New Melones Unit Project

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The primary function of New Melones Dam and Lake is flood control. Of the 2,400,000 acre-feet capacity, 450,000 acre-feet is reserved for flood control purposes The remaining capacity is used for a number of purposes including the satisfaction of preexisting water rights, fisheries enhancement, water quality improvement, and electrical generation. http://www.usbr.gov/mp http://www.usbr.gov/mp/tours.html The New Melones powerplant provides power for the equivalent of 72,000 households. The table below shows gross power generation in fiscal year 1998 The New Melones Dam and Powerplant are located on the Stanislaus River, about 60 miles upstream from its confluence with the San Joaquin River and 40 miles east of Stockton. The river forms the boundary between Calaveras and Tuolumne Counties, and drains an area of about 980 square miles on the western slope of the Sierra Nevada Mountains in east central California. The Stanislaus River Basin has three major tributaries, the North, South and Middle Forks, and the annual average flow is almost 1,000,000 acre/feet (ac/ft). The climate is semiarid with hot, dry summers, and cool wet winters.(2) Evidence of human activities in the Sierra Nevada Mountains indicates that scattered, seasonal incursions into the region occurred more than 10,000 years ago, with more permanent settlement beginning between 3,000 and 4,000 years ago. Among the evidence of early human occupation in the Stanislaus River Basin are village sites, mortars, and petroglyphs. As early as 1850, reports told of gold prospectors finding artifacts and human skeletal remains in the Stanislaus River area. In 1840, just prior to the start of the gold rush, the Central Sierra Miwok Indians were the primary inhabitants of the Stanislaus River Basin.(3) Development of the Stanislaus River Basin began during the gold rush of the late 1840s. Water companies diverted water for use by miners. In the 1890`s utility companies began generating hydroelectric power on the river, much of which they sent outside the area. The early 1900`s saw development of several irrigation districts to serve local farmers. In 1926, the Oakdale and South San Joaquin Irrigation Districts built the Melones Dam and Powerplant. The peak of construction by irrigation districts came in the 1950`s with construction of the Tri-Dam Project. That consisting of the Donnells and Beardsley Dams on the upper Stanislaus River, Tulloch Dam on the lower Stanislaus River, and the enlargement of Goodwin Dam, also on the lower river.(4) The Flood Control Act of December, 1944 authorized construction of a dam to replace Melones Dam, the New Melones Dam. The dam was to be built and operated by the Army Corps of Engineers for flood control. In the Flood Control Act of October, 1962, Congress reauthorized and expanded the project to a multi-purpose unit to be built by the Corp of Engineers and operated by the Secretary of Interior as part of the Central Valley Project, thus creating the New Melones Unit. The multi-purpose objectives of the unit include flood control, irrigation, municipal and industrial water supply, power generation, fishery enhancement, water quality improvement, and recreation. While the 1944 authorization called for construction of a 355 foot high concrete arch dam with a capacity of 450,000 acre/feet (ac/ft) and the continued use of the existing powerplant, the reauthorization of the project in 1962 changed the design to an earth and rock fill dam, and required construction of a new powerplant.(5) Initial construction work on New Melones Dam began in July 1966. This work consisted of building access and haul roads; construction of the low-level intake structure for the outlet works; construction of the administration building, visitor overlook and parking lot; clearing the dam site; and excavation and grouting of the foundation. Construction of the diversion tunnel began in 1966 and was completed in December 1973. In May 1972, the Corps of Engineers released the Final Environmental Statement (FES) for the project and announced that bids for construction of the main dam would be opened in October 1972. On June 8, 1972, the Environmental Defense Fund filed suit in Federal court (EDF vs Armstrong) challenging the FES. The Fund hoped to delay further construction on the dam until questions about the FES could be resolved.(6) Bids for construction of the main dam were opened on October 10, 1972. The Corps received a low bid of $83,200,000, but delayed awarding of the contract pending the court`s decision concerning the FES. The case was heard in Federal Court, and on October 16, 1972, the court ruled the FES adequate, but ordered submission of a supplemental FES addressing certain issues. The Corps submitted a supplemental FES in January 1973, and on March 16, the district court ruled the statement adequate. The Ninth Circuit Court of Appeals upheld the ruling of the District Court, and in April 1974, the Supreme Court refused to hear further appeal.(7) Delays caused by the legal proceedings resulted in the bidder withdrawing the low bid due to rising costs. The request for bids was readvertised in December 1973, and a new low bid of $109,709,637 was received from the Melones Contractors of Jamestown, California, a joint venture of the Guy F. Atckinson Company, Gordon H. Ball, and the Arundel Corp. Several other supplemental contracts were awarded. Allis-Chalmers was awarded a $5,300,000 contract for two power turbines, and General Electric received a $6,200,000 contract for two 150- megawatt (mw) generators. The $39,944,975 contract for construction of the powerplant and appurtenant structures was awarded to Melones Contractors.(8) The reservoir formed behind the dam required relocation of several roads and construction of a number of bridges. Relocation work was carried out by The California Department of Transportation, Roy E. Ladd, Inc., and the S. J. Groves and Sons Company. The cost of bridge construction and road relocations was almost $28,000,000.