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66-710: The 19,564-acre (7,917 ha) park was established in 1956 after the creation of the Folsom Dam . Folsom Lake is the ninth largest reservoir in California and a major recreational asset for the Sacramento area. It consists of two reservoirs: Folsom and Natoma. About 2 million people visit the Folsom Lake State Recreation Area every year. Generally, Folsom Lake State Recreation Area experiences hot summers and mild winters. Campgrounds in

132-507: A 355,000 acre⋅ft (0.438 km ) flood control unit, and was reauthorized in 1949 as a 1,000,000 acre⋅ft (1.2 km ) multiple-purpose facility. The current Folsom Dam replaced an earlier, smaller dam that had been completed in 1893 by Horatio Gates Livermore. The earlier dam had fed the Folsom Powerhouse , generating electricity that was transmitted to Sacramento over a 22 mi (35 km)-long distribution line,

198-538: A 5-day period. However, this time the Bureau of Reclamation was able to limit releases to less than 110,000 cubic feet per second (3,100 m /s). The 1997 storm was a classic example of a "rain on snow" event, during which a warm tropical storm melted existing snowpack at lower and middle elevations, effectively doubling the volume of runoff. Prior to the New Year's storm, the winter of December 1996 had also been one of

264-457: A beach. Black Miners Bar group campsites Black Miners Bar is located on the west side of Lake Natoma. It can be accessed off Greenback Lane in Folsom. Campground facilities include 3 Group sites. Sites A & B accommodate 50 people and Site C can accommodate 25 people. Flush toilets are available. A Group must contain at least 9 people. Gold was first discovered along the south bank of

330-576: A matter of weeks, and preventing $ 20 million of property damage. The dam was officially dedicated on May 5, 1956, and operation was transferred to the Bureau of Reclamation on May 14. On the morning of July 17, 1995, the Folsom Dam power plant was shut down and Spillway Gate 3 was opened to maintain flows in the American River. As the gate was operated, a diagonal brace between the lowest and second lowest struts failed. The failure resulted in

396-558: A new spillway, is designed to handle the runoff from large storms and snowmelt floods that might cause damage in the region. The new spillway is built with gates 50 ft (15 m) lower than the existing spillway, allowing for more efficient evacuation of reservoir storage before flooding events. Nimbus Dam The Nimbus Dam is a base load hydroelectric dam on the American River near Folsom, California . Approximately 8,700 acre-feet (10,700  dam ) of water

462-404: A system of collecting steelhead and adult salmon for the hatchery. The project would also include changes that would minimize flow fluctuations in the river associated with the weir of the hatchery, as well as eliminate safety concerns associated with the existing weir. Nearly half of the annual precipitation in the Sacramento area occurs during a span of 60 days in the winter months, while during

528-700: Is a cooperation between students at Sacramento State, the University Union at Sac State, California Department of Boating and Waterways, and the California Department of Parks and Recreation. Folsom Dam Folsom Dam is a concrete gravity dam on the American River of Northern California in the United States, about 25 mi (40 km) northeast of Sacramento . The dam is 340 ft (100 m) high and 1,400 ft (430 m) long, flanked by earthen wing dams. It

594-532: Is a remote campground which can be subject to winter and/or road closures. Campsite reservations can be made only on-season and during off-season it is first-come, first-served. Beals Point campground Beals Point is located on the west shore of Folsom Lake, just north of the dam. It can be accessed off Auburn-Folsom Road, south of Douglas Blvd. There are 69 Sites allowing trailers and RVs up to 31’. Facilities include flush toilets, hot showers, piped water, sanitation station, snack bar, beach equipment rentals, and

660-425: Is commonly used as a horseback riding trail. Avery's pond is a historical pond made in the 1880s by a pioneer rancher named Ira Avery. Elevation of the pond is at 530 feet, about 20 feet above Folsom Lake. The 1854 North Fork Diversion ditch provided water for Avery's Pond and water from the pond became a reliable year-around water source for Avery's extensive orchards. Avery used to supply lumber, fruit, and sheep to

726-488: Is home to many species of plants and animals. Some of the common plants in the area include blue oaks, interior live oaks , foothill pines and annual grasses. In the spring, wildflowers include Indian paintbrush , larkspur, lupine , brodiaea , fiddleneck , Dutchman's pipe and monkey flower . In addition to plant life, there are also several species of animals including black-tailed deer , raccoons , skunks , opossums , gray foxes and coyotes . Birds commonly found in

