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Home My WebLink About015 - Sanitary Sewer ReportDiscount Tire 5889 E Valley Center Road Bozeman, Montana, 59718 Sewer Service Design Engineering Report 6814 Greenwood Avenue N T 206.522.9510 Seattle, WA 981093 www.pacland.com Prepared By: Bill Fortunato, P.E. February 2026 Revised : May 2026 06/05/2026 Per the requirements of the Montana Department of Environmental Quality (DEQ) Design Standards For Public Sewage Systems, this engineering report has been prepared to address Sections 11.11 through 11.19 of DEQ-2. These sections are addressed below: 11.11. Problem Defined: Description of the existing system should include an evaluation of the conditions and problems needing correction.: The site does not have an existing connection to the local municipal system. There are no existing known issues with the system in place. The existing system flows north and across I-90 to a water treatment plant operated and maintained by the City of Bozeman, 0.36mi north of the project site. • Identification of the municipality or area served: City of Bozeman • Name and mailing address of the owner, developer and official custodian: Owner/Developer: Discount Tire (Colten Ellsworth) 20225 N Scottsdale Rd Scottsdale, AZ 85255 Engineer/Applicant: PACLAND (Bill Fortunato) 6814 Greenwood Avenue N Seattle, WA 98103 11.12. Design Conditions: The anticipated average and peak flows and waste load for existing and ultimate conditions must be established. The basis of the projection of initial and future flows and waste loads must be included and must reflect the existing or initial service area and the anticipated future service area. Hydraulic and organic load information and data needed for new facilities are included in Sections 11.24 (Hydraulic Capacity) and 11.25 (Organic Capacity). The average day demand is 135 gallons per day and the maximum day demand is 311 gallons per day. These quantities are obtained from the calculation of the water demand calculations which were deemed as appropriate to make equivalent to the sewer demand numbers. Please see the calculation below: Average demand: Per City of Bozeman Design and Construction Standards Table 4.2.2: Discount Tire is classified as zone B-2, average daily demand per acre is 614 gpad. The indoor demand is 0.22 acre-feet. 0.22 x 614 gpad = 135 gallons per day Maximum Demand: Per City of Bozeman Design and Construction Standards Table 4.2.6: Maximum Day Demand Peak Factor is 2.3 135 gallons (ADD) x 2.3 peak factor = 311 gallons per day Average Day Demand: 135 gallons per day Maximum Day Demand: 311 gallons per day The existing waste loads are nonexistent for the site due to lack of development. Sections 11.242-244 and 11.25 are intended for large capacity treatment systems or design components which do not apply to this project. 11.13. Impact on Existing Wastewater Facilities: The impact of the proposed project on all existing wastewater facilities including gravity sewers, lift stations, and treatment facilities must be evaluated. The site proposes utilizing gravity sewer lines to connect to the sewer main that is going to the city treatment plant. Collected sewage in the building will leave through piping at a minimum of 2% slope as it may contain solids. Wastewater leaving through the workshop area will be conveyed through an oil water separator to prevent mixing oils and unwanted contaminants in the downstream flow. The oil water separator device will be maintained and monitored by the owner or otherwise authorized personnel. The existing wastewater treatment system that has been built for the City of Bozeman has already been built to manage the capacity of the city limits which its system extends to. 11.14. Project Description: A written description of the project is required. The proposed development is in the City of Bozeman, Montana, and is bordered to the north and south by hotels, on the east by a southbound off-ramp from I-90 and on the west by East Valley Center Road. The property is zoned B-2 (Community Business District) and is located on Lot 1 of minor subdivision No. 358B, Parcel Tax ID RFG52005. The property is approximately 2.5 acres and is generally undeveloped except for a private driveway/access road along the west side. Existing easements encumbering the property include, a 30-foot sewer, water and access easement and a 50-foot mutual access easement on the north side of the site, a 30-foot sewer pipeline easement and a 20- foot wide utility easement on the east side of the site, a 12-foot pedestrian access easement and a 20-foot utility easement on the west side of the site and a 30-foot joint access easement and a 20- foot water pipeline access easement in the middle of the site. The project involves construction of an approximately 7,300 square foot commercial tire sales store (Discount Tire) with associated driveways, drive aisles, parking, sidewalks, landscaping, utilities, and stormwater management facilities. The existing 24-ft wide private driveway will be removed, realigned and replaced. A new 8’ wide asphalt trail will be constructed west of the proposed private driveway adjacent to E. Valley Center Rd. 11.15. Drawings: Preliminary drawings identifying the site of the project, including the location and alignment of proposed facilities are required. A preliminary utility plan and plumbing plans are provided in Appendix A. 11.16. Design Criteria Engineering design criteria to be used in design of the project must be included. The private sewer system design is simple and minimal. Pipes are to maintain a minimum cover of 4 feet per the City of Bozeman design standards. From the building the sewer service is to leave the building at 2% to ensure that solids and liquids do not separate in the pipe. Wastewater leaving through the workshop area will be conveyed through an oil water separator to prevent mixing oils and unwanted contaminants in the downstream flow. The oil water separator device will be maintained and monitored by the owner or otherwise authorized personnel. Pipe material is proposed to be PVC and to be connected to the main with a wye tee connection. 11.17. Site Information Project site information should include topography, soils, geologic conditions, depth to bedrock, groundwater level, floodway or floodplain considerations, and other pertinent site information. The project site generally slopes from the southwest (elevation +/-4655’) to the north (elevation +/- 4650’), with slopes typically ranging from 1% to 18%. The existing site ground cover is earthen, lightly to moderately vegetated. The Web Soil Survey identifies two predominant soil types for this site. Most of the site is comprised of Turner loam, 0 to 4 percent slopes. The remainder of the site is Meadowcreek loam, 0 to 4 percent slopes. The geotechnical characterization of the on-site soils are summarized as follows: Some areas of existing fill up to 1.5 feet deep. Lean clays to about 5.5 to 7.0 feet below existing grade. Clayey to Silty, Well Graded Gravel below 5.5 to 7.0 feet. Groundwater observed at 6.0 to 7.5 feet below ground surface during our exploration. 11.18. Alternative Selection/ Analysis The reasons for selection of the proposed alternative: including any lift station sites, feasibility and how the project fits into a long term plan, should be discussed. This section does not apply to this project. 11.19. Environmental Impacts Adverse environmental impacts, including cumulative and secondary impacts, resulting from the project must be addressed along with mitigation efforts. Consideration should be given to minimizing any potential adverse environmental impacts of the proposed project. If appropriate, compliance with planning requirements of federal, state and local regulatory agencies must be documented. There are no environmental impacts or expected due to this development. Appendix A - Drawings: