Grimes Creek and Granite Creek Restoration Projects
The Southwest Idaho RAC funded a project to improve water quality and habitat on Grimes and Granite Creeks. Many miles of both creeks are lined with mine tailings from past dredging operations. The tailings have impinged the creek and limit riparian vegetation. Grimes and Granite Creeks are listed on the Clean Water Act 303(d) list for temperature and sediment. This project addresses both of these impairments through tested treatment methods. Expected outcomes will be lower stream temperatures over time, as vegetation grows, and decreased sediment loads in the near term as erosive stream banks are treatmented. These pollutant reductions will result in a healthier aquatic environment. Grimes Creek, flowing through public lands, below the confluence of Granite Creek, will benefit from the improved quality of the water entering this reach.
Specifically, this project outcomes address the purpose of the Secure Rural Schools Act by implementing stewardship objectives through public and private landowners and volunteer participation. The goal of improving and restoring land health and water quality is the foundation of all of a number of projects in the watershed that have been organized by Trout Unlimited.
Cooperative relationships between the Forest Service and adjacent landowners are strengthened by working together.
The partnership has gained significant efficiencies and boosted the local economy by promoting the “restoration economy” concept. Trout Unlimited hires work locally, as many skilled loggers and construction trades people are available to put their talents to work restoring the land. This approach is complimented by using schools, church groups, and conservation club members to volunteer.
Similar to the work on Mores Creek, this project creates floodplain and vegetatation along a newly formed riparian “green ribbon” along Grimes and Granite Creek. Multiple landowners, the Forest Service, BLM, Dept. of Lands, and private landowners participate in this restoration project. The newly formed riparian area is being revegetated and the increased hyporheic exchange will allow ground water to be recharged during high flows. The ground water will subsequently cool the streams during low flows, as it supplements the surface water flow at this time. Both solar and thermal radiation will be reduced and sediment will be filtered through this process.
The scope of work can be summarized as removing mine tailings from the stream bank to the two to five year flow event elevation that will allow natural hydraulics to exist and replant vegetation. Habitat improvement, shade will lower water temperatures, and sediment filtration are permanent benefits that will be achieved through project implementation. Bank stabilization will be achieved and erosion reduced through floodplain creation. Additionally, some uplands tailings will be leveled and ponderosa pines will be planted to reduce the solar loading currently incurred from miles of exposed cobble covering most of the valley floor. Sand excavated from erosive banks will be utilized to cover mine tailings on uplands reaches, providing a media for root growth for seedlings.
Excavation of mine tailings has been performed with an excavator, dozer, and dump trucks. Volunteers in turn plant the newly formed riparian corridor. Instream structures such as large woody debris and boulder clusters are installed to create aquatic habitat. Banks with active erosion are stabilized using J hooks, barbs, and vegetation plantings. Approximately three miles of stream have been treated so far.
A minimum of six boulder clusters, and six large woody debris installations have been be added for habitat. J hook and barb numbers will be determined on assessment of erosive banks. Six planting events occured in the first year. Approximately 180 volunteers participated annually, with two field seasons to complete this reach. The original goal of a total of 360 volunteers to be involved was surpassed with about 800 people volunteering on the project since 2009.
A unique aspect to our project is the use of retired fisheries biologist and engineering expertise. The low overhead, coupled with solid experience allow us to put more dollars “on-the-ground” and “in-the-stream” than “on paper.”