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792-500: Is located at the end of Rattlesnake Bar Road, on the peninsula between the North and South Forks of the American River. It can be accessed from Pilot Hill on Highway 49 by following Rattlesnake Bar Road 11 miles to the campground. It is also accessible by boat for Boat-In camping. It has 100 campsites with facilities including flush toilets, hot showers, piped water, sanitation station, two boat launch ramps, and oaks nature trail. Peninsula

858-429: Is located just north of the city of Folsom , and consists of a 340-ft-high (100 m), 1,400-ft-long (430 m), hollow-core, concrete gravity dam containing 1,170,000 cu yd (890,000 m ) of material. The dam is flanked by two earthen wing dikes, and the reservoir is held in place by an additional nine saddle dams on the west and southeast sides. The wing dams total a length of 8,800 ft (2,700 m), and

924-482: Is located on the north side of the river, at the base of the dam. It has three Francis turbines with a combined capacity of 198.72 megawatts (MW), uprated from its original capacity of 162 MW in 1972. The power plant's electricity production is intermediate, between peaking and base load . It generally operates during the day, when the demand and price for electricity is the highest. The plant produces an average of 691,358,000 kilowatt hours each year. Folsom Dam

990-582: Is located on the opposite side of the American River. The site was temporarily renamed in 2022, while a permanent name is being decided. Avery's Pond environmental campsites Avery's Pond is located Near Rattlesnake Bar, north of the Rattlesnake Bar Equestrian Assembly Area. It can be accessed by parking at Rattlesnake Bar and walking 1.1 miles to the sites. There are 2 Sites and each holds 8 people. There are no water or garbage service and no dogs or fires allowed. It

1056-522: Is retained by the dam. It is responsible for the impoundment of water from the American River to create the Lake Natoma reservoir . The dam stands 87 feet and spans 1,093 feet. The Nimbus powerplant consists of two generators. Each generator produces enough electrical power to power over 200,000 100-watt light bulbs, about 15,500 kilowatts of electrical power. Nimbus Dam consists of 18 radial gates, each with their own gate bays. These 18 gates today are

1122-422: Is transmitted from the cylindrical skin plate, which is in contact with the reservoir, through a number of struts to a convergence at the trunnion hub. The hub collects the load from the struts and transfers it across an interface to the trunnion pin, which is stationary and is connected to the dam. When the gate is operated, the hub rotates around the pin. The struts are primarily compression members, but friction at

1188-522: The Folsom South Canal , which carries water to an area approximately 10 miles northeast of the city of Lodi. The canal once provided cooling water for the SMUD nuclear power plant, Rancho Seco. Today, it continues to provide water for irrigation, water supply, and industrial purposes to its surrounding area. The United States Bureau of Reclamation released a final environmental assessment for

1254-535: The U.S. Army Corps of Engineers . On October 29, 1952, the first concrete was poured for the foundation. Flooding washed out the temporary cofferdam three times in 1953, delaying work and causing damage to Nimbus Dam which was also under construction at the time. Water storage in Folsom Lake began in February 1955, and the final concrete in the main dam was poured on May 17, 1955. The first hydroelectric power

1320-442: The 1940s, very few families were left in the area due to fire, diminished gold, and a new railroad. The Natoma Water Company was formed in 1851 by local miners to construct a 20-mile ditch that would supply water for miners seeking gold. The ditch started up by the new salmon falls bridge and reached down to Granite City, which today is named Folsom. The ditch was named the "Natoma Ditch" and it cost around $ 175,000 to build. In 1912

1386-619: The American River in the area originally known as Negro Bar. This site received its name because it was one of the earliest recorded locations mined by African-American gold miners during the California Gold Rush of 1849. At the time, Negro Bar was a large sand bar located on the south bank of the lower American River, in what is now the City of Folsom. Most African American miners left by 1852 to nearby mining sites that were more successful. Today, Black Miners Bar State Recreation Area

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1452-524: The American continent"), which from 1885 to 1952 produced 11,000 volts of electricity for Sacramento residents. For cyclists there is a 32-mile-long (51 km) bicycle path that connects Folsom Lake with many Sacramento County parks before reaching Old Sacramento. The park also includes Lake Natoma , downstream from Folsom Lake, which is popular for crew races, sailing , kayaking and other aquatic sports. The primary recreation season coincides with

