Modelling Rainfall-Runoff Process of Kabul River Basin in Afghanistan Using ArcSWAT Model

Abstract

Kabul River Basin is the most populated and an important source of water resources in Afghanistan. The Soil and Water Assessment Tool (SWAT) model, together with the ArcGIS and SWAT-CUP, is employed to predict the runoff in the basin. Nine years of meteorological and hydrological data are employed in the study. The DEM, the soil cover, and the land use/cover data are downloaded from the available global database. The ArcGIS based soil classification, the land use/cover, the elevation, the drainage, and the slope distribution maps of the basin are generated. The meteorological data from 18 different stations and the hydrological data from 7 different stations are obtained from the Ministry of Energy and Water of Afghanistan. The basin is divided into 48 sub-basins with a total number of 770 hydrological response units (HRUs). The sensitivity analysis results revealed that the flow characteristics of KRB are highly influenced by the groundwater and snowmelt.  The model is calibrated using the data from 2010 to 2014 and validated employing the data from 2015 to 2017 at seven different hydrological stations. The SWAT-CUP is successfully used to calibrate the model for predicting monthly and daily runoffs. The calibrations and validations for the seven stations are achieved, on the average, with the correlation coefficient (R) of 0.78 (for daily flows) and 0.82 (for monthly flows), respectively. Total water yield in the basin is estimated to be 432.9 mm/year, corresponding to 31 176 Mm³/year, hardly meeting the demand of 26 512 Mm³/year in the basin.