Rainbow Valley Wildlife Linkage Special Management Area

Rainbow Valley Corridor
© Jim Vaaler

Size: 23,365 acres

The purpose of the Rainbow Valley Wildlife Linkage Special Management Area (SMA) is to ensure that the wildlife habitat and linkages between the Sonoran Desert National Monument (SDNM) and Sierra Estrella Wilderness are protected as future development occurs. In January of 2007, the City of Goodyear adopted the Sonoran Valley General Plan Amendment and subsequently annexed a 67 square-mile area, including the Rainbow Valley. Projections at that time estimated 90,000 housing units with nearly 250,000 residents by buildout. To support this growth, there are plans for a new I-11 freeway and a Sonoran Parkway as well as the potential for a new rail line and other utility infrastructure. Given this substantial planned growth for the area, it is essential to establish a plan for the Rainbow Valley that preserves a functioning wildlife habitat and linkages.

Natural Values

The Rainbow Valley is nestled between two mountainous areas. To the east, the knife-edged ridgelines, steep slopes, and rough rocky canyons of the Sierra Estrella Mountains tower above the Rainbow Valley some 2,600 feet from the range’s tallest peak, Butterfly Mountain. To the west, the North Maricopa Mountains, a wilderness area within the SDNM, differs from a single ridgeline mountain by having a mix of isolated peaks bisected by numerous washes.

Javelina

Javelina are one of many wildlife species that travel the
Rainbow Valley corridor; Courtesy AZGF

Each mountain range creates numerous small washes that cross the Rainbow Valley and form the headwaters of Waterman Wash. The valley is dominated by palo verde-mixed cacti plant associations. Vegetation includes creosote bush, cholla, barrel cactus, plus trees like ironwood, mesquite, and foothill palo verde. As visitors climb in elevation, plant variety changes to include ocotillo, hackberry, acacia, and triangle-leaf bursage.

The Rainbow Valley has significant wildlife movement between the Sierra Estrella and Sonoran Desert National Monument. A recent statewide Arizona Missing Linkages study done by Northern Arizona University builds upon a wildlife linkages study authored by the Arizona Game & Fish Commission and the Arizona Department of Transportation and documents the critical linkages in the Rainbow Valley. The study identified over a dozen species including desert bighorn sheep, mule deer, Gila monster, desert tortoise, bobcat, mountain lion and javelina in the Rainbow Valley. Collaborative, early-stage, planning among numerous agencies and local communities has occurred and strong consensus exists among the collaborating groups for maintaining functioning connectivity.

Recreational Opportunities and Cultural Significance

Rainbow Valley offers ideal opportunities for photographers and wildlife enthusiasts. From the iconic desert bighorn sheep to other Sonoran Desert residents like mule deer, mountain lions, bobcats, javelinas, and Gila monsters, recreationalists will find plenty of opportunities to catch a glimpse of nature at its wildest.

The region contains significant cultural and historic trails. Father Kino, in 1699, first recorded crossing this plain, climbing to a low pass in the Sierra Estrella, and seeing a multitude of Pima Villages along Gila River. In 1858, Butterfield Overland Mail Company began an overland mail route from St. Louis to San Francisco. This historic route passed through this area to Fort Yuma.

Benefits of a Special Management Area

Lands within the proposed Rainbow Valley Wildlife Linkage SMA are faced with a range of pressures that threaten the long term sustainability of the area’s ecological and recreational values. The proposed SMA will protect wildlife habitat and linkages while permitting opportunities for a diverse set of recreational uses for tourists and future growth of neighboring West Valley communities. The Rainbow Valley Wildlife Linkage SMA does not prescribe the location or type of wildlife accommodations, but rather it requires that any future development on these Federal lands be constructed in accordance with the best wildlife management practices of the time.

Protecting this fragile piece of Sonoran Desert and maintaining critical wildlife linkages will safeguard this important portion of western Maricopa County’s living legacy for generations to come.