1518-768: The Bureau of Reclamation as part of California's Central Valley Project to control the waters of the American River. Other functions of the dams include flood protection, household water supply, power and irrigation. In May 1979, the California State Park and Recreation Commission approved the General Plan for the Folsom Lake State Recreation Area. The public participated heavily in this plan through six public workshops and over 3,500 mail in questionnaires. The public agreed that Lake Natoma should retain its quiet character but Folsom Lake needed to be upgraded for recreational use. Folsom Lake State Recreation Area

1584-489: The California Department of Fish and Wildlife to operate the hatchery. Lake Natoma is an intermediate lake along the American River , located between Folsom Dam and Nimbus Dam. It is primarily a recreational lake. It includes Negro Bar State Recreation Area. The Sacramento State Aquatic Center is also located here and equipment rentals are available for paddling, rowing, water ski and wakeboard, boating and jet skiing, and sailing and windsurfing. The Sac State Aquatic Center

1650-579: The Folsom-Nimbus project was completed in 1958, most of the spawning and rearing areas for the fish were cut off. Nimbus Hatchery was constructed to replace the salmon and steelhead runs that were blocked by Nimbus dam. The Nimbus Fish Hatchery located at Nimbus Dam raises Chinook salmon and steelhead for release to the American River. About 4 million Chinook salmon and 43,000 steelhead are released each year. Educational activities for children and adults are offered. The U.S. Bureau of Reclamation pays

1716-715: The Natoma Water Company lined 13,000 feet of the ditch with concrete. In 1953 the government bought most area to build Folsom Lake. The Natoma Water Company is now called Natoma Company. People from all over the world came to the South Fork and North Fork of the American River to mine for gold. People were from England, Scotland, Wales, New York, Virginia, Kentucky, Hawaii, China, etc. They camped next to their mining areas and eventually these camps became small towns. Among these are Rattlesnake Bar, Mormon Bar, Mormon Ravine, Oregon Bar, and Manhattan Bar. Folsom Dam

1782-604: The Nimbus Dam Radial Gates Maintenance Project in May 2015. This report laid out the purpose and need for the project, the details of what the construction would consist of, and the environmental impact of the project on existing federal wildlife protection acts. The report argues that over half the radial gates of Nimbus Dam need a new coating system, along with other repairs that fall outside of normal maintenance. No major work has been done to

1848-633: The Nimbus Fish Hatchery was built in 1958. However, the amount of fishing that was being done severely impacted the spawning locations of fish once passed the fish ladder at the hatchery. On March 1, 2018, the Nimbus Basin became permanently closed to all fishing. The closure of the basin is an effort to reorienting the fish ladder as part of the Nimbus Hatchery Fish Passage Project, which would create

1914-644: The Western States/ Pioneer Express Trail between Sacramento and Carson City, Nevada also runs through the park. A paved bicycle trail loops around Lake Natoma, linking to Beals Point and the American River Bike Trail. Native Americans of the Maidu or Nisenan tribe inhabited the land around Folsom Lake for thousands of years. During the winter, they lived in permanent villages around the American River and in

1980-541: The area consist of the Peninsula Campground, Beals Point Campground, Negro Bar, and Avery's Pond. The lake and recreation area offer opportunities for hiking , biking, running , camping , picnicking, horseback riding , water-skiing and boating. Fishing offers trout , catfish , largemouth and smallmouth bass or yellow perch . Visitors can also tour nearby Folsom Powerhouse State Historic Park (once called "the greatest operative electrical plant on

2046-466: The area include nesting egrets, herons and cormorants , Canada geese , blackbirds, scrub jays , quail , wrens , bushtits and towhees . There are also wrentits , California thrashers , kingfishers and grebes near the water. Red-tailed hawks , American kestrels , ospreys and eagles may be spotted flying over the area. Rattlesnakes are also common. The park has many ancient blue oak trees that range from 400 to 500 years old. Vegetation in

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2112-606: The area is 50 percent interior live oak, 25 percent blue oak, 14 percent annual grassland, 5 percent cottonwood/willow riparian, freshwater marsh and seasonal wetlands, and less than 5 acres of vernal pools. Birdwatching is a year-round activity. Bird migration occurs in autumn and spring. Lake Natoma and Folsom Lake have up to 80,000 wintering gulls and some waterfowl. Great blue herons, great egrets and double-crested cormorants begin setting up breeding territories in February and stay until August. Their young can be seen March though August. Peninsula campground Peninsula campground

