FINDING GROUNDWATER-CONTAMINANT PLUMES USING MEASUREMENTS IN DISCHARGE ZONES
Semi-quantitative methods are towed bottom contact probes (towed slowly along the sediment water interface and measureing electrical conductivity and gamma radiation) and thermal probes (inserted a few tens of centimeters below the interface).
Quantitative methods are mini-piezometers (permanent, temporary or portable; used to measure hydraulic gradient, hydraulic conductivity and porewater concentration); seepage meters (used to measure water flux directly and in combination with piezometers providing vertical hydraulic conductivity); tracer studies; and manual coring for stratigraphic and geochemical information near the interface.
Cross checking of information from these methods can provide a level of confidence that is seldom possible from the information based on conventional hydrogeological methods.