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Hidroituango, a hydroelectric dam under construction in the Cauca River bed, would be the largest hydroelectric dam in Colombia capable of to generate a fifth of the energy used in the country
For more than 1,350 kilometers, the Cauca River flows through Colombia, from its source high up in the Andes Mountains to the Caribbean Sea. An estimated 10 million people, about one-fifth of the Colombian population, live on its shores
. On this route, Cauca crosses some of the most fertile land in the country. In addition, it provided hydroelectric power plants, mining complexes, various industries, towns and villages, and provided a livelihood for farmers and fishermen.
In May 2018, excessive rains and a serious construction problem at a location where the river was being dammed resulted in downstream flooding. As a result, thousands of people have had to leave their homes.
But now, the Cauca River has practically disappeared. Between December 2018 and February 2019, the water level was so low that it was no longer possible to record it.
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Hidroituango: the floods of May
May 17, 2018
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Cauca would feed the dam of 39; Hidroituango, a hydroelectric power station under construction.
Cauca, Cauca River satellite "
near the city of Puerto Valdivia and Ituango, in northwestern Colombia.
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Map of the Cauca River and Hidroituango Dam
The construction of the dam is a project carried out by the company EPM – which has come to build three tunnels to allow Cauca to sink during the works.
In the photo below, made by the company Planet Labs in March 26, 2018, it was possible to see the project in its entirety, with hydropower being located at the top of the image.
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Hydroituango dam on March 26, 2018, when construction was in progress
It is possible to see that the water of the river has flowed from the bottom of the image upwards. From the point of interruption of the river by the hydroelectric station, in the center, the water pbaded through the three tunnels that crossed the hydroelectric dam. Then he resurfaced on the other side of the building, to the right of the factory.
But two of these tunnels were unusable. From that moment, the river flowed only through the third tunnel.
Then, on April 8, 2018, the water dam of Cauca began. The image below shows the rising water level of the river (at the bottom of the image).
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This image of April 8, 2018 shows the beginning of the dam. fill
But in early May, problems began to appear. The image below, carried out on May 7, reveals the emergence of a crater. The crater is visible to the right of the river in the lower part of the satellite image. He even swallowed a part of a dirt road that was pbading.
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On May 7, 2018, there was evidence of a crater eruption and a landslide.
A little higher up, towards hydropower, it is possible to see a landslide.
As a result, the tunnel in service was blocked. The engineers tried to reopen the other two that had been closed, but could not. Thus, the water was trapped before the hydroelectric station and the tank began to fill up without any flow mechanism.
Ten days later, the water level was so high that the crater was swallowed by water. In addition, it was evident that other lands would have collapsed around the dam.
By this time, the water had already reached the site where the hydroelectric work area was under construction – this water invasion was not planned in the plan.
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On May 17, 2018, the water level was high but it had not yet reached the summit, where water could be drained in a controlled manner
The above picture already shows that the water is drained from the other side of the hydroelectric station, since one of the closed tunnels has ended up working again – not by human intervention.
This caused a sudden change in conditions. from the river at this point. The water flow has reached three times the average value, causing flooding and 25,000 evacuations.
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The City of Puerto Valdivia, located after the Hidroituango Project, suffered floods
But the problems of the Hidroituango hydroelectric plant were not yet over. In the following weeks, precipitation and sediment accumulation increased at the workstation. The hydroelectric dam caused the spread of water in the galleries and the erosion and weakening of some of its structures.
Engineers feared that the hydroelectric plant would be destroyed. Thus, the EPM has left more than 130,000 people on evacuation alert.
Floods after drought and then disappear
Since then, the main concern with Hidroituango has been to prevent the dam from breaking down.
Since the tunnel system is no longer reliable, the only way to control the release of water is to allow it to reach the top of the tank and then open constructed gates. to this end.
The problem is that when the dry season started, it became difficult to accumulate enough water to fill the dam up to the top.
On January 16, 2019, EPM decided that the best way to deal with the problem was to drastically reduce the amount of water discharged – from 800 cubic meters per second to 395. (Data from the Colombian Ministry of Fisheries and Oceans). ;Environment).
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about 4 meters to zero in a few weeks
EPM then considered that this measure would not be sufficient. On February 5, he completely shut off the flow of water. In this way, the river Cauca disappeared.
According to measurements made by officials of the Ministry of the Environment in Puerto Valdivia, the water level was 196 centimeters on 4 February. Two days later, he had fallen to 42 centimeters.
According to the organ, where the river once flowed, today there is a long mud and rock path, filled with thousands of stranded fish and over 700 volunteers trying to save [19659002] Image caption
On February 5, the company EPM cut the flow of water, making the river disappear in a few hours.
After closing the water valves, EPM stated that it no longer measured the flow of the river on the other side of the hydroelectric dam because it was recalibrating its sensors. At the same time, officials from the Ministry of the Environment reported that there was not enough water to carry out measurements – their measurements therefore showed that the flow of 39, water was nil.
At the same time, communities that had been previously evacuated due to flooding are now facing flooding.
Coping with additional environmental pressures
This is not the first crisis that we are facing, but it is not the first crisis. affect the Cauca River. Over time, about 10 million people have been dumped in wastewater.
According to information published in the local newspaper El Tiempo Cauca received at that time about 500 tons of waste per day.
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