2178-539: The area is protected from a flood that has a 0.5% chance of occurring in any given year), the Corps of Engineers recently constructed an auxiliary spillway, which was completed in October 2017; it enables Folsom Dam operators to increase outflows to prevent the lake level from reaching or exceeding the height of the main dam gates. Another Central Valley Project dam, Nimbus Dam , is located further down river. Folsom Dam

2244-412: The coefficient of friction and, therefore, the bending stress in the strut and the axial force in the brace. The capacity of the brace connection was exceeded and it failed. This caused the load to redistribute and the failure progressed, eventually buckling the struts. After a year-long investigation, the Bureau of Reclamation attributed the failure to a design flaw: the Corps of Engineers, which designed

2310-403: The dam forms Folsom Lake , with a normal maximum pool of 977,000 acre⋅ft (1.205 km ) and a surcharge capacity of 110,000 acre⋅ft (0.14 km ), for a total capacity of 1,087,000 acre⋅ft (1.341 km ). The original capacity was 1,010,000 acre-feet (1.25 km ), but it has been reduced somewhat due to sedimentation . At its maximum elevation of 480 ft (150 m),

2376-411: The dam, did not consider trunnion friction (at the pin-hub interface) in the gate analyses. While this is true, this was one of five identical service gates that operated under the same circumstances for nearly 40 years without problems being observed. This suggests that the failure resulted from a condition that changed over time. Specifically, there was a gradual increase in the coefficient of friction at

2442-492: The dam. To make sure the salmon had a place to spawn, through the California Department of Fish and Game, the Bureau of Reclamation opened the Nimbus Fish Hatchery in 1958 downstream from Nimbus Dam. The purpose of the hatchery was to provide the salmon with an artificial spawning habitat before they are let back out into the wild. Fishing has been a popular recreational use of the waters below Nimbus Dam since

2508-411: The gates since the construction of the dam in the 1950s. In 2014, the Bureau of Reclamation contributed an $ 11,141,820 contract for the construction. The project is expected to be completed by the end of 2019 and will focus on replacing the coating on the fourteen gates that have the original quoting. The project will also include the construction of a storage facility. Along with laying out the plan for

2574-434: The gold miners in the area. His ranch consisted of about 117 acres, of which 40 acres had 1,500 fruit trees (pears, persimmons, cherries). The pond is lined with fine-grained alluvium. Nimbus Dam and Lake Natoma are also included in the vicinity of the Folsom Lake State Recreation Area. Historically, the American River provided approximately 100 miles of stream in which salmon and steelhead could spawn and rear. When

2640-528: The government initially considered. Continued security concerns prevented them from re-opening the road and a new bridge, named Folsom Lake Crossing, was constructed and opened on March 28, 2009. During a severe storm in December 1964, the inflow into Folsom Lake reached a record high of 280,000 cu ft (7,900 m ) per second, with a river release of 115,000 cu ft (3,300 m ) per second. In February 1986, nearly 500,000 people faced

2706-584: The lake during the summer season increases with the operation of the Auburn-Folsom South Project. This ultimately lowers water temperatures. 125 miles of habitat for Chinook and steelhead salmon were accessible in the American River Watershed before the construction of Nimbus Dam. When the dam was constructed in the 1950s, this habitat area was dramatically decreased in size, as the salmon were not able to pass through

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2772-636: The longest electrical distribution system in the world at the time. The remains of the earlier dam can be seen downstream from the Folsom Lake Crossing. Construction of the dam began in 1951 with preliminary excavations for the Folsom Power Plant. The primary contract was awarded to Savin Construction Corp. of East Hartford, Connecticut, and Merritt-Chapman & Scott of New York for $ 29.5 million, with oversight by

2838-408: The mountains was deposited in Folsom Lake, considerably reducing its capacity. The consequence was a reduced capacity to store winter rainfall for summer use. Folsom Dam may have prevented as much as $ 4.7 billion in damages in 1986 alone. The New Year's Day storm of 1997 was the most severe in recent history, with a total inflow of 1 million acre feet (equal to the entire capacity of Folsom Lake) over

2904-491: The ones that were completed in 1955 along with the rest of the dam. Of the eighteen gates, four of them have had their coating system replaced. This protects the gates from a faster rate of corrosion. The other fourteen gates have the original coating. As part of the Central Valley Project (CVP), a federal water project that provides irrigation and municipal water to much of California's Central Valley , it

