Hydrological modeling in a basin of the Brazilian Cerrado biome

Jéssica Assaid Martins Rodrigues,Marcelo Ribeiro Viola,Michael Silveira Thebaldi,Alberto Carlos De Oliveira Andrade,Carlos Rogério De Mello,Danton Diego Ferreira

doi:10.4136/ambi-agua.2639

Jéssica Assaid Martins Rodrigues, Marcelo Ribeiro Viola + Show 4 more

Open Access

https://doi.org/10.4136/ambi-agua.2639

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Abstract

The Brazilian Cerrado biome (BCB) is among 25 biodiversity hotspots identified worldwide, and covers the recharge area of important aquifers and rivers in South America. The increase in deforestation has been threatening water availability in this region. In order to assist in the water-resource management of the BCB, this study models the daily streamflow in a basin of the Cerrado, using two approaches: a process-based model (Soil and Water Assessment Tool - SWAT) and the data-driven model (Artificial Neural Network - ANN). The performance of the models was evaluated by the Nash-Sutcliffe coefficient (NSE), coefficient of determination (R2) and flow-duration-curves (FDC). The results indicate that SWAT (NSE > 0.61; R2 > 0.68) and ANN (NSE > 0.91; R2 > 0.79) models are suitable tools in daily streamflow modeling of the studied basin, with the ANN model being the most accurate. Based on FDC, the ANN model was also better than the SWAT model for all frequencies evaluated. Thus, the ANN model is a promising new approach for daily streamflow modelling in this region. Moreover, the results of this study can help water-resource managers in planning and implementing appropriate water allocation and conservation measures in the Brazilian Cerrado biome.

Highlights

The Brazilian Cerrado biome is one of the most important areas in South America, covering the recharge areas of important aquifers and rivers, and approximately 204 million ha, which corresponds to 24% of Brazil (Medrado and Lima, 2014); it is recognized as the "cradle of Brazil’s water" (Lima, 2011)
In order to assist in the water-resource management of the Cerrado biome, this study assesses the suitability of the Soil and Water Assessment Tools (SWAT) and Artificial Neural Network (ANN) models to simulate the daily streamflow in the Manuel Alves da Natividade River Basin (MRB), located in the Brazilian Cerrado biome, and compares their performances to determine which is more appropriate for the studied basin
Regarding the Nash-Sutcliffe coefficient (NSE), values of 0.67 and 0.61 were obtained for the calibration and validation periods, respectively. These values allow classifying the model as “satisfactory” in both periods (Moriasi et al 2015). These results demonstrate that the model is able to satisfactorily simulate the observed daily streamflow

Summary

Introduction

The Brazilian Cerrado biome is one of the most important areas in South America, covering the recharge areas of important aquifers and rivers, and approximately 204 million ha, which corresponds to 24% of Brazil (Medrado and Lima, 2014); it is recognized as the "cradle of Brazil’s water" (Lima, 2011). The Brazilian Cerrado biome is one of 25 biodiversity hotspots in the world, with high biological and endemic diversity, has suffered loss of vegetation due to agriculture and pasture expansion (Silva et al 2006), which has resulting in a large number of endangered species (Myers et al, 2000; Rodrigues et al, 2020). These agriculture and pasture expansions threaten the stream flows from watersheds (Silva and Bates, 2002); the understanding of their impacts on streamflow in the Cerrado biome is still limited (Beuchle et al 2015). Rodrigues et al (2020) applied a SWAT model to simulate the monthly streamflow for three basins of the Brazilian Cerrado biome. Despite the wide use of the SWAT model, it requires a large amount of temporal and spatial data, maps, and input parameters, that are sometimes hard to predict (Makwana and Tiwari, 2014)

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