Saguaro National Park encompasses two geographically distinct areas: Rincon Mountain District and Tucson Mountain District. Of the two, only Rincon Park has significant riparian habitat due to Tanque Verde Ridge. The scope of this study includes Rincon Creek, its tributary riparian areas and Tanque Verde Creek riparian tributary areas within or immediately adjacent to the Park. Both of these creeks have riparian resources that will likely be impacted by proposed development adjacent to the Park boundaries.

We have an opportunity now that we have not had in the past 25 years to develop some comprehensive planning so that we can continue to enjoy the environmental amenities that make it so nice to live in Tucson. These species include not only the common one that we live with on a day to day basis, but also some of the rare species that most of us are not lucky enough to see (but still care about preserving).

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.