Hidroituango: EPM implements new operational measures

Thursday, January 31, 2019

EPM press release

After the controlled and safe closing of gate No.2 of the Ituango hydroelectric project, on January 16, EPM implemented new indicators and advanced in the analysis, testing and preparations for the safe and controlled closure of gate No.1 of the power house.

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After the closure of gate No.2, the group of international experts advising the project recommended closing gate No.1 based on the monitoring of variables. It is important to note that there is a change in the way water enters the machine house today. Before it entered pressurized and now it does it in free flow. This circumstance modified the risk map of the project, which includes the monitoring of the cavity (which is not growing and which will not compromise the catchment structure area) and the monitoring of the sewer grid located at the beginning of the catchment .

After the technical analysis of the new risk scenarios, from the closing of gate No.2, EPM implemented a permanent monitoring system with about 15 variables that would indicate if it is necessary to close gate No.1 before that the reservoir reaches the vertimiento of vertimiento.

In this case, EPM, in coordination with national, regional and local institutions that are part of the Unified Command Post (PMU), led by the National Disaster Risk Management System (SNGRD), has implemented a contingency plan to mitigate the social and environmental impacts that would be generated under that situation.

The company has in its protocol of environmental attention, in the case of diminution of the flow of the Cauca river, preparation and preparation for the activities of inspection and rescue of fish, monitoring of water quality, marshes and strategic ecosystems; supply and alternate sources of drinking water, monitoring of economic activities, social contracting, real-time communication with communities and monitoring of physical conditions on the banks of the river.

Reservoir level and shedding

Due to the dry season that occurs in the country and the few contributions of the Cauca River to the dam of the Ituango hydroelectric project, it could take more than 60 days to reach the water flow through the dump in a natural way. After analyzing the possibilities that would allow accelerating the filling rate of the reservoir, it was found that, through a greater discharge of the Salvajina reservoir, located at the beginning of the Cauca river bed, the number of days needed to reach the level could be significantly reduced. of shedding.

Thanks to the collaboration of the company EPSA of the Celsia Group and, through the interaction between the National Authority of Environmental Licenses (ANLA) and the Autonomous Corporation of Valle del Cauca (CVC), since January 25, it was possible to increase the discharge from Salvajina for eight consecutive days, after which the CVC will determine the magnitude of the following discharges based on the evolution of the Salvajina reservoir and its tributary flows.

A desirable factor for proceeding to close the No.1 gate of the powerhouse, in an operation that does not pose a risk to the community, is to have the landfill operating again, as happened safely for 47 continuous days at the end of 2018 and that today due to climatic factors does not occur. Under normal conditions the level of landfill would arrive at the end of March, but with the contribution of the Salvajina could be by the end of February.

The operation of the landfill would allow the passage of water from the reservoir in a controlled manner to the canal and from there back to the Cauca riverbed. For this to happen, the reservoir must reach a minimum of 401 meters above sea level (msnm).

If (based on the results of the monitoring) during the process of unloading the Salvajina reservoir it is required to close the No.1 gate of the powerhouse before it reaches the vertimiento level naturally, To mitigate the possible environmental impact in the swamps of Bajo Cauca and La Mojana, EPM will increase the reserves in the reservoirs of Porce II and Porce III, of their property, so that they are able to discharge the water level associated with their maximum production. during the days in which the flow of the Cauca River decreases (downstream from the municipality of Nechí) as a result of the closure of the gate.

With this measure, it would be possible to reduce the area of exposure and thus mitigate significantly the impacts on the river from the mouth of the Nechí River in the Cauca River, since it would reach flows close to the historical minimums at that point. It is worth mentioning that this area contains most of the swampy complex, which would be protected by this determination, with the greatest social and environmental impact being limited to the section between the foot of the dam and the mouth of the Nechí River.

Thus, EPM remains committed to mitigating the social and environmental impacts associated with the closure of gate No.1 of the powerhouse of the Ituango hydroelectric project, in order to protect communities, take care of the environment and recover the play.