Company News Sep 23, 2021 4:52 PM
Róbinson Miranda, Hidroituango’s environmental and social director, spoke about the controls and care of the quality of the water that reaches the project.
He explained that with the construction of the wall in the Cauca river it went from being a lotic ecosystem to a lentic one, El Espectador reported.
This means that the river ceased to be a body of flowing water to become one of relatively still water.
“That was expected to happen, it is in the project’s Environmental Management Plan,” Miranda said.
There are three conditions that add up to change the appearance of the water in the reservoir: first, contaminants that, despite deteriorating the water quality, become nutrients; second, direct sunlight; and third, slow flowing water.
Juan Guillermo Uribe, head of the University of Medellín’s Laboratory Center, said that carbon will oxidize as CO2, nitrogen to nitrates and phosphorus to orthophosphates, elemental nutrients from the natural point of view.
“What the river does is degrade that organic matter, and when it reaches the reservoir, those nutrients, due to the action of light, begin to bloom and a biological phenomenon begins to occur, which is eutrophication: an accelerated growth of algae and macrophysics,” Uribe said.
He said that this process, plus the presence of bacteria, contribute to the green coloration and floating plants that can be seen in several places in the reservoir.
Miranda said that the reservoir improves water quality, as it serves as a barrier for many of the pollutants that settle or precipitate and others are removed.
The expert said that there are physical barriers with nets and floating baskets in the reservoir that trap plants and large debris and are then pulled by boats to the shores, where they are collected.
Uribe said that the water that reaches the tail of the dam is of low to medium quality, but within it “goes from medium to good” thanks to the benefits of the reservoir basin.