Santa Maria River on the Central Coast of California

Central Coast of California

The Central Coast is an area of California, United States, roughly spanning the area between the Monterey Bay and Point Conception. It extends through Santa Cruz County, San Benito County, Monterey County, San Luis Obispo County, and Santa Barbara County...

, is formed at the confluence of the Sisquoc River

Sisquoc River

The Sisquoc River is a river in northeastern Santa Barbara County, California. It is a tributary of the Santa Maria River, which is formed when the Sisquoc River meets the Cuyama River. The river is long and originates on the north slopes of Big Pine Mountain, at approximately...

 and Cuyama River

Cuyama River

The Cuyama River is a river in southern San Luis Obispo County, northern Santa Barbara County, and northern Ventura County, in the U.S. state of California. It joins the Sisquoc River forming the Santa Maria River...

, just east of the city of Santa Maria

Santa Maria, California

Santa Maria is a city in Santa Barbara County, on the Central Coast of California. The 2010 census population was 100,062, putting it ahead of Santa Barbara for the first time and making it the largest city in the county...

, and flows 24.4 miles (39.3 km) to its delta at the Pacific Ocean

Pacific Ocean

The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...

.

The entire river defines the border between northern Santa Barbara County

Santa Barbara County, California

Santa Barbara County is a county located in the southern portion of the U.S. state of California, on the Pacific coast. As of 2010 the county had a population of 423,895. The county seat is Santa Barbara and the largest city is Santa Maria.-History:...

 and southern San Luis Obispo County

San Luis Obispo County, California

San Luis Obispo County is a county located along the Pacific Ocean in the Central Coast of the U.S. state of California, between Los Angeles and the San Francisco Bay Area. As of the 2010 census its population was 269,637, up from 246,681 at the 2000 census...

, up to the Sisquoc River, with a major bridge on Highway 101

Highway 101

Highway 101 is an American country music band founded by Paulette Carlson , Jack Daniels , Curtis Stone and Scott "Cactus" Moser . With Carlson as lead vocalist, the band recorded three albums for Warner Bros. Records Nashville and charted ten consecutive Top Ten hits on the Hot Country Songs...

 passing over it. The Santa Maria River Fault

Santa Maria River Fault

Santa Maria River Fault is a tectonic fault that roughly corresponds with the Santa Maria River in Santa Barbara County, USA, but veers south towards Santa Ynez. It passes just north of the city of Santa Maria, California, and lies south of the potentially dangerous Hosgri fault and newly...

 is a tectonic fault that roughly corresponds with the course of the river.

There are no dam

Dam

A dam is a barrier that impounds water or underground streams. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees are used to manage or prevent water flow into specific land regions. Hydropower and pumped-storage hydroelectricity are...

s or lake

Lake

A lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...

s on the Santa Maria River itself, although Twitchell Reservoir

Twitchell Reservoir

Twitchell Reservoir is a reservoir in southern San Luis Obispo County and northern Santa Barbara County in California. The reservoir has a capacity of and is formed by Twitchell Dam on the Cuyama River about from its headwaters in the Chumash Wilderness Area and about from its confluence with...

 is formed by a dam on the tributary Cuyama River. Twitchell Dam was built by the United States Bureau of Reclamation

United States Bureau of Reclamation

The United States Bureau of Reclamation , and formerly the United States Reclamation Service , is an agency under the U.S...

 and provides flood

Flood

A flood is an overflow of an expanse of water that submerges land. The EU Floods directive defines a flood as a temporary covering by water of land not normally covered by water...

 control and groundwater

Groundwater

Groundwater is water located beneath the ground surface in soil pore spaces and in the fractures of rock formations. A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water. The depth at which soil pore spaces or fractures and voids in rock...

 recharge of the aquifer

Aquifer

An aquifer is a wet underground layer of water-bearing permeable rock or unconsolidated materials from which groundwater can be usefully extracted using a water well. The study of water flow in aquifers and the characterization of aquifers is called hydrogeology...

. The Sisquoc River is also free-flowing, and a National Wild and Scenic Rivers System.

During much of the year, the Santa Maria River has very little water, but it can swell greatly during winter storms.