Groundwater recharge in a macroporous clay-rich aquitard as affected by soil water saturation and storm flow events

Three typical seasonal situations of groundwater infiltration through the unsaturated zone of a macroporous clayey till soil are evaluated. In the winter period, precipitation rapidly percolates to the groundwater table. Consequently, primary risk of pesticide leaching to the shallow groundwater excists when the pesticides are applicated in late autumn and winter.