On December 2, 2021, the U.S. Army Corps of Engineers (USACE) and the strategic public company Electric Corporation of Ecuador (CELEC EP, in Spanish) signed a memorandum of understanding (MOU) to articulate technical cooperation to “mitigate the effects of regressive erosion on the Coca River and protect the water catchment works of the Coca Codo Sinclair hydroelectric plant.”
The goal of the MOU is “the development of joint activities in engineering services; environmental sustainability; river infrastructure operation, construction, and maintenance; damage reduction; risk analysis; [and] protection and restoration of the environment along rivers.” In addition, it seeks to develop experience exchanges in river engineering technologies, sedimentation and dredging, slope erosion and stability, and physical modeling and experimentation.
This hydroelectric plant, located in Napo and Sucumbíos provinces, in the cantons of El Chaco and Gonzalo Pizarro, respectively, is the largest in Ecuador. It is projected to generate 1,500 megawatts to cover 30 percent of the country’s electricity demand. However, the advance of regressive erosion seriously threatens water catchment works and puts the operations of this strategic project at risk.
According to Dr. Esteban Terneus, director of the School of Environmental Management at the International University of Ecuador, regressive erosion is a natural phenomenon. “The hydrodynamics of a river is so strong that it can eat away at the banks and slopes surrounding its channel, changing the river’s course. It is regressive when the undermining eats up the riverbed, but in the opposite direction of its course.”
CELEC EP’s General Manager Gonzalo Uquillas said that the scale to which regressive erosion and progressive sedimentation are advancing in the Coca River, after the collapse of the San Rafael waterfall, is unprecedented worldwide, making it essential for subject matter experts to advise and guide as to the best solutions.
U.S. Ambassador to Ecuador Michael J. Fitzpatrick said that this collaboration process began in 2020, when the erosion started. “Our government activated a response group in May […] in order to facilitate and channel cooperation processes to address this phenomenon,” he said. In fact, U.S. technical assistance teams working with their CELEC EP counterparts made three visits to the site to assess the situation and develop additional erosion and damage mitigation options.
While this memorandum of cooperation between the U.S. and Ecuadorian governments is not a binding document, it is a precursor to a formal agreement (letter of agreement) to contract USACE’s engineering services, which anticipates five years of cooperation from the date of signing.