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HomeMy WebLinkAboutWPO201500085 Correspondence 2016-03-17John Anderson From: John Anderson Sent: Friday, March 18, 2016 6:40 AM To: 'Graham Murray' Subject: RE: Charlottesville Self Storage at Crozet (WPO201500085) Exactly, it is an information -only note for anyone who might pick up the plans in the future in the event you and I are not present to discuss it. Thanks, Graham —take care From: Graham Murray [mailto:graham@collins-engineering.com] Sent: Friday, March 18, 2016 6:32 AM To: John Anderson <janderson2@albemarle.org> Subject: RE: Charlottesville Self Storage at Crozet (WPO201500085) Good morning John, I apologize for not sending you everything in one e-mail, I forgot to inquire about your SWPPP comment (attached at top). Is this an information -only note for anyone who might pick up the plans in the future in the event you and I are not present to discuss it, or does CE need to submit a complete/new SWPPP report? Thanks for your time, and if today is your day off then it can wait until Monday. A man has to have a little down time. Graham From: John Anderson [ma iIto: janderson2@albemarle.org] Sent: Thursday, March 17, 2016 5:23 PM To: Graham Murray Subject: RE: Charlottesville Self Storage at Crozet (WPO201500085) Hi, Graham, Thanks for your thorough note —it helps with decisions. blue text, below From: Graham Murray [mailto:graham@collins-engineering.com] Sent: Thursday, March 17, 2016 1:48 PM To: John Anderson <janderson2@albemarle.org> Subject: Charlottesville Self Storage at Crozet (WPO201500085) Good afternoon John, In my meeting today with Max for the Villas at Belvedere I'd like to discuss a couple of items with you regarding the Charlottesville Self Storage development in Crozet. In particular, I'd like to discuss SWM comments 4A, 4C, 4E and 4F (below and attached). Thanks, Graham Comment 4A: During my January 7th meeting with County Engineering, where you were unfortunately unable to attend due to a family emergency, I met with Glenn and we agreed the previously approved WW & Associates calculations packet could be used for the pre - development conditions. This was then e-mailed to you following the meeting (see attached). This is important because depicting the pre -development conditions from so long is challenging, and the prior calculations being approved would be a better and more accurate account of the watershed (both total area and imperviousness). I hope that this methodology is still acceptable. It is. Comment 4C: Previous underground detention plans that I have worked with you on have been CMP, so installing a 100% steel weir plate on these CMP's make sense. However this plan proposes the use of reinforced steel polyethylene and the manufacturer has advised me this weir plate should be installed at the plant at the same time as the pipe to ensure its structural strength and watertight joints. The manufacturer has further advised me the SRPE material should be used for the weir plate. I have attached an e-mail concerning this from the manufacturer. I hope that a reinforced steel polyethylene weir plate is sufficient. It is —please also include 200- DuroMaxx STANDARD BACKFILL detail with plans. Comment 4E: I spoke with the manufacturer and he confirmed the storm pipe is designed to handle stormwater. He went on to say the Duromaxx pipe, which is actually more expensive due to the fact it is reinforced with steel and is why I selected it, is best suited for detention and it can handle inundation at full capacity. Thus, lowering the bypass pipe shouldn't be required. Currently the bypass pipe's invert is set at the top elevation of the underground detention system's pipe. This immediate bypass once the pipe is at full capacity, the attached correspondence, the weir plate's oversized 8" low -flow orifice and the weir plate's top elevation located at the midpoint of the 30" pipe, should alleviate your concerns. I think so —please also include 30" REINFORCED BULKHEAD detail with plans (comparison w/ delivery). Comment 4F.- Given F:Given the manufacturer's assurance the pipe can withstand detention at full capacity, I do not think adjustments to the bypass pipe, and consequently the routing calculations, are required. I hope that you agree. Alright, comment withdrawn. Thanks, Graham Graham Murray, P.E. COLLINS ENGINEERING www.collins-engineering.com 200 Garrett Street, Suite K Charlottesville, VA 22902 Cell: (434) 566-3011 graham(�collins-engineering.com