The park occupies eastern San Diego County and reaches into Imperial and Riverside counties, enveloping two communities: Borrego Springs, which is home to the park's headquarters, and Shelter Valley.
ABDSP includes 500 mi (800 km) of dirt roads, 12 designated wilderness areas, and 110 mi (180 km) of hiking trails to provide visitors with many opportunities to experience the park's unique version of the Colorado Desert environs. Park information and maps, interpretive events and displays and listening devices for the hearing impaired are all available in the Visitor Center.[2] ABDSP has Wi-Fi access to the Internet in various sections of the park, as do 55 other California state parks.
Many visitors approach ABDSP from the east-Coachella Valley side via County Route S22 and State Route 78. Visitors can also approach from the west-Pacific Ocean side via California County Routes S79 or S67 and add experiences of passing through the high and forested Laguna Mountains, such as in Cuyamaca Rancho State Park.[3] These highways climb from the coast to 2,400 ft (730 m) above sea level, then descend 2,000 ft (610 m) down into the Borrego Valley in the center of the park.
The great bowl of the surrounding desert is surrounded by mountains, with the Vallecito Mountains to the south and the highest Santa Rosa Mountains to the north. They are in the park's wilderness area, without paved roads and with the only year-round creeks in ABDSP.
The park contains bajadas and desert washes; rock formations and colorful badlands, large arid landscapes, and mountains. The bajadas are predominantly creosote bush-bur sage with creosote bush (Larrea tridentata) and the palo verde-cactus shrub ecosystems with the palo verde tree (Parkinsonia microphylla), cacti, and ocotillo. In the washes, Colorado/Sonoran microphylla woodlands can be found. These woodlands include such plants as smoke tree (Psorothamnus spinosus), velvet mesquite (Prosopis velutina), and catclaw (Acacia greggii).[4]
Some areas of ABDSP are habitats for the Peninsular bighorn sheep, often called desert bighorn sheep. Few park visitors see them, and the sheep avoid human contact. Observers count this endangered species to study the population, and monitor its current decline from human encroachment.[6]
Panoramic view from Font's Point westward over Borrego Valley to the Laguna Mountains
The expanses of ABDSP's eroded badlands also provide a different view into the region's long-vanished tropical past. The inland of southeastern California was not always a desert. Paleontology, the study of the fossilized remains of ancient life, is the key to understanding this prehistoric world. ABDSP has an exceptional fossil record which includes preserved plants, a variety of invertebrate shells, animal tracks, and an array of bones and teeth. Most fossils found in ABDSP date from six million to under a half million years in age (the Pliocene and Pleistocene epochs), or about 60 million years after the last dinosaur age ended.[7]
ABDSP lies in a unique geologic setting along the western margin of the Salton Trough. This major topographic depression with the Salton Sink having elevations of 200 ft (61 m) below sea level, forms the northernmost end of an active rift valley and a geological continental plate boundary. The trough extends north from the Gulf of California to San Gorgonio Pass, and from the eastern rim of the Peninsular Ranges eastward to the San Andreas Fault zone along the far side of the Coachella Valley.
Over the past seven million years, a relatively complete geologic record of over 20,000 ft (6,100 m) of fossil-bearing sediment has been deposited within the park along the rift valley's western margin. Paleontological remains are widespread and diverse, and are found scattered over hundreds of square miles of eroded badlands terrain extending south from the Santa Rosa Mountains into northern Baja California in Mexico.
Both marine and terrestrial environments are represented by this long and rich fossil record. Six million years ago, the ancestral Gulf of California filled the Salton Trough, extending northward past what would become the city of Palm Springs. These tropical waters supported a profusion of both large and small marine organisms. Through time, the sea gave way as an immense volume of sediment eroded during the formation of the Grand Canyon spilled into the Salton Trough. Little by little, the ancestral Colorado River built a massive river delta across the sea way. Fossil hardwoods from the deltaic sands and associated coastal plain deposits suggest the region received three times as much rainfall as now.
The Anza-Borrego region gradually changed from a predominately marine environment into a system of interrelated terrestrial habitats. North of the Colorado River Delta and intermittently fed by the river, a sequence of lakes and dry lakes has persisted for over three million years. At the same time, sediments eroded from the growing Santa Rosa Mountains and other Peninsular Ranges to spread east into the trough. These sediments provide an almost unbroken terrestrial fossil record, ending only a half million years ago. Here, the deposits of ancient streams and rivers trapped the remains of wildlife that inhabited a vast brushland savannah laced with riparianwoodlands.
