SWAT Modeling and Water Quality Analysis of Meenachil River, Kerala

Abstract

The Meenachil River is an important river serving Central Kerala. The rapid growth of population and change in land use have had an adverse effect on the river basin. A hydrological research in Meenachil River Basin (MRB) would aid in implementing an enhanced management program to prevent degradation of soil and water resources in the area. Soil and Water Assessment Tool (SWAT) modeling for streamflow has done in MRB for analyzing the water quality of the river. Using the SuFi2 algorithm in SWAT-CUP, the model was successfully calibrated and validated for Kidangoor gauging station. The model was calibrated during a ten-year period (1997–2006) and verified over a nine-year period (2007–2015). As reflected by coefficient of determination (R2) and Nash–Sutcliffe simulation efficiency (NSE) values, model predictions done remarkably efficient on monthly basis during the calibration and validation periods. The R2 and NSE for the simulated monthly streamflow are 0.79 and 0.77 for the calibration period, and 0.82 and 0.75 for the validation period. The calibrated model was used to study the effects of landscape, climate condition, and fertilizer application on sediment and nutrient loadings. From the investigation, it was observed that hydrological processes play an important role in the transport of pollutants and fertilizer which led to excessive nutrient loadings in the river. The model performs effectively, indicating that it can be used to estimate streamflow in MRB and provide knowledge about the water quality under various land scape and climate conditions. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.