New Bullards Bar Reservoir 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 through a mountain to the
New Colgate Powerhouse, which is located downstream. The added distance increases the
hydraulic head. Its two
Pelton wheels have a combined capacity of 340 megawatts and are the largest of their kind in the world. At maximum generation, the powerhouse uses a flow of , and is an important source of
peaking power for the region. 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 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 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. On February 13, 2026, the New Colgate Powerhouse penstock ruptured. The steel pipe, which runs a half mile between Bullards Bar Reservoir and the powerhouse, failed during testing, releasing an estimated 400 acre-feet of water down the canyon hillside. Downstream, river flows on the lower Yuba fell from 1,400 cubic feet per second to 560 cubic feet per second within about two hours as the second powerhouse on the river was also forced offline. Repair cost projections are ranging as high as one billion dollars, and the powerhouse was expected to remain offline for potentially several years. This loss reduced the regional grid's ability to meet peak electricity demand. Agricultural irrigators in
Yuba County also face reduced water delivery flexibility during the repair period. ==See also==