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Home My WebLink AboutWPO201400095 Correspondence 2015-05-07 r� W COLLINS - - . . /lARRETT ST, SUITE K CHARLOTTESVILLE VA 22902 434.293.3719 PH 434.293.2813 FX www.collins-engineering.com May 7, 2015 John Anderson Department of Community Development 401 McIntire Road Charlottesville,VA 22902 RE: Glenmore Section K2C—VSMP Permit Plan Review—WPO 201400095 Thank you for your comments dated April 10, 2015,and your follow up e-mails in late April concerning detention within biofilters,on the above-referenced project. The updated plans reflect changes to address your comments as described below: A. Stormwater Pollution Prevention Plan 1. SWPPP PDFs and comment responses shall be provided via email per Comment#14. B. Stormwater Management Plan 1. Sheet 8 has been revised to correct note'Q'.The note now references pervious areas and not pervious pavers. 2. a. The biofilter planting schedule has been revised to be more readable. Please see sheet 11's 'Bioretention Basin Construction Notes'subsection entitled 'Facility Planting Specifications'. b. The plans have been revised and now provide underdrains 10'on center. c. The plans have been revised and now provide underdrains 10'on center. d. The plans have been revised and now label the western edge of the emergency spillway.Additionally, all of the spillways have been revised to more clearly define the limits.The spillways have also been revised to show intermediate contour lines, helping to further define the limits,and to demonstrate the proposed 4:1 slopes along the emergency spillways where they are concurrent with the access roads. e. Please see the response above to'd'addressing this comment in plan view.The plans have also been revised to show profile views of the emergency spillways for basins A,C and D.These profiles mandate the contractor install 4:1 side slopes or flatter for the emergency spillways where they are positioned along the access roads. f. Please see the response above to'd'addressing this comment. g. The landscaping plans for the stormwater management facilities have been revised accordingly.Trees are no longer proposed on the down slope side of the embankment. h. While bioretention basin 'C'has been revised to be an extended detention facility,the applicant attempted to address all comments in hopes of an approval.As such,the plans were revised to show the north-to-south floor length dimension for the extended detention basin. i. The applicant appreciates this comment and has revised the plan accordingly.The riser has been increased by 200%and now has a 24"diameter. j. The profiles have been revised to label the embankment side slopes. k. The bioretention basin profiles have been revised to label the top of mulch elevations. I. The applicant appreciates this recommendation and has revised the plans to reference OSHA shoring requirements for the 6'deep excavations associated with the bioretention basins. Please see note#5 on sheet 10 for Basins'A'and'D'. m. The applicant has revised the plans to correct this previous error. 3. The plans have been revised such that the bioretention basins now have a 30' long base emergency spillway crest set 12"above the top mulch layer.This design creates a maximum ponding depth within the 441w, Awe biofilter of 12"before runoff is released from the water quality facility into the downstream detention cell/water quantity facility. Please note the downstream detention cell/water quantity facility is not a standard BMP and phosphorous removal credit for the detention cells were therefore not assumed in the VRRM calculations. C. Erosion Control Plan 1. Diversions added to Phase II E&S plan. 2. "Area of select clearing..." note added to Lots 24-26 on Sheets 4/5. 3. Filtrexx runoff diversion product detail removed from plans. 4. Right-of-way diversions have been specified at areas where diversions cross access paths. 5. Ditch provided to the north of Basin C access path,design included with road plan submittal. 6. Sheet 6: a. Trap now a basin due to increased area,see Basin#2 calculations/details. b. Trap now a basin due to increased area,see Basin#2 calculations/details. c. Trap now a basin due to increased area,see Basin#2 calculations/details. d. Sediment trap at entrance to site redesigned. e. Sediment basin#1 redesigned. f. Profiles included for each sediment basin g. Invert of dewatering devices labeled on basin details. h. Concrete foundation design provided on each basin detail. i. SWM orifices not being utilized during the E&S phases of the project. E&S orifices shall be sealed and replaced with the final SWM orifices at the time of E&S-to-SWM conversion. j. Basin slopes labeled on basin profiles. 