Restoration of Wadi Aquifers by Artificial Recharge with Treated Waste Water

Abstract

Fresh water resources within the Kingdom of Saudi Arabia are a rare and precious commodity that must be managed within a context of integrated water management. Wadi aquifers contain a high percentage of the naturally occurring fresh groundwater in the Kingdom. This resource is currently overused and has become depleted or contaminated at many locations. One resource that could be used to restore or enhance the fresh water resources within wadi aquifers is treated municipal waste water (reclaimed water). Each year about 80 percent of the country's treated municipal waste water is discharged to waste without any beneficial use. These discharges not only represent a lost water resource, but also create a number of adverse environmental impacts, such as damage to sensitive nearshore marine environments and creation of high-salinity interior surface water areas. An investigation of the hydrogeology of wadi aquifers in Saudi Arabia revealed that these aquifers can be used to develop aquifer recharge and recovery (ARR) systems that will be able to treat the impaired-quality water, store it until needed, and allow recovery of the water for transmittal to areas in demand. Full-engineered ARR systems can be designed at high capacities within wadi aquifer systems that can operate in concert with the natural role of wadis, while providing the required functions of additional treatment, storage and recovery of reclaimed water, while reducing the need to develop additional, energy-intensive desalination to meet new water supply demands.

Trends of Climate Change in Saudi Arabia: Implications on Water Resources

“…These dams are often used as potential sources for drinking water. The southern part has the valley basins, which often dry up due to higher evaporation, excessive use of water and low precipitation [26][27][28]. Past studies reported an approximately 50% increase in evaporation between 2011 and 2050 [2].…”

Managed Aquifer Recharge (MAR) Economics for Wastewater Reuse in Low Population Wadi Communities, Kingdom of Saudi Arabia

“…Notes: 1 The assumed total dynamic head is estimated to be 122 m; 2 Real cost of electric power in the KSA is estimated to range from $0.05-0.15/kw-h.…”

“…For centuries, these agrarian communities relied upon shallow groundwater resources to supply potable and irrigation water demands [1]. Anthropogenic impacts, including over-pumping and contamination, have combined to deplete or render unusable the groundwater in shallow alluvial aquifers underlying the wadis [1][2][3]. Because of the low population density, generally small contribution of crop production to the national economy, and the arid nature of the climate, there are quite limited options available to supply the necessary water to maintain these populations.…”

Experimental Measurement of Diffusive Extinction Depth and Soil Moisture Gradients in a Dune Sand Aquifer in Western Saudi Arabia: Assessment of Evaporation Loss for Design of an MAR System

“…When rainfall does occur, it is an intense event that causes flash floods through ephemeral channels, known as wadis [2,3]. Flood water passing through the wadi channels allows some recharge to the underlying alluvial aquifer, but most of the water is lost to discharge to tidal water or evaporates with only 3% to 10% being captured as recharge [4][5][6]. Recent research on future climatic changes in this region suggests that a greater degree of variability will occur with longer drought periods and more intense rainfall events with corresponding floods [7,8].…”