Application of SWAT Hydrological Model and GSMap Satellite Rainfall Data to Estimate Runoff in Ungauged Watershed: A Case Study of Lam Paniang Watershed

A Case Study of Lam Paniang Watershed

Abstract

The amount of runoff is related to the amount of rainfall distributed over the watershed area. While the runoff station and rainfall in the regional watershed, especially in the northeast area, are still few which affect water management in the whole watershed. The objective of this study was to study the trend of change of runoff in ungauged area of Lam Phaniang watershed by applying SWAT model together with GSMap satellite rainfall data between 2010 - 2020. The study results were found that SWAT model runoff analysis integrated with GSMap satellite rainfall data with the total number of 55 stations covered watershed. The value results were in acceptable criteria compared with E.64 and E.68A runoff stations that had reliability shown with almost R²>0.6, NSE>0.5 and PBIAS±25%. As a result, the runoff simulation in unguage upstream, could be carried out efficiently and the results of sub-watershed runoff were displayed in spatial map form. This study results study showed that SWAT model and GSMap satellite rainfall data could be appropriately applied to estimate the amount of runoff in unguaged watershed. The results of this analysis were expected to be used to support effective water management planning to reduce the impact of flooding or drought in the area.