This record of changing environments and habitats includes over 550 types of fossil plants and animals, ranging from preserved microscopic plant pollen and algalspores to baleen whale bones and mammothskeletons. Many of the species are extinct and some are known only from fossil remains recovered from this park. Combined with a long and complete sedimentary depositional sequence, these diverse fossil assemblages are an unparalleled paleontologic resource of international importance.
Both the Pliocene-Pleistocene epoch boundary and the Blancan-IrvingtonianNorth American land mammal ages boundary fall within the long geological record from the Anza-Borrego region. Environmental changes associated with these geological time divisions are probably better tracked by fossils from the Anza-Borrego region than in any other North American continental platform stratum. These changes herald the beginning of the Ice Ages, and the strata contain fossil clues to the origin and development of modern southwestern desert landscapes.
The first fossils, marine shells from the ancient Gulf of California and freshwater shells from a prehistoric era Lake Cahuilla, precursor of present-day Salton Sea, were collected and described by William Blake in 1853. Blake was the geologist and mineralogist for the Pacific Railroad Surveys commissioned by Congress and President Franklin Pierce to find a railway route to the Pacific. Blake first named this region the Colorado Desert.
Marine environments such as outer and inner shelf, platform reef, and near shore beach and lagoon, are all represented within the "Imperial Formation". As the sea became more shallow, estuarine and brackish marine conditions prevailed, typified by thick channel deposits of oyster and pecten shell coquina that now form the "Elephant Knees" along Fish Creek. Many of the marine fossils are closely related to forms from the Caribbean Sea. They document a time before the Isthmus of Panama formed, when the warm Gulf Stream of the western Atlantic Ocean invaded eastern Pacific Ocean waters.
As North and South America connected about three million years ago, terrestrial faunal north-south migrations began on a continental scale called the Great American Interchange, and are present in Anza-Borrego's fossils. Animals such as giant ground sloths and porcupines made their first appearance in North America at this time.
The oldest terrestrial vertebrate fossils from the Colorado Desert predate the late Miocene invasion of the Gulf of California. These very rare fossils, which include a gomphothere (elephant-like mammal), rodent, felid and small camelid, and were collected from 10– to 12-million-year-old riverine and near-shore lake deposits. However, the most significant and abundant vertebrate fossils have been recovered from the latest Miocene through late-Pleistocene riverine and flood plane deposits of the Palm Spring Formation in the Vallecito and Fish Creek Badlands and Ocotillo Conglomerate exposed in the Borrego Badlands. These fossil assemblages occur in a 3.5-million-year-long, uninterrupted stratigraphic sequence that has been dated using horizons of volcanic ash and paleomagnetic methods.
The Native Americans of the surrounding mountains and deserts included the Cahuilla, Cupeño, and Kumeyaay (Diegueño) Indian tribes. It was the homeland of these peoples for thousands of years, and their artists created petroglyph and pictogramrock art expressing their cultures.[8]
The Anza-Borrego Foundation (ABF), founded in 1967, is a non-profit educational organization and is the sole cooperating association of ABDSP. It manages all sales at the State Park Visitor Center and State Park Store.
The Anza-Borrego Institute, the education arm of ABF, provides in-depth educational courses to more than 100,000 visitors each year. The institute offers in-depth field programs, a fifth grade environmental camp, citizen science research, and Parks Online Resources for Teachers and Students. ABF's mission is to protect and preserve the natural landscapes, wildlife habitat, and cultural heritage of ABDSP for the benefit and enjoyment of present and future generations.[9]
Robin Halford. 2005. Hiking in Anza-Borrego Desert: Over 100 Half-Day Hikes (Anza Borrego Desert Natural History Association, Borrego Springs). ISBN0-910805-13-X
Lowell Lindsay and Lindsay, Diana. 2006. The Anza-Borrego Desert Region: A Guide to the State Park and Adjacent Areas of the Western Colorado Desert. Fifth Edition (Wilderness Press, Berkeley). ISBN0-89997-400-7
Serenity (film) – location shooting in the park for the 2005 feature film shows the environs.
Wild, Peter (2005). Marshal South, of Yaquitepec. Johannesburg, California: The Shady Myrick Research Project. p. 157. OCLC58796769. – Marshal South and his wife, Tanya, wrote a series of highly popular "Desert Refuge" articles (1940–1946) for the Desert Magazine about their primitive life in the desert. They lived in a home they called Yaquitepec on a mountaintop named Ghost Mountain near Blair Dry Lake
The Imperial Valley lies in the California counties of Imperial and Riverside. It is located in southeastern Southern California, and is the site of an urban area largely centered on the city of El Centro. The Valley is bordered by the Colorado River to the east and, in part, the Salton Sea to the west. Farther west lies the San Diego and Imperial County border. To the north is the Coachella Valley region of Riverside County, which together with Imperial Valley form the Salton Trough, or the Cahuilla Basin, also the county line of Imperial and Riverside counties, and to the south the international boundary with the U.S. state of California and Baja California.
