Water Resources Research Act Program

Details for Project ID 2016CO323B

Channel restoration monitoring of the Upper Colorado River, Rocky Mountain National Park, CO

Institute: Colorado
Year Established: 2016 Start Date: 2016-03-01 End Date: 2017-02-28
Total Federal Funds: $5,000 Total Non-Federal Funds: $2,500

Principal Investigators: Sara Rathburn

Abstract: In September 2015, Rocky Mountain National Park staff redirected a ~100 m reach of the Upper Colorado River as it flows into an important high-elevation wetland. This completes the experimental, low-impact restoration phase of the Park’s management response to 35,000 m3 of sediment introduced to the Upper Colorado River by a 2003 debris flow. Coarse sediment deposition at the head of this critical wetland resource has resulted in dispersed channel flow, irregular and unpredictable flood pulses, and an inconsistent water table. Aggradation and minimal fine sediment retention from the 2003 debris flow have created hydrologic conditions in the wetland that no longer support the tall willow and beaver communities that historically existed there. The objectives of the initial channel realignment are focused on restoring the hydrologic processes necessary to 1) support a consistent flood pulse and fine sediment deposition within the floodplain, 2) drain overly wetted areas of the wetland and 3) transport coarse-grained sediment through the wetland. My research will evaluate the effectiveness of the channel restoration activities. I will monitor channel discharge and sediment transport beginning with snowmelt 2016 and continuing through water year 2016. I will utilize electrical resistivity imaging - in a novel, noninvasive approach - to monitor changes to subsurface wetland hydrology and hyporheic exchange imposed by the channel restoration. Results from this work will inform a larger-scale Upper Colorado River restoration project planned for summer 2017 and will be applicable to other sensitive wetlands impacted by sediment aggradation from disturbance events.