In the early 1990s, a study of the Tanque Verde Creek by Dr. Julie Stromberg and others described the relationship between the depth to groundwater and the health of the mesquite woodland habitat in the area. This report revisits the Stromberg study to describe variations in groundwater levels since the report was completed early last decade. They identified around 3,000 acres of riparian vegetation in the Tanque Verde-Agua Caliente shallow groundwater zone.

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.