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HomeMy WebLinkAbout1.12_Gallatin Subaru_Cover Letter Response_5-28-2020 2304 N. 7 TH AVENUE | SUITE L | BOZ EMAN, MT 59715 | (406) 587 -2781 Professional Consulting Engineers and Land Surveyors Equal Opportunity Employer | www.hyaliteeng.com May 28, 2020 City of Bozeman- Community Development Department PO Box 1230 Bozeman, MT 59771 Attn: Danielle Garber- Assistant Planner RE: Gallatin Subaru Site Plan, Application 20086 Dear Danielle: The purpose of this submittal is to provide you with the additional material/responses requested in your comment letter for the Site Plan Application for the above referenced project. The following matches the review letter response as received from you (via Lance Lehigh dated April 20, 2020) on April 21, 2020; Planning Comments: - See the memo response from the Architect, included within this response application. Engineering Comments: 1. Noted & agreed, a departure will be applied for in regards to the stormwater facilities occupying more than one-third of the required front setback. Per BMC 38.410.080.F, “departures will be considered for stormwater facilities with Low Impact Development (LID) components, underground components, or exceptional design.” I believe, with the site constraints that present themselves here, that this stormwater design/layout classifies as both LID and exceptional. 2. The proposed post-construction stormwater management controls are designed to capture the first 0.5 inches of rainfall from a 24-hour storm. The extended detention basins are designed remove 80 percent TSS and contain an orifice in the outlet structure to drain the pond in a 48-hour (minimum) period. The site visit conducted by COB Engineering (April 16, 2020) occurred after multiple spring snow/rain events. The southern pond (Audi) was unfinished at the time and the pond bottom needed to be raised an additional 6” to coincide with the pond outlet elevation. At this time, after repeated back-and-forth’s with the City Engineering Department, we have concluded that the southern portion of the Audi parking lot (and included storm pond) will be raised to coincide with the high groundwater levels that we are currently seeing out at the site (these changes will be tracked with a forthcoming MOD application). In response to this, the entire Subaru site was also raised, as well as shifting the high point further south to incorporate less stormwater to the south pond, all to better reflect the current groundwater conditions being seen at the Audi site. 3. Groundwater will be monitored further to ensure no usable pond volume will be occupied by seasonal high groundwater, and updated per the above #2 repsonse. Letter to City of Bozeman Re: Gallatin Subaru Site Plan Comment Response May 28, 2020 Page 2 of 2 4. Noted, the gas line is now shown on all applicable plan sheets. Conditions of Approval 1. The Waiver of Right to Protest, for the noted items, will be recorded prior to building permit approval. I hope that the enclosed information allows you to approve this application. If for any reason you have any questions, or need any additional information during the review of this project, please feel free to give me a call at 587-2781 or send an email to bmegaard@hyaliteeng.com . Sincerely, ______________________________ Brett Megaard, PE Project Manager Cc: File: 193290 Owner Enclosures: As Noted