Investigating Spatial and Temporal Changes of Quantitative Parameters of Underground Water Resources Using Inverse Distance Weighting Interpolation Method (Case Study: Mashhad Plain)

The management of water resources, especially groundwater, is of particular importance in arid and semi-arid regions. Improper understanding and unsustainable exploitation in these areas will result in irreparable damage, such as severe and irreversible groundwater level decline, reduction in well and aqueduct discharge, and changes in the pattern of groundwater flow. Therefore, the aim of this research is to investigate the decline in the groundwater levels of Mashhad Plain, which is selected as one of the most important and largest plains in Khorasan Razavi province. In order to conduct this study, the data from 62 observation wells were examined over a period of five years (2011-2016, 2016-2021). Initially, the statistical data was collected and organized using Excel 2017 software, and the hydrograph representing the aquifer of Mashhad Plain was plotted. Subsequently, using ArcMap 10.8 software and the Inverse Distance Weighting (IDW) method, maps of the groundwater level and water table for an 11-year period and two consecutive five-year periods were generated. The results obtained in this study indicate that the groundwater level in this aquifer has, on average, increased by 0.36 meters in the first five years and 0.32 meters in the second five years for the specified time period. The central, southeast, and northwest parts show the highest increase in reaching the groundwater level. Additionally, the hydrograph representing the Mashhad aquifer shows an average annual decrease of 0.33 meters in groundwater level over the 11-year period.