Assessing River Erosion and Sedimentation in Ecuador
In cooperation with the U.S. Army Corps of Engineers, USGS is helping Ecuadorian government officials from the Electric Corporation of Ecuador (CELEC) develop strategies for managing sediment and erosion in the Río Coca basin after the 2020 collapse of the 144-meter-tall San Rafael waterfall.
Background
Río Coca changed its course when the San Rafael waterfall collapsed, causing catastrophic erosion and landslides upstream of the former waterfall site. In May 2020, a USGS team was formed at the request of the U.S. State Department to assist the Ecuadorian Government in the initial assessment of multiple erosion hazards in the river. The team consisted of experts in
- landslide hazards,
- volcanology,
- geology,
- remote sensing,
- fluvial geomorphology,
- hydraulics, and
- hydrology.
The team worked remotely with representatives from the U.S. Pipeline and Hazardous Materials Safety Administration to evaluate the possible extent of upstream knickpoint erosion and landslides affecting roads, bridges, pipelines, and a hydropower plant. Four potential equilibrium river slopes were identified, and two of the four resulted in knickpoint migration extending close to or upstream of the Coca Coda Sinclair (CCS) hydropower intake operated by CELEC, indicating the potential for damage to its infrastructure.
Based on this preliminary assessment, additional U.S. assistance was requested for experts in dams, river engineering, and sediment transport from the Bureau of Reclamation, the U.S. Army Corps of Engineers, U.S. Department of Agriculture, and USGS.
To date, the sediment yield from this event has been orders of magnitude greater than yields from major continent-draining rivers. Few global scientific experts have experience with erosion events of this magnitude.
The erosion is rapidly migrating upstream and continues to threaten approximately $3 billion of Ecuadorian infrastructure, including the CCS hydropower facility. In addition to the effects of the 2020 waterfall collapse, the same hydropower facilities are threatened by reservoir sediment accumulation upstream of the CCS intake and downstream at the CCS outlet.
Objectives
USGS is assisting USACE and CELEC in
- quantifying the total magnitude of erosion from the waterfall collapse,
- estimating upstream erosion migration and downstream sediment deposition timelines,
- evaluating impacts of sediment on CCS hydropower facilities, and
- developing a sediment and streamflow monitoring program for the Río Coca basin.
Landscape Response to Disturbance
In cooperation with the U.S. Army Corps of Engineers, USGS is helping Ecuadorian government officials from the Electric Corporation of Ecuador (CELEC) develop strategies for managing sediment and erosion in the Río Coca basin after the 2020 collapse of the 144-meter-tall San Rafael waterfall.
Background
Río Coca changed its course when the San Rafael waterfall collapsed, causing catastrophic erosion and landslides upstream of the former waterfall site. In May 2020, a USGS team was formed at the request of the U.S. State Department to assist the Ecuadorian Government in the initial assessment of multiple erosion hazards in the river. The team consisted of experts in
- landslide hazards,
- volcanology,
- geology,
- remote sensing,
- fluvial geomorphology,
- hydraulics, and
- hydrology.
The team worked remotely with representatives from the U.S. Pipeline and Hazardous Materials Safety Administration to evaluate the possible extent of upstream knickpoint erosion and landslides affecting roads, bridges, pipelines, and a hydropower plant. Four potential equilibrium river slopes were identified, and two of the four resulted in knickpoint migration extending close to or upstream of the Coca Coda Sinclair (CCS) hydropower intake operated by CELEC, indicating the potential for damage to its infrastructure.
Based on this preliminary assessment, additional U.S. assistance was requested for experts in dams, river engineering, and sediment transport from the Bureau of Reclamation, the U.S. Army Corps of Engineers, U.S. Department of Agriculture, and USGS.
To date, the sediment yield from this event has been orders of magnitude greater than yields from major continent-draining rivers. Few global scientific experts have experience with erosion events of this magnitude.
The erosion is rapidly migrating upstream and continues to threaten approximately $3 billion of Ecuadorian infrastructure, including the CCS hydropower facility. In addition to the effects of the 2020 waterfall collapse, the same hydropower facilities are threatened by reservoir sediment accumulation upstream of the CCS intake and downstream at the CCS outlet.
Objectives
USGS is assisting USACE and CELEC in
- quantifying the total magnitude of erosion from the waterfall collapse,
- estimating upstream erosion migration and downstream sediment deposition timelines,
- evaluating impacts of sediment on CCS hydropower facilities, and
- developing a sediment and streamflow monitoring program for the Río Coca basin.