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Home My WebLink AboutWPO201400039 Review Comments WPO VSMP 2014-08-29�pF 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 Project: Van Dine Plaza Plan preparer: Mike Myers, Dominion Engineering [172 S. Pantops Drive, Charlottesville, VA 22911, mmy ers(a-dominioneng com] Owner or rep.: Auto LLC [1389 Richmond Road, Charlottesville VA 22901] Plan received date: 29 April 2014 (Rev. 1) 29 July 2014 Date of comments: 27 May 2014 (Rev. 1) 29 August 2014 Reviewer: John Anderson A. VSMP: SWPPP and Pollution Prevention Plan (WP0201400039) (The Virginia stormwater management program, stormwater pollution prevention plan application and documents) 1. SWPPP dated July 28, 2014, requires revision: a. Please use 5 -pg document titled VSMP Construction Permit Site Inspection Report shared during separate project meeting Aug. -28 to guide SWPPP revision (language /content). b. Table, p. 4, incorporates SWM and ESC plans by reference (LOCATION). While table is helpful, plans referenced by SWPPP must be included with SWPPP. Legal document retention limits pose risk that plans referenced by SWPPP (but not included) may be difficult to locate or cease to exist. The table is a good idea, but please include tri -fold sheets of each referenced plan sheet. c. Ensure that Location , b., above, actually reports or presents information. For example, SWM Sheet 1 does not present "receiving water names, including the ultimate receiving water." d. As an alternative to format submitted, you may elect to use EPA SWPPP template which may become the default standard since it reflects VAR10 requirements well. If you request word file of template, I will be glad to send it. e. If continue to rely on current form (not template), please number pages up to Appendices. It is difficult to refer to unnumbered pages of SWPPP. (Table on p. 4 refers to p. 3) f. TOC, II, B, 5: Inspections: Ensure that inspections are conducted at required frequency: [§ II F 2. A -c.: Construction GP No. VAR10] g. TOC, II, B, 2, c (i) /Fuels and oils —SWPPP states `On -site vehicle refueling will be conducted in a dedicated location away from access to surface waters. Since the location of fueling activities will periodically move during construction, the design plans do not contain a specific location.' While reasonable, this statement is unacceptable. A location is precise level of detail required to be shown on (plans included with) a SWPPP. Please include plan sheet that shows one or more vehicle refueling locations. SWPPP: "Containment berms will be located adjacent to the refueling area that will contain any inadvertent spills until they can be cleaned up." Statement requires revision: furnish design details for containment berm downslope of refueling area. Show refueling area and design details on plans; include on plans in SWPPP. "Any on -site storage tanks will have a means of secondary containment. In the event of a spill, it will be cleaned up immediately and the material, including any contaminated soil, will be disposed of Engineering Review Comments Page 2 of 6 according to all federal, state, and local regulations." Any on -site fuel storage tanks must include impermeable passive design that limits accidental or inadvertent loss. Fuel loss can occur any time. Fuel spill /storage containment section of SWPPP must furnish details of on -site systems that operate less as response to emergency than to prevent emergency. SWPPP narrative commitment should be supplemented by designs for refueling/fuel storage containment. h. TOC, II, B, 2, c (iii) —Show petroleum product storage location on plans (in SWPPP). i. TOC, II, B, 2, f —Show paint and chemical storage location on plans (in SWPPP). j. TOC, II, B, 2, g (i) —Show concrete truck washout area on plans; site may not drain to inlet or stream. k. TOC, II, B, 2, i /Sanitary Waste —Show portable lavatory locations, equip with berm or silt fence downslope to contain sanitary waste in event of spill; show on plans (in SWPPP). 