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HomeMy WebLinkAboutWPO201900057 Other 2019-12-16 (2)PROJECT MANAGEMENT SHIMCIVIL ENGINEERING LAND PLANNING ENGINEERING a November 26, 2019 Emily Cox County Engineering Albemarle County Community Development WPO 201900057 Proffit Rd Townhomes North — Comment Response for Resubmittal 1 Dear Emily, Thank you for your review of the VSMP Plan for Proffit Rd Townhomes North. We have revised the design of the VSMP Plan per your Comments dated Nov. 14, 2019. See below for our comment response. A. Stormwater Pollution Prevention Plan (SWPPP) 1. JCUUUI I V, JlyI ICU UCI LIIII:dUUI I I IIU— — Iyl ICU. hlbo, it appears it needs to be updated as it currently says Stony Point Design Build. Noted, SWPPP updated. The owner's rep (Brent Hall) wishes to sign when everything else is completed. B. Pollution Prevention Plan (PPP) 'I . INo comments. C. Stormwater Management Plan (SWMP) 1 MnOCn chnlni fhn nlgn number WPO201900057 on the cover sheet. Noted, this is shown. z. H ovvlvl maimenance agreement must be recorded before plan can be approved. Contact Ana Kilmer to complete this process. (akilmer@albemarle.org or 434-296-5832). Noted, we have contacted Ana. 3. Nutrient credits must be purchased before plan can be approved. Contact Ana Kilmer before purchasing credits. (akilmarnalhamnrla nrn nr A.IA-996-5832). Noted, we have contacted Ana. `F.1 ., CQJCI I lints as well as the forest & open space easements must be shown on the plan. Noted, these have been shown. 5. All easements, including: SWM facility easements & forest & open space easement must be recorded on a plat with a deed. Per our meeting, since this is a subdivision, these items just need to be recorded with the subdivision plat before building permits are issued. o. mease aaa the following note on the plan and plat regarding the forest & open space: "The SWM Forest and Open Space Easement is subject to the guidance set forth by DEQ in the Virginia Stormwater Management Program. The areas will remain undisturbed in a natural, vegetated state, except for activities as approved by the local program authority, such as forest management, control of invasive species, replanting and revegetating, passive recreation (e.g., trails), and limited bush hnnninn fn mninfnin Ancir-nd vegetative community (but no more than four times a year)." Note added to cover sheet. i . n uvluC uul IIII I I Iduul l u lat Army Corps of Engineers does not need to be involved with intermittent stream and/or wetlands (as commented by Frank Pohl on the ZMA). Noted, we are waiting on Vinny Peirot to send a Nationwide 18 permit compliance acknowledgement. 8. There are existing managed slopes on the County GIS. Please show these existing managed slopes on all applicable sheets of the plan. Managed slopes now shown. 9. Ensure this plan is compliant with ZMA201800006 (show buffers/open space on all applicable sheets, etc.). Also ensure all proffers are met (ZMA says 44 unit, this plan shows 59?). Noted, it is compliant, (ZMA has 44 units minimum, 109 max). 10. Does this plan match the current ZMA201900010 amendment that was submitted? Any changes that affect this plan will need to be shown. It does, however we will amend the VSMP plan at a later time if the ZMA is approved. 11. Provide a note on the plan regardinq 2:1 slopes. Ground must be stabilized with something that can handle steep slopes. Note added, ground cover mix listed under permanent seeding spec. 12. Prov,u This is being prepared. 1' 0~„.." r„ ­;�+­nce requirements for the SWM facility. Added to cover sheet. 14. 16neet L.-i sj Hao access riser manholes at Al and C1 (inlets to the underground detention). Added as requested. 15. [Sheet C12] Provide manufacturer information allowing 20% and 18% slopes of pipe E2-E1 & A2-Al. Plan revised to make these slopes <15% 16. re1AIRA ro1ri dofinne Porlrnfl nnn„imum allowed velocity is 15 ft/s. Pipe A2- Al is currently 20 ft/s. Plan revised to make max. velocity <15% 17. rivasu b ww uiu uxi5uriy iiaUai channel where the concentrated runoff from this site outfalls. It is not clear on the existing conditions or on the BMP details sheet. This is noted on the plans now. 18 rC'"'" ° .Intions Packet] Provide a legend for the VRRM maps. Legend now included. 19_ 1 �vvivi Lalculations Packetl Provide a channel section from the culvert outfall (F1) to the point of analysis. Channel section not needed as EBE is met at the outfall, see revised calc booklet. D. Erosion and Sediment Control Plan (ESCP) 1. [Sheet C6] What is the estimated amount of import necessary? Please add a note on the plans that the imports must be noted in the SWPPP. This is unknown, note added to PPP. 2. [Sheet C6] A critical area is identified in the narrative, however it is not shown on the plans. If the contractor is to protect this area, it must clearly be shown on the plans. Critical area shown. 3. [Sheets C7,8&9] A wash rack (with a place for it to drain) should be shown with all Construction Entrances (CE). Ensure all phases have a CE. There is not one shown on Sheet C9. Wash rack shown. 4. [Sheets C7,8&9] TS, PS, MU and DC should be shown on all E&S phases. Noted, now shown. 5. Is anv tree protection necessary? For example, along the proffered undisturbed buffer? Noted, now shown. 6. Picaac piuvide staging/parking/stockpile area locations. Noted, now shown. 7. [Sheet C7] Provide slopes of the diversion dike. Ensure there is positive drainage to the sediment basin. Noted, now shown (min. 2% slope). 8. [Sheet C10] Please check design of sediment basin. Wet and dry storage should be 301 CY for 4.5 AC of drainage area, however 268 CY is shown (for only 4 acres of drainage area?). Calculations booklet differs from Sheet C10. Noted, VSMP plan details updated to match calcs. 9. [Sheet C10] Please check design of sediment basin. Detail shows a 406 elevation and design table shows a 424 elevation. These numbers seem out of place. Noted, VSMP plan details updated to match cales. 10. [Sheet C10] Please provide a detail of the trash rack / anti vortex device, the riser anchor/base, anti -seep collars, and baffles if necessary, as required per VESCH 3.14. It needs to be clear for the contractor. Noted, now shown. 11. Show that the flow length is twice the flow width of the sediment basin. Noted, now shown on C12 12. Show outlet protection on all applicable sheets and locations. Calculations were provided on Sheet C11, however no outlet protection was shown on the E&S plans. This includes the inlet(at the end of DID) and outlet of the sediment basin. Noted, now shown. 13. [Sheet C8] Please clarify the note which states, "Set up sand bags and pumps ...". This should have a detail(s) and a c--- ---- -1 --.nc+ri ir"- -n+; —+ a simple note. Noted, now shown and detailed. 14. [sheet C;8] 1 here is a note in the middle of the sheet regarding sequence of construction of lots 18-21. This should be outlined clearly in a sr not just a note on the plan. Noted, now shown and detailed. If you have any questions or concerns about these revisions please feel free to email me at keane(c�shimp-enqineerinq.com and copy Justin Shimp at Justin()shimp-engineerinq.com or call at (434) 299-9843 and we can discuss in further detail. Best Regards, Keane Rucker, E.I.T. Shimp Engineering, P.C.