Enhancement of infiltration rate of clogged porous beds in the vicinity of dams in arid zones by the roots of indigenous Ziziphus spina-christ trees

Siltation of reservoir beds of recharge dams in arid climates seriously diminishes dams' storage capacity, lessens infiltration and deep percolation rates, increases water loss via evaporation, and ultimately lowers the recharge efficiency to the underlying unconfined aquifer. This study explores possibilities for enhancing the infiltration rate of a silt-clogged recharge-dam bed by cultivation of the Christ's thorn tree (Ziziphus spina-christ), locally known as Sidr, as a hydro-ecoengineering technique. We experimentally quantified the effect of this indigenous tree on the infiltration rates and moisture dynamics in soil tanks and pots. Descriptive statistics and a two-way-repeated-measures analysis at p <.05 were used to compare the effects of the Christ's thorns' roots and plant growth over time on the infiltration rate of silty loam soils (sediments) in the pots and tanks. The Christ's thorn trees significantly increased the steady state infiltration rate of the sediments by 1.9–5.9 times and by 1.7–3.3 times compared to the control (bare soil) in the tank and pot experiments, respectively (p <.05). This study demonstrates the possibility of applying hydro-ecoengineering techniques for improving the infiltration rate and hence the recharge efficiency of recharge dams in arid areas.