The Science

Solute tracer studies are the most common way to measure the role of the near-stream subsurface, or hyporheic zone, in stream processes. However, such studies are limited in scope and known to be biased toward only the shortest and fastest flowpaths. In contrast, some ecosystem processes of interest only occur along slower or longer flowpaths. Thus, scientists have an incomplete understanding of the hyporheic zone.

In the past, flowpaths beyond a “window of detection” were necessarily overlooked, along with ecosystem processes along these paths. Using a new approach, scientists can quantify what was lost, shattering the former window of detection and including a more complete understanding of hyporheic zones in predictions and forecasts. Ultimately, this study initiates a new approach to stream solute tracers, overcoming a limitation that has plagued the tracer technique for more than 30 years.

The Impact

The approach pioneered in this study enables scientists to assess more accurately the timescale of water and solute transport in study reaches. This is a critical variable in predicting the transport, transformation, and fate of nutrients, pollutants, and energy in river corridors.

Summary

Although water and solute transport are known to have timescales spanning orders of magnitude, the full range is seldom observed. Here, a new approach is established to see longer-in-time flowpaths, enabling scientists to systematically probe portions of the system traditionally unstudied.

References