Prediction of short-time and long-time of land use change in groundwater vulnerability by DRASTIC index and TerrSet software

Today, due to widespread land use changes, including increasing urban population and drinking needs, industrial and agricultural growth of communities on the one hand and further reduction of surface water resources on the other hand has increased the use of groundwater resources. Therefore, it is necessary to evaluate the effect of land use change on aquifer vulnerability. Since the potential for pollution in different parts of an aquifer is different in terms of contaminants reaching the groundwater, predicting the extent of vulnerability changes in aquifers by predicting future land uses. In this study, for the first time, the effect of the future land use changes on the vulnerability of Hashtgerd aquifer for the periods of 2025, 2035 and 2045 has been investigated and compared with the current situation in 2018. In this regard, first, using the Markov chain method in TerrSet software, land use changes for the three periods of 2025, 2035 and 2045 were extracted. Land use mapping was performed using Landsat satellite images for 1998, 2008 and 2018 in ENVI 5.3 software. The generated maps were added as a parameter to the DRASTIC vulnerability method and finally DRASTIC-Lu was predicted for three periods. This study shows that the vulnerability in high and very high class in 2045 will increase by 34% and 83%, respectively. Furthermore, the increasing trend of vulnerability in the classroom is very high for three incremental periods and will increase from 14% in 2025 to 20% and 83% in 2035 and 2045. This study shows that in the coming years, in order to preserve groundwater resources, it is necessary to consider special monitoring measures in the northern and northeastern regions of the aquifer.