Garfield County, CO

Colorado Trout Unlimited and the Bureau of Land Management desired to reestablish a sustainable population of native Colorado River Cutthroat Trout (Oncorhynchus clarkia pleuriticus) within the Roan Plateau. The project site is located more than an hour from a paved road requiring special attention to constructability and long-term maintenance. ERC was selected to complete the design, permitting and construction of a barrier that would be used to separate the upstream habitat from non-native downstream fish. Our work scope included defining a location that was suitable for a barrier and evaluating a range of potential barrier types. A vertical barrier was selected over velocity barriers and fish screens given its ability to operate over a wide range of flows and its favorable maintenance requirements. Detailed hydrologic, hydraulic and geomorphologic analysis were conducted to ensure the barrier would prevent upstream migration, be in balance with the surrounding stream conditions and be capable of conveying flows ranging from typical baseflows to peak runoff from the 100-year flood event.

The result was a six foot high structure that utilized cast in place concrete and native channel substrate. A low flow channel created a stream width that mimicked the upstream and downstream channel planform and an overflow allowed for passage of the 100-year event. Scour pools were prevented using a concrete apron and banks were stabilized with rock and native vegetation. ERC constructed the barrier at this remote site using primarily hand labor and an on-site concrete batching operation.