The Carquinez Strait (; Spanish: ''Estrecho de Carquinez'') is a narrow tidal strait in

Northern California Northern California (colloquially known as NorCal) is a geographic and cultural region that generally comprises the northern portion of the U.S. state of California. Spanning the state's northernmost 48 counties, its main population centers incl ...

. It is part of the tidal estuary of the

Sacramento ) , image_map = Sacramento County California Incorporated and Unincorporated areas Sacramento Highlighted.svg , mapsize = 250x200px , map_caption = Location within Sacramento ...

and the San Joaquin rivers as they drain into the

San Francisco Bay San Francisco Bay is a large tidal estuary in the U.S. state of California, and gives its name to the San Francisco Bay Area. It is dominated by the big cities of San Francisco, San Jose, and Oakland. San Francisco Bay drains water f ...

. The strait is long and connects

Suisun Bay Suisun Bay ( ; Wintun for "where the west wind blows") is a shallow tidal estuary (a northeastern extension of the San Francisco Bay) in Northern California. It lies at the confluence of the Sacramento River and San Joaquin River, forming the ...

, which receives the waters of the combined rivers, with

San Pablo Bay San Pablo Bay is a tidal estuary that forms the northern extension of San Francisco Bay in the East Bay and North Bay regions of the San Francisco Bay Area in northern California. Most of the Bay is shallow; however, there is a deep wate ...

, 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 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 primar ...

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.

History

Suisun Bay, Carquinez Strait, San Pablo Bay

Andrei Sarna-Wojcicki, a geologist emeritus of the

US Geological Survey The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and ...

(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 An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages and gre ...

. 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.Wong, Kathleen. "Carquinez Breakthrough." ''Bay Nature''. September 30, 2006.
Accessed July 19, 2017. The strait forms part of the county border between Solano (to the north) and Contra Costa (to the south), and it's approximately 15 mi (25 km) north of

Oakland Oakland is the largest city and the county seat of Alameda County, California, United States. A major West Coast port, Oakland is the largest city in the East Bay region of the San Francisco Bay Area, the third largest city overall in the Bay ...

. The cities of

Benicia Benicia ( , ) is a waterside city in Solano County, California, located in the North Bay region of the San Francisco Bay Area. It served as the capital of California for nearly thirteen months from 1853 to 1854. The population was 26,997 at th ...

and Vallejo lie on the north side of the strait, while Martinez,

Port Costa Port Costa is a small village and census-designated place (CDP) in Contra Costa County, California, located in East Bay region of the San Francisco Bay Area. Situated on the southern shore of the Carquinez Strait, the population was 190 at the 20 ...

, and

Crockett Crockett may refer to: People and fictional characters * Crockett Gillmore (born 1991), American National Football League player *Crockett Johnson, pen name of David Johnson Liesk (1906-1975), American cartoonist and children's book illustrator * ...

sit on the southern coast. The Napa River joins the strait, via the short

Mare Island Strait The Mare Island Strait is a strait, channel at in the San Pablo Bay separating Mare Island and the mainland in Vallejo, California in Solano County. The strait was formerly used by the Mare Island Naval Shipyard until its closure in 1995. The st ...

, near its entrance into San Pablo Bay. Its watershed covers , approximately 40 percent of California's total surface.

Etymology

The strait is named after the Karkin people ( in Spanish), a linguistic division of the

Ohlone The Ohlone, formerly known as Costanoans (from Spanish meaning 'coast dweller'), are a Native American people of the Northern California coast. When Spanish explorers and missionaries arrived in the late 18th century, the Ohlone inhabited the ...

indigenous peoples Indigenous peoples are culturally distinct ethnic groups whose members are directly descended from the earliest known inhabitants of a particular geographic region and, to some extent, maintain the language and culture of those original people ...

who resided on both sides of the strait.

Installations

The California Maritime Academy is at the western end of the strait on the northern waterfront. The C&H Sugar refinery is located on the southern shore in the small town of

Bridges

The strait is crossed by two highway bridges: the

Carquinez Bridge The Carquinez Bridge is a pair of parallel bridges spanning the Carquinez Strait at the northeastern end of San Francisco Bay. They form the part of Interstate 80 between Crockett and Vallejo, California. The name Carquinez Bridge originally ...

Interstate 80 Interstate 80 (I-80) is an east–west transcontinental freeway that crosses the United States from downtown San Francisco, California, to Teaneck, New Jersey, in the New York metropolitan area. The highway was designated in 1956 as one ...

and the Benicia–Martinez Bridge on Interstate 680. Each highway bridge consists of two spans.

Interstate 780 Interstate 780 (I-780) is an east–west auxiliary Interstate Highway in the San Francisco Bay Area of Northern California. It runs from Curtola Parkway and Lemon Street in Vallejo to I-680 just north of the Benicia–Martinez Bridge in ...

connects the two highways on the northern slope of the strait. State Route 4 connects these highways south of and inland from the strait. A rail bridge just east of the Benicia–Martinez Bridge is used by the Capitol Corridor,

California Zephyr The ''California Zephyr'' is a passenger train operated by Amtrak between Chicago and the San Francisco Bay Area (at Emeryville), via Omaha, Denver, Salt Lake City, and Reno. At , it is Amtrak's longest daily route, and second-longest overall ...

