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HomeMy WebLinkAboutWPO201600008 Review Comments WPO VSMP 2016-06-24 sloe •,ode • � PROJ CIVILECTMANAGEMENT ENGINEERING LAND PLANNING ENGINEERINGa June 24, 2016 Albemarle County Department of Community Development Regarding: WPO 2016 00008 Carroll Creek Road VSMP Plans To Whom It May Concern, We have submitted revisions to the VSMP plans for Carroll Creek Road. John Anderson's comments for the first submittal and the changes we have made in response are below. A. Stormwater Pollution Prevention Plan (SWPPP) 1. Sec. 6—provide details specific to stream diversion; recommend attention to potential downstream impacts due to failure of(sandbag) coffered areas. A PPP sheet for the stream diversion is now provided. 2. Sec. 7— Status of waterbody(Carroll Creek) is impaired. Please revise Sec. 7. The note in Section 7 has been revised to correctly indicate the status of the waterbody. 3. Recommend stipulate inspections every four days [VAR 10, Part I, B4d(1)]; increased for impaired waters. The inspection report form now stipulates inspections every four days. 4. Recommend check Registration Statement Estimated Area to be Disturbed; please confirm 25.94 Ac. is accurate, and limited to Carroll Creek Road stream crossing/culvert project. The VSMP plans for the Carroll Creek Culvert and the Glenmore K2C-II subdivision have now been combined as discussed in a meeting. B. VSMP: SWPPP: Stormwater Management Plan (WP0201600008) 1. Ref. Sec. 5, SWPPP: "Stormwater quality shall be addressed via excess treatment from the concurrent Glenmore K2C subdivision to the north." County accepts approach, but requires VRRM estimate of lb. TP/year pollutant removal requirement. Provide VRMM .xls calculations for Carroll Creek new 10' x 10' box culvert crossing. The note has been revised to reflect the current design,which proposes the use of nutrient credits and combines the culvert development and the subdivision into one VSMP plan. 2. 9VAC25-870-66-B4a defines limits of analysis,not compliance evaluation found at 9VAC25-870- 66-B3. It is appropriate, however,to recognize difficulty of meeting energy balance at this location. Attached DEQ Memorandum(23-Apr 2015, without diminishing review requirements) bears on review determination. This is a linear/stream crossing project, but not strictly exempt from SWM regulations, and quality and quantity considerations inform design. County accepts channel/flood protection, given project location. Carroll Creek DA at crossing is Approx. 5.77 Mi2. So noted. 3. C2—Please label Existing RW to be vacated(nearly in entirety). New roadway alignment will require new platted private right-of-way(See sheet C3/ROAD Plan, SUB201500202). Sheet C3 from the road plan is now included in the VSMP plan. C.VSMP: SWPPP: Erosion Control Plan (WP0201600008) 1. LOD,please label estimated area of land disturbance (acreage), consistent with Registration Statement, LOD (various sheets). The area of land disturbance in the Registration Statement has been updated to reflect the current design. 2. Provide demolition plan, narrative, and sequence. A demolition plan, narrative, and sequence of construction are now provided. 3. Provide ESC measures required for demolition of pavement/removal of existing 3-line 48" culverts. Temporary damming with siphoning as necessary is now specified for the removal of the existing culverts. 4. SWPPP Exhibit uses phase II ESCP/C11. This appears impractical as PPP is required with phase I. Please indicate initial on-site locations of PPP practices on C10, or similar base template. The SWPPP exhibit is now changed to use Phase 1 as the background. 5. C4—Show grading (if any) at Staging Area(Item#25). No grading is proposed for the Staging Area. 6. C8—Review stream diversion sequence of construction. Revise to provide clarity of detail required to divert Carroll Creek, a challenging aspect of this work. Unless details are clearly articulated/shown, too much is left to chance. DA=5.77 Mi2 at crossing. The new 10' x 10' box culvert may take several weeks to install under ideal conditions. The sequence of construction for the stream diversion has been expanded to show extensive detail. Ultimately,the successful installation of the stream crossing is the responsibility of the contractor,with supervision by the County. The details for the stream diversion will aid the contractor in planning the work. 7. C8—Sequence,phase II, Note 3: Revise to ref. sheet Cl 1. The reference in the sequence of construction has been updated. C9—Stream Diversion 8. Please provide plan view of stream diversion, with specific location and detail (VESCH typ. detail is insufficient). Stream stationing/profile indicate diversion>200-ft. The previous submittal had a significant problem with the layer state,so the designed stream diversion measures were not shown.This has been corrected. • 9. Recommend plan-view graphic sequence: diversion installation; box culvert construction; 3-line existing culvert removal; stream returned to native channel; and diversion removal. A plan view graphic sequence is now included. 