Sun River Channel study underway

A new study being developed by the Sun River Watershed Group and Cascade Conservation District will investigate the historic movement and channel locations of the Sun River, according to a release.

The study, known as a Channel Migration Zone map, will use historic photos, data and local knowledge to understand how the Sun River moves through the basin. The outcome will be a public, non-regulatory tool that can be used for planning and development, or avoiding development, along the main Sun River, according to the release.

The project is being managed by the Sun River Watershed Group.

Watershed Coordinator Tracy Wendt said the report will be a valuable resource for the public.

“We’ve met with folks who live in the communities along the river and we know they worry about losing land and structures when the river moves. This report will help us understand where risk is high, and it can be used to help people plan and prepare,” she said in a release.

The study will assess a portion of the main Sun River from near where the river crosses Highway 287 to just downstream of Muddy Creek. This is an important section because of the significant impacts channel relocation has on farms, ranches, towns and roads, according to the release. The study will break down this section of the river into reaches and assess the risk of river movement based on past patterns. This risk assessment will support planning for future river work, infrastructure locations and protection, flood mitigation, and other activities to ensure the best use of funding and effort, as well as to maximize ecological benefits.

The project will be performed by Karin Boyd of Applied Geomorphology and Tony Thatcher of DTM Consulting.

“We’ll be mapping the Sun River prior to the 1964 flood, so we’ll be able to gain some insight as to the impacts of that incredible event. We will carry the mapping through to 2019, so recent floods will also be captured in the assessment. In our experience, the results have been useful to landowners making plans to locate or protect infrastructure,” Boyd said in the release.

Funding for the report comes from a DNRC 223 Grant issued to Cascade Conservation District and from the Montana Department of Environmental Quality.