(9) Construction of the main dam by the Melones Contractors began on March 6, 1974, with embankment placing operations beginning in January 1976. Even after construction resumed, opponents of the project continued their fight. One of the primary controversies centered around the amount of water that would be allowed to accumulate behind the dam. In March 1973, the California State Water Resources Control Board issued Decision 1422, regarding Reclamation`s application for permits to store water a New Melones. The decision granted Reclamation permits to store only enough water at New Melones to meet pre-existing water rights, and obligations for wildlife enhancement and water quality. The permits did not allow storage of water for consumptive use or power generation. Decision 1422 further stated that only when Reclamation could show firm commitments for use of any additional water would the terms of the decision be changed. Reclamation filed a suit claiming the State could not place conditions on Federal reclamation projects. The State countered with a suit seeking a judgement that the Bureau be bound to the conditions of Decision 1422.(10) While lawsuits where pending in the courts, parties seeking to limit the size of New Melones Lake took their case to the voters of California. Proposition 17, which sought to limit the size of New Melones Lake, was defeated in the November 1974 election. In October 1975, the District Court entered a judgement in favor of Reclamation holding that the State could not place conditions on the permits for water storage at New Melones. The State appealed the decision to the Ninth Circuit Court of Appeals. On August 12, 1977, the Ninth Circuit Court of Appeals upheld the decision of the District Court in favor of the Bureau of Reclamation. On July 3, 1978, the Supreme Court of the United States, in a six to three decision, upheld the State`s right to impose conditions on water permits provided that those conditions were not inconsistent with Congressional directives. The Supreme Court remanded the case to District Court to determine the consistency of the conditions. In January 1979, Senate Bill 1482, which sought to place portions of the Stanislaus River in California's Wild and Scenic Rivers System, thus protecting the river from inundation, failed.(11) While the controversy raged, construction on the main dam continued. The dam embankment was `topped out` on October 28, 1978, and all work on the embankment was completed in November. Not restricted by legal battles and court orders, the Army Corps of Engineers allowed water to begin to back up behind the dam. The powerplant was completed, and the turbines and generators installed by the end of 1978. Testing of the generating units was completed in June 1979.(12) Some of those opposed to construction of New Melones Dam went to extremes to attempt to halt the filling of the lake. In May 1979, Mark Dubois, director of Friends of the River, a group opposed to the project, chained himself to a rock in the reservoir area. Several of his supporters joined him at the edge of the rising waters. They were soon released unharmed, but not before the Corps of Engineers was forced to make releases from the dam to prevent the protesters from being overcome by the rising waters.(13) New Melones Dam is California`s second largest earthfill dam, containing 15,700,000 cubic yards (cu/yd) of material. The dam is 625 feet high and 1,560 feet long. The outlet works consist of a 3,774 foot long, 23-foot diameter, concrete lined, multipurpose, tunnel, and two 6-foot diameter steel conduits for emergency releases. The two emergency release conduits are embedded in the concrete lining of the multipurpose tunnel, and flows through the conduits are controlled by two 72-inch ring follower gates, and two 66-inch fixed-cone valves. Releases for flood control and irrigation are made through a 13-foot diameter branch of the multipurpose tunnel that branches into two 8-foot diameter pipes. Flows are controlled by 96-inch ring follower gates and 78-inch fixed cone gates. Flows into the outlet works are controlled by a 13-foot by 27-foot sliding gate located at the intake structure. The outlet works have a capacity of 8,300 cubic feet per second (cf/s). The spillway has an uncontrolled concrete crest and an unlined channel that was excavated through solid rock about 1.5 miles northwest of the dam. The spillway cut is 5,945 feet long and 200 feet wide with a capacity 112,600 cf/s. Material excavated from the spillway went into the dam embankment. New Melones Lake has a capacity of 2,400,000 ac/ft and a surface area of 12,500 acres with the water level at 1,088 feet above sea level. The shoreline is over 100 miles long. The New Melones Powerplant contains two generators each rated at 150,000 kilowatts (kw) with a total rating of 300,000 kw. Water is supplied to the power units by two, 17-foot diameter, concrete lined tunnels that branch from the multipurpose outlet tunnel. Flows into the power turbines are controlled by two, 174-inch butterfly valves. A 55-foot diameter, 620-foot tall surge protection shaft protects the penstock tubes and control valves from water hammer damage.(14) The East Side Division and the construction of the New Melones Dam and Powerplant is one of the more controversial chapters in the history of the Central Valley Project. Development of the Division brought the need for water and flood control into direct conflict with concerns over damage to cultural resources and the environment. The battle over construction of New Melones Dam was a signal at the end of the era of large dam construction. The controversy focused on the loss of a popular stretch of recreational white water, inundation of archeological sites, and flooding of the West`s deepest limestone canyon. Controversy over the project lasted over a decade before the decision to proceed and provide irrigation water, flood control, and power generation occurred.(1)