2970-564: The pin-hub interface and cause the corrosion that resulted in increased friction. This failure caused no fatalities, and it had a significant positive impact on the dam industry. A renewed focus was placed on maintenance and monitoring of radial gates, many of which were retrofitted to strengthen struts and bracing and ensure sufficient lubrication. After the 9/11 terrorist attacks , the Bureau of Reclamation analyzed potential targets for vulnerability and measures that could be taken to eliminate or reduce possible threats. With 500,000 residents in

3036-413: The pin-hub interface induces a bending stress during gate operation. Typically, and in this case, the struts are oriented such that the trunnion friction stress is applied to the weak axis of the struts (see Section modulus ). To better handle these loads, the struts are connected with diagonal braces that take the stress as axial loads. At Folsom Dam, increasing corrosion at the pin-hub interface had raised

3102-427: The pin-hub interface. While one would expect maintenance frequency to increase as a gate ages, Reclamation decreased the frequency of regular maintenance and lubrication over time due to budget constraints. In addition, the lubricant used by Reclamation did not conform to the Corps' original design specifications; it was a new, environmentally-friendly lubricant that was not sufficiently waterproof, allowing water to enter

3168-472: The possibility of flooding when engineers at Folsom Dam were forced to open the spillway gates after heavy rains. The flooding was made worse by the failure of the Auburn Dam cofferdam upstream which released an extra 100,000 acre-feet (120,000,000 m ) into the American River. A peak flow of 250,000 cubic feet per second (7,100 m /s) entered Folsom Lake, forcing operators at Folsom Dam to open all

3234-547: The project would be completed without significant environmental damage. The water in Lake Natoma, which is the lake created by Nimbus Dam, is too cold for warmwater production of fish, and never has the lake been a natural producer of fish. The rapid water exchange from Nimbus Dam sharply decreases the production of plankton, which inhibits trout growth. The Department of Fish and Game annually plants Lake Natoma with 20,000 to 30,000 catchable-sized trout. The water exchange in

3300-560: The project, managers were to abide by federal and state environmental regulations. In the writing of the final report for the maintenance project, the regulations that the project would abide by include the Fish and Wildlife Coordination Act, Endangered Species Act, Migratory Bird Treaty, executive orders for floodplain management and the protection of wetlands, Clean Air Act, and the Clean Water Act. Complying with these regulations means

3366-462: The reservoir covers 11,930 acres (4,830 ha), with 75 mi (121 km) of shoreline. The dam and reservoir control runoff from an area of 1,875 sq mi (4,860 km ), or 87.6% of the 2,140 sq mi (5,500 km ) American River watershed. The average amount of runoff entering the reservoir is 2,700,000 acre-feet (3.3 km ), forcing the release of 1,700,000 acre-feet (2.1 km ) for flood control. Folsom Power Plant

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3432-482: The saddle dams measure 16,530 ft (5,040 m) long combined. The dam and appurtenant dikes total a length of 26,730 ft (8,150 m), more than 5 mi (8.0 km). Floodwaters are released by a spillway located on the main channel dam, controlled by eight radial gates with a capacity of 567,000 cu ft/s (16,100 m /s), as well as a set of outlet works with a capacity of 115,000 cu ft/s (3,300 m /s). The impounded water behind

3498-494: The spillway gates, releasing 130,000 cubic feet per second (3,700 m /s) into the American River. This was 15,000 cubic feet per second (420 m /s) above the safe capacity of downstream levees. Although the dam and the Sacramento levee system held without major damage, the requisite winter flood control space was increased 50%, from 400,000 to 600,000 acre feet, to protect against future floods. In addition, about 33,000 acre-feet (41,000,000 m ) of sediment carried down from

3564-402: The spring and summer months when temperatures are in the 80s, 90s and 100s. Visitation is highest from April through September. In the spring months when school is still in session, evenings and weekends are the times of highest lake activity. There are 95 miles of trail at Folsom Lake State Recreation Area. These trails are used by hiker, bicyclists, runners, and horseback riders. A portion of

3630-572: The summer made temporary homes made of bark. The Nisenan used local resources found around the lake like acorns and berries to trade with coastal tribes. They wove their baskets from willow, redbud, tule, milkweed, sedge grass and native grapevine. In 1848, the California Gold Rush began and most of the Nisenan land was given away. The Nisenan became overwhelmed and their population was severely decimated due to diseases. However, some survived and still live in surrounding reservations. The Folsom Lake Area

