The Investigation of the Effects of the Regional Development in the Form of Change in Land Use on the Groundwater Aquifer Level (A Case Study: Damghan Watershed)

Groundwater resources are the second largest freshwater source in the world after the polar glaciers. The study of groundwater fluctuations has significant importance in the planning and sustainable management of each region. The purpose of this study is to investigate the spatial and temporal changes in groundwater levels in Damghan watershed concerning land-use changes. This study is conducted using geostatistical methods and remote sensing and routing of changes using R software in the statistical period of 1994-2020.  Groundwater table data were collected for 1760 wells including deep wells, semi-deep wells, and main wells of qanats. After controlling the accuracy and quality of data and checking the data normality, interpolation was performed. The Kriging method was used for interpolation and Inverse Distance Weighting, and changes were routed using R software. Land-use changes for 2000, 2010, 2015, and 2020 were studied using remote sensing and their relationship with groundwater level changes was analyzed. The results show that the groundwater level has decreased in most parts of the basin, including the east, north, and southwest. In these areas, the groundwater level has decreased by 14.7 m, over 26 years, which means an average of 56 cm per year. Also, the most land-use changes have occurred in these areas in that the area of gardens has increased by 10016.37 hectares, urban areas have increased by 637.02 hectares, barren lands have increased by 76907.4 hectares, and surface water resources  -due to the construction of the dam - have increased by 453.15 hectares, and rangelands have increased by 30337.58 hectares, forests have decreased by 48325.86 hectares and agricultural lands have decreased by 90350.47 hectares for the time interval between 2000 to 2020.