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HomeMy WebLinkAboutWPO201800051 Review Comments WPO VSMP 2018-10-31�OF Aign. COUNTY OF ALBEMARLE ah 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 title: Brookhill Blocks 4A & 4B Apartments Project file number: WP0201800051 Plan preparer: Bohler Engineering — Ryan Yauger [ryauger@bohlereng.com] Owner or rep.: Riverbend Development — Alan Taylor [alan@riverbenddev.com] Rev. 1 Received date: 24 Sept 2018 Rev. 2 Received date: 19 Oct 2018 Rev. 1 comments: 18 Oct 2018 Rev. 2 comments: 31 Oct 2018 Reviewers: Emily Cox 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 pending execution of SWM agreements. Please provide 4 copies of the plan for approval stamps. The rationale is given in the comments below. The application may be resubmitted for approval if all of the items below are satisfactorily addressed. 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. Comment 1: Ensure approved plans get inserted into the SWPPP book on site. Response 1: Acknowledged, the plans will be inserted into the SWPPP book on site following approval. Rev. 1: Comment addressed. Rev. 1: Provide updated, signed registration statement showing total disturbed area to match Sheet C-107. Rev. 2: Comment addressed. B. Pollution Prevention Plan (PPP) The PPP content requirements can be found in County Code section 17-404. Rev. 1: Ensure PPP on site gets updated to include areas associated with this plan. Rev. 2: Comment acknowledged. C. Stormwater Management Plan (SWMP) VSMP Regulation 9VAC25-870-108 requires the VSMP authority to approve or disapprove a SWMP. This plan is disapproved, and the reasons are provided in the comments below. The stormwater management plan content requirements can be found in County Code section 17-403. Comment 2: Change title as discussed with County Engineer (Brookhill Blocks 4A and 4B (apartments) VSMP Plan WP0201800051 or something similar. Engineering Review Comments Page 2 of 10 Response 2: The title has been revised as requested, see Sheet C-100. Rev. 1: Comment addressed. Comment 3: Provide overall sheet showing approved WPOs and the disturbed areas they cover. If the area increases, a new DEQ registration statement must be submitted. Response 3: An Overall Key Sheet has been provided, see Sheet C-107. Rev. 1: Digital Copy shows correct key, however, print copy does not. Print copy only has 2 colors/areas, digital copy shows correct, 3 areas. Please ensure the correct key sheet is inserted in the printed copy. Rev. 2: Comment addressed. Comment 4: Provide existing conditions sheet. If necessary, show existing conditions as proposed grading from approved plans. Response 4: Existing conditions can be found on the Erosion and Sediment Control Plan, Sheet C- 200 to C-201. Rev. 1: Comment addressed. Existing conditions shown on E&S Phase I. Comment 5: Show sleep slopes on all applicable sheets. Response 5: Steep slopes have been added as requested. Steep slopes impact on Block 4B is currently being field tested to verify. Rev. 1: Preserved slopes cannot be disturbed. Sheet C-200 & Sheet C-202 show disturbance through steep slopes. Rev. 2: Comment addressed. Comment 6: Provide maintenance requirements for all SWM facilities on the plan. This comes from section 9 of the DEQ specifications. Response 6: Relevant maintenance requirements have been provided as requested. Rev. 1: Comment addressed. Comment 7: Show ex. Soil types on one sheet of the plan. Response 7: Existing soil types have been provided in the Erosion and Sediment Control Narrative, see Sheet C-204. Rev. 1: Soil types/areas should be shown on the plan, not just summarized in a narrative. This website can be used: https://websoilsurvey.sc.egov.usda.gov/App/WebSoilSurvey.aspx Rev. 2: Comment addressed. Comment 8: Stormwater maintenance agreement is necessary for the stormwater facilities. Contact Ana Kilmer ( 434-296-5832 ext 3246 or akilmergalbemarle.org). This must be recorded before plan can be approved. Response 8: Acknowledged, Ana Kilmer has been contacted to finalize process. Rev. 1: Comment still valid. Rev. 2: Comment still