3696-593: The summer, only about one percent of the annual precipitation falls. In the American River Basin, approximately 40% of the annual runoff is a result of melting snow in the Sierra Nevada Mountains. As a result, low natural flow rates in the American River system in the later summer months. As a result, the dam fluctuates water output throughout the year. Due to the contamination of the groundwater because of environmental degradation in

3762-419: The two generators contain approximately 7,700 kilowatts of electrical power. What drives the two generators through six penstocks, each about 47 feet long, are the two turbines with 9,400 horsepower. Water is supplied through these turbines. The Western Area Power Administration markets the power that is generated by the powerplants at Nimbus Dam and Folsom Dam. The dam serves as a diversion to direct water into

3828-471: The uncontrolled release of nearly 40% of Folsom Lake and a flood of 40,000 cubic feet per second (1,100 m /s) moving down the American River. The freshwater reaching San Francisco Bay was atypical for the summer season. This confused Pacific salmon and striped bass, whose instincts told them that fall rains had arrived, thus they began their annual fall migrations months ahead of schedule. The hydraulic load on this type of spillway gate ( Tainter gate )

3894-414: The vicinity of the Folsom Dam, the possibility of an attack on the dam was great enough concern for Bureau officials to close Folsom Dam Road. The road over the dam had been a major artery for the city of Folsom. With its closure, traffic became severely congested during rush hour. The impact was so great that residents and city officials petitioned the federal government to reconsider the road closure, which

3960-456: The wettest ever recorded, saturating the ground and depositing a considerable amount of snow. The Bureau of Reclamation's Safety of Dams Program determined the risk of flooding in the Sacramento area, labelling it as one of the most at-risk communities in the United States. Two projects to increase flood protection are currently underway. The first will raise the surrounding dikes by 7 feet (2.1 m) to increase flood protection. The second,

4026-502: Was also a significant mining site during the California Gold Rush of 1849. During recent drought years, water levels had been so low at Folsom Lake that the old mining town of Mormon Island was revealed. Mormon Island was a sandbar about 300 feet long where gold was found by members of the Mormon Battalion. When news of gold discovery spread, Mormon Island grew and gained a population of up to 2,500 people by 1853. However, By

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4092-402: Was authorized in 1949 as a regulating reservoir for Folsom Dam , and a diversion pool for the Folsom South Canal . Construction began in 1952, and it opened in 1955. The Nimbus Powerplant is located on the north side of the American River and on the left side of Nimbus Dam via looking east. The powerplant provides backup to the main powerplant that is located upstream at Folsom Dam. Each of

4158-555: Was built in 1955 as a concrete dam flanked by earth wing dams and dikes, with a total length of about nine miles. The shoreline extends about 15 miles up the forks of the American River. Lake levels at Folsom Lake State Recreation Area normally vary from 460 feet in early spring to less than 400 feet by summer as the rainy weather passes and snow in the Sierras melts. Downstream, behind Nimbus Dam , smaller Lake Natoma has about 500 surface acres of water. Folsom and Nimbus Dams were built by

4224-726: Was completed in 1955, and officially opened the following year. Located at the junction of the north and south forks of the American River, the dam was built by the United States Army Corps of Engineers , and was transferred to the United States Bureau of Reclamation upon its completion. The dam and its reservoir, Folsom Lake , are part of the Central Valley Project , a multipurpose project that provides flood control , hydroelectricity , irrigation, and municipal water supply. To increase Sacramento's flood protection to 200-year flood protection (meaning that

4290-472: Was generated in September of that year. In order to acquire the necessary land in the future Folsom Lake bed, the government had to relocate families on 142 properties, including the settlements of Mormon Island and Salmon Falls . Even before the dam was complete, it demonstrated its effectiveness as a flood control facility during the record storms of December 1955, which completely filled Folsom Lake in

4356-431: Was proposed as early as the 1930s under California's State Water Plan, in response to chronic flooding in low-lying Sacramento. The flood risk to the state capital had been exacerbated since the 1850s by hydraulic mining debris and the construction of levees to protect farms and towns, which reduced the channel capacity of the Sacramento and American Rivers. The current dam was originally authorized by Congress in 1944 as

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