The study had three main goals: (1) to assess the vulnerability of groundwater-dependent agriculture to climate variability, (2) to identify historical and current processes of adaptation to the vagaries of climate in the region— these refer to both system wide adaptations and individual farmer’s adaptations, and, (3) to assess the use of and needs for seasonal climate forecast information in agricultural decision making. The report is targeted at institutional stakeholders (i.e., agricultural extension personnel), physical scientists (particularly climatologists), and policymakers (at the level of NOAA and other federal agencies). Specific recommendations are made to these groups in order to improve the delivery of seasonal forecasts, set research priorities, and inform public policy.

This report provides a simplified method to be used for evaluating the skin friction and tip resistance of axially loaded drilled shafts. A summary of literature and current practice was completed and then a comprehensive set of field and laboratory tests was performed. Several soil samples were collected from different sites from Arizona and surrounding states. Large scale direct shear apparatus was developed and used to determine the friction between soil and concrete. Finite element analyses were conducted on several prototype cases to determine effect of soil parameters such as dilation on the skin friction values. A step-by-step simplified approach was introduced to determine the skin and tip resistance of drilled shaft foundations in gravelly soils. An example application was presented to guide users in utilizing the simplified approach.