Describes a number of streams within watershed planning units and prioritizing these streams according to their existing contribution to the overall conservation of biological diversity in Pima County. Over 50 percent of the priority streams within the County are found within the Altar Valley and the Cienega Rincon area.

Provides an overview of Pima County's (1) natural, constructed and administrative form makers, (2) the origins and implementation of planning and zoning legislation and regulations, and (3) a decade-by-decade review of some of the major land use decisions made within Pima County since the 1920s.