A study of soil moisture controls on stremflow behaviour: results for the OCK basin, United Kingdom

Abstract

In humid temperate areas ground wetness plays a key role in storm runoff generation, but until recently there have been no instruments capable of providing continuous, reliable, records of changing soil moisture conditions in the field. A new instrument, the IH capacitance probe, can provide continuous measurements of soil water contents. Together with rainfall records these data have been used to study the variations in river flow response of a medium sized (234 km2) rural catchment. Daily flows were simulated, firstly using a standard rainfall runoff model (MACRES) with conventional hydrological and climate data and, secondly, by replacing the net rainfall calculation by a simple functional relationship to the measured soil moisture contents. It was found that incorporating soil moisture measurements in the runoff model: a)Reduced the length of record required for model calibration, b) Improved the simulation of strearnflow.