Impact of floodwaters on vertical water fluxes in the deep vadose zone of an alluvial aquifer in a semi-arid region

Abstract

ABSTRACTThe spatial and temporal variation of moisture distribution, overall water balance and quantity of infiltrated water in the vadose zone of the Sidi Bouzid Plain (Tunisia) during successive flooding events is quantified in this study. The variation in water content in response to environmental factors such as evaporation and water root uptake is also highlighted. One-dimensional flow simulations in the deep vadose zone were conducted at three spreading perimeters located near Wadi El Fekka. The hydraulic boundary conditions of a time-dependent water blade applied to the soil surface were determined from measured flood hydrographs. For the chosen wet year, the successive flooding events contributed to a significant artificial recharge of the natural groundwater. Although the soil hydraulic parameters did not vary strongly in space, flow simulations showed significant differences in the overall water balance of approximately 9–16% for the various spreading perimeters.