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Two calibration methods for modeling streamflow and suspended sediment with the swat model

Brighenti, Tássia Mattos, Bonumá, Nadia Bernardi, Grison, Fernando, Mota, Aline de Almeida, Kobiyama, Masato, Chaffe, Pedro Luiz Borges
Ecological engineering 2019 v.127 pp. 103-113
Soil and Water Assessment Tool model, basins, dynamic models, environmental factors, soil resources, stream flow, suspended sediment, uncertainty, water management, water quantity
The proper estimation of streamflow (Q) and suspended sediment (SS) have important implications for sustainable water management. The Soil and Water Assessment Tool (SWAT) is a distributed, physically-based and dynamic model that integrates water quantity and quality routines. SWAT is considered an effective tool for assessing water and soil resources problems in a worldwide range of environmental conditions; however every hydrological model application is limited by the choices made in the calibration process. The aim of this paper was to assess the differences between the sequential and simultaneous calibration methods when simulating streamflow and suspended sediment with SWAT. We used the Sequential Uncertainty Fitting (SUFI-2) combined with SWAT for: (i) sensitivity analysis; (ii) parameter calibration using Q and SS data with a combined multi-site and multi-objective approaches; and (iii) evaluation of the differences in the estimated uncertainty of both calibration methods. Our results suggest that the simultaneous calibration was more accurate, especially for SS values with King-Gupta Efficiency (KGE) objective function. The simultaneous calibration was less time consuming and the sensitivity analysis indicated that it needed less parameters in the calibration process. The multi-site calibration method improved the model results in 3 out of 4 simulations of suspended sediment in the basin outlet.