Soil bioengineering interventions for erosion control in hydroelectric power plant reservoirs

The banks of water reservoirs are highly susceptible to erosion processes. Thus, interventions to mitigate and control erosion must be performed which are traditionally done using traditional engineering techniques (gabions, riprap, etc.), which have high execution and maintenance costs and high environmental impact. Soil Bioengineering is a viable alternative since it considers technical criteria in dimensioning works and values ecological and environmental factors. The objective of this work is to present a Soil Bioengineering intervention performed to stabilize and control erosion processes in a section of the Itá Hydroelectric Power Plant (Itá HPP) reservoir. The area is located in the Itá HPP reservoir and presents erosion processes with soil loss and transport causing reservoir silting. The section is 169 m long and was divided into subsection 1 (vegetated geotextile wall, vegetated palisades, planting of herbaceous, shrub and tree seedlings), and subsection 2 (vegetated coconut wall, vegetated palisades, planting of herbaceous, shrub and tree seedlings). The project was prepared in June 2020 and the work was performed in June-August 2021. The techniques were then monitored. The plants showed excellent survival and growth rates, the structures did not move or settle, and no erosion was detected. Soil Bioengineering techniques proved to be technically efficient in mitigating erosion processes on the banks of the Itá HPP reservoir. In addition to the technical benefits, the implemented solutions improved ecological and environmental functions, with reestablishment of native vegetation and an increase in floristic and faunal biodiversity.