Plan

New Melones Dam is located about 0.75 mile downstream from the original Melones Dam, built by the Oakdale and South San Joaquin Irrigation Districts in 1926. The original dam, a 183-foot concrete arch structure, is now submerged under the reservoir. The new dam, an earth and rockfill structure, stands 625 feet above streambed, has a crest length of 1,560 feet, and has a total embankment volume of 16 million cubic yards of material. New Melones Dam is California`s second largest earthfill dam, containing 15,700,000 cubic yards of material. The reservoir, New Melones Lake, has a capacity of 2.4 million acre-feet at a gross pool elevation of 1,088.0 ft, a water surface area of 12,500 acres, and 100 miles of shoreline. Initial construction of New Melones Dam began in July 1966. This work consisted of building access and haul roads; constructing the low-level intake structure for the outlet works; constructing the administration building, visitor overlook, and parking lot; clearing the dam site; and excavating and grouting the foundation. Construction of the diversion tunnel began in 1966 and was completed in December 1973. Construction of the main dam began on March 6, 1974, with embankment placing operations beginning in January 1976. The dam embankment was `topped out` on October 28, 1978, and all work on the embankment was completed in November. Initial filling of the reservoir occurred in 1983. The outlet works consist of a 3,774 foot long, 23-foot diameter, concrete lined, multipurpose tunnel and two 6-foot diameter steel conduits for emergency releases. The two conduits are embedded in the concrete lining of the multipurpose tunnel, and flows through the conduits are controlled by two 72-inch ring follower gates and two 66-inch fixed-cone valves. Releases for flood control and irrigation are made through a 13-foot-diameter branch of the multipurpose tunnel that branches into two 8-foot-diameter pipes. Flows are controlled by 96-inch ring follower gates and 78-inch fixed-cone gates. Flows into the outlet works are controlled by a 13-foot by 27-foot sliding gate located at the intake structure. The outlet works have a capacity of 8,300 cubic feet per second (cfs). The spillway has an uncontrolled concrete crest and an unlined channel that was excavated through solid rock about 1.5 miles northwest of the dam. The spillway cut is 5,945 feet long and 200 feet wide, with a capacity 112,600 cfs. Material excavated from the spillway went into the dam embankment. New Melones Lake has a capacity of 2,400,000 acre-feet and a surface area of 12,500 acres with the water level at 1,088 feet above sea level. The shoreline is over 100 miles long. The New Melones Powerplant contains two generators, each rated at 150,000 kilowatts (kW). It is located on the north bank, immediately downstream from the dam. The dependable generating capacity is about 279 megawatts, producing about 455 million kilowatt-hours of energy annually. This energy is equivalent to the annual electrical requirements of some 72,000 households. Water is supplied to the power units by two, 17-foot-diameter, concrete-lined tunnels that branch from the multipurpose outlet tunnel. Flows into the power turbines are controlled by two, 174-inch butterfly valves. A 55-foot-diameter, 620-foot-tall surge protection shaft protects the penstock tubes and control valves from water hammer damage. The powerplant consists of two vertical shaft, synchronous, 3-phase generators with a combined rating of 300,000 kW. The generators were manufactured by General Electric were commissioned in 1979. The generators are rated at 166,667 KVA at 0.90 power factor, 171.4 rpm, 13.8 kV, 60 hertz. The turbines are Francis type manufactured by Allis Chalmers and have a rated head of 460 feet. The powerplant was completed and the turbines and generators installed by the end of 1978. Testing of the generating units was completed in June 1979. The New Melones Dam was originally designed for flood control and has provided significant flood control benefits. Through 1993, the dam and lake prevented a cumulative total of $128,500,000 in flood damage Reclamation is developing a flexible operating plan for New Melones Dam and Reservoir that establishes how available water supplies will be managed within and outside of the Stanislaus River Basin. New Melones Reservoir on the Stanislaus River is currently operating under an `Interim Operating Agreement.