Groundwater response to precipitation



Rapid responses of shallow groundwater tables, located between the soil surface and depths of about 10 m, to heavy storms of at least 30 mm/d are quite frequently observed. Heath [1983], for instance, reported rapid response to occur about twice per month in 1978 in an observation well near Washington, D.C. The rise and fall of the water table was more pronounced when it was closer to the soil surface; when the water table was deeper than approximately 1.8 m, the rises were spread over a longer time interval and were less pronounced in height. Figure 1 shows another example from an observation well near Charlottesville, Va., where a response of the water table at a depth of 7.0 m was observed within 2 days following a 2-day storm that yielded 130 mm.