This research investigates the phenomenon of salt water coning below a discharge well partially penetrating an aquifer in which fresh water is underlain by saline water. The first portion of this report is concerned with the evaluation of techniques presently available for analyzing the performance of such wells. Both theoretical considerations as well as experimental results have shown that some of the assumptions used in the analytical techniques available are not valid while others are acceptable only under limited conditions. The study also presents a mathematical model developed for evaluating the performance of a skimming well under a wide range of field situations. The practical utility of the results in deciding the optimum discharge from a skimming well is discussed. It is shown that for given aquifer conditions and well geometry the maximum steady-state production of uncontaminated fresh water is obtained at shallower well penetrations and closer well spacings than that predicted by the theory previously available.