Evaluation of Evapotranspiration in Brazilian Cerrado Biome Simulated with the SWAT Model

Abstract

Evapotranspiration represents a significant part on the water balance and, thus, the correct evaluation of this hydrological parcel is relevant when modeling a watershed. The objective of this work is to evaluate the Soil and Water Assessment Tool (SWAT) model’s capability in adequately simulating evapotranspiration in a watershed with predominance of the Brazilian Cerrado biome. Hydrological modeling of the Gama watershed located in the Federal District, which has 57.5% of its total area covered by pristine Cerrado, was conducted. Hydrometeorological and turbulent flow variables have been monitored in weather station and Eddy Covariance (EC) tower, respectively. SWAT simulations were performed for potential evapotranspiration methods: Hargreaves (H), Priestley–Taylor (PT) and Penman–Monteith (PM). Modified versions of SWAT for estimating actual (ET) by Strauch and Volk (2013) (SV) and Arroio Junior (2016) (AR) were also tested. The calibration and verification of the SWAT model, in terms of daily flow, were carried out using a Particle Swarm Optimization algorithm, and fair results were obtained with all the methods evaluated. The actual evapotranspiration (ET) simulated with SWAT (ETsim) using the PM, PT, H, SV and AR methods for a Cerrado hydrological response unit (HRU) were evaluated and compared with the ET obtained using the turbulent flow (Eddy Covariance) method (ETobs). Comparing ETobs and ETsim results, the PM method showed the best fitness and the H and PT methods showed better fit for the dry and the rainy periods, respectively. Although representing an advance on ET modeling, the SV and AR modifications did not improve the response in terms of simulation of the studied area.

Impacts of the landscape changes in the low streamflows of Pantanal headwaters—Brazil

“…PPT is the precipitation, ET is the real evapotranspiration and PET is the potential evapotranspiration which was calculated using the Hargreaves method because of the available measured data. Hargreaves has shown to reach acceptable estimations for Cerrado and Amazon Forest (Ferreira et al, 2021; Monteiro et al, 2021).…”

“…Hargreaves has shown to reach acceptable estimations for Cerrado and Amazon Forest (Ferreira et al, 2021;Monteiro et al, 2021).…”

Dynamic characteristics of drought conditions during the growth of summer maize

“…The model is flexible and extensible, and it is computationally very efficient for doing continuous daily simulations for a longer period. However, the SWAT model cannot accurately simulate real-time crop water requirements (Harikrishna & Sanat, 2020;Navideh et al, 2020;Ferreira et al, 2021;Hanna et al, 2021). Therefore, in this study, the following modifications were made to the SWAT model:…”

Soil water repellency in the Brazilian neotropical savanna: first detection, seasonal effect, and influence on infiltrability

“…Constant land use changes directly in uence water in ltration into the soil and, consequently, impact the hydrological cycle (Spera et al, 2016). On a global scale, researchers have observed that most hydrological prediction models have been developed and applied in humid and temperate regions (Gao et al, 2016), which leaves a signi cant gap in our understanding of ecohydrological components in savanna regions, especially in neotropical savannas (Ferreira et al, 2021). In the latter case, most publications address topics such as evapotranspiration (Ferreira et al, 2021;Nóbrega et al, 2017), soil water balance (Garcia-Montiel et al, 2008;Oliveira et al, 2015), and land use changes (Hunke et al, 2015).…”