Multi-objective planning in order to manage the quantitative and qualitative effects of optimal utilization of groundwater resources in Shahriar plain

Development of agriculture, industry and population growth, the exploitation of groundwater resources has increased and has affected its quality. In order to prevent the occurrence of quantitative and qualitative problems of aquifers, management of optimal operation of groundwater resources is essential. Therefore, the purpose of this study is the optimal utilization of groundwater resources and to investigate its quantitative and qualitative effects on the Shahriar plain aquifer.

Groundwater level changes and its quality from the perspective of index (TDS) in Shahriar plain aquifer have been simulated by ANN. Then (TDS) of groundwater has estimated by regression. Finally, the multi-objective genetic algorithm (NSGA-II) was used for optimal utilization of groundwater resources and with the aim of minimizing groundwater level changes and total dissolved solids of groundwater.

According to the results of the study, the evaluation criteria (RMSE) in three modes of training, testing and validation for groundwater level changes are equal to 1.27e-06, 0.0025 and 0.003, respectively, and for total dissolved solids of groundwater was calculated to be 0.24, 27.64 and 14.608 and the correlation coefficient (R) at the level (0.05) in three situations was significant for both variables. Also, during the study period, the volume of optimal withdrawal from the aquifer has decreased by 29.12 percent and the optimal amount (TDS) of groundwater on average, 120.87 Mg./l, has been calculated less than the estimate of artificial neural network. And Groundwater level has also increased by an average of 9.27 meters per year.

The results confirm that the proposed simulation-optimization method as an application tool with good performance, low cost and desirable speed can support several effective factors simultaneous with optimal operation policy. It also reduces the quantitative and qualitative problems of the aquifer and cause increases the stability of the groundwater system.