valid. Comment 9: Stormwater management facility easements must be platted and recorded with a deed. What plat are these intended to be recorded on? Response 9: Acknowledged. Easements to be finalized on separate plat after HUD closing. Rev. 1: Comment addressed. Comment 10: Per County Code 14-410, show the principle access is free of flooding during 25-yr storm. Engineering Review Comments Page 3 of 10 Response 10: A note has been added to Stormwater Compliance Sheet C-901 to satisfy this requirement. Rev. 1: Comment addressed. Comment 11: Should be field verified within the past year. Provide that date. Response 11: A field verified date has been added as requested, see Sheet C-100. Rev. 1: Comment addressed. Comment 12: Should include the SWM master plan, WPO 201700027. Response 12: The SWM Master Plan, WP0201700027, has been added as requested, see Sheet C-100. Rev. 1: Comment addressed. Sheet 7 Comment 13: Ensure building does not cross buffer line. Response 13: The proposed building does not cross the buffer line. This can be seen more clearly on Stormwater Compliance Sheet C-902. Rev. 1: Comment addressed. Comment 34: Again, re -word this paragraph to explain that your concentrated discharge drains to a man- made system and show the rates that are leaving your site and the rates that the downstream man-made system can handle. Response 34: The paragraph has been revised for clarification. See Sheet C-901. Rev. 1: As discussed on the phone, show the adequacy of the downstream system to the limit of analysis as required in 9VAC25-870-66. A note is not sufficient. Calculations must be shown. Rev. 2: Comment addressed. Comment 35: Final pond design is part of WP0201800013. Response 35: The callout has been revised to reference WP0201800013. See Sheet C-901. Rev. 1: Note still says WP0201700013. Rev. 2: Comment addressed. Comment 36: Need to analyze from your point of concentrated discharge. Response 36: The point of concentrated discharge is analyzed in the Adequate Outfall Narrative. The area contributing to overland flow in the ditch to Pond 11 decreases in the post - development condition and the ditch has been found adequate. See Sheet C-901. Rev. 1: As discussed on the phone, show the adequacy of the downstream system to the limit of analysis as required in 9VAC25-870-66. A note is not sufficient. Calculations must be shown. Rev. 2: Comment addressed. Comment 37: This is not necessary. Also, this is not approved yet. (Flood Protection Section) Response 37: The statement has been removed from Sheet C-901. Rev. 1: Comment addressed. Comment 38: Provide a Label/designation (BR-4A). Response 38: A label has been provided on Sheet C-901. Rev. 1: Comment addressed. Engineering Review Comments Page 4 of 10 Comment 39: Show proposed storm drain network on this sheet. Need to show how water is leaving the site. Response 39: The proposed storm drain network has been added as requested. See Sheet C-901. Rev. 1: Storm drain network is not clear. Use larger scale or different linetypes to show how water gets to the limit of analysis. Rev. 2: Comment addressed. Comment 40: Re -word this paragraph. It should say Channel protection requirements in block 4A are being satisfied by... (just like the 413 paragraph). Also, elaborate. Show the approved drainage area to pond 11 and show how you are meeting that design and approved release rate. You need to show how your concentrated discharge leaving the site meets the state requirements. Response 40: The paragraph and drainage areas have been revised as requested. See Sheet C-901. Rev. 1: Comment not addressed. Show the approved drainage area to pond 11 proving it can handle the flow/drainage from your site. (show you are in compliance with the approved pond design). Also, provide pond routings. Rev. 2: Comment addressed. Sheet 17 Comment 41: How does this get to pond I I? Show storm drain network. Response 41: The storm drain network in Archer Ave and Stella Lane is shown, which conveys the southern Block 4B runoff to Pond 11. See Sheet C-902. Rev. 1: Storm drain network is not clear on Sheet C-902. Use a different linetype if