The Study of Parameter Sensitivity of SWAT Model for Runoff and Groundwater: A Case Study of Phetchaburi Basin
Keywords:SWAT, Parameter sensitivity, Runoff, groundwater, Phetchaburi Basin
Soil and Water Assessment Tool (SWAT) is important for planning and sustainable use of water
resources to meet various demands. Since it is a distributed parameter values model, the user must set parameters
to suit the studied area. The purpose of this research was to investigate the sensitivity of SWAT model parameters
on the runoff and groundwater content. This case study of Phetchaburi Basin used the relative sensitivity index
to determine the sensitivity of parameters. The results of this research showed that the top 4 ranking of parameters sensitivity value index to runoff were: 1) the curve number (Cn2), 2) the available water capacity (Sol_Awc),
3) the soil evaporation compensation factor (Esco), and 4) the saturated hydraulic conductivity (Soil_K). While
the top 5 ranking of parameters sensitivity value index to groundwater were: 1) the available water capacity
of soil (Sol_Awc), 2) the groundwater delay (Gw_Delay), 3) the soil evaporation compensation factor (Esco), 4)
the saturated hydraulic conductivity (Soil_K), and 5) the curve number (Cn2). The results of this study could be
further used for SWAT mode calibration to simulate runoff in Phetchaburi Basin in the future.
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