UC Santa Barbara

Draft rules for artificial recharge operations, which use recycled waste water as a source water, require minimum travel times to production wells in California. Deliberate tracer experiments are the accepted method for determining travel times. An example of a tracer experiment using sulfur hexafluoride is discussed at an artificial recharge site located within a regional water table depression. The study shows the complexity in interpreting travel times because of the influence of recharge rates and water production. It also demonstrates the effectiveness of recovering recharged water at spreading basins surrounded by production wells.