Estimation of Groundwater Recharge from Precipitation and Evapotranspiration by Lysimeter Measurement and Soil Moisture Model

Abstract

Estimation of water fluxes, such as groundwater recharge and loss, is vital for water resources assessment and planning. In this study, lysimeter measurements at the Wudaogou Hydrological Experiment Station in the Huaihe River plain region are used for analyzing characteristics of groundwater recharge from precipitation and groundwater loss due to evapotranspiration. A multilayer soil moisture model integrating water fluxes between vegetation, soil, and aquifer is used for simulating soil moisture dynamics and groundwater recharge and loss. The model is calibrated against observed soil moisture content from 1994 to 2000. Model validation is conducted by comparing model simulated groundwater recharge and loss with the corresponding lysimeter-measured values. Statistical results from lysimeter measurements reveal influences of vegetation, depth to groundwater, and soil moisture content on groundwater recharge and loss. Modeling results prove that the model is able to reliably simulate soil moisture content and water fluxes. Water budget analysis shows that the multiyear mean of groundwater recharge is approximately 25% of the mean of potential evapotranspiration and the multiyear mean groundwater evapotranspiration loss is 22% of the precipitation amount.