Four adjacent ranges define the western edge of the Avra and Altar valleys. Even though desert ironwood has dark green, lush foliage much of the year, this tree is almost exclusively a Sonoran Desert species. The same is true of the distribution of saguaros, foothill palo verdes, fishhook barrel cacti, and most of the hundreds of other plants growing here. These rugged ranges also provide natural refuges for a variety of wildlife, including desert bighorn and migratory pollinators. In addition to the biological resources, the area has abundant rock art sites and other archaeological sites.

Conservation of the Tortolita Alluvial Fan landscape has been promoted by Pima County and Town of Marana over the past two decades. An interdepartmental team was formed to evaluate flood and debris flow hazards and the potential to create an expanded Tortolita Fan Preserve. This report provides an overview of the alluvial fan characteristics and evaluates information on the significance of the biological and cultural resources to determine of the area meets the criteria to create a federal preserve.