See SWM design disclaimer. Provide Floodplain Development Narrative (cut paste Verbatim) i. Albemarle County will prepare a Floodplain Permit Application, and requests Schnabel Engineering sign the Application and provide PE -certification LETTER to County Engineer (Floodplain Administrator) that spillway design causes no increase in the base flood elevation of Powell Creek and Hollymead Lake, to either Zone AE floodway, or floodway fringe. Schnabel statement that the `hydrologic routings and hydraulic design of spillway improvements to this high -hazard classification dam contained in a Final Design Report (March 9, 2018) are sufficient evidence to support PE -seal `No rise' in BFE Certification. ii. No Rise PE -certification is prerequisite to VSMP approval. (Code Sec. 30.3.12). iii. Include imaee. below /black & white (VFRIS: httn://cman2.vims.edu/VaFloodRisk/vfris2.htm11 Engineering Review Comments Page 3 of 3 B. Pollution Prevention Plan (PPP) — Addressed, included with SWPPP. The PPP content requirements can be found in County Code section 17-404. C. Erosion and Sediment Control Plan (ESCP) — (Rev. 1) Prior review comments addressed. Virginia Code §62.1-44.15:55 requires the VESCP authority to approve or disapprove an ESCP. This plan is approved. Also, please see thirty-six (36) VSMP review comments sent as email attachment on 3/28/2018 4:08 AM. 1. Revise text on title sheet to read VSMP/WPO2018-00039. ES -3 2. Provide LOD label that defines Area of LOD (4.291 Ac.) 3. Copy silt trap dimensions (ST -1, ST -2) to ES -3; show bottom of trap dimensions on plan view, each trap. 4. Provide diversion dike upslope of silt fence that runs downslope at LOD, east to west, both north and south of the stream. Diversion dikes are required to divert runoff to silt traps. Silt fence does not divert runoff. 5. Revise Phase I LOD to stop at shoreline (See 3/28 comment #33.a.) 6. SWPPP Exhibit: Provide on-site fuel station note requiring double-wall and 10-m1 plastic -lined containment; berm sufficient to hold 1.1 X 10 -yr. rainfall event Vol. (See 3/28 comment #33.b.) 7. SWPPP Exhibit: Provide note that contractor may change initial locations of storage areas, concrete washout, vehicle fueling, portable sanitary facilities, and solid waste dumpster. 8. ES -4: (Work with Schnabel) to show bypass extension of Ex. 54" diameter outfall known to be required that is sufficient to allow construction of the new mass concrete outfall structure. 9. ES -3, ES -4: Label proposed riprap lined channel `permanent.' Provide dimensions (ES -4) to supplement Plate 3.17-1. Provide ditch design computations for proposed riprap lined channel (2 -yr velocity; 10 -yr. capacity). 10. Note: Comments relating to temp haul road (comment #26) no longer applicable with haul road re -design. Process 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 (by Albemarle County) directly to the state. For fastest processing, this is done electronically with the emails provided on the application. DEQ should notify applicants (Walter Harris, IV, Albemarle County /PMD) with instructions on how to pay fees. When DEQ approves the application, they will issue a permit coverage letter to the county. After DEQ coverage is issued, via the coverage letter, the County can hold a pre -construction conference. Applicants (FES /PMD) will need to complete the request for a pre -construction conference form. The form identifies the contractor and responsible land disturbed, 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; Ifyou have any questions or concerns, please contact me either by email (janderson2(&albemarle.org) or by phone at 434.296-5832 ext. 3069. Thank you. J. Anderson, Engineering Division VSMP_Hollymcad Dam Spillway Improve_WPO201800039_062918revl.doc