necessary. Rev. 2: Comment addressed. Sheet 18 Comment 42: Why is this not labeled as a manufactured treatment device, like the isolator row? Response 42: Treatment labels have been added for clarification. See Sheet C-903. Rev. 1: Comment addressed. Comment 43: Please label these specifically when appicable, for ex. BR-4A. This will have to be done outside of the spreadsheet, but it will make it a lot easier to follow. Response 43: Treatment labels have been added for clarification. See Sheet C-903. Rev. 1: Comment addressed. Sheet 19 Comment 44: These should correspond to plan # that contains the approved design for the facility. Response 44: Plan numbers have been added as requested. See Sheet C-904. Rev. 1: Ensure these are all correct. For example, one pond 11 says WPO201800013, another says WPO201800051. Rev. 2: Comment addressed. Sheet 20 Comment 45: This table would make the most sense on Sheet C-901. Response 45: The table has been relocated as requested. See Sheet C-901. Engineering Review Comments Page 5 of 10 Rev. 1: Comment addressed. Sheet 21 Comment 46: Provide pond routings, stage/storage, etc. Response 46: Pond routings, stage/storage, etc. to be provided under separate cover. Rev. 1: Please submit a hard copy of this information. No pond routings were provided. Rev. 2: Comment addressed. Comment 47: 1. Provide aquatic bench. 2. Provide a lower bottom elevation than the sediment basin. Response 47: Pond design has been revised as requested. See Sheet C-906. Rev. 1: The aquatic/safety bench is unclear. Please label. Rev. 2: Comment addressed. Comment 48: Provide landscaping & planting plan per Section 6.7 of DEQ specification. Response 48: Landscaping and Planting Plan to be provided in Final Site Plan. Rev. 1: DEQ specification (section 6.7 of ED) must be met with the WPO Plan. Rev. 2: Comment addressed. Comment 49: Forebay should be at least 4ft. deep. Confirm forebay meets all requirements of Section 6.4 in DEQ spec. for wet pond #1. Response 49: Forebay is 4.5' deep and has been confirmed to meet the specified requirements. See Sheet C-906. Rev. 1: Comment addressed. Comment 50: What is this section for? Response 50: The section is provided to give reference to Sheets C-900, C-901, and C-905, where POI — 4131 is located and profiled. Rev. 1: Comment addressed. Sheet 22 Comment 51: Provide calculations and a section for these ditches. Response 51: Calculations for these ditches have been provided on Sheet C-905. Rev. 1: Sheet C-907 shows 3 cross sections without labels, however, Sheet C-905 has 2 cross sections. C-905 is also referencing section A -A, which is a different location? Please clarify. Ensure there are calculations for the ditches going to the level spreaders. Rev. 2: Comment addressed. Comment 52: Level spreaders must meet all requirements of DEQ specification 2. Specifically, Table 2.2, and Sections 5.1 and 6.3: https://www.vwrrc.vt. edu/swe/documents/2013/DEq%20BMP%2OSpec%2ONo%202_SHEE T%20FLOW_Final%20Draft_v l-9_03012011.pdf Response 52: Acknowledged. Sheet C-907 has been revised to show compliance. Rev. 1: Comment addressed. Sheet 23 Comment 53: Verify this section is accurate. 2 chambers vs. 5 on plan view? Provide a section showing the Engineering Review Comments Page 6 of 10 retaining wall. Response 53: This comment is no longer applicable as the Contech Bioretention is no longer proposed in the plan. Rev. 1: Comment addressed. Comment 54: -Is this proprietary device approved for use by DEQ? Show sizing calculations, drawdown time, etc. Response 54: This comment is no longer applicable as the Contech Bioretention is no longer proposed in the plan. Rev. 1: Comment addressed. Sheet C-904 Rev. 1: Phosphorus credits required are 0.33. The deficit its 1.27lb/yr based on proposed conditions. The amount purchased previously is 0.94 lb/yr, therefore, the remaining balance is 0.33, not 0.18. Please revise narrative. Rev. 2: Comment addressed. Sheet C-906 Rev. 1: Double check this sheet. Digital copy and paper copy were different. Detail referenced Sheet C-911 which doesn't exist. Also, notes were different. Rev. 2: Comment addressed. Sheet C-908 Rev. 1: There are no proposed changes to Pond-1 1, correct? If so, please clarify on this sheet. This is for reference only and no changes proposed. Current note says changes are shown in bold text. Rev. 2: Comment addressed. Sheet C-909 Rev. 1: Are there two proposed CDS facilities or one? Please clarify. Rev. 1: How will the grate inlet stay un-clogged? Provide detail. Rev. 1: Provide routings for this (and all ponds (413,11 4A). Rev. 2: Comment addressed. 