Simulating the effect of capillary flux on the soil water balance in a stochastic ecohydrological framework

Abstract

Groundwater uptake can play a major role in the survival of vegetation in semiarid areas, but this has not yet been included in an earlier developed ecohydrological stochastic framework. In this paper we provide a piecewise linear equation which includes capillary fluxes from shallow groundwater in the loss function of the ecohydrological stochastic model. The results indicate that this model is able to simulate the capillary fluxes, and the model also reflects the impact of the fluxes on the soil moisture balance. In addition, the results are analytically tractable and allow calculation of the probability density functions of soil water saturation and water stress for different groundwater depths below the root zone. Copyright 2008 by the American Geophysical Union.