GWC and the City of Bozeman are teaming up with CATS (Community-engaged And Transformational Scholarship), a Western Transportation Institute initiative, to utilize the capacity and curiosity of MSU students to help us address local watershed priorities. This semester, students will investigate if and how native plants may be effectively incorporated into stormwater facilities in the City of Bozeman to further the Stormwater Division’s goals: protect public safety, improve waterway health, mitigate flooding, and comply with state and federal regulations.

This research question about vegetation in stormwater facilities was instigated when the City of Bozeman announced in 2024 that it would be updating its Stormwater Facilities Plan, a document that guides how post-construction facilities are maintained, enforced, and adhere to best management practices. There are approximately 1,500 existing stormwater detention and retention facilities across the City of Bozeman, 1000 of which are privately owned and maintained by Home Owners Associations. Many of these facilities have become overgrown with trees and shrubs, and are considered out of compliance. The current practice requires that stormwater facilities be maintained to their original design specifications and that all the volunteer trees and shrubs be removed. 

Vegetation, when incorporated effectively into stormwater facilities, can facilitate water infiltration, reduce pollutant loads, and stabilize soil. Native wetland and riparian vegetation is known for its ability to improve water quality in surface water and shallow groundwater and is a fundamental tool in stream and wetland restoration, agricultural best management practices, and treatment wetlands. The Stormwater Division is obligated by their MS4 (Municipal Separate Stormwater and Sewer System) permit to address sediment, which is easily settled out in detention basins. In addition to abiding by the regulations in the MS4 permit, the Stormwater Division also strives to improve watershed health. Our urban streams provide significant recreational and ecological value and are tributaries to the East Gallatin River, so designing facilities that target other pollutants, such as nitrogen and phosphorus, is important too. The question becomes: When is vegetation beneficial in stormwater facilities to achieve co-benefits while still maintaining compliance with the MS4 permit?

By engaging MSU students and faculty through the CATS program, GWC and its partners are able to tap into the technical expertise needed to address pressing local water issues. We are excited to see how the findings from this semester's research will help inform best management practices for Bozeman’s stormwater facilities.