The Integrated Storage-Flux Model For Groundwater Storage and Baseflow Dynamics

The integrated storage-flux model is proposed based on the storage-flux relations and tested against the Richards equation in the idealized stream-aquifer system. The groundwater storage-baseflow relation and soil water storage-effective infiltration relation are identified by numerical analysis of the Richards equation under the steady-state conditions. The relationship between groundwater and baseflow exhibits a linear relation, while the relationship between soil water storage and effective rainfall is appeared to be the inverse linear relation. This inverse linear relation agrees with the results of Duffy (1996) and Lee (1993) who investigated the storage-flux relations on the hillslope terrain. The integrated storage-flux model is constructed by coupling the storage-flux relation with water balance equation. The coefficients of the integrated storage-flux model are based on the steady-state storage-flux relations and are calibrated against the response of the Richards equation. Under the step input condition, the dynamic response of the integrated storage-flux model agrees favorably with that of Richards equation. The development of the integrated storage-flux model has implication for predicting the groundwater storage and baseflow when the limited hydro-geologic data are available. Acknowledgement This research was supported by a grant (2-2-1) from Sustainable Water Resources Research Center of 21st Century Frontier Research Program.