` This agreement was completed in 1996 with significant input from stakeholder interests. The Interim Agreement was not developed to cover drought conditions because the stakeholders could not reach agreement on how to manage the facility during periods of extended drought. Reclamation is conducting investigations to develop and evaluate alternative operating scenarios and will start developing an Environmental Impact Statement/Environmental Impact Report under the National Environmental Policy Act and California Environmental Quality Act in 2001. It is now clear that water availability for the New Melones Project is significantly different from what had been expected. When New Melones was studied, estimates of the water available from the project used historical data on annual flows and data pertaining to preexisting claims to water in the Stanislaus River Basin. The model constructed for the study used data from the years 1922 through 1978. Under this model, the amount of water predicted to be available from the project, approximately 200,000 acre-feet, justified its construction. When data for the years 1979 through 1992 were factored into the model, Reclamation found that the previous estimates of drought and demand were off by a significant amount. (California experienced a severe drought beginning in 1987 and lasting through 1992, and demands for releases for water quality improvement were higher than anticipated.) Original estimates anticipated that approximately 200,000 acre-feet would be available after pre-existing obligations were met. As a result of those estimates, contracts were negotiated with the Stockton East Water District and the Central San Joaquin Water Conservation District for up to 155,000 acre-feet per year. But during the drought of 1987 to 1992, preexisting obligations were not always met, and no water was available to service those contracts. As a result, the Stockton East Water District has filed suit against Reclamation seeking a judgment forcing Reclamation to meet the obligations of their contract. In 1994, Reclamation had to purchase 50,000 acre-feet of water from the Tri-Dam Project at a cost of $50.00 per acre-foot to meet the release requirements for the fall salmon run. When the lake lowers, the old dam, now submerged, prevents cold water at the bottom of the lake from reaching the outlet works of the new dam. Thus, temperatures are too high for the fish downstream from the dam. The situation becomes most critical when the amount of water in the lake drops below 350,000 acre-feet, about the point where the layer of cold water above the old dam is exhausted. Maintaining a minimum water level above 350,000 acre-feet is difficult when the inflows are not great enough to increase storage while meeting downstream water obligations. When the water level is around 400,000 acre-feet, power operations are suspended to make low level releases. This solution is effective until the layer of cold water above the old dam runs out. Suspending power operations reduces revenues from the project. The estimated loss from suspended power operations during the fall of 1994 was over $200,000. The Central Valley Project Improvement Act (CVPIA) in 1992 changed water usage priorities. Environmental, water, and wildlife enhancement priorities moved to a level equal to or ahead of other water use priorities. As a result, less water is available to meet the obligations. The 2.4 million acre-feet gross storage capacity of New Melones Lake includes a flood control reservation of 450,000 acre-feet. Under flood control conditions, release operations are designed not to exceed a flow of 8,000 cfs (channel capacity) in the Lower Stanislaus River from Goodwin Dam downstream to the San Joaquin River. Unit operations provide releases for downstream fishery requirements, water quality, water rights, and a water supply yield estimated at about 180,000 acre-feet to meet present and projected agricultural and municipal and industrial water needs in the service area. The New Melones Unit was officially transferred to Reclamation in November 1979 for integrated operation as a unit of the Central Valley Project. The Oakdale and South San Joaquin Irrigation Districts own and operate the downstream Goodwin Diversion Dam, which diverts Stanislaus River water into the district`s canals. The two districts also own and operate the Tri-Dam Project, which consists of Donnells Dam, Reservoir, and Powerplant; Beardsley Dam, Reservoir, and Powerplant, on the Middle Fork Stanislaus River upstream from New Melones Dam; and Tulloch Dam, Reservoir, and Powerplant, located immediately downstream from New Melones Dam. Tulloch Reservoir provides afterbay storage for reregulating power releases from New Melones Powerplant under contractual arrangements between the Bureau and the two districts. On the North Fork Stanislaus River, storage developments consist of Pacific Gas and Electric (PG & E) Company`s Lake Alpine, Utica Reservoir, Union Reservoir, and Spicer Reservoir. Also owned and operated by PG & E are Relief Reservoir; Stanislaus Powerplant; Spring Gap Powerplant, on the Middle Fork; and Strawberry and Lyons Reservoirs on the South Fork.

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Organization: Central California Area Office
Address: 7794 Folsom Dam Road
City: Folsom, CA 95630
Phone: 916-989-7200

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Address: 2800 Cottage Way E-1705
City: Sacramento, CA 95825-1898
Fax: 916-978-5114
Phone: 916-978-5100

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Organization: Commissioner`s Office
Address: 1849 C Street NW
City: Washington, DC 20240
Fax: 202-513-0575
Phone: 202-513-0305

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