Characteristics of groundwater recharge under deep vadose zone at Luancheng, China

Accurate estimation of groundwater recharge is essential for efficient and sustainable groundwater management in the semi-arid region. In this paper, a lumped parametric approach (EARTH model) was used to evaluate the actual groundwater recharge at Luancheng experimental station under semi-arid climatic conditions and deep groundwater tables. The model was calibrated by both soil moisture and groundwater level fluctuations. The modelling results indicate the amount of the recharge is 721.66mm during the modelling periods, about 22.3% of the total rainfall and irrigation, and a mean daily recharge rate is 0.54 mm/d, which is accordant with the result of 0.56 rnm/d estimated by the tritium tracing. Based on the simulation result, the stepwise regression analysis method was used to determine the dominant factors that influence the recharge rate (or leakage of root layer) under deep water table depth, and the correlative model was founded between recharge rate and the determinants.