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Home My WebLink About03 Engineering Comment Response LetterMONTANA | WASHINGTON | IDAHO | NORTH DAKOTA | PENNSYLVANIA 406.586.0277 tdhengineering.com 234 East Babcock Street Suite 3 Bozeman, MT 59715 July 13, 2023 RE: BRAXTON OFFICE BUILDING INFORMAL REVIEW COMMENT RESPONSES - CIVIL TD&H ENGINEERING JOB NO. B23-029 The following responses are being provided to explain how the Engineering Comments received for the Braxton Office Building (1001 Oak Building D) Informal Review Application (23058) are being addressed with this site plan application submittal: Ref. #4. BMC 38.410.130. – Water Adequacy: The development will need to satisfy the water adequacy code requirement prior to a future site plan approval. If sufficient water rights can’t be provided to offsets the development's annual demand then a cash-in-lieu of water rights (CILWR) payment will be required. The City assesses the CILWR fee at a rate of $6,000 per acre-foot. The fee determination will take place during the site plan review, however if there are any questions or if a preliminary review is desired please contact Griffin Nielsen with the Engineering/Utilities Department directly at gnielsen@bozeman.net or (406) 582-2279. Finally, the City would like to make the owner aware of an available CILWR rebate of approximately 20% for residential units if high-efficiency fixtures (toilets, washers, and shower heads) meeting the City Water Conservation Division standards are installed. The rebate would be released at occupancy and requires an agreement defining the terms and amount rebate be finalized and executed prior to final plan approval. If the owner is interested or has any questions please reach out to Griffin Nielsen. RESPONSE: CILWR determination is attached. Ref. #5. From MOD Approval 16137: The applicant is advised that the proposed project falls within the Bozeman Solvent Site boundary. The property is underlain by an aquifer contaminated with perchloroethylene (PCE). No irrigation wells may be installed on this property. RESPONSE: Existing on-site irrigation well has been determined to not fall within the Bozeman Solvent Site boundary, correspondence with MT DNRC is attached. Ref. #7. DSSP Section V. B. - Sanitary Sewer System Design Criteria: The applicant must provide an estimate of the peak-hour sanitary sewer demand certified by a professional engineer for the proposed project prior to site plan approval. RESPONSE: Peak-hour sanitary sewer demand is provided in attached design report. Ref. #8. DSSP Section II A. 4. - The applicant must include a storm drainage plan with post- construction storm water management controls that are designed to infiltrate, evapotranspire, and/or capture for reuse the post-construction runoff generated from the first 0.5 inches of rainfall from a 24-hour storm preceded by 48 hours of no measurable precipitation. RESPONSE: Storm drainage plan is provided in attached design report. July 13, 2023 PAGE NO. 2 tdhengineering.com Ref. #9. DSSP II - confirm stormwater metrics for the site match the metrics in approved master site plan storm water design report RESPONSE: The existing approved design report has not been provided to us for design of the proposed stormwater system, proposed design report is attached. Ref. #10. Montana Post Construction Storm Water BMP Design Manual - The proposed project is located in an area that is known to have seasonally high groundwater. The applicant must demonstrate that seasonal high groundwater will not impact the function or maintenance of the proposed facilities. Industry guidance recommends a three-foot minimum separation from the bottom of the proposed facility to the underlying groundwater table. The applicant must provide local seasonal high groundwater elevations to support the proposed design. RESPONSE: Groundwater data is attached; measured groundwater elevations are sufficient for sub-surface infiltration chambers with three-foot minimum separation. Ref. #11. DSSP Section II C. - The applicant must provide on-site detention with release rates limited to predevelopment runoff rates. Retention ponds must be sized based on a 10-year, 2-hour storm intensity. RESPONSE: On-site subsurface infiltration chambers proposed, design report and construction plans are attached. Ref. #12. The applicant must provide and file with the County Clerk and Recorder's office executed Waivers of Right to Protest Creation of Special Improvement Districts (SIDs) on City standard record Form. Contact sryan@bozeman.net for the template. RESPONSE: We have sent a request to Suzanne Ryan for receipt of the waiver template, correspondence is attached. Ref. #13. DSSP Plans and Specifications Review Policy A. -Plans, specifications, and submittals for public infrastructure improvements must be submitted to the City Engineering Department through the engineering Project Dox Portal (https://www.bozeman.net/services/development-center) for infrastructure review. (Fireline). RESPONSE: No public infrastructure improvements proposed. Ref. #14. The subject property is located within the (Baxter Lane Hampton Water Loop) payback district boundary. If the subject property did not participate in the original cost of construction of improvements the subject property will be accessed a payback charge prior to (planning application approval).Reference document: https://weblink.bozeman.net/WebLink/ElectronicFile.aspx?dbid=0&docid=181706& RESPONSE: Acknowledged. Ref. #15. The applicant is advised that the proposed project falls within the Bozeman Solvent Site boundary. The applicant must contact the Citys solvent site consultant, Jim Sullivan, the Principal Engineer at Tasman Geosciences, Inc. and the DEQ project manager, Katy Frye for additional information on construction requirements within the solvent site. RESPONSE: Acknowledged, we are in the process of contacting pertinent entities. Current correspondence with each entity is attached. Ref. #19. DSSP Section II A. 4. - The applicant must include a storm drainage plan with post- construction storm water management controls that are designed to infiltrate, evapotranspire, and/or capture for reuse the post-construction runoff generated from the first 0.5 inches of rainfall from a July 13, 2023 PAGE NO. 3 tdhengineering.com 24-hour storm preceded by 48 hours of no measurable precipitation. RESPONSE: On-site subsurface infiltration chambers proposed, design report and construction plans are attached. Ref. #20. DSSP Section II C. - The applicant must provide on-site detention with release rates limited to predevelopment runoff rates. Retention ponds must be sized based on a 10-year, 2-hour storm intensity. RESPONSE: On-site subsurface infiltration chambers proposed, design report and construction plans are attached. Ref. #21. BMC 38.220.080 A. 2.g. - The applicant must submit a peak hour trip generation value to the City to determine whether a traffic impact study is required. RESPONSE: Peak hour trip estimates have been submitted, TIS waiver confirmation is attached. Ref. #23. BMC 38.220.080 - Site Plan Submittal Requirements. Please label all easements and applicable setbacks on the site plan. There does not appear to be a label for the drainage easement in the SW corner. RESPONSE: Acknowledged, all easements and applicable setbacks are included on the attached site plan. Ref. #24. Elevations and floor plans that appear to have been approved through the PUD for building D at 1001 Oak have been uploaded to the city documents and staff reports folder. Staff is working to determine if a MOD to or withdrawal from the PUD is required, or if plans may proceed as-is. A discussion board post will be used to notify applicants of the determination. RESPONSE: Understood.