Trend between the renewal rate of the aquifer and the extreme climate events

Groundwater storage is already over-tapped in many regions, yet available subsurface storage could be utilized to meet the combined demands of agriculture, industry, municipal and domestic water supply, and ecosystems during times of shortage. For arid to semi-arid Oman, groundwater is the key for its sustainability. Agriculture accounts for as much as a 92% of the water use there, from which 56% is drawn from agricultural wells and another 33% from Aflaj systems. The general trend for unconfined aquifers in Oman is drying and expected to be worsening under climate change scenarios. The joint behaviors of climate and groundwater are poorly understood, especially the effects of increased frequency and intensity of extreme events to the replenishment of groundwater aquifers. In this proposed study, future intensity and frequency of dry periods and extreme precipitation events combined with warming trends will be predicted using the state-of-the-art GCMs from the Coupled Model Inter-comparison Project Phase 5 (CMIP5). These changes will later be incorporated with a transient groundwater flow model to understand the response of subsurface flow to the extreme climate events. The results will be useful for planning countermeasures for aquifer depletion and quality degradation due to saline water intrusion and increased frequency of flood and droughts under changing climate conditions.