SR-1-2004-05 : Recharge through ephemeral stream- a status report

Abstract

Ephemeral stream transmission loss represents an important groundwater surface water exchange in arid and semiarid regions and is potentially a significant source of recharge at the basin scale. However, identification of the processes and dynamics that control this exchange is a challenging problem. Specifically, data on the proportion of runoff transmission losses that escapes from near channel transpiration and wetted channel evaporation to become deep groundwater recharge are difficult to obtain. The estimation of transmission losses is also required to provide adequate in stream flow requirements to maintain healthy stream ecosystems. In addition, the effect of transmission losses on river flow has direct implications on water supply planning issues such as water consumption, water conservation and groundwater recharge.

In this study, literatures related to recharge through ephemeral stream have been reviewed and compiled. There have been several attempts to quantify ephemeral stream recharge using different methods. The selection of most appropriate method often depends on the circumstances related to the individual study and the availability of the data. Of all the methods reviewed in this report, the combined use of differential equations physical based and regression offer the most promise and seem more realistic as they consider the physical processes related to losses and recharge to study the generic form of the equations and then use regression to develop site specific prediction equations.