10. Provide ESC measures required for diversion, or to protect coffered work areas. The ESC measures required for the diversion are now shown after the layer state was fixed. 11. Existing 3-line culvert demolition and new box culvert installation should coincide-3-line removal may not occur in live stream. Show diversion beginning upstream of existing 3-line 48" DIA culverts, and ending downstream of 104'(±), 10' x 10' box culvert. The stream diversion plan has been updated in response to this comment. Leaving the existing road accessible to construction traffic for as long as possible is important, as the surrounding neighborhood is averse to construction traffic travelling through from both directions.The stream diversion now calls for temporarily damming the stream during a low-flow period to remove the existing culverts in one day. 12. Specify impermeable barrier in addition to/beneath geotextile beneath riprap as diversion lining to prevent saturation in areas of fill for road crossing. Once diversion is removed, subgrade must retain adequate bearing properties. A 6mm plastic underlay is now specified in addition to the geotextile to prevent saturation and maintain the bearing capacity of the soil. 13. Evaluate sandbag diversion against 2-yr storm event WSE, against lateral static/dynamic force of stream. The sandbag diversion is now designed to only be in use during a period of minimal predicted rainfall, and the diversion will be in place for as little time as possible. The contractor will be responsible for installing the sandbag diversion properly and reinforcing it as necessary if unexpected rainfall occurs. 14.Note 2: Clarify. Explain how existing traffic patterns will be preserved while stream is diverted. Explain whether temporary traffic detour across Carroll Creek/stream diversion will be part of this design. The existing Carroll Creek Road will remain open for construction traffic only for as long as possible during construction. Non-construction traffic will be diverted through detours within the neighborhood. 15. Show location of road closed/detour signs, east/west sides. Show sign locations on ROAD plan, as well. Road closed signs are now shown to the east and west of the culvert. 16. Note 6: Clarify. Existing streambed should not be disturbed except to prepare grade/stone bed for 10 x 10' box culvert. All other sections of native streambed within diversion should remain dry/undisturbed. C9 should direct 'No disturbance' beyond minimum required to divert stream/construct 10' x 10' box culvert. The note has been revised to clarify that only the portion of stream bed where the culvert will be placed should be disturbed. 17. Note 10: Provide/show stream protective measures (coffered work areas) for wing wall construction. A sandbag dam is now shown for wing wall construction. Noise *ft.01 18. Recommend safety fence for stream diversion. Safety fence is now shown for the stream diversion. Sheet C10 19. Show/design/dimension new 10' x 10' box culvert outfall protection. The dimension of the box culvert outfall protection is now shown on all plan views. 20. Provide SAF at STs. (Recommend SAF, ROAD Plan: box culvert site.) SAF is now specified for the ST's. 21. Label length of box culvert. The length of the box culvert is now labelled. 22. Show stream diversion on this plan sheet(will be in place at this stage: box installed,prior to removal of existing 3-line culvert). The current stream diversion plan is for Carroll Creek to be routed through the box culvert at this stage, so fill can be placed above the box culvert while the existing Carroll Creek Road is still accessible to construction traffic. Sheet C11 23. Provide SF west of ST-1, ST-2 at toe of 2:1 slope to protect stream, east bank of Carroll Creek. SF is now provided west of the sediment traps to protect the stream. 