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HomeMy WebLinkAboutPreAp Response Letter_051021 ENGINEERING& LAND SURVEYING May 10, 2021 City of Bozeman Engineering Dept. Attn: Griffin Nielsen, Engineer 1 20 E. Olive Street P.O. Box 1230 Bozeman, MT 59771-1230 RE: Gran Cielo Subdivision, Phase 1, Multifamily Lots, Lot 9, Block 13 and Lot 4, Block 12, Site Plan Review Application No.19479 Dear Griffin, The following is proposed on two multifamily lots within Gran Cielo Subdivision, Phase 1: Lot 4, Block 12 is proposed to have two triplex units. Both buildings on this lot will be 27 feet and 8.5 inches tall. Each dwelling unit has 2,064 sq.ft. of living space. The lot has 21 parking spaces for all of the units. Lot 9, Block 13 is proposed to have two duplex units and two triplex units. All buildings on this lot will be 38.5 feet tall. Each dwelling unit has 2,186 sq.ft. of living space. The lot has 36 parking spaces for all of the units. The following is a transcription of your Concept Plan review memorandum that applies to each of these lots, along with responses (in bold italics) detailing how each item is addressed. 5tormwate 1. BMC 38.410.080 and 40.04.500.A: Requirement to control and reduce stormwater pollutants - a. A stormwater drainage/treatment grading plan and maintenance plan for a system designed to treat the first 0.5 inch of stormwater to remove solids, silt, oils, grease,and other pollutants must be provided to and approved with the Site Plan application.The drainage design must also comply with subdivision drainage design. If the intent is to utilize capacity within the subdivisions system the applicant must provide the relevant section of the subdivisions design report demonstrating capacity.The plan must demonstrate adequate site drainage (including sufficient spot elevations), storm water detention/retention basin details (including basin sizing and discharge calculations,and discharge structure details), storm water discharge destination, and a storm water maintenance plan.The approved I T: 406.581.4097 IF-: MCOTTERMAN@CADDISENG.COM I PO BOX 11805,BOZEMAN, MT 597191 WWW.CADDISE-NG.COM stormwater maintenance plan must be incorporated into the Owners Association Documents and a copy must be submitted prior to Site Plan approval. A design report has been included in this submittal that includes storm water design. The storm water design meets City of Bozeman Standards and complies with the subdivision drainage design. Verification of available storage was also included in the Design Report. A grading and drainage plan has been included in the drawings for each lot. A storm water management plan is included in Appendix E of the Design Report. b. In addition, the proposed project is located in an area that is known to have seasonally high groundwater. The applicant must submit information on the seasonal high groundwater elevation with a site plan application and confirm that 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. Groundwater monitoring has been conducted in coordination of the buildings currently under construction within Gran Cielo. Floor and footing elevations have been specified at heights above the high groundwater level. Stormwater facilities are proposed at surface with with maximum depths of 1 foot, ensuring that groundwater will not be encountered. c. Adequate accessible snow storage must be designated on site. Snow storage has been designated on each lot on the grading and drainage plan sheet. 1. BMC 38.410.070. : Municipal water, sanitary sewer, and storm sewer system. a. The applicant must submit an estimate for the developments peak hour wastewater demand and verify if the estimates exceed the original estimate for the property defined with the subdivision's wastewater report. The estimate must be provided by a professional engineer registered in the state of Montana. A design report has been completed for these multi-family lots in Gran Cielo Subdivision. This design report includes a sanitary sewer evaluation based on the capacity of the original subdivision. 2. BMC 38.400.090.C.3.c and D.2:Access - a. The drive access must meet the City's residential drive access separation requirements from the adjacent property line. The drive accesses proposed for each lot are set back a minimum of 5 ft from the property lines. b. The applicant must submit an estimate for the developments peak hour vehicle trips generated by the development and verify if the estimates exceed the original estimate for the lots defined with the subdivision's traffic impact study. The estimate must be provided by a professional engineer registered in the state of Montana. If the estimates exceeds the original estimate for the lot an analysis of the increased impact must be provided. A traffic variance request has been included in this application that evaluates the proposed development and concludes that it will not impact the anticipated peak hour traffic. c. Laydown curb should be installed along the property line crossing the parking area to delineate the public alley from the private site. Concrete valley gutters are proposed along the property lines that adjoin alleys. The concrete valley gutters will delineate the public alley from the private site. Please don't hesitate to contact me if you have any questions or need any additional information to complete your review of this project. Sincerely, eatgtO, E., . .S. 20120\city submittal itemslengineering preap narrative response letter.docx