An integrated conceptual and modeling framework for studying groundwater recharge in and and semi-arid regions

Rapid population growth in arid/semi-arid regions like the southwestern U.S. is increasing the demand and reliance on groundwater resources each year. These resources are limited and require reliable long-term management plans to ensure sustainability. Basin scale groundwater models are typically developed and used as the primary tool supporting management plans. Successful long-term plans depend heavily on specifying realistic rates of recharge to the saturated zone. Typical groundwater models for basins in more and environments however, generally over-simplify recharge. In most cases this is inappropriate because recharge is complex, depends on many factors, and exhibits pronounced spatial and temporal variability within a basin. Two key steps are proposed to obtain more accurate recharge estimates. First, important sub-regional scale recharge mechanisms within the basin need to be identified. Second, important surface and subsurface hydrologic processes associated with these mechanisms must be evaluated and better understood.