24. Provide STs, diversions, and SF on west side of Carroll Creek, similar to east side. On the east side of Carroll Creek,significant amounts of water will be collected by the new stormwater conveyance channels to the north and to the south, necessitating sediment traps. To the northwest, an existing ditch will convey water,so a new diversion is not necessary. Silt fence is specified for the northwest and southwest,along contours to ensure the runoff does not bypass the silt fence.To both the northwest and the southwest,the silt fence will catch water from less than 60'of horizontal flow. To the southwest, a diversion would need to be constructed in order to guide the runoff into a sediment trap,which would expand the limits of disturbance in a sensitive area.We believe the E&S measures currently specified will protect the stream without expanding the limits of disturbance beyond necessity. 25. Provide SF, Staging Area. Show grading to construct staging area, if any. Silt fence is now provided for the Staging Area. No grading is proposed for the staging area, as it will be located in existing right-of-way. 26. Include Staging Area within LOD if grading required. Grading is not proposed for the Staging Area. • NOMle NOS 27. Provide accurate LOD, across sheets. It is our understanding that the Registration Statement may include disturbance required to develop future lots. Carroll Creek crossing is under a zoning compliance schedule; plan review/approval must proceed quickly in keeping with compliance schedule. The VSMP plan has been expanded to show the limits of disturbance for both the culvert and the subdivision. 28. Provide culvert/hydraulic analysis for culvert. Consider poured apron/plunge pool. Provide calculations similar to analysis provided with Shimp Engineering Rocky Hollow project, box culvert stream crossing. Hydraulic analysis for the culvert is included in this submittal. 29. Recommend provide label/reference to C4 landscaping: periwinkle ground cover(or equivalent) for slopes steeper than 3:1. A reference to the groundcover shown in the landscaping plan is now included. 30. C12—Provide Albemarle County paved construction entrance detail (PCE) rather than stone CE. The paved construction entrance detail is now provided. D. Mitigation Plan (WP0201600008) 1. Provide landscaping typical details to aid installation/plant survival. (Ref. Attached unrelated design). Typical planting details for shrubs and trees are now included. 2. Revise Mitigation Area 1, 2, and 3 plant quantities. See Attached Riparian Buffer Guidance Manual Table B/every 400 ft2 plant: 1 canopy tree; 2 understory trees; 3 small shrubs. A slight variation exists as an option. (Ref. unrelated design). The plant quantities for the Mitigation Areas have been updated to correctly show the computed requirements. 3. Pre-select/list a limited number of canopy/understory tree, shrub (large/small), and evergreen species. A list of selected plant species is now included. 4. Include plan notes on minimal survival requirement(Ref. unrelated design/Attached Table B) A note on minimal survival is now included with the mitigation plan. E. Floodplain Development Permit(FDP201600001) 1. Provide PE-Seal No-Rise' Certificate. (Ref. Attached/example.) In certificate, please ref. 30-Oct 2015 letter submitted with Application, with letter Attachments: Contents,pg. 2/18. A PE-Seal"No-Rise" Certificate is included with this submittal. 2. C2—Please revise 100-yr floodway label to read 100-yr floodway of Rivanna River. The label has been revised accordingly. stove 3. Include FEMA Panel (Attached) with revised FDP submittal. Revised submittal will consist of PE- seal 'No Rise' certificate; cover letter; attachments. Include FEMA Firm Panel 51003C0450D/Carroll Creek. A FEMA panel is included with this submittal. 4. Please reference WPO201600008 in cover letter with revised FDP submittal. WPO 2016 00008 is referenced in the no-rise certificate. If you have any questions, please do not hesitate to contact me at your earliest opportunity. I may be reached at lauren a skimp-engineering.com or by phone at 434.227.5140 x4. Justin Shimp may be reached at Justin4shimp- engineerinq.com or 434-953-6116. Best Regards, / I / auren Gilroy Shimp Engineering, P.C. COUNTY 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 Project: Carroll Creek Road (VSMP) / Floodplain Development Permit (FDP) Plan preparer: Lauren Gilroy/Justin Shimp, Shimp Engineering, 201 E. Main St. Suite M, Charlottesville, VA 22902 f iustin(&shimp-enizineering com] Owner or rep.: Glenmore Partners LLC, P.O. Box 645, Charlottesville, VA 22902 Plan received date: 10 Feb 2016 Date of comments: 15 Mar 2016 Reviewer: John Anderson WP0201600008 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. Sec. 6 —Provide details specific to stream diversion; recommend attention to potential downstream impacts due to failure of (sandbag) coffered areas. 