Calibração hidrológica do modelo SWAT em bacia hidrográfica caracterizada pela expansão do cultivo da cana-de-açúcar

Abstract

A dificuldade na gestão de recursos hídricos aliada à dinâmica do uso e ocupação do solo em bacias hidrográficas agrícolas são fatores relevantes para a conservação da água e solo. A gestão de bacias hidrográficas, bem como o monitoramento de cenários de expansão agrícola e mudança no uso do solo, podem se beneficiar de ferramentas de modelagem hidrossedimentológica, como o SWAT (Soil and Water Assessment Tool). Entretanto, para que os resultados obtidos sejam confiáveis, os modelos precisam ser calibrados. Objetivou-se, neste trabalho, calibrar e validar o modelo SWAT, para a variável vazão, tendo como base a bacia hidrográfica do Ribeirão do Pinhal, Limeira -São Paulo, que se caracteriza pela expansão da cana-de-açúcar sobre áreas citrícolas. Dados de vazão de um posto fluviométrico localizado no exutório da bacia foram utilizados para a calibração e validação, a partir de séries temporais diferentes. Utilizou-se o software QSWAT para a simulação hidrológica e o SWAT-CUP para a calibração e validação do modelo. O modelo foi calibrado e validado resultando nos seguintes índices estatísticos NSE=0,64; PBIAS=15,2 e RSR=0,60 para calibração e NSE=0,68 PBIAS=-2,8 e RSR=0,56 para a validação. O ajuste de parâmetros do SWAT (USLE_P, USLE_C, CN2) e do calendário de operações da cana-de-açúcar em acordo com a situação real da bacia foi necessário para a calibração do modelo. Os resultados indicam que o modelo SWAT subestima as vazões extremas, no entanto, dentro de faixa aceitável. O SWAT, após a calibração, pode ser utilizado na gestão de recursos hídricos na bacia do Ribeirão do Pinhal.Hydrological calibration of the SWAT model in a watershed characterized by the expansion of sugarcane cultivationA B S T R A C TThe difficulty in water resources management combined with the dynamics of land use and occupation in agricultural watersheds are relevant factors for water and soil conservation. River basin management, as well as monitoring scenarios of agricultural expansion and land-use change, can benefit from hydrossedimentological modeling tools such as the SWAT (Soil and Water Assessment Tool). However, for the results to be reliable, the models must be calibrated. The objective of this study was to calibrate and validate the SWAT model for the flow variable, based on the Ribeirão do Pinhal watershed, Limeira-São Paulo, which is characterized by the expansion of sugarcane over citrus areas. Flow data from a fluviometric station located in the basin's outfall were used for calibration and validation from different time series. QSWAT software was used for hydrological simulation and SWAT-CUP for model calibration and validation. The model was calibrated and validated resulting in the following statistical indices NSE = 0.64; PBIAS = 15.2 and RSR = 0.60 for calibration and NSE = 0.68 PBIAS = -2.8 and RSR = 0.56 for validation. Adjustment of SWAT parameters (USLE_P, USLE_C, and CN2) and the sugarcane operation schedule according to the actual basin situation was necessary for model calibration. The results indicate that the SWAT model underestimates the extreme flow rates, however, within an acceptable range. After calibration, the SWAT can be used to manage water resources in the Ribeirão do Pinhal basin.Keywords: Hydrologic simulation; land use; flow rate.

Reduction of sediment yield by riparian vegetation recovery at distinct levels of soil erosion in a tropical watershed

“…The calibration and validation of streamflow data (Figure 3) produced satisfactory NS, PBIAS (percent bias), and RSR (ratio of the root mean square error) values (Table 8). Similar values of these indices for the calibration of the SWAT model have been reported in several studies in Brazilian watersheds (Pereira et al, 2014;Fukunaga et al, 2015;Brighenti;Bonumá;Chaffe, 2016;Blainski et al, 2017;Paz et al, 2018;Martins et al, 2020).…”

How Far Can Nature-Based Solutions Increase Water Supply Resilience to Climate Change in One of the Most Important Brazilian Watersheds?

“…The following supporting information can be downloaded at: https: //www.mdpi.com/article/10.3390/earth3030042/s1, Figure S1: Annual mean water yield for each climate condition and each LULC scenario; Figure S2: Annual mean streamflow into the basin's outlet reach for each climate condition and each LULC scenario; Figure S3: Annual mean groundwater contribution to streamflow for each climate condition and each LULC scenario; Table S1: Confusion matrix used to assess the accuracy of the land use map; Table S2: Sources of climate data and the weather dataset combinations analyzed; Table S3: Plant growth factors altered according to regional studies; Table S4: Initial plant growth parameters altered according to regional studies; Table S5: Universal soil loss Equation C factor altered according to regional studies; Table S6: Universal soil loss Equation C factor altered according to regional studies; Table S7: Parameters altered to represent best management practices adopted in pasture areas in the land use scenarios of the focal conservation and the combined solutions; Table S8: List of NEX-GDDP models used for the mean multi-model ensemble; Table S9: Streamflow stations and periods used for calibration and validation; Table S10: More sensitive parameters according to global sensitivity analysis for each streamflow gauge; Table S11: Parameters used for calibrating the base model, original values, modification range applied, and final fitted value and the respective sub-basin of application; Table S12: Performance statistics of base model calibration and validation for monthly streamflow. References [55][56][57][58][59][60][61][62][63][64][65][66][67][68][69][70] are cited in the Supplementary Materials.…”

Use of Soil Moisture as an Indicator for Climate Change, Using the SUPer System

“…The hydrological model Soil Water Assessment Tools-SWAT is very widespread in Brazil and due to the need for adjustments in the results obtained through modeling and observed data, it is necessary to carry out a calibration. Different studies have been developed to calibrate the swat model to Brazil, [2,13,23,27] northeast of Brazil, [11], and for the Pernambuco basins [1,5,11,[24][25][26]. The intention was and is to provide a system that can facilitate the monitoring and planning of watersheds.…”