Simulating the hydrologic responses of the watersheds of Nilgiri Mountain with SWAT2005 model

摘要

Two adjacent mountainous watersheds in Nilgiris district, South India, with complex topographic landscape and land cover/use features were selected to simulate their hydrological response using SWAT2005 model. The watersheds comprise the head water part areas of the major rivers in Tamil Nadu state that are harnessed for hydroelectric power generation, irrigation and other water uses. The values of spatial parameter of input files of the model were created from ArcGIS 9.2 compatible ESRI grid and shape file datasets using ArcSWAT2.1.5 and the model was executed from the same framework. The topographic parameters were derived from a 15 m grid resolution DEM which was in turn developed from contours of a topographic map of scale 1: 25,000. Land cover/use parameters were derived from 30 m grid resolution land cover/use map developed from multi-spectral imagery acquired by IRS-P6, LISS-Ⅲ sensor on Feb. 27, 2006. Soil parameters were derived from shape file soil data customized from soil survey report of the district. The stream flow simulations of the model were calibrated using carefully recorded daily weather and continuous stream flow dataset and validated using two years stream flow data outside the calibration dataset. The goodness of the simulations was evaluated using Nash-Sutcliffe Efficiency (NSE) and coefficient of determination (R~2). The result indicated that the simulated stream flow hydrographs of SWAT2005 model were acceptable in both watersheds.