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, and the reasons are provided in the comments below. The erosion control plan content requirements can be found in County Code section 17-402. Comment 14: It appears the construction entrance will be washed out. Water needs to be diverted away from construction entrance. Response 14: The construction entrance has been removed from the plan. See Sheet C-200. Rev. 1: Comment addressed. Engineering Review Comments Page 7 of 10 Comment 15: How will vehicles traverse this steep slope? Are both CE's necessary? Response 15: The construction entrance in question has been removed as suggested. The remaining Block 4B construction entrance on Stella Lane is adequate for construction activity. See Sheet C-200. Rev. 1: Comment addressed. Comment 16: Provide Ex. Approved Plan # for Ex. Sed. Basin. Also label Sed. Basin with # as called out in approved plan. Existing label says sediment trap. Please clarify. If it is changing from a trap to a basin, provide the calculations. Response 16: The Road Improvement Plan has been revised and no longer proposes the sediment basin. For compliance, Sediment Trap ST-4C has been proposed. See Sheets C-200 and C-206. Rev. 1: Comment addressed. Comment 17: Show baffles. Response 17: Proposed baffle has been added to the plan, see Sheet C-200. Rev. 1: Comment addressed. Comment 18: Silt fence should be inside limits of disturbance. Response 18: Silt fence has been revised to be within the limits of disturbance. See Sheet C-200. Rev. 1: Comment addressed. Comment 19: Provide perimeter controls (SF). Response 19: Perimeter controls have been added as requested. See Sheet C-200. Rev. 1: Comment addressed. Comment 20: Label this as greenway/stream buffer and/or open space per the approved ZMA and overlot grading plan. Response 20: The greenway/stream buffer has been labeled as requested. See Sheet C-200. Rev. 1: Comment addressed. Comment 21: Show calculation for silt fence (0.25 AC drainage area per 100 ft. SF) Response 21: Silt fence calculations have been added as requested. See Sheets C-200 to C-201. Rev. 1: Comment addressed. Comment 22: This diversion dike will not function. Re-evaluate drainage area and path water will flow. Response 22: The diversion dike has been revised. See Sheet C-200. Rev. 1: Comment addressed. Sheet 9 Comment 23: Show calculation for silt fence (0.25 AC drainage area per 100 ft. SF) Response 23: Silt fence calculations have been added as requested. See Sheets C-200 to C-201. Rev. 1: Comment addressed. Sheet 10 Engineering Review Comments Page 8of10 Comment 24: This drainage divide sheet must accompany the storm drain calculations in the site plan. Response 24: The drainage divide sheet will be provided with storm drain calculations in the site plan. Rev. 1: Comment addressed. Comment 25: 2:1 slopes must specify non -erosive ground cover (not grass). This applies everywhere on site. Please label the 2:1 slope. Response 25: 2:1 slopes have been called out and specified to contain crown vetch plantings. See Sheets C-200 to C-203. Rev. 1: Albemarle County recommends a steep slope seed mix, such as the one by ERNST. Crown Vetch is invasive and should be avoided. Rev. 2: Comment addressed. Comment 26: Will need some form of inlet protection. Response 26: Inlet protection has been added as requested. See Sheet C-202. Rev. 1: Comment addressed. Sheet 11 Comment 27: needs inlet protection. Response 27: Inlet protection has been added as requested. See Sheet C-202. Rev. 1: Comment addressed. Comment 28: Concentrated flow going offsite? Response 28: The flow is conveyed to a proposed road culvert