Impact of Land Use Change on the Hydrological Regime and Flood Susceptibility in the Teusacá River Basin

Abstract

In recent years, the Teusacá River basin has experienced economic development based on agroindustrial activities, intensive grazing, and construction material exploitation. Furthermore, urban expansion and water abstraction in the San Rafael Reservoir have contributed to changes in land use and vegetation cover. These changes generate impacts that affect the hydrological balance, triggering events such as floods, droughts, and forest fires. Therefore, it is necessary to establish a relationship between land use and land cover changes and the hydrological response of the basin and, at the same time, assess the likelihood of flooding events. To this end, an integrated approach was used, utilizing models in HEC-HMS, HEC-RAS, and various maps from open data and ArcGIS to analyze the watershed's hydrological response to changes in land cover and precipitation between 2000 and 2018. The results showed that, although the curve numbers showed minimal changes between the two years, they were sufficient to generate an increase in flows of between 1 and 2 m3 /s over the different return periods. The model also demonstrated that there are areas susceptible to flooding with a 5-year return period. It was evident that, in 2018, these areas showed flood patches with a depth greater than those recorded in 2000.