7. Sequence of Construction/Sheet 3: a. Note 12 revised. b. Note 14 revised. 8. Contours revised for readability. 9. Additional proposed contour labels added to Sheet 5. Should you have any questions, please feel free to contact Adam Long at 434-293-3719. If you have any questions concerning the stormwater management plan and calculations, please contact Graham Murray at 434-566-3011. Sincerely, Adam Long, PE Collins Engineering John Anderson From: Graham Murray <graham@collins-engineering.com> Sent: Thursday, May 28, 2015 2:56 PM To: John Anderson Subject: RE: Glenmore K2C-VSMP 2nd Submittal Attachments: 150528 Glenmore K2C Sheet 10- REVISED.pdf Good afternoon John, Thanks for your favorable review,kind words towards my design and willingness to review PDFs for approval. I revised sheet 10 to address your comments below,as well as to update the outlet protection dimensions referenced in your follow up e-mail. I've highlighted these revisions in red for your convenience in the attached PDF. If you need anything else or have any questions,please feel free to shoot me an e-mail or give me a call. Thanks! Graham P.S.Sheet 6 of the VSMP plans will also be updated to reflect the new OP dimensions with the next submission. From: John Anderson [mailto:janderson2@albemarle.org] Sent:Thursday, May 28, 2015 10:11 AM To: Graham Murray Cc: Adam Long; Scott Collins Subject: RE: Glenmore K2C-VSMP 2nd Submittal Thanks, Graham Only comments on SWMP:provide fence and warning sign, or close plantings and warning sign to limit/discourage trespass on 2:1, 11' D Basin A detention cell(detained depth may approach 7.75'), and; (ii)Elev. labels for: • Floor,4' D micropool • Rim micropool(ED basin C) • Floor,detention cell,basin A • Floor,detention cell,basin D ...but need to check VaRRM.xls +storm calc report. Several weeks ago, I said I planned to comment within a week,and didn't. Yesterday, I told Adam I will comment on CCS and Glenmore WPONSMP by the end of this week. I commit to that. Graham, it is clear you take unusual care with design, I appreciate conceptual response to SWMP comments on this project. I welcome .PDF revisions so we can be certain that the final 4-copy submittal is for Approval. Adam has sent the SWPPP. Thank you. Adam, I appreciate your care with Glenmore road plans. Thank you both- From:Graham Murray [mailto:graham@collins-engineering.comj Sent:Thursday, May 28, 2015 9:23 AM To:John Anderson 1 Cc:Adam Long Nom. Subject: RE: Glenmore K2C-VSMP 2nd Submittal John, Thanks for the follow up e-mail.Someone else from our office completed the SWPPP report and Adam will be e-mailing it to you later this morning. If you need anything else,or have any questions,please do not hesitate to contact me. I'll be glad to trouble shoot any items or concerns you may have. Graham From: John Anderson [mailto:janderson2Calalbemarle.orq] Sent: Thursday, May 28, 2015 9:12 AM To: Graham Murray Subject: RE: Glenmore K2C-VSMP 2nd Submittal Graham,did we receive Glenmore K2C digital SWPPP?—did I overlook? Thanks! From:John Anderson Sent: Friday, May 08,2015 10:47 AM To:Graham Murray Subject: RE: Glenmore K2C-VSMP 2nd Submittal Graham, Thanks, will try to review as soon as possible yes,to digital till review complete. I may work a bit this weekend, maybe on this. Will try to move quickly, have a nice weekend. From: Graham Murray [mailto:graham(acollins-engineering.com] Sent: Thursday, May 07, 2015 12:08 PM To: John Anderson Subject: Glenmore K2C-VSMP 2nd Submittal Good afternoon John, I hope this e-mail finds you well. You have previously requested I provide you with the MS Excel file for VRRM calculations.And in anticipation of submitting the 2nd submittal of the Glenmore K2C VSMP plan in the upcoming days I want to provide you with this file(attached). Also,thank you again for stating you would be available to trouble shoot any questions/issues I foresaw leading up to the formal submittal.As it turns out,this won't be necessary. I basically addressed all of your comments and complied with everything without dispute. Or at least I hope I did O And lastly,your comment letter stated we could provide you with a digital copy of the SWPPP report to save time and resources. Collins Engineering appreciates this. Similarly,would you like to do the same with the attached SWM report until the plans/calculations are approved?®.This may avoid mass printings and cluttering of everyone's desks. Thanks, 2 Graham Graham Murray,P.E. COLLINS ENGINEERING www.collins-engineering.com 200 Garrett Street,Suite K Charlottesville,VA 22902 Cell: (434) 566-3011 grahamt7a collins-engineerinq.com 3