Water and soil resource assessment using GIS-based modelling of climate variability (WaterWorld Policy Support System) in Karkheh hydrological unit - southwestern Iran

Abstract

Abstract Presently, human-induced activities are the primary drivers of land degradation and a decline in the anticipated benefits of water resources. Consequently, there is a pressing need for increased attention to adaptively manage and propose viable solutions to disruptions in water and soil resources. This study focuses on evaluating the water budget, runoff, soil erosion, and water pollution potential within the hydrological unit of Karkheh in southwestern Iran, utilizing the WaterWorld Policy Support System (WWPSS). Additionally, it aims to assess the cost efficiency of water sources and soil conservation practices, offering a systematic perspective on basin-wide water challenges. Geospatial data integration and the development of a soil and water vulnerability map were executed using ArcGIS 10.3. The result showed that the southern area of the hydrological unit experienced the minimum precipitation. In total, the precipitation declines over the surfaces of this hydrological unit from north, which has led to a decrease in vegetation and an increase in runoff generation in the southern areas. The total runoff generated in this hydrological unit is based on the upstream–downstream relationships from the north to the south was estimated at 81000648 mm3 yr− 1. The soil erosion rate spiked in the southern area with the vegetation decline and the intensification of runoff, which indicates its very severe and dangerous erosion regimen in downstream areas. It could be result in water pollution. Economic valuation represents the real value of water generation and soil conservation per hectare in the study area was estimated at US$ 6.63 and the real value of per hectare in the study area was estimated at US$ 912.2, respectively.