Where Did the Sand Dunes Come From?
Tremendous earth upheavals that elevated the area above the ocean some 200 million years ago and the constant action of erosional forces over the eons have all had a part in sculpting this vast region.
For millions of years, the climate of California's desert region was tropical. As the earth's crust shifted along the San Andreas fault, the coastal mountains were pushed up, cutting off the moisture laden air coming from the ocean. At the same time, the interior plains of Southern California began to drop, forming a basin known as the Salton Sink. Gradually, the region dried, forcing many plants and animals to adapt or perish.
The Colorado River flowed through country so flat that the course of the river varied over a wide area, being periodically diverted in one direction or another by silt deposits remaining after floods. Sometimes the river flowed into the Gulf of California, as it does today; other times it turned westward toward the Salton Sink. Each time the Salton Sink received the river flow, a large freshwater lake formed. Scientists refer to this ancient body of water as Lake Cahuilla. The last Lake Cahuilla covered much of the Imperial, Coachella and Mexicali Valleys as late as 1450.
The most popular theory holds that the Imperial Sand Dunes were formed from windblown beach sands of Lake Cahuilla. The prevailing westerly and northwesterly winds carried the sand eastward from the old lake shore to their present location. This process continues today. Prevailing winds cause the dunes to migrate southeast at the rate of approximately one foot per year.
The Imperial Sand Dunes have played a significant role in shaping the human history of the Imperial Valley. Located west of the Lower Colorado River, the ISDRA is a unique landscape in Southern California and northeast Baja California. The ISDRA is within or near the traditional lands of the Cahuilla, Chemehuevi, Cocopah, Kamia, Kumeyaay, Mohave and Quechan. The sand dunes are a part of the sacred world for these contemporary tribes. The dunes are a part of their religious and secular history. They contain burial and cremation areas and trail crossings. They offer a variety of resources, such as plants for foods and medicine, and animals for hunting. These tribes advocate protective management of the natural and cultural environment of the dunes.
In early historic times, the dunes would become thought of, not as a resource, but as a barrier to be avoided by the Spanish explorers, like De Anza and Garces, and the American pioneers moving west along the southern emigrant trail. Thus the trail dropped south of the Mexican border to avoid the dunes. It was also a barrier to the expanding railroad network, which diverted the 1877 line north through Mammoth Wash to reach the west coast.
In the twentieth century the Imperial Sand Dunes continued to be a barrier to be conquered. The dunes figured prominently as part of the heroic struggle to tame the Colorado River. An eminent auto enthusiast, named Colonel Ed Fletcher, built a plank road just to demonstrate that the dunes could be traversed by automobile. (The Plank Road has been designated an Area of Critical Environmental Concern. The Plank Road was determined eligible for the National Register of Historic Places in 1986 and nominated for inclusion in 2001.) This travel route would later be paved and used by families of migrant workers escaping the dust storms of Oklahoma and Arkansas.
These same workers also helped to excavate a large channel known as the All American Canal, which was cut through the dunes to convey water from the Colorado River to the agricultural fields of the Imperial Valley. (The All-American Canal has been determined to be eligible for inclusion to the National Register of Historic Places.)
Soon the entertainment industry discovered the unique scenery of the dunes and they became the backdrop for major Hollywood movies, like Beau Gueste and a Bob Hope and Bing Crosby classic movie called the Road to Zanzibar. The dunes have also been used for television commercials, and both commercial and artistic photography.
During World War II, Generals George S. Patton Jr. and Walton Walker were instrumental in developing a facility to train U. S. troops for the North African Theater. The Desert Training Center/California-Arizona Maneuver Area (1942-1944) spanned from Searchlight, Nevada south through eastern California and western Arizona to the United States/Mexico International Border. The Imperial Sand Dunes offered a unique training environment for combat maneuvers.
Finally, the recreational use of the dunes also has historical roots beginning with local families who would travel to the dunes to drive the plank road and have a Sunday picnic. The dunes also became a place for families to camp and try out, or develop, new machines for driving in the sand. A milestone in the evolution of OHV use came after World War II when surplus Jeeps were available for purchase by the private sector. The Imperial Sand Dunes is also believed to be the birthing place for the early dune buggies. Model A cars with their bodies removed were some of the first buggies attempting the challenges of the sand dunes. Multiple generations of families have loyally followed this tradition, flocking to the dunes to recreate and socialize several times a year. Thus a social culture, unique to the dunes, has developed and will evolve as new generations of families continue to observe their family traditions.