Streambank Stabilization on the East Gallatin River
The Gallatin Watershed Council (GWC) stabilized two sections of eroding streambank on privately owned land along the East Gallatin River. This project will be used as an educational tool for nearby landowners. Through this project, GWC hopes to demonstrate effectiveness of different techniques at halting bank erosion, providing education and outreach about best management practices for streambank stabilization and the importance of working collaboratively.
Project construction commenced on December 11, 2018 and was completed on December 15, 2018. The contractor, Glacier Excavation conducted $12,000 worth of revegetation for the first stage of the project, which included seeding, willow harvest/plantings, and sod mat placements. Five volunteers and the GWC Coordinator gathered approximately 320 willow stems that were integrated into the bank treatments by the contractor. The project accomplished:
- Re-grading 825 feet of incised stream banks
- Seeding and sod mat placements
- Addition of woody debris
- Willow harvesting and planting by local volunteers
Stream Restoration on Dry Creek
Dry Creek, a tributary of the East Gallatin River, is impaired for sediment, total phosphorus, and total nitrogen. These impairments can be traced directly to changes in land use and the impacts of channel realignment to make way for roads and agriculture, resulting in undercutting of the streambanks and a severely incised channel. The goals of the Dry Creek restoration project included laying back the streambank to make room for higher flows, increasing vegetative cover on the streambanks, and ultimately reducing sediment loading into Dry Creek from eroding streambanks.
The bank construction was completed on the 1.85-mile reach of Dry Creek in April 2019, with some follow-up construction completed in May after a rare rain-on-snow flooding event associated with spring runoff. In November of 2018, GWC had volunteers help with harvesting willows and bundling them. These hardwood willow cuttings were incorporated into the revegetation plan. In April 2019, GWC and Trout Unlimited coordinated a volunteer day to plant the 1,713 willow stems harvested on-site using water-jet stingers. The remainder of the revegetation efforts were contracted out, and 315 containerized plants were planted in June. Since then, vegetation mortality rates have been monitored as well as bank stability and erosion rates in order to measure success of the project and progress toward implementing the Lower Gallatin Watershed Restoration Plan (LGWRP).