New protection works aim to stop the riverbed collapse threatening Ecuador’s largest hydroelectric plant.
Erosion advances faster than expected
The government has ordered the construction of a second protective dam on the Coca River as rapid regressive erosion continues moving upstream toward the intake works of the Coca Codo Sinclair hydroelectric plant, the country’s largest source of electricity. The phenomenon, which has consumed highways, pipelines, and entire sections of riverbank, now stands within striking distance of the infrastructure that feeds water to the plant’s turbines. If it reaches that point, Coca Codo Sinclair could be left permanently inoperable.
The erosion began advancing in early 2020, when the sudden collapse and disappearance of the San Rafael waterfall altered the river’s hydraulic behavior. In the months that followed, the eroded zone carved its way steadily upstream—from a distance of 19.2 kilometers from the plant’s intake structures to just 3.6 kilometers today. Its progression has been relentless, swallowing land in large sections and forming cavernous sinkholes that deepen with each flood cycle.
The intake structures that now face this threat consist of a low dam designed to divert water from the Coca River into the plant’s pressurized conduits. Without them, the facility’s 1,500-megawatt generation capacity would be rendered useless.
A second permeable dam will be added
Facing this accelerating risk, the Minister of Environment and Energy, Inés Manzano, announced on November 19, 2025, that a second permeable dam will be built upstream of the one already under construction. These dams—composed of piles driven into the riverbed—allow water to pass between their columns while slowing its flow and promoting sediment buildup. Over time they create hardened sections of riverbed that help absorb the erosive force of the current.
The first permeable dam is 80% complete and expected to be delivered in early 2026. The government hopes the contractor will finish as early as January, though the formal delivery date is set for February. However, the original design placed the structure 7.8 kilometers downstream of the intakes. By the time construction began in 2023, erosion had already advanced to 7.3 kilometers. Today it has long surpassed that point, leaving the dam behind the erosion front.
Still, despite being incomplete and outflanked, the partially built structure has already helped stabilize the river during recent floods, according to Minister Manzano and CELEC technical reports. The government expects to launch a contracting process for the second dam in February 2026, though assessments by the U.S. Army Corps of Engineers indicate that at least four such structures will ultimately be required to contain the river’s transformation.
Six additional protection works under way
Beyond the permeable dams, CELEC is advancing six complementary projects designed to reinforce the river channel and stabilize key points near the plant. These projects form part of a broader defense system intended to delay or halt the upstream migration of the erosion.
At kilometer 1.2, erosion control works considered essential to the overall gradient-management system have already been completed. A second project at the same location—a stepped landfill designed from a U.S. Army Corps conceptual plan—is now in final-design studies.
Further upstream at kilometer 3, engineers are studying how to divert the river toward a natural hard point on the right bank. Final studies should be completed by November 2025, with construction set to begin in February 2026.
At kilometer 9, a quarry area is being prepared to provide rock material from the Misahuallí Formation. The project is being advanced with the help of the state oil pipeline operator and Petroecuador, as the supplied rock will be essential for future erosion-control structures. Work here can only begin once safe access is available—something the first permeable dam is expected to enable once operational.
At kilometer 12.5, CELEC is analyzing the consolidation of the riverbed beneath the old Ventana Bridge 2, where volcanic outcrops have created a natural hard spot. Engineers are evaluating how to reinforce this section, so it resists further degradation.
Meanwhile, 61 kilometers downstream, CELEC has just completed the second sediment-removal campaign at the plant’s discharge point. The accumulated material has not yet affected electrical generation, though the agency continues monitoring to determine how future river changes might alter sediment flow.
As erosion continues pressing toward Coca Codo Sinclair, the government’s plans now hinge on building an interconnected system of dams, landfills, diversions, and reinforced hard points to buy time. Whether the river can be stabilized before it reaches the plant’s intake structures remains the central question guiding each new intervention.
With so much dependence on hydro and so much sun in this country, we need to continue to develop our alternative energies. The technology is clearly developed into a low-cost and highly reliable way to generate electricity.
And I remain sad that we did such poor evaluation of the ability of the Coda Coda watershed as a good place to build a dam. I mean, duh. Some of the money spent on corruption should have been used to do a better environmental evaluation. We all pay the price of bribery.