Application of hydrological and hydraulic models to quantify surface runoff in the endorheic system of the La Picasa Lagoon basin

Abstract

The basins in the plain present particularities from the approach of the hydrological processes that take place there. They are characterized by presenting a predominance of vertical water movements (evapotranspiration-infiltration) over horizontal movements (runoff), showing a strong interrelation between surface and underground water. The La Picasa Lagoon basin is defined as a naturally depressed humid pampa region with an undulating plain relief that has low sectors of temporary flooding and permanent lagoons without a defined drainage network. It is an inter-jurisdictional endorheic basin between the provinces of Córdoba, Santa Fe, and Buenos Aires (Argentina) that has suffered recurrent floods between 2014 and 2017 caused by an increase in the average level of the lagoon reaching historical maximums, producing floods, and affecting infrastructure, transport, and agricultural activity. Due to these problems, through the application of hydrological and hydraulic models, the behavior of La Picasa basin system is quantified and evaluated to avoid future floods. In the present work, a hydrological model is applied using the HEC-HMS free tool and a 1D/2D hydraulic model using the HEC-RAS free tool, where the system of channels and reservoirs that make up the system is considered. The flood marks in reservoirs and La Picasa Lagoon are analyzed, and it is defined as regulating the variation of levels in the different reservoirs within permitted ranges. These models are a useful tool for studying future hydrological situations that may occur around the study area.