Measuring flows using streambed temperature

Posted on June 26, 2010

How best to study the exchange of water between  surface flows and subsurface aquifers?  Although a number of methods are available, most have drawbacks in terms of the effort involved, the variable quality of the data obtained, or the potentially adverse impacts of environmental intervention.  A relatively easy and effective monitoring solution relies on changes  in streambed temperature to track flows between surface water and groundwater.  Research on a perennial stream in Mississippi, carried out as part of a study to assess fate of agricultural contaminants, shows that long duration data collected during extreme high-flow events (in this case, Hurricane Katrina and Hurricane Rita in 2005) can give reliable indications of the direction and rate of vertical exchange.  At the study site the stream normally received water from the aquifer, which was higher than the streambed, but during strong rain events the levels of stream and aquifer reversed and water recharged the aquifer.  At such times the amount of water moving down through the streambed was about 1% of the total discharge. 

Reference:  Barlow, J.R.B. & Coupe, R.H.  2009.  Use of heat to estimate streambed fluxes during extreme hydrologic events.  Water Resources Research 45, W01403, doi:10.1029/2007WR006121.