Stormwater Projects

Bitterroot Outfall Project

Location:  On the Bitterroot River just south of the Highway 93 bridge.

Description:  The project will include improvements to the outfall area to address Bitterroot River water quality impairment from stormwater flow from Pattee Creek. Sediment from the swale area is deposited in the river.

• Best Management Practices (BMPs) to address heavy loads of sediment that reach this outfall. The source of sediment is primarily due to road sanding operations in the South Hills during the winter. BMPs could include a hydrodynamic separator installed upstream of the outfall or a sediment forebay that enables sediment removal in a designated location. To facilitate maintenance of this type of BMP, a bypass channel or pipe would be installed.
• Clearing sediment from the energy dissipaters so that they are fully exposed.
• Removal of trees and vegetation that is encroaching on the facilities before damage occurs. 
• Re-grading or otherwise modifying the swale so that flow meanders through and accumulated sediment can settle out.
• Additional vegetation to provide enhanced nutrient uptake and sediment deposition.
• Upgrading the undersized culvert crossing located downstream of the flap gate to accommodate the 1% annual chance flood event.

Benefits:  Improved water quality in the Bitterroot River by improving infrastructure so that sediment is better filtered and settled out of the stormwater before it reaches the river. Planting and installing better green infrastructure helps remove nutrients from the stormwater as well.

Project Dates:  Construction is anticipated in 2025. This page will be updated as further information becomes available.

Contractor: Dit It Excavating

Cost: $364,925.00

Public Meeting:  A public meeting was held on July 12, 2023. Link to Bitterroot Outfall meeting recording

Project Area Map

Project Contact:  Adam Marsh, Utility Engineer, at MarshA@ci.missoula.mt.us or 406-552-8835

Location:  From W. Broadway south

Description:  Realigns and restores Grant Creek from W. Broadway south to eliminate the "horseshoe bend." Work will include construction of a base flow channel, 200-foot wide floodplain, and a 100-foot riparian buffer area on both sides of the floodplain. A multi-user trail will be partially installed on the east side of the riparian buffer.

Benefits:  The project will help to protect and restore the Grant Creek watershed that will provide a clean, healthy creek for fish and wildlife, provide flood control, naturally treat stormwater runoff, and provide recreational opportunities with the future addition of a multi-use trail.

Project Dates:  Start date April 26, 2025 and completion date November 15, 2025

Contractor: J&J Excavating

Cost: $2,557,996. Funding sources include $910,296 in federal ARPA Competitive Funds, $580,296 Sxwtpqyen Impact Fees, $500,000 from Missoula County Trails, Bond, and $567,404 in funding from project partners.

Area Map:  100% Design Plans

Project Contact:  Andy Schultz, City Engineer for Utilities, 406-552-6758 or SchultzA@ci.missoula.mt.us 

Takima Park Stormwater Bioretention Basin Project

Location:  Takima Park (at Takima Dr. and Pattee Canyon Rd.)

Description:  Build a tiered stormwater bioretention basin to prevent flooding and protect water quality.

Benefits:  The facility will capture and filter runoff and reduce the amount of toxins and pesticides entering local waterways. By improving water quality, the project supports healthier fish habitat and enhances biodiversity. Native vegetation will be planted throughout the basin, providing valuable habitat for pollinators and wildlife.

Project Dates:  Expected to go out for bid late April 2025 with construction dates anticipated to be summer to fall 2025. Specific dates will be added once available. 

Project Partners:  Missoula Parks and Recreation, University of Montana, Montana Pesticide Stewardship Partnership Program, and U.S. EPA Columbia River Basin Toxic Reduction Lead Grant

Area Map

Project Contact:  Tracy Campbell, Stormwater Superintendent, 406-830-5455 or CampbellTL@ci.missoula.mt.us