Quantification of impact of changes in land use-land cover on hydrology in the upper Indus Basin, Pakistan

Abstract

Empirically based lumped hydrologic models have an extensive track record of use for various watershed managements and flood related studies. This study focuses on the impacts of land use land cover change for a 10 year period (2000–2010) on the stream discharge in a sub-watershed of Indus River using lumped model HEC-HMS. The input variables for model building in HEC-HMS were calculated based on the DEM, LULC, soil and precipitation data which was collected and pre-processed in HEC-GeoHMS. The model was calibrated for the year 2000 and validation was done for 2010. The statistics shows correlation coefficient = 0.96, relative Bias = −9% and Nash-Sutcliffe coefficient of efficiency (NSCE) = 0.87. The validation statistics are Correlation Coefficient = 0.95, Bias = −14% and NSCE = 0.91. The model results shows that LULC change analysis using Landsat images in 10 years the overall concussion of change on discharge has been negligible in the study area. Due to decrease in forest the percent of bare soil and built up area increases. This conclusion was further supported by the LULC change analysis conducted on a local scale metropolitan district of Mansehra (16 km2). Soil and built up area in this sub-watershed increased from 69%, 8.2% in 2000 to 78%, 13.76% in 2010 respectively, whereas the corresponding river discharge increased by 33.61% from year 2000–2010, proving strong positive correlation on a local scale between the LULC and the river discharge.