Old Shoreline of Lake Cahuilla, Santa Rosa Mountains near the Salton Sea
|Primary inflows||Colorado River|
|Primary outflows||Colorado River, Evaporation|
|Basin countries||United States, Mexico|
|Max. length||180 km (110 mi)|
|Max. width||50 km (31 mi)|
|Surface area||5,500 km2 (2,100 sq mi)|
|Max. depth||90 m (300 ft)|
|Shore length1||400 km (250 mi)|
|Surface elevation||12 m (39 ft)|
|1 Shore length is not a well-defined measure.|
Prehistoric Lake Cahuilla (also known as Lake LeConte and Blake Sea) was an extensive freshwater lake that filled the Coachella, Imperial, and Mexicali valleys of southeastern California and northeastern Baja California during the centuries prior to Spanish entry into the region. The Salton Sea, now about 55-kilometre (34 mi) long, 25-kilometre (16 mi) wide, and at an elevation of 69 m (226 ft) below sea level), which was accidentally created in 1905, is a much smaller analog of its prehistoric predecessor Lake Cahuilla, that was about 180-kilometre (110 mi) long, 50-kilometre (31 mi) wide, and rising to 12-metre (39 ft) above sea level, drowning the present sites of the cities of Mexicali, El Centro, and Indio.
Lake Cahuilla was created when the lower Colorado River shifted its course within its delta. Instead of flowing directly south to the head of the Gulf of California, the river's waters were diverted northwest into the Salton Basin, the base of which lay about 80-metre (260 ft) below sea level. Under climatic conditions similar to those of the early twentieth century, it would have taken about two decades of uninterrupted river flow to fill the basin to 12-metre (39 ft) above sea level (D. Weide 1976; Wilke 1978; Waters 1983; Laylander 1997). At that point, the lake would have overflowed to the south, feeding half of its waters through the Rio Hardy to the Gulf but losing the other half through evaporation. When the river shifted its course back to the south, the isolated basin would have taken more than five decades to completely dry out again.
The former large lake in the Salton Basin was remembered by the region's historic-period native inhabitants, the Cahuilla and the Kumeyaay (Wilke 1978; Laylander 2004). By the mid-nineteenth century, Euro-American visitors, including the geologist William Phipps Blake (1858), had recognized the lake's traces, including tufa deposits along the maximum shoreline, beaches, and deposits of freshwater mollusk shells.
Malcolm J. Rogers (1945), a pioneering archaeologist in the region, examined aboriginal pottery left on shoreline sites and concluded that the lake had been present between about 1000 and 1500. Subsequent studies have established that there were not one but several high stands of the lake, before 1000 and after 1500, including a stand in the seventeenth century, when Spanish explorers had already reached the lower Colorado River although not entering the Salton Basin (Wilke 1978; Waters 1983; Laylander 1997; Love and Dahdul 2002).
Native peoples harvested a range of resources associated with Lake Cahuilla in the otherwise-parched Colorado Desert. Prominent were freshwater fish (primarily bonytail, Gila elegans, and razorback sucker, Xyrauchen texanus), freshwater mussels (Anodonta dejecta), water birds (particularly American coot (Fulica americana), and marsh plants (cattail, Typha, tule, Scirpus, and reed, Phragmites). Researchers have disagreed as to how important the role of Lake Cahuilla resources was within native subsistence strategies, and consequently how dramatically the lake's rises and falls shaped the region's late prehistory. Some have envisioned many permanent or semi-permanent settlements on the shores, producing severe regional upheavals when their supporting resources disappeared, while other researchers have seen the lake as only a marginal area within stable regional subsistence patterns (e.g., Aschmann 1959; M. Weide 1976; Wilke 1978; Schaefer 1994; Laylander 2006).
The modern Lake Cahuilla in La Quinta was constructed as a reservoir in 1969. (See: Lech, Steve (2011). More Than a Place To Pitch a Rent: The Stories Behind Riverside County's Regional Parks. Riverside, CA: Steve Lech. p. 150. ISBN 978-0-9837500-0-0. OCLC 768249467. and Riverside County Parks: Lake Cahuilla.)
- Aschmann, Homer. 1959. The Evolution of a Wild Landscape and Its Persistence in Southern California. Annals of the Association of American Geographers 49(3):34-57.
- Blake, William Phipps. 1858. Report of a Geological Reconnaissance in California Made in Connection with the Ejxpedition to Survey Routes for a Railroad from the Mississippi River to the Pacific Ocean, under the Command of Lietu. R. S. Williamson, Corps Top. Eng'rs, in 1853. H. Baillière, New York.
- Laylander, Don. 1997. "The Last Days of Lake Cahuilla: The Elmore Site". Pacific Coast Archaeological Society Quarterly 33(1-2):1-138.
- Laylander, Don. 2004. "Remembering Lake Cahuilla". In The Human Journey & Ancient Life in California's Deserts: Proceedings from the 2001 Millennium Conference, edited by Mark W. Allen and Judyth Reed, pp. 167–171. Maturango Museum, Ridgecrest, California.
- Laylander, Don. 2006. "The Regional Consequences of Lake Cahuilla". San Diego State University Occasional Archaeology Papers 1:59-77.
- Love, Bruce, and Mariam Dahdul. 2002. "Desert Chronologies and the Archaic Period in the Coachella Valley". Pacific Coast Archaeological Society Quarterly 38(1-2).
- Rogers, Malcolm J. 1945. "An Outline of Yuman Prehistory". Southwestern Journal of Anthropology 1:167-198.
- Schaefer, Jerry. 1994. "The Challenge of Archaeological Research in the Colorado Desert: Recent Approaches and Discoveries". Journal of California and Great Basin Anthropology 16:60-80.
- Waters, Michael R. 1983. "Late Holocene Lacustrine Chronology and Archaeology of Ancient Lake Cahuilla, California". Quaternary Research 19:373-387.
- Weide, David L. 1976. "Regional Environmental History of the Yuha Desert". In Background to Prehistory of the Yuha Desert Region, edited by Philip J. Wilke, pp. 9–20. Ballena Press, Ramona, California.
- Weide, Margaret L. 1976. "A Cultural Sequence for the Yuha Desert". In Background to Prehistory of the Yuha Desert Region, edited by Philip J. Wilke, pp. 81–94. Ballena Press, Ramona, California.
- Wilke, Philip J. 1978. Late Prehistoric Human Ecology at Lake Cahuilla, Coachella Valley, California. Contributions of the University of California Archaeological Research Facility No. 38. Berkeley.