Managerial sustainability indices for improving the coastal groundwater decisions by a parallel simulation–optimization model.

Seawater intrusion is one of the causes of groundwater quality degradation in coastal zones. This phenomenon is intensified by overexploitation of coastal aquifers. In this paper, optimal management strategies have been determined to prevent the advance of seawater using a parallel simulation–optimization decision model. This model has been applied to a real case study of Ajabshir aquifer located in Urmia Lake basin, Iran, for a 20-year planning horizon (2015–2034). Four categorizes of new sustainability indices (indices of protection, reliability, vulnerability, and aquifer area with a groundwater problem) as the objective functions have been examined for the first time. The developed management problems based on these four categories have been solved under two different conditions of groundwater elevation and salinity concentration. The results of 20-year period simulations indicate that by changing the extraction pattern in different regions of the aquifer (as the decision variables) based on the solution of management problems, the largest decrease in net recharge (0.065 million cubic meters) occurs in the second half of the hydrologic year (October to March) compared to the continued condition in which all factors are similar to 2014. The contribution of using indices in this study can help the local water managers to identify the high-risk areas for better planning and other coastal settings. [ABSTRACT FROM AUTHOR]