and the ditch proposed with the overall mass grading plan, as designed. Rev. 1: Any concentrated outflow must be analyzed for channel protection and flood protection per 9VAC25-870-66. Rev. 2: Comment addressed. Sheet 13 Comment 29: Provide outlet protection sizing calculations. Response 29: Outlet protection sizing calculations have been provided as requested. See Sheet C-205. Rev. 1: Calculations are unclear. The pipes shown in the Rip -rap outfall calculations table are not referenced on the plan. OP shown on plan for C80, S134A and SB4B, but no corresponding calculations. Please clarify. Rev. 2: Comment addressed. Comment 30: Provide paved construction entrance w/ wash rack detail from County Design Standards Manual. Response 30: Paved construction entrance w/ wash rack detail has been provided on Sheet C-205. Rev. 1: Comment addressed. Engineering Review Comments Page 9of10 Comment 31: This will need a variance request. Specification from manufacturer must be kept in the SWPPP. Response 31: A variance request has been added to the plan on Sheet C-205. Rev. 1: Manufacturer's specifications referenced, but not shown. Rev. 2: Comment addressed. Sheet 14 Comment 32: Show this drainage divide. Sheet C-200 says DA=2.54 AC. Response 32: The drainage divide has been added on Sheet C-200. Rev. 1: Comment addressed. Comment 33: Update or remove note. Response 33: The note has been removed as requested. Rev. 1: Comment addressed. The VSMP permit application and all plans may be resubmitted for approval when all comments have been satisfactorily addressed. For re -submittals please provide 2 copies of the complete permit package with a completed application form. Engineering plan review staff are available from 2-4 PM on Thursdays, should you require a meeting to discuss this review. 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. After bonding and agreements are complete, 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 directly to the state. For fastest processing, this is done electronically with the emails provided on the application. DEQ should notify applicants with instructions on how to pay fees. When DEQ approves the application, they will issue a permit coverage letter. This should be copied to the county. After DEQ coverage is issued, via the coverage letter, the County can hold a pre -construction conference. Applicants will need to complete the request for a pre -construction conference 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. Engineering Review Comments Page 10 of 10 County forms can be found on the county website forms center under engineering; htip://www.albemarle.org/deptfonns.asp?department--cdengno WP0201800051 Plan - VSMP 2018-06-27 (1).pdf Markup Summary Markup Page Label Comments 1 (4) 1 Plan not approved yet. 1 -Ensure approved plans get inserted into the SWPPP book on site. -Change title as discussed with County Engineer (Brookhill Blocks 4A and 4B (apartments) VSMP Plan WP0201800051 or something similar. -Provide overall sheet showing approved WPOs and the disturbed areas they cover. If the area increases, a new DEQ registration statement must be submitted. -Provide existing conditions sheet. If necessary, show existing conditions as proposed grading from approved plans. -Show sleep slopes on all applicable sheets. -Provide maintenance requirements for all SWM facilities on the plan. This comes from section 9 of the DEQ specifications. -Show ex. soil types on one sheet of the plan. -Stormwater maintenance agreement is necessary for the stormwater facilities. Contact Ana Kilmer (434-296-5832 ext 3246 or akilmer@albemarle.org). This must be recorded before plan can be approved. -Stormwater management facility easements must be platted and recorded with a deed. What plat are these intended to be recorded on? -Per County Code 14-410, show the principle access is free of flooding during 25-yr storm. =__ 1 I Should be field verified within the past year. Provide that date. - 1 Should include the SWM master plan, WPO 201700027. 