ANALYSIS OF PRECIPITATION RECHARGE USING OBSERVED DATA OF LYSIMETER

Based on the lysimeter data taken from water balance experimental station in Zhengzhou,we have analysed the features of lag and the yearly variation of the infiltration recharge process.By calculating precipitation recharge coefficient,we have set up the quantitive relationship between precipitation and recharge in large time scale and evaluated precipitation recharge amount under various precipitation and lithology of vadose zone.Analytic results indicate that the precipitation recharge coefficient becomes larger along with increasing of the water table depth while water table is shallower than 1 m and becomes smaller under 1 m and then tends to stabilize below 3 m.It is also clear that among homogeneous vadose zone,precipitation recharge coefficient of sand soil is larger than that of clay soil,and moreover,the precipitation recharge coefficient of sabulous clay involved lamella clay is minimum.