1. TOC, II, B, 4 1Maintenance — Revise bold text to read "shall be repaired before the next anticipated storm event or as soon as practicable" to "as soon as practicable but no later than seven days after discovery." [VAR 10 §II G.1]. m. TOC, II, B, 5 1Inspections — Revise inspection frequency to be consistent with VAR 10, Part 11, F. See also, Erosion Control Plan comments, #11, below. n. Registration statement dated 7/29/14, item 9, states Area to be disturbed - 2.19Ac. This appears inconsistent with SWM plan estimate of disturbance. o. Darrin Duvalois (Scott's Backhoe Service, Inc; RLD #: 34433) is authorized as SWPPP Coordinator, but unless this individual exercises overall responsibility for environmental matters on this project or holds a position equivalent to positions outlined in VAR 10, then authorize alternate as SWPPP Coordinator. Responsibilities attendant upon SWPPP Coordinator surpass expectations placed on a RLD. [Ref. Part III K 2 of GP] 2. SWPPP (maintained at site) should not be bound: 3 -ring binder allows addition and revision, including plan revisions, and mandatory records of self - inspection, monitoring, incident logs. 3. Although SWPPP (cover) is signed (07/29/14), Certifications Statement is missing. Furnish certification, exactly as follows: Certification, Any person signing a document under Part III K 1 or 2 shall make the following certification: "I certify under penalty of law that 1 have read and understand this document and that this document and all attachments were prepared in accordance with a system designed to assure that qualified personnel properly gathered and evaluated the information submitted. Based on my inquiry of the person or persons who manage the system, or those persons directly responsible for gathering the information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations." 4. Have proper corporate or partnership Authority sign and date Certification Statement. [VAR 10 §III K. La/ K.4]. B. VSMP: SWPPP: Stormwater Management Plan ((WPO201400039) 1. Include Albemarle County General Stormwater Notes. (Rev. 1) Comment addressed. 2. Provide Stormwater Narrative. (Rev. 1) Comment addressed. 3. Identify critical slopes. (Rev. 1) Comment addressed — Follow -up: As discussed during unrelated project meeting on August 28, 2014, Steep Slopes applicability (§ 18- 30.7.4) and design standards (§ 18- 30.7.5) limiting retaining walls to 6' on managed slopes appear to apply. However, 9 -24 -09 Final Site Plan approval exempts project from applicability (§ 18- 30.7.4) or design height requirements. Engineering Review Comments Page 3 of 6 4. Include inlet structure detail (DI -313, DI -3C). (Rev. 1) Comment addressed. 5. Revise plan date (title sheet references topography field verified in April 2014, yet plans are dated March 19, 2009). (Rev. 1) Comment addressed. 6. Review and revise (if necessary) Redi -rock Gravity Wall design to accommodate vehicle surcharge (sheet C4); this wall is required for SWM facilities and other infrastructure. (Rev. 1) Applicant response confirms design will accommodate vehicle surcharge. 7. Use impervious cover computations to calculate %RR for developed area. Evaluate %RR against SWM water quality requirements and proposed design. (Rev. 1) Comment addressed. %RR listed as 70% - Filterra unit expected phosphorus removal =74 %; ref VDEQ, Technical bulletin #6/Part 1I -C review criteria [link: http: / /www.deq.vir ig nia.gov/Portals /0 /DEQ/ Water /Publications /TechBulletin6.pdf ] 8. Provide SCS routing calculations, to include: storage input data for underground detention system; outfall control structures; inflow hydrographs; and routing method - storage- indication. Furnish a profile for the 6'DIA underground storage system that shows WSE for 2 -yr and 10 -yr storm events. (Rev. 1) Comment partially addressed — Follow -up: As discussed during Aug 28, 2014 meeting, ACCD requests underground detention system slope 0.5% to outfall to ensure positive drainage. With change in system slope, please revise connecting pipe grades (detail 4, sheet SWM5). Please revise Hydraflow inputs to match plans (Model v. plan): Crest Len, 15.70' v. 3.85'; 24" DIA outfall, L= 71.00' v. 59.00'; slope ( %) outfall: 1.40 v. 1.70 (Model data: see Pond Report, Wed, 07/9/2014, included with Final Hydrologic /Hydraulic Calculations for Van Dine Plaza, d. 16 -Jul 2014.) Supplement General Construction Notes for Stormwater Management, sheet C4: Provide details for 6' DIA CMP underground system: include bedding/backfill material, depth, compaction, lift, and any other details necessary to properly install this system (Rev. 1) Comment addressed. 10. Revise Str -2 detail, sheet C5; provide scale drawing of outlet structure section detail. (Rev. 1) Comment addressed. 11. Revise OP detail, sheet C5, consistent with stone apron length/width shown in OP detail, ESC Plan, sheet E4. (Rev. l) Comment addressed. 12. Review pipe lengths on Storm Sewer Profile, Str 1 - >7, sheet C5, and sheet C4 (plan view); lengths are inconsistent. Confirm that total storage length is 300 -ft, 6' DIA pipe. (Rev. 1) Comment addressed; total pipe length =350'. This includes two, 9 -ft L connecting pipes at each end bridging 4 lines (3 @85', 1 @75'). 13. Furnish Filterra (Mfr) design chart: drainage area vs. unit dimensions. (Rev. 1) Comment partially addressed. Identical 6' x 6' units for DAs ranging 0.14 to 0.46 Ac. are inconsistent with Filterra design chart —ref detail, sheet SWM4, and Detail 5, sheet SWM5. Do not use impervious acreage to size units, but total acreage. Units receive runoff from total acreage. It appears that units F3 and F7 should be 6' x 10', units F4 and F6, 6' x 8'. 14. Relocate Filterra -F3; it must be immediately adjacent to a storm drain structure. (Rev. 1) Comment addressed, review error. 15. Label existing edge of pavement, sheet C4. (Rev. 1) Comment addressed. 16. Revise design of 23'— 15" HDPE to avoid slope > 16 %. (Rev. 1) Comment addressed. Engineering Review Comments Page 4 of 6 17. Please confirm that 12" pine, 15" poplar, and 15" maple (sheet C4) remain; photos (6- May -14) and aerial photos indicate change between 2009 and 2014. Contact Albemarle County Zoning Division for questions relating to Approved Site Plan, Conservation Plan (tree preservation requirements), and possible mitigation requirements. If trees scheduled to remain have been removed, revise pre - development drainage area map, Sheet D2, and revise location of tree protection fence to reflect existing conditions. (Rev. 1) Comment not addressed. A Landscape plan for site (Letter of Revision #1, labeled C6, dated 7- 28 -14, sent by cover July 29, 2014 to David Benish) does not match Landscape plan, SWM6, 7- 29 -14. Sheets must match. SWM6 must be identical with Landscape plan, sheet C6. 18. Sheet D1: relocate Filterra DA data (3, 4, 4A, 413, 6, 7) to table, or drawing margins. Uncover underlying details. For 0.46 Ac. ST -7 DA, show how runoff above the parking lot (508' contour, and falling) reaches STR -7. It appears that a portion of runoff may not reach Filterra F7 as indicated. (Rev. 1) Comment addressed. 19. New: Revise calculations /report, after revising hydraulic model input data, see #8 above. 20. New: Remove sheet SWM3. Site plans are not approved as part of SWM plans. 21. New: Provide safety railing for retaining walls >4 -ft high. Show railing in plan views, and furnish detail. [ACDSM,8.B.3] 22. New: Do not show riprap outlet protection (detention system) extending into stream, sheets SWM4 /6, D1, D2. 23. New: Plan view length of detention system outfall pipe (SWM4) is 55'; profile view is 59'. Reconcile. 