The Kerber Creek Restoration Project is an ambitious partnership between Trout Unlimited, federal and state agencies, non-profits, and local landowners to address the impacts of mining and erosion on a high-value trout stream in Colorado. The headwaters of Kerber Creek start above Bonanza, Colorado, and flow for 26 miles past Villa Grove, until its confluence with San Luis Creek at the base of the Sangre de Cristo Mountains. Since the inception of the project in 2008, Trout Unlimited and project partners have restored seven miles of stream and 14 miles of stream bank. Unstable stream conditions were created by several flood events in the 1900’s that deposited historic mine wastes throughout the downstream floodplain. The highly acidic soils did not provide a good growing medium for riparian plants, resulting in unstable stream banks throughout the lower watershed.
This short video provides an example of the restoration techniques used to stabilize an eroding stream bank. The operator first knocks down the steep, unstable bank to a 3:1, gradual slope. Two sets of in-stream rock barb structures are then installed on the outside of the bend to provide bank stabilization and trout habitat. Anchored and dredged into the bank, these rock barbs push the energy portion of the stream away from the bank to help create pools and establish a point bar.
After installation of each rock barb, the operator transplants sedge mats and willow clumps to provide immediate vegetation and bank stabilization. The sedge mats and willow clumps will provide erosion resistance on the newly graded bank until the planted seed comes up the following year. After completion of the in-stream restoration, soil amendments will be added into the bank behind the structures to neutralize any acidic soil, and provide good growing conditions for the native seed mix.
TU has had great success with this type of stream restoration procedure, and post-project monitoring has shown an improvement of water quality and an increase in trout density throughout the watershed.
Jason Willis is Mine Restoration Field Coordinator for Trout Unlimited in Salida, Colorado.