, and

Coast Starlight The ''Coast Starlight'' is a passenger train operated by Amtrak on the West Coast of the United States between Seattle and Los Angeles via Portland and the San Francisco Bay Area. The train, which has operated continuously since Amtrak's format ...

trains. A

rail ferry A train ferry is a ship (ferry) designed to carry railway vehicles. Typically, one level of the ship is fitted with railway tracks, and the vessel has a door at the front and/or rear to give access to the wharves. In the United States, train f ...

, with the ferries '' Contra Costa'' and '' Solano'' provided service across the strait near the location of the current rail bridge until the rail bridge was built in 1930. Tall

pylons Pylon may refer to: Structures and boundaries * Pylon (architecture), the gateway to the inner part of an Ancient Egyptian temple or Christian cathedral * Pylon, a support tower structure for suspension bridges or highways * Pylon, an orange mar ...

carrying

power line An overhead power line is a structure used in electric power transmission and distribution to transmit electrical energy across large distances. It consists of one or more uninsulated electrical cables (commonly multiples of three for three-p ...

s cross the strait as well. The

Carquinez Strait Powerline Crossing Carquinez Strait Powerline Crossing was the world's first powerline crossing of a large river. It was built in 1901 for a 60 kV powerline operated by Bay Counties Power Company to deliver electric power from their Colgate powerhouse to Oakland, C ...

was the world's first powerline crossing of a large river.

Ship traffic

The channel is navigable and is used for commercial and military shipping. Deep water ship traffic bound for both the

Port of Sacramento The Port of Sacramento, now known as the Port of West Sacramento, is an inland port in West Sacramento, California, in the Sacramento metropolitan area. It is northeast of San Francisco, and is centered in the California Central Valley, one of t ...

and the Port of Stockton traverse the strait through the

Stockton Deepwater Shipping Channel California’s Green Trade Corridor, is part of the Stockton Deepwater Shipping Channel Stockton Deepwater Shipping Channel also called the Baldwin-Stockton Deepwater Shipping Channel or Stockton Deep Water Channel is a manmade deepwater water ...

and

Sacramento Deep Water Ship Channel The Sacramento Deep Water Ship Channel (also known as Sacramento River Deep Water Ship Channel or SRDWSC) is a canal from the Port of Sacramento in West Sacramento, California, to the Sacramento River, which flows into San Francisco Bay. It wa ...

. Carquinez Strait is part of the Baldwin Deepwater Shipping Channel.

Formation of delta

The narrow gap in the Coast Range that forms the strait has led to the formation of the San Joaquin–Sacramento River Delta, an

inverted river delta {{noref, date=July 2008 An inverted river delta is special category of river delta in which the narrow end of the delta emerges on the seafront and the wide end is located further inland, so that with respect to the seafront, the locations of both ...

, upstream of it, a rare geological feature. The strait is too small to allow the passage of huge amounts of floodwaters created during years with heavy rainfall/snowmelt events. Because the Delta area is the first to fill and last to drain in a flood event, silt and soil have more time to drop out of suspension, creating the inverted river delta feature.

Saltwater intrusion

Seawater is more dense than fresh water because of its higher concentration of salts. Under stable conditions, this means that an invisible boundary forms where two such streams meet, as where the fresh water from Sacramento and San Joaquin Rivers meet the sea water contained in the San Francisco Bay. By the early 20th century, farmers in the Sacramento-San Joaquin Delta, who depended on irrigating their fields with fresh water from the two rivers noticed an increase in salinity farther inland than before. It became obvious that fresh water was being pumped out of the Delta faster than it could be replenished by rain and snow during the wet season. Farmers, businessmen and politicians complained that allowing fresh water to flow to the ocean was wasteful. While many solutions were proposed, few appeared practical. A political consensus formed that damming the Carquinez Strait should solve the seawater intrusion problem.Bowen, Jerry."A dam across Carquinez Strait?" Historical Articles of Solano County Online Database. Posted August 12, 2001.
Accessed July 21, 2017 In September 1923, the California Legislature appropriated $10,000 (equivalent to $ today) for a saltwater dam survey. The Federal government added a $20,000 contribution ($ 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 San Pablo Point, 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 The Great Depression (19291939) was an economic shock that impacted most countries across the world. It was a period of economic depression that became evident after a major fall in stock prices in the United States. The economic contagio ...

taking hold, President

Herbert Hoover Herbert Clark Hoover (August 10, 1874 – October 20, 1964) was an American politician who served as the 31st president of the United States from 1929 to 1933 and a member of the Republican Party, holding office during the onset of the Gre ...

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.

Notes

References

External links

Wong, Kathleen. "Carquinez Breakthrough." ''Bay Nature''. September 30, 2006.
{{Authority Control Straits of California Sacramento–San Joaquin River Delta Bodies of water of Contra Costa County, California Bodies of water of Solano County, California San Francisco Bay San Pablo Bay Landforms of Contra Costa County, California Landforms of Solano County, California Landforms of the San Francisco Bay Area Tributaries of San Pablo Bay