Low Desert
The Low Desert is a common name for any desert in California that is under 2,000 feet (609.6m) in altitude. These areas include, but are not exclusive to, the Colorado Desert and Yuha Desert, in the Southern California portion of the Sonoran Desert. These areas are distinguished in biogeography from the adjacent northern High Desert or Mojave Desert by latitude, elevation, animal life, climate, and native plant communities.
Santa Rosa Mountains (California)
The Santa Rosa Mountains are a short mountain range in the Peninsular Ranges system, located east of the Los Angeles Basin and northeast of the San Diego metropolitan area of southern California, in the southwestern United States.
Colorado Desert
California's Colorado Desert is a part of the larger Sonoran Desert. It encompasses approximately 7 million acres (28,000 km2), including the heavily irrigated Coachella and Imperial valleys. It is home to many unique flora and fauna.
Equus scotti
Equus scotti is an extinct species of Equus, the genus that includes the horse.
Vallecito Mountains
The Vallecito Mountains are located in the Colorado Desert, in eastern San Diego County, Southern California. They are about 28 miles (45 km) north of the U.S. border with Mexico.
Ocotillo Wells, California
Ocotillo Wells is an unincorporated community in San Diego County, California. It is 3 miles (4.8 km) west of the Imperial County line on State Route 78 at an elevation of 163 feet (50 m). The name became official in 1962 when it was adopted for federal use by the Board on Geographic Names. A federally recognized variant name, Ocotillo, can cause confusion. The community of Ocotillo, in Imperial County, is only 29 miles (47 km) to the southeast.
Coyote Mountains
The Coyote Mountains are a small mountain range in San Diego and Imperial Counties in southern California. The Coyotes form a narrow ESE trending 2 mi (3.2 km) wide range with a length of about 12 mi (19 km). The southeast end turns and forms a 2 mi (3.2 km) north trending "hook". The highest point is Carrizo Mountain on the northeast end with an elevation of 2,408 feet (734 m). Mine Peak at the northwest end of the range has an elevation of 1,850 ft (560 m). Coyote Wash along I-8 along the southeast margin of the range is 100 to 300 feet in elevation. Plaster City lies in the Yuha Desert about 5.5 mi (8.9 km) east of the east end of the range.
Pinyon Mountains
The Pinyon Mountains are a mountain range in eastern San Diego County, Southern California. The range is protected within Anza Borrego Desert State Park.
Sawtooth Mountains (California)
The Sawtooth Mountains are a mountain range of the Peninsular Ranges system, located in eastern San Diego County, California.
Sawtooth Mountains Wilderness
The Sawtooth Mountains Wilderness is a federal wilderness area of 32,136 acres (130.0 km2) located in the Sawtooth Mountains in eastern San Diego County, California. It is located in the Colorado Desert, 35 miles (56 km) south of Borrego Springs, near Anza Borrego Desert State Park.
Santa Rosa Wilderness
The Santa Rosa Wilderness is a 72,259-acre (292.42 km2) wilderness area in Southern California, in the Santa Rosa Mountains of Riverside and San Diego counties, California. It is in the Colorado Desert section of the Sonoran Desert, above the Coachella Valley and Lower Colorado River Valley regions in a Peninsular Range, between La Quinta to the north and Anza Borrego Desert State Park to the south. The United States Congress established the wilderness in 1984 with the passage of the California Wilderness Act, managed by the both US Forest Service and the Bureau of Land Management. In 2009, the Omnibus Public Land Management Act was signed into law which added more than 2,000 acres (8.1 km2). Most of the Santa Rosa Wilderness is within the Santa Rosa and San Jacinto Mountains National Monument.
List of California desert topics
Goat Canyon (Carrizo Gorge)
Goat Canyon is a valley in San Diego County, California, United States, located within the Carrizo Gorge in the Jacumba Mountains. The rock forming the canyon is crystalline basement. One feature of the canyon is a dry waterfall. The canyon is bridged by a wooden railroad trestle, the Goat Canyon Trestle, which is the world's largest curved all-wood trestle. The canyon is accessible by trail by traveling west from Mortero Palms.