7 (2) 7 Ensure building does not cross buffer line. ;../ 7 8 (9) 8 8 Ensure building does not cross buffer line. It apppears the construciton entrance will be washed out. Water needs to be diverted away from construction entrance. How will vehicles traverse this steep slope? Are both CE's necessary? 713 Markup Page Label 8 Comments Provide Ex. Approved Plan # for Ex. Sed. Basin. Also label Sed. Basin with # as called out in approved plan. Existing label says sediment trap. 8 8 8 8 Please clarify. If it is changing from a trap to a basin, provide the calculations. Show baffles. Silt fence should be inside limits of disturbance. Provide perimeter controls (SF). Label this as greenway/stream buffer and/or open space per the approved ZMA and overlot grading plan. s t i rPo� 8 8 9 (2) 9 9 10 (3) 10 10 Show calculation for silt fence (0.25 AC drainage area per 100 ft. SF) This diversion dike will not function. Re-evaluate drainage area and path water will flow. Show calculation for silt fence (0.25 AC drainage area per 100 ft. SF) Show calculation for silt fence (0.25 AC drainage area per 100 ft. SF) This drainage divide sheet must accompany the storm drain calculations in the site plan. 2:1 slopes must specify non -erosive ground cover (not grass). This applies everywhere on site. Please label the 2:1 slope. \ti „ l 10 Will need some form of inlet protection. 11 (3) 11 needs inlet protection. Concentrated flow going offsite? -= 11 i�- 11 Concentrated flow going offsite? Markup Page Label Comments Provide outlet protection sizing calculations. Provide paved construction entrance w/ wash rack detail from County Design Standards Manual. This will need a variance request. Specification from manufacturer must be kept in the SWPPP. 13 (3) p 13 13 13 14 (2) .. 14 Show this drainage divide. Sheet C-200 says DA=2.54 AC. 14 Update or remove note. 16 (7) 16 16 16 16 16 16 Again, re -word this paragraph to explain that your concentrated discharge drains to a man-made system and show the rates that are leaving your site and the rates that the downstream man-made system can handle. Final pond design is part of WPO201800013. Need to analyze from your point of concentrated discharge. This is not necessary. Also, this is not approved yet. Provide a Label/designation (BR-4A). Show proposed storm drain network on this sheet. Need to show how water is leaving the site. Re -word this paragraph. It should say Channel protection requirements in block 4A are being satisfied by ..... Oust like the 4B paragraph). Also, elaborate. Show the approved drainage area to pond 11 and show how you are meeting that design and approved release rate. You need to show how your concentrated discharge leaving the site meets the state requirements. W16 -= 17 (1) 17 How does this get to pond 11? Show storm drain network. = Markup Page Label 18 (2) 18 18 Comments Why is this not labeled as a manufactured treatment device, like the isolator row? Please label these specifically when appicable, for ex. BR-4A. This will have to be done outside of the spreadsheet, but it will make it a lot easier to 19 (1) 19 20 (1) follow. These should correspond to plan # that contains the approved design for the facility. J TORMWATE] \-- _-_- 20 21 (5) 21 21 This table would make the most sense on Sheet C-901. Provide pond routings, stage/storage, etc. 1. Provide aquatic bench. 21 2. Provide a lower bottom elevation than the sediment basin. Provide landscaping & planting plan per Section 6.7 of DEQ specification. m 21 Forebay should be at least 4ft. deep. Confirm forebay meets all requirements of Section 6.4 in DEQ spec. for wet pond #1. 21 22 (3) 22 22 What is this section for? Provide calculations and a section for these ditches. Level spreaders must meet all requirements of DEQ specification 2. Specifically, Table 2.2, and Sections 5.1 and 6.3 https://www.vwrrc.vt.edu/swc/documents/2013/DEQ°/a20BMP%2OSpec%2ONo%202_SHEET%20FLOW_Final°/a2ODraft_vl-9_03012011.pdf 22 Markup Page Label 23 (2) f _= 23 - --- 23 Comments Verify this section is accurate. 2 chambers vs. 5 on plan view? Provide a section showing the retaining wall. -is this proprietary device approved for use by DEQ? Show sizing calculations, drawdown time, etc.