Channel geomorphology cross sectional surveys, pre/post high-flow release, lower Dolores River, 2017

Cross sectional elevation data for Dolores River long term monitoring sites was collected before and after high flow releases to understand changes in channel hydraulic geometries associated with these flows. Colorado Parks and Wildlife (CPW) conducted geomorphic monitoring associated with managed releases from McPhee Reservoir in 2017. CPW and partners in the Dolores River Native Fish Monitoring & Recommendation Team (M&R Team) sought to assess impacts of release flow targets identified in the 2014 Lower Dolores River Implementation Monitoring and Evaluation Plan. Target flows in the plan include flushing flows--fine sediment scouring, flushing flows--d50 mobilization, habitat maintenance flows--bankfull, and habitat maintenance flows--overbanking/floodplain access. Cross sectional surveys and pre/post release photopoints documented effects of flow magnitude and duration on channel geometries. Evidence of scouring and evacuation of sediment within the channel and re-deposition onto the floodplain was present at multiple sites, as well as scouring and evacuation of material within pools. Little bank erosion occurred at 4 of 5 sites, suggesting the river is stabilizing within a narrower channel.