Abstract
Rapid drainage flow increases at the 2·4 m depth in the Coshocton lysimeters were related to the storms that most likely initiated them. The time lapsed between the onset of the storm and rapid drainage response was less than 2 days in 98 per cent of the 389 cases observed in five lysimeters between 1976 and 1982.A pronounced seasonal variation in the frequency of rapid responses was found, with the first quarter of the year comprising the highest number of events. During winter, when soil moisture is generally high, a storm yielding 6 mm/d was already sufficient to initiate this response while summer storms producing more than 50 mm/d did not always initiate a drainage response. Average drainage yield per event was found to be more closely related to the type and usage of a soil than to seasonal effects.