2. Sec. 7 —Status of waterbody (Carroll Creek) is impaired. Please revise Sec. 7. Link: https:Hiaspub.epa.,gov/watersIO/attains waterbody.control?p an id VAV- H29R CAROIA06&p cycle=2012 3. Recommend stipulate inspections every four days [VAR10, Part I, B4d(1)]; increased for impaired waters. 4. Recommend check Registration Statement Estimated Area to be Disturbed; please confirm =25.94 Ac. is accurate, and limited to Carroll Creek Road stream crossing/culvert project. B. VSMP: SWPPP: Stormwater Management Plan (WP0201600012) VSMP Regulation 9VAC25-870-108 requires the VSMP authority to approve or disapprove a SWMP. This plan is disapproved for reasons provided in comments below. The stormwater management plan content requirements can be found in County Code section 17-403. 1. Ref. Sec. 5, SWPPP: "Stormwater quality shall be addressed via excess treatment from the concurrent Glenmore K2C subdivision to the north." County accepts approach, but requires VRRM estimate of lb. TP/year pollutant removal requirement. Provide VRMM .xls calculations for Carroll Creek new 10' x 10' box culvert crossing. 2. 9VAC25-870-66-B4a defines limits of analysis, not compliance evaluation found at 9VAC25-870-66-B3. It is appropriate, however, to recognize difficulty of meeting energy balance at this location. Attached DEQ Memorandum (23 -Apr 2015, without diminishing review requirements) bears on review determination. This is a linear/stream crossing project, but not strictly exempt from SWM regulations, and quality and quantity considerations inform design. County accepts channel/flood protection, given project location. Carroll Creek DA at crossing is Approx. 5.77 Mie. 3. C2 —Please label Existing RW to be vacated (nearly in entirety). New roadway alignment will require new platted private right-of-way (See sheet C3/ROAD Plan, SUB201500202). Engineering Review Comments Page 2 of 7 C. VSMP: SWPPP: Erosion Control Plan (WPO201600012) Virginia Code §62.1-44.15:55 requires the VESCP authority to approve or disapprove an ESCP. This plan is disapproved for reasons provided in comments below. The erosion control plan content requirements can be found in County Code section 17-402. 1. LOD, please label estimated area of land disturbance (acreage), consistent with Registration Statement, LOD (various sheets). 2. Provide demolition plan, narrative, and sequence. 3. Provide ESC measures required for demolition of pavement/removal of existing 3 -line 48" culverts. 4. SWPPP Exhibit uses phase II ESCP/C11. This appears impractical as PPP is required with phase I. Please indicate initial on-site locations of PPP practices on C10, or similar base template. 5. C4 -Show grading (if any) at Staging Area (Item #25). 6. C8 -Review stream diversion sequence of construction. Revise to provide clarity of detail required to divert Carroll Creek, a challenging aspect of this work. Unless details are clearly articulated/shown, too much is left to chance. DA =5.77 Mie at crossing. The new 10' x 10' box culvert may take several weeks to install under ideal conditions. 7. C8 -Sequence, phase 11, Note 3: Revise to ref. sheet C11. C9 -Stream Diversion 8. Please provide plan view of stream diversion, with specific location and detail (VESCH typ. detail is insufficient). Stream stationing/profile indicate diversion >200 -ft. 9. Recommend plan -view graphic sequence: diversion installation; box culvert construction; 3 -line existing culvert removal; stream returned to native channel; and diversion removal. 10. Provide ESC measures required for diversion, or to protect coffered work areas. It. Existing 3 -line culvert demolition and new box culvert installation should coincide -3 -line removal may not occur in live stream. Show diversion beginning upstream of existing 3 -line 48" DIA culverts, and ending downstream of 104'(±), 10' x 10' box culvert. 12. Specify impermeable barrier in addition to/beneath geotextile beneath riprap as diversion lining to prevent saturation in areas of fill for road crossing. Once diversion is removed, subgrade must retain adequate bearing properties. 13. Evaluate sandbag diversion against 2 -yr storm event WSE, against lateral static/dynamic force of stream. 14. Note 2: Clarify. Explain how existing traffic patterns will be preserved while stream is diverted. Explain whether temporary traffic detour across Carroll Creek /stream diversion will be part of this design. 15. Show location of road closed/detour signs, east/west sides. Show sign locations on ROAD plan, as well. 16. Note 6: Clarify. Existing streambed should not be disturbed except to prepare grade/stone bed for 10 x 10' box culvert. All other sections of native streambed within diversion should remain dry/undisturbed. C9 should direct `No disturbance' beyond minimum required to divert stream/construct 10' x 10' box culvert. 