Application of a decision making analysis to evaluate direct recharging ofan unconfined aquifer in Jordan

This case study describes the application of the Freeze et al. (1991) decis ion analysis approach to design an artificial recharge program for a basin, known in Jordan as Yarmouk Basin. This approach of design was selected bec ause it suits projects in which the hydrogeological environment plays an im portant role; and because the approach to design involves quantifying benef its, costs, and risks for recharge alternatives under consideration. Risk, which is added here, is defined as the expected costs of failure. It reflec ts both performance uncertainties and failure costs. Probability of failure to attain a prescribed drawdown at each of the compliance points was estim ated by coupling a parameter uncertainty model with a groundwater flow simu lation model and a reliability model. The simulations were based on an ense mble of thirty realizations of hydraulic conductivity field which were gene rated by a parameter uncertainty model after assuming the hydraulic conduct ivity field log-normally distributed spatially. Finally, the decision betwe en alternatives was made by a decision making model which considers both th e costs and risks. Decision variables consist of the number, location, and recharge rate of the injection wells. The results showed how the preferred design alternative depends upon the hydrogeological, and economic considera tions. Moreover, the preferred alternative under the adopted criteria for r echarge was found less sensitive to the cost of failure, but highly depende nt upon the total cost of the system.