Morphohidrological disturbances in the Cuarto River lower reach (Córdoba, Argentina), due to flood control structures

Abstract

The Cuarto River drains an area of 2500 km² from the Comechingones Range to Saladillo Wetlands. This river constitutes the main input of water and sediments to the wetlands environment. The Cuarto River lower basin is located in the Pampean Plain of southeastern Córdoba province, characterized by a low-slope relief that includes fluvial/alluvial, lake/palustrine and eolian Quaternary landforms. In this area of the basin, the main processes are overflows, floods and sedimentation. In order to mitigate these processes, since 1970s the river has been strongly modified by canalization works and artificial levees. This paper analyzes the morphohidrological changes in the lower section of the Cuarto River associated to the construction by artificial levees. Morphological, hydrological and sedimentological aspects are analyzed by satellite and photograph images and topographic maps. In addition, field works were made. The Cuarto River lower reach has a permanent hydrological regime and meandering channel pattern (Is = 1.41). River cross-section decrease downstream (41 m to 17 m of width and 5 m to 3 m of depth) while the overflow features tend to increase. Levees constructions have generated vertical accretion in the meandering fluvial belt, and river cross-section narrowing. Also, these artificial landforms have interrupted the natural connectivity between the channel and its alluvial plain, and generated upstream displacement of overflows increasing their intensity by breaking.