Semi-Rigid Erosion Control Techniques with Geotextiles Applied to Reservoir Margins in Hydroelectric Power Plants, Brazil

Maria Aparicio Ardila,Jefferson Lins Da Silva,Marta Pereira Da Luz,Marlon Silva Schliewe,Marcelo Kobelnik,Arnaldo Teixeira Coelho,Ricardo Dos Santos Junior,Clever Aparecido Valentin

doi:10.3390/w13040500

Abstract

In Brazil, hydroelectricity represents close to 70% of the energy consumed in the country. However, hydroelectric plant operations may be affected by the deposit of sediments for erosive processes on reservoir margins. This study presents the results of implementing two semi-rigid erosion control techniques installed on reservoir margins of two Brazilian Hydroelectric Power Plants (HPPs). These techniques were the gabion and gabion mattress used as a mixed technique and geogrid mattress technique. This paper highlights the importance of implementing geotextiles in the construction process of these erosion control techniques, taking advantage of their separation properties. The performance of the techniques was evaluated using qualitative performance variables and by differential bathymetry studies performed in 2016 and 2020 in the experimental units installed in each HPP. Moreover, the degradation of the geotextiles in each installation was evaluated through thermal analysis. The erosion control techniques that showed the best results were gabion and gabion mattress. Regarding the exhumed geotextiles, thermal analyses have shown that the commercial geotextiles that were used can withstand temperatures of up to 200 °C leading to no changes to their structure.

Highlights

Erosion on slopes and margins of water bodies consists of separating and transporting sediment by water, wind, or gravity
This study presents the results of implementing two semi-rigid erosion control techniques installed on reservoir margins of two Brazilian Hydroelectric Power Plants (HPPs)
This study presents the implementation of semi-rigid erosion control techniques on the reservoir margins of two Brazilian UHE: Porto Colômbia and Volta Grande

Summary

Introduction

Erosion on slopes and margins of water bodies consists of separating and transporting sediment by water, wind, or gravity. This can be caused by the suppression of the existing vegetation, disturbances in the soil, and the creation of more steep surfaces, among other factors. The variables that have the most significant influence on the intensity of erosion are the topography, the origin and composition of the soil of the margin and the bed of water bodies, and the qualitative and quantitative aspects of the vegetation associated with the local hydraulic conditions (height of waves and wind speed) [4]. Other factors to consider are the hydrological and sediment connectivity of the margin, which indicates the paths followed in the transport of sediments and is mainly influenced by the relationship between the topography of the local and the intensity of the rains [5], as well as the moisture changes in the topsoil layer, which is the layer more susceptible to erosion [6]

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