17. Note 10: Provide/show stream protective measures (coffered work areas) for wing wall construction. 18. Recommend safety fence for stream diversion. C10 19. Show/design/dimension new 10' x 10' box culvert outfall protection. 20. Provide SAF at STs. (Recommend SAF, ROAD Plan: box culvert site.) 21. Label length of box culvert. 22. Show stream diversion on this plan sheet (will be in place at this stage: box installed, prior to removal of existing 3 -line culvert). C11 23. Provide SF west of ST -1, ST -2 at toe of 2:1 slope to protect stream, east bank of Carroll Creek. 24. Provide STs, diversions, and SF on west side of Carroll Creek, similar to east side. 25. Provide SF, Staging Area. Show grading to construct staging area, if any. Engineering Review Comments Page 3 of 7 26. Include Staging Area within LOD if grading required. 27. Provide accurate LOD, across sheets. It is our understanding that the Registration Statement may include disturbance required to develop future lots. Carroll Creek crossing is under a zoning compliance schedule; plan review/approval must proceed quickly in keeping with compliance schedule. 28. Provide culvert/hydraulic analysis for culvert. Consider poured apron/plunge pool. Provide calculations similar to analysis provided with Shimp Engineering Rocky Hollow project, box culvert stream crossing. 29. Recommend provide label/reference to C4 landscaping: periwinkle ground cover (or equivalent) for slopes steeper than 3:1. 30. C12 —Provide Albemarle County paved construction entrance detail (PCE) rather than stone CE. D. Mitigation Plan (WPO201600008) 1. Provide landscaping typical details to aid installation/ plant survival. (Ref. Attached unrelated design). 2. Revise Mitigation Area 1, 2, and 3 plant quantities. See Attached Riparian Buffer Guidance Manual Table 13/every 400 ft2 plant: 1 canopy tree; 2 understory trees; 3 small shrubs. A slight variation exists as an option. (Ref. unrelated design). 3. Pre-select/list a limited number of canopy/understory tree, shrub (large/small), and evergreen species. 4. Include plan notes on minimal survival requirement (Ref. unrelated design/Attached Table B) E. Floodplain Development Permit (FDP201600001) 1. Provide PE -Seal `No -Rise' Certificate. (Ref. Attached/example.) In certificate, please ref. 30 -Oct 2015 letter submitted with Application, with letter Attachments: Contents, pg. 2/18. 2. C2 —Please revise 100 yr floodway label to read 100 yr floodway of Rivanna River. 3. Include FEMA Panel (Attached) with revised FDP submittal. Revised submittal will consist of PE -seal `No Rise' certificate; cover letter; attachments. Include FEMA Firm Panel 51003C0450D/Carroll Creek. 4. Please reference WPO201600008 in cover letter with revised FDP submittal. GIS Images 0 0 Help M blle arab Y -Oft a52a+"" J© 941 f� eft -- ]A1 -A1 92 -ft *v Fs 4C „zpa ft Google Mapa • Go s..a a�� ml MpGm Save Map ae Engineering Review Comments Page 4 of 7 0 E Help mobile scale Y=imOA Engineering Review Comments Page 5 of 7 1 E a I �tu QFql-� Help nubile scale V — loo ft a®0+1101° 0 0 z r"^- I �' + �A •''-TON HILLS nR Z RE i•T^ ZONE x- �? DEER VALLEY CT OZONE A � Creek ' YX GELLETLY ZONE RD IONCHRANCM X + FARM ZONE A 0 .A ZONE z 0 + + f THOMAS .yFEFER50� ZONE X `Sa ZONE X WAY f, LL ZONE AA LN17 4 :: Engineering Review Comments Page 6 of 7 T Ci CT ZONE A 42080M 1 DNE X ARROU CREEK ONE X 207 " •CARROLL CREEK RD ZONE X .RIVANNA R -nTR 4275<r...,.., Engineering review staff are available 2-4 PM on Thursdays if you wish to discuss project, comments, or design. Plan review staff available at 434.296-5832 -0069, should you have any questions. 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. Stormwater Management Facilities Maintenance agreements will also need to be completed and recorded. The County's Management Analyst or other staff will prepare the forms and check for ownership and signature Engineering Review Comments Page 7 of 7 information. The completed forms will need to be submitted along with court recording fees. 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 request a pre -construction conference by completing a 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. County forms can be found on the county website forms center under engineering; htW://www.albemarle.org/deptforms.asp?department--cdengnoo Thank you. 434.296-5832 —0069 File: WP0201600008 Carroll Crk Road +FDP201600001 031516.doc