24. New: Profile underground detention system length given as 300' (SWM5) but elsewhere as 350'—reconcile. 25. New: Select appropriate size Filterra units and revise size chart, sheet D1; see # 13 above. 26. New: Re- number one of the detail /s #5, sheet SWM5. C. VSMP: SWPPP: Erosion Control Plan (WPO201400039) 1. In Phase 1, extend temporary diversion dike shown on sheet E2, upslope, toward Rio Road. (Rev. 1) Comment addressed. 2. In Phase 2, provide sediment trap at NE corner of site to intercept flow from 20 -ft fall in grade, sheet E3. (Rev. 1) Comment addressed, per tel. conversation 7/9/14 (ST impractical). 3. Revise plan date (title sheet references topography field verified in April 2014, yet plans are dated March 19, 2009). (Rev. 1) Comment addressed. 4. Provide CIP and OP for existing 3 -24" HDPE culvert in addition to SF. (Rev. 1) Comment addressed. 5. Tree protection, sheet E3, may be unnecessary if 12" pine, 15" poplar, and 15" maple were removed. (Rev. 1) Comment addressed. 6. SF near 3 -24" HDPE appears to conflict with grade. Ensure SF will not prevent grading to final contour. (Rev. 1) Comment addressed. Engineering Review Comments Page 5 of 6 7. Sediment trap, sheet E4: given embankment height, embankment width (3') is insufficient. Embankment height of 6 -ft. exceeds 5 -ft maximum. Please revise. (Rev. 1) Comment partially addressed; sediment trap 58' x 23'dimensions reference 484' contour. Area wet storage (1:1 sideslopes) =55' x 20' x 3' = 3300 cf (122.2cy). Storage required =67cy x 1.9 Ac, 127.3 cy. Revise ST to provide 67cy wet (and dry) storage. 8. Furnish SAF between LOD and sidewalk, Rio Road, and commercial property to SE. (Rev. 1) Comment addressed. 9. New: Erosion and Sediment Control Narrative (a separate report), p. 2, item # 17: paved CE with wash rack is required. Pg. 4, Narrative, TEMPORARY CONSTRUCTION ENTRANCE (CE) — 3.02 — reference wash rack. 10. New: Include ACDSM paved CE detail on ESC plans (detail below). 11. New: Pg. 5/ESC Narrative: Transfer BI 1. MAINTENANCE SCHEDULE to plans. Ensure that ESC inspection frequency satisfies minimal General VPDES (VSMP) Permit requirements. Owner- maintained ESC inspections are required. [link: http: / /www.deq.viri4inia.jzov/ Portals/ 0/ DEQ /Water/Publications /CGP2014.pdf ] 12. New: Pg. 7/ESC Narrative, 18 1minor: Revise to read "Straw mulch is to be applied at 80lbs /I000sf." 13. New: Sheet E2: CE appears to lie on adjacent property and on existing paved commercial entrance (TM 45- 102). Locate paved CE on TM 45 -101, or obtain temporary easement. Avoid damaging existing commercial entrance paved surface. 14. New: Stone weir L -W and outfall apron (L) may be scaled, or extracted from detail 2 schematic /table data, sheet E4, which may leave dimensions to chance. Label weir L -W and apron length in plan view, sheet E2. 15. New: Estimate Area of limits of disturbance, sheet E3. Ensure that ESC plan and VPDES registration statement, Item 9, are consistent. Label sheet E3 with Area of LOD (sf, or Ac). Engineering Review Comments Page 6 of 6 Paved construction entrance for erosion control plans --ONE 70' NIIN. - ?NSTR uCT10N LESS 3" SIJ -2A ASPHALT TOP COURSE EXISTING 2V 29 PAVEMENT �C- %A N. 2!A AGi FREWE BASE ❑p FI STONE 70 MIK. C4NSTRIjCTQN ASPHALT PAVED ACCESS A WASHRACK EXI: 2 %% PAVEYENI �2% 12' M9N.• 'MUST EXTEND �= PO5111VE DR,11NAGE OF INGRE$$ E54$ A ND ECRE$$ M LL WIDTH A TO SEOtENT OFERAT64N TRAPP[NG DEVICE ELM 12' MIN, POSITIVE DRAINAGE TO SEDIMENT TRAPPING DEVICE FILTER CLOTH SECTION A —A A ukinn IIkni l5'ater tap oft dell tmi.Rl be i&talled %itb A ,ifinJi mni L ilicli UAtleock Ali e:ttpyf, A wah lloe wtl canetea f 1 -5 It toff u�chee far A�e[j4,Ate mutant pregrlu e. Wash Rater umst be carried a% -w from the enhance to m approv4ad settling area to vanove se(ta]]ent- .0 sediment stall be pre4 fatted from @Utk1yag storatt draung, aii hes or uatercwuses- PAVE❑ WASH RACK File: WP0201400039 -Van Dine Plaza- 082914rev1