Investigating the Long-Term Changes in the Quality and Quantity of Groundwater Resources (Case Study: Delfan Plain)

The increasing use of groundwater resources as the most important sources of water supply in arid and semi-arid regions has led to quantitative and qualitative problems of these resources. Therefore, maintaining and monitoring the quantity and quality of groundwater resources is one of the strategies for proper management of water resources in these areas. In this research, the process of quantitative and qualitative changes in the groundwater resources of Delfan plain is studied. For this purpose, 32 year deep well data in the plain including: Ca, Mg, Na, EC, SAR, HCo3, SO4, TDS, TH, Cl and K, as well as information about 12 piezometric wells for Years 1381-1395. Non-parametric Mann-Kendall test was used to study the process of time series changes in qualitative parameters. The results of analysis of this test showed that the changes in SAR and TH parameters were significant at 95% confidence level and in general, the anion sources of the plain had a decreasing trend while the cations of these sources had an incremental trend. Investigating the trend of groundwater level changes in the plain showed that the water balance of the resources decreased during the statistical period, which is in the Peymmetric wells of Sikond at 99% level, and in the wormhole, Azizabad and Lazar wells at 95% Has been.