Methods of In Situ Assessment of Infiltration Rate Reduction in Groundwater Recharge Basins

As an alternative to the use of tracers, easy-to-measure soil moisture dynamic parameters (e.g., water content) provide in situ estimates of the infiltration rate reduction state of a soil medium. For instance, managed aquifer recharge operations control the hydraulic state of their infiltration basinsby measuring the infiltrated volume under constant head conditions. Instantaneous profile measurement systems can be used to manage the basins by determining the reduction of the infiltration rate over time. This study combines the empirical methods of Libardi, the self-developed water contentand root mean square difference-based procedures and the trigger time method, to get a similar reproduction of tracer results from river water spreading basins. The methods based on water contentshowed a good fitting in comparison to the results obtained with the tracer experiment and represent a promising source for detecting changes in the flow impedance during infiltration events.