Estimation of groundwater recharge in Wadi Al-Yammaniyah,Saudi Arabia

Groundwater recharge by natural replenishment for the unconsolidated alluvial aquifer in Wadi Al-Yammaniyah is estimated on a daily basis instead of the conventional monthly basis The study reveals that during the two-year period (1978 and 1979), the estimated recharge in the area is about 40% of the total average annual rainfall of 155 mm Subsurface underflow estimated at 36×10⁻⁶ m³/yr from the Wadi Al-Yammaniyah aquifer occurs in the vicinity of Wadi Ash-Shamiyah A comparison of the recharge and extracted volumes of water from the aquifer indicates that there is a net increase of 10 million m³ and 38 million m³ of water in the storage for 1978 and 1979, respectively