A NEW METHOD FOR MEASURING NEAR-SURFACE MOISTURE BUDGETS IN HYDROLOGICAL SYSTEMS

Preliminary results from a groundwater experiment set up near Matamata (New Zealand) reveal that confined aquifers can act as giant weighing lysimeters, with pore water pressures giving real-time measures of ch anges in amounts of surface and near-surface water. This opens the pos sibility of water balance studies at the scale of hectares using measu rements from a single site. Given suitable confined aquifers, the tech nique has application in various environments for hydrological measure ments as diverse as quantification of evapotranspiration loss, areal p recipitation measurement, monitoring the water content of an accumulat ing snowpack, and net lateral groundwater transfers in unconfined aqui fers.