Poso Creek or Posey Creek is an intermittent stream in

Kern County, California Kern County is a county (United States), county located in the U.S. state of California. As of the 2020 United States census, 2020 census, the population was 909,235. Its county seat is Bakersfield, California, Bakersfield. Kern County compris ...

. The headwaters of Poso Creek are located within the

Sierra Nevada The Sierra Nevada ( ) is a mountain range in the Western United States, between the Central Valley of California and the Great Basin. The vast majority of the range lies in the state of California, although the Carson Range spur lies primari ...

and the Sequoia National Forest, at elevations of up to . The high Spear Creek Falls (often known as Poso Creek Falls) is located along a tributary of Poso Creek within the national forest. Poso Creek proper begins at the confluence of Spear Creek and Von Hellem Creek on the west slope of the

Greenhorn Mountains The Greenhorn Mountains are a mountain range of the Southern Sierra Nevada (U.S.), Sierra Nevada, in California. They are protected within the Sequoia National Forest. Geography The range is located in eastern Kern County, California, Kern Count ...

. The upper reaches of the creek flow south through the Linn Valley past Posey and Glennville, then to Poso Flat, where it receives Cedar Creek and Little Poso Creek from the east. Below the confluence with Little Poso Creek, it turns west, passing through the Mount Poso and Poso Creek oil fields, which are a likely source of petroleum pollutants during flooding events. Below the oil fields the creek emerges to the intensively farmed

San Joaquin Valley The San Joaquin Valley ( ; Spanish language in California, Spanish: ''Valle de San Joaquín'') is the southern half of California's Central Valley (California), Central Valley. Famed as a major breadbasket, the San Joaquin Valley is an importa ...

, where it passes between Wasco and McFarland. The creek is crossed by Highway 99 and the

Southern Pacific Railroad The Southern Pacific (or Espee from the railroad initials) was an American Railroad classes#Class I, Class I Rail transport, railroad network that existed from 1865 to 1996 and operated largely in the Western United States. The system was oper ...

at Famoso and by the Friant-Kern Canal a few miles downstream. Most of the lower creek flows through artificial channels beginning north of Wasco. Its mouth is on the

Kern River The Kern River is an Endangered, Wild and Scenic river in the U.S. state of California, approximately long. It drains an area of the southern Sierra Nevada The Sierra Nevada ( ) is a mountain range in the Western United States, between ...

floodway in Kern National Wildlife Refuge, which connects the normally dry

Buena Vista Lake Buena Vista Lake was a fresh-water lake in Kern County, California, in the Tulare Lake Basin in the southern San Joaquin Valley, California. Buena Vista Lake was the second largest of several similar lakes in the Tulare Lake basin, and was fed ...

with

Tulare Lake Tulare Lake () or Tache Lake ( Yokuts: ''Pah-áh-su'', ''Pah-áh-sē'') is a freshwater lake in the southern San Joaquin Valley, California, United States. Historically, Tulare Lake was once the largest freshwater lake west of the Mississippi R ...

. As a primarily rain fed stream, Poso Creek flows only seasonally (November to May) in its upper reaches, while the lower part is an

ephemeral Ephemerality (from the Greek word , meaning 'lasting only one day') is the concept of things being transitory, existing only briefly. Academically, the term ephemeral constitutionally describes a diverse assortment of things and experiences, fr ...

wash. The

United States Geological Survey The United States Geological Survey (USGS), founded as the Geological Survey, is an agency of the U.S. Department of the Interior whose work spans the disciplines of biology, geography, geology, and hydrology. The agency was founded on Mar ...

operated a stream gage on Poso Creek from 1959 to 1985, recording an average annual flow of . The greatest flow was on February 25, 1969, while the creek was dry for six straight months in 1977.

Luxilis occidentalis

Poso Creek (or 0-co-ya, creek) is the only place that the fish ''Luxilis occidentalis'' is known to have lived except for Four Creeks in the Tulare Valley. It was collected here in 1855 by Dr A.L. Heerman.

References

{{Tulare Basin Hydrography, state=collapsed Rivers of the Sierra Nevada (United States) Rivers of Kern County, California Kern River Tulare Basin watershed Greenhorn Mountains Central Valley Project History of Kern County, California History of Southern California Rivers of Southern California Rivers of the Sierra Nevada in California