Management of Groundwater Resources in Eastern Saudi Arabia
Effective management of groundwater in arid countries, such as Saudi Arabia, is an important factor in sustainable development. A regional numerical simulation model of a multi-aquifer system including the Dammam and Umm Er Radhuma (UER) aquifers was developed to assess the behaviour of the aquifer system under long-term water stresses. The model was utilized to predict the responses of the aquifer system under three alternative pumping schemes over a planning horizon of 31 years (1995-2025). Model results postulate that dewatering of the Dammam aquifer will occur at low productivity sites and along the outcrop with the current trend towards increasing abstraction. The UER will exhibit significant cones of depression at large irrigation projects. Aquifer dewatering and drawdowns will be minimal with the conservation alternative. This management scheme should be adopted for the future development and protection of groundwater in the province.
Effect of Natural Pozzolana and Sodium Dodecyl Sulfate on Clathrate Hydrate Formation Kinetics with CO2 as a Guest-Gas
The scarcity of natural freshwater resources drives research efforts worldwide on developing innovative and energy efficient desalination technologies to fulfill the needs for freshwater. Multistage flash distillation and reverse osmosis desalination are the most applied industrial methods for desalination; however, these two methods are energy intensive. With the trend of the world to go green, the method of clathrate (gas) hydrate desalination is attracting more interest as it is believed to be a low energy use method. In this study, carbon dioxide was used as a guest gas in gas hydrate formation experiments enhanced by the addition of SDS and pozzolana powder having main particle size of 6  m as kinetic promoters. Stirring can improve the kinetics of the process by breaking the hydrate thin layers formed on top of the solution at the onset of hydrate induction period and also due effect of mixing on improving heat dissipation. Sodium dodecyl sulfate helps increase gas consumption and water recovery. A Synergetic effect on water recovery and the kinetics of the process was observed when both SDS and pozzolana powder were used all together.
Flow of fossil groundwater
Summary The great groundwater basins of North Africa and Arabia extend over an area of some 6.5 million square kilometres. Gradients on the isopiezometric surfaces of their confined ground-waters are generally interpreted as indicating present-day flow of groundwater. Can such flow occur in basins where most or all of the groundwater is fossil and where effective infiltration and recharge may have ceased some 10 000 years ago? Assuming that there is indeed no current recharge in these arid and sem-arid regions, the paper identifies seven groups totalling 12 possible mechanisms which can contribute in varying degrees to maintaining flow of groundwater long after effective recharge has ceased. These are: (i) Residual heads; (ii) Tilting of basin; (iii) Compaction effects, in terms of sediment loading, basalt loading and water loading/unloading; (iv) Thermal drive; (v) Gas drive; (vi) Lowering of discharge level, by tectonic displacement, by pressure bursts and by collapse of cover; and (vii) Evaporation in the discharge zone, such as lowering of lake levels and evaporation from sabkhas. Nine additional mechanisms were considered but rejected. Combinations of these mechanisms can produce heads inducing flow of fossil groundwater, but appear to be insufficient to account for present hydraulic regimes without some current surface recharge. The findings have direct application to studies leading to the development, use and management of these major water resources of the arid zones of the Sahara and Arabia.