Using Tracer Techniques to Characterize Streamflow Gains and Losses

Research Task: WRD
Task Manager: Cory Williams

Gain-loss characteristics of streams are used in water-quantity and water-quality studies to understand the interactions between surface-water and ground-water systems. Streamflow in high-gradient streams is often divided by cobble bars or boulders in areas of relatively flat gradient or consists of riffles and waterfalls in areas of steeper gradient. These conditions are less than ideal for conventional discharge measurements using current meters, which creates challenges for accurate and expedient determination of gain-loss characteristics of river reaches. Streamflow can be more accurately measured under these conditions using tracer techniques, but only along reaches where streamflow losses to the ground-water system are minimal. Modification of continuous tracer injection methods was needed to accommodate study reaches where losing reaches are present or where the presence of losing reaches is unknown. We expanded the continuous tracer technique to multiple injection locations to measure gain-loss characteristics in study areas that contain losing reaches under steady-state conditions. Each injection location provides a point measurement of streamflow that can be compared to other locations to determine relative streamflow gain and loss within any reach.

 For more information contact Cory Williams