New Bullards Bar Dam is a variable radius concrete

arch dam An arch dam is a concrete dam that is curved upstream in plan. The arch dam is designed so that the force of the water against it, known as hydrostatic pressure, presses against the arch, causing the arch to straighten slightly and strengthen ...

constructed in the early 1960s in

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

on the

North Yuba River The North Yuba River (also called the North Fork Yuba River) is the main tributary of the Yuba River in northern California in the United States. The river is about longU.S. Geological Survey. National Hydrography Dataset high-resolution flowlin ...

. Located near the town of Dobbins in

Yuba County Yuba County (; Maidu: ''Yubu'') is a county in the U.S. state of California. As of the 2020 U.S. Census, the population was 81,575. The county seat is Marysville. Yuba County is included in the Yuba City, California Metropolitan Statistical A ...

, the dam forms the

New Bullards Bar Reservoir New Bullards Bar Reservoir is a large reservoir in northeastern Yuba County, California, United States, at an elevation of in the Tahoe National Forest and about 30 miles (50 km) northeast of Yuba City. The reservoir is formed by New Bullard ...

, which can hold about of water. The dam serves for irrigation, drinking water and

hydroelectric power Hydroelectricity, or hydroelectric power, is electricity generated from hydropower (water power). Hydropower supplies one sixth of the world's electricity, almost 4500 TWh in 2020, which is more than all other renewable sources combined and ...

generation.

History

New Bullards Bar Dam was constructed by the Yuba County Water Agency. The agency was created through an act of the state legislature in 1959 specifically to construct a flood control reservoir in response to a flooding event in 1955. The bulk of the financing for the dam came from the issuance of revenue bonds. The dam was completed in 1969. The dam is the fourth constructed on the Bullards Bar site, succeeding

diversion dam A diversion dam is a dam that diverts all or a portion of the flow of a river from its natural course. Diversion dams do not generally impound water in a reservoir; instead, the water is diverted into an artificial water course or canal, which ...

s built in 1899 and 1900 as well as a concrete arch dam built by the Yuba River Power Company and transferred to

Pacific Gas and Electric Company The Pacific Gas and Electric Company (PG&E) is an American investor-owned utility (IOU). The company is headquartered in the Pacific Gas & Electric Building, in San Francisco, California. PG&E provides natural gas and electricity to 5.2 milli ...

in 1922. The dam generated power from 1924 until its inundation by the New Bullards Bar Reservoir in 1969. Although the 1899 diversion dam was washed away, the 1900 dam is still in place about a quarter mile (0.4 km) downstream from the present dam.

Operations

provides flood control space between September 15 and May 31 of each year. There are of flood control storage space between October 31 and March 31. The reservoir controls water flows from the North Yuba River, as well as from the Middle Yuba River and Oregon Creek via diversion tunnels. The Our House Diversion Dam is situated on the Middle Yuba about above its mouth and diverts water into a tunnel with a capacity of , running northwest to the Log Cabin Diversion Dam on Oregon Creek. From here the combined waters of the Middle Yuba and Oregon Creek are sent west into a shorter tunnel with a capacity of into the eastern (Willow Creek) arm of New Bullards Bar Reservoir. The diversions add about to the effective catchment area of New Bullards Bar Reservoir. The entire diversion and reservoir system is collectively known as the Yuba River Development Project. Flood operations in the New Bullards Bar Reservoir water control manual are in part defined with being linked to operations in Marysville Dam. Marysville Dam was supposed to be built as part of a system of dams in the Sacramento Basin along with New Bullards Bar and Oroville Dam, but it was never built. Marysville Dam is still a defining function in the downstream channel capacity constraints even though it is non-existent. The dam furnishes water via a

penstock A penstock is a sluice or gate or intake structure that controls water flow, or an enclosed pipe that delivers water to hydro turbines and sewerage systems. The term is inherited from the earlier technology of mill ponds and watermills. H ...

through a mountain to the New Colgate Powerhouse, which is located downstream. The added distance increases the

hydraulic head Hydraulic head or piezometric head is a specific measurement of liquid pressure above a vertical datum., 410 pages. See pp. 43–44., 650 pages. See p. 22. It is usually measured as a liquid surface elevation, expressed in units of length, ...

, ''i.e.'', elevation change. Its two

Pelton wheel The Pelton wheel or Pelton Turbine is an impulse-type water turbine invented by American inventor Lester Allan Pelton in the 1870s. The Pelton wheel extracts energy from the impulse of moving water, as opposed to water's dead weight like the trad ...

s have a combined capacity of 340 megawatts and are the largest of their kind in the world. At maximum generation, the powerhouse utilizes a flow of , and is an important source of

peaking power Peaking power plants, also known as peaker plants, and occasionally just "peakers", are power plants that generally run only when there is a high demand, known as peak demand, for electricity. Because they supply power only occasionally, the powe ...

for the region.http://www.ycwa-relicensing.com/Project%20Maps%20Schematics%20and%20Fact%20Sheets/YCWA%20Relicensing%20Fact%20Sheet%20and%20Flow%20Schematic.pdf The small Fish Release powerhouse was constructed in 1986 at the base of the dam. It has a capacity of 150 kilowatts and generates power from water releases for fish on the Yuba River. Total annual generation at New Colgate Powerhouse is about 1,314,000 megawatt hours (MWh), while the Fish Release powerhouse produces 1,300 MWh. The aforementioned 14-foot (4.3 m)-diameter penstock drains water from the New Bullards Bar Reservoir several miles through a mountain and down a large hill to deliver water to the New Colgate Powerhouse. In 2006 a 168-inch (4.3 m) butterfly valve was designed and manufactured in Europe for installation in the penstock at the top of the hill to protect the powerhouse from flooding in the event that an earthquake or other event caused the penstock to rupture. This valve uses a design similar to that of the dam's base release works.

Images

Image:2007_06_13_-_New_Bullards_Bar_Dam_in_Yuba_County_California.jpg Image:2007_06_13_-_New_Bullards_Bar_Dam_in_Yuba_County_California2.jpg Image:2007_06_13_-_New_Bullards_Bar_Dam_in_Yuba_County_California3.jpg Image:2007_06_13_-_New_Bullards_Bar_Dam_in_Yuba_County_California4.jpg

References

External links

Yuba County Water AgencyNew Bullards Bar Dam — Northern California Water Association
{{Generating stations in California, state=autocollapse Dams in California Dams in the Feather River basin Yuba River Arch dams Buildings and structures in Yuba County, California United States local public utility dams Dams completed in 1969 1969 establishments in California Hydroelectric power plants in California

History

Operations

Images

See also

References

External links