Солтүстік Калифорниядағы Каркинес бұғазы

Tidal strait in Northern California

The Carquinez Strait (/k//ɑːr/'/k//iː//n//ə//s/; Spanish: Estrecho de Carquinez) is a narrow tidal strait located in the Bay Area of Northern California, United States. It is part of the tidal estuary of the Sacramento and the San Joaquin rivers as they drain into the San Francisco Bay. The strait is long and connects Suisun Bay, which receives the waters of the combined rivers, with San Pablo Bay, a northern extension of the San Francisco Bay. The strait formed in prehistoric times, near the close of one of the past ice ages, when the Central Valley was a vast inland lake. Melting ice from the Sierra Nevada raised the water level while seismic activity created a new outlet to the Pacific Ocean, draining the lake into the ocean and exposing the valley floors.

The strait is named after the Karkin people (los Carquines in Spanish), a linguistic division of the Ohlone indigenous peoples who once resided on both sides of the strait.

Andrei Sarna Wojcicki, a geologist emeritus of the US Geological Survey (USGS), estimates that the Carquinez Strait was likely formed about 640,000 to 700,000 years ago, while much of modern California was emerging from an ice age. The present Sacramento Valley and San Joaquin Valley were covered by a huge lake (now extinct), which has been called Lake Corcoran. Initially, this lake drained into the ocean through a valley near present day Monterey. However, ongoing seismic activity raised the coastal mountains sufficiently to plug this outlet. Concurrently, ice melting off the Sierras raised the water level in Lake Corcoran until the lake began to carve a new outlet to the ocean. At some point, the coastal barrier collapsed between today's cities of Crockett and Benicia, releasing lake water in a cataclysmic flood. The strait forms part of the county border between Solano (to the north) and Contra Costa (to the south), and it is approximately 15 mi (25 km) north of Oakland. The cities of Benicia and Vallejo lie on the north side of the strait, while Martinez, Port Costa, and Crockett sit on the southern coast. The Napa River joins the strait, via the short Mare Island Strait, near its entrance into San Pablo Bay. Its watershed covers , approximately 40 percent of California's total surface. In September 1923, the California Legislature appropriated $10,000 (equivalent to $10000.0 in 1923 is equivalent to about <calculated amount> in recent years today) for a saltwater dam survey. The Federal government added a $20,000 contribution ($20000.0 in 1923 is equivalent to about <calculated amount> in recent years today) through the US Reclamation Service. Under Reclamation Service rules, another $10,000 needed to be raised from local supporters of the project. The necessary money was raised by March 1924, and the first of three site surveys was announced. The first survey was at Army Point, near Benicia, which was the preferred site based on preliminary studies. The second choice was Dillon Point, near Southampton Bay, while the third survey was at Point San Pablo, near Richmond. The three surveys were completed by the end of 1924. However, it took four years to complete the decision making process that officially named Army Point as the future dam site. Still more wrangling in the legislature was required before the "Salt Water Barrier" was officially adopted in May 1929, and made part of the state water conservation project. On January 24, 1930, with the Great Depression taking hold, President Herbert Hoover cancelled the Carquinez Strait project, saying that it was too costly. All efforts to revive the project failed. Years later, the Central Valley Project attempted to mitigate the effects of seawater intrusion by constructing other dams much farther inland and canals to send fresh water to the San Joaquin Valley.