Hydrological Response of Land Use Land Cover Change on Stream Flow of Anger Watershed, Blue Nile Basin, Ethiopia

Abstract

ABSTRACT

The soil and water assessment tool (SWAT) model was applied to simulate the streamflow from the Anger watershed (7,982 km2), located in Western Oromia Regional State, Ethiopia. ArcGIS was applied to layer staking, mosaicking, image classification, and accuracy assessment. The purpose of the study was to examine the applicability of the SWAT model and to detect the effect of past land-use land-cover change on streamflow of the watershed. The automated calibration process was used to calibrate the model parameters using time series data from 1990 to 1999. Data from 2000 to 2004 were used to validate the model using the input parameter set. Time series plots and the statistical measures were used to evaluate the performance of the SWAT model. The results of the model during calibration and validation showed respectively dependable estimates of monthly streamflow with R2= 0.90, ENS= 0.76, and R2= 0.84, ENS= 0.63. The validation of image classification is achieved through the Mosaicking image and Google Earth image. The overall accuracy and kapa coefficient was used to evaluate the performance of the Arc GIS model. The result of the image of 1986 land-use classification showed a good agreement between classified image and ground truth with the result of overall accuracy=88%, and kapa coefficient=81%. This study showed that the SWAT model is capable of simulating the stream flow of the watershed under the impacts of past land-use land-cover changes and hence can be used as a tool for water resources planning and management in the study watershed.

Keywords: SWAT model; Arc GIS; Land-Use Land-Cover; Stream Flow; Anger watershed

*Author for Correspondence E-mail: [email protected], Tel: +251910460019