Optimization of Groundwater Quality Monitoring Network in Mashhad City Aquifer Using Spatial-Temporal Modeling

Optimization of monitoring network is the best possible process for decision-making among existing networks. Considering economical objectives and for reducing the cost of monitoring, optimization approach is based on decreasing monitoring stations in this study. Using an algorithm based on entropy and nitrate pollution index, optimizing the monitoring network was conducted with 287 wells in the period of 2002 to 2011. First, the average of each station rank was calculated based on statistical years. Then, some models were proposed for the network entropy in terms of stationnumbers and time. After fitting the best network entropy model, the results showed that 111 wells are sufficient as groundwater quality monitoring stations for Mashhad aquifer. In order to approve the proposed network, 111 randomnetworks were selected in each year, and by comparing the entropy of those networks to the proposed network, the performance of selected network was confirmed. Also, the selected network performance was confirmed for the future of Mashhad aquifer.