ASSESSING THE IMPACTS OF LAND USE/LAND COVER CHANGE AND CLIMATE VARIABILITY ON WATER BALANCE IN THE FARAH RIVER BASIN, AFGHANISTAN

Abstract

The significant needs of water resources for humans, plants, animals, and water sources give the importance of this study. It is required for residential, agricultural, industrial, amusement, human, and life-beings. Land use and land cover (LULC) and climate change directly affect water resources and hydrological systems in a basin. Because of hydrologic systems and climatological conditions, the impact of climate change varies from one region to other. This study's findings might help decision-makers understand the climate change effects in Farah River basin. LULC are crucial considerations for the collaboration of human accomplishments with the earth. The ability to simulate changes is critical. Empirical observations revealed a shift in LULC classification in Farah basin, Afghanistan. So even though LULC change is the most influential parameter for hydrological modeling on a river basin, this study attempts to evaluate the impact of changes in LULC in the Farah sub-basin from 2000 to 2020. Land use and land cover classification were carried out using satellite images from 2000, 2010, and 2020. Farah river is a sub-basin of Helmand river, Afghanistan. Remote Sensing and GIS techniques with Landsat images were used in the study to examine the impact of changes in LULC on the Farah river basin hydrological modeling. Satellite images help in hydrological modeling and determining LULC changes. Remote Sensing and GIS technology are simple methods for assessing the effects of LULC change in water resources. ArcGIS 10.7.1 and ERDAS.Imagine were used to detect LULC changes in the Farah river basin over the last three decades, from 2000 to 2020. According to the current study, Farah's basin forest area had decreased from approximately 6.01 % in 2000 to 4.04 % in 2020. Change has also occurred in agricultural plantations, built-up areas, and barren land/wasteland. The built up area (settlement) has risen from 0.31 % to 0.69 % of total area. Agricultural zones have grown from 0.89 percent to 2.55 % of the total area. Drought and civil war, on the other hand, are the primary causes of deforestation. LULC change indicates water scarcity in the study area, which must be taken seriously. The LULC map is a critical parameter for hydrological modeling in order to assess the effects of LULC change in a river basin. Proper land-use planning is required for the long-term development of Afghanistan's Farah River Sub-basin. In this study, the Soil and Water Assessment Tool (SWAT) model was used under a scarcity of data condition to evaluate the Farah River basin watershed discharge prediction at the Farah gauge station. The monthly data from 2010 to 2016 were used for model calibration, and data from 2017 to 2019 were used for validation using SWAT-CUP. The calibrated SWAT model is applied to assess the effect of past climate change on surface flow and LULC change.