Hydrological and hydrogeochemical methods for the delineation of complex groundwater flow systems as evidenced in the Bet-Shean Valley, Israel

Abstract

The Bet-Shean Valley (Northern Israel) is the base level of groundwater draining from three regional aquifers. In the natural undisturbed state, i.e. at the beginning of the six-ties, groundwater drained through many springs with widely different chemical composition and with a total discharge of about 135 million m 3. For the efficient utilization of water resources, it was decided to recover groundwater from wells at the cost of a considerable reduction of spring discharges. Since the sequence and the rate of spring-decay diverged from the pattern that had been predicted, it became necessary to delineate aquifers and their connections to the various springs. Three groups of methods were employed for this purpose: (a) analysis of discharge characteristics and their relation to source aquifers; (b) methods for the identification of well fields that affect the discharge of a particular spring; and (c) hydrogeochemical methods for the delineation of flow paths. The paper presents the relevant data, the methods employed and the results that were achieved. The utility and the limitations of the various methods were discussed and general guidelines for the delineation of groundwater flow in multi-aquifer systems were formulated.