Central Valley Project
California's Central Valley extends nearly 500 miles (800 km) from the Sacramento River in the north to the San Joaquin River in the south. Development of the region by non-Native Americans began in earnest after gold was discovered in 1848, and can be characterized by three overlapping stages of agricultural progress. It began with cattle ranching, followed by dry farming of grain, and presently the specialized and heavily irrigated farming practices of today. While demand for water remains high, average rainfall can fluctuate significantly throughout the Central Valley, ranging from as few as five inches (127 mm) annually in the south to as many as 30 inches (760 mm) in the north. Furthermore, greater than 75 percent of the yearly precipitation occurs in the five months between December and April, making it difficult to sustain crops during the summer months. "Agriculture in the Central Valley prove[s] almost as much a gamble as prospecting for gold. When nature cast[s] the die, the roll [can] literally result in flood or famine." Complicating matters further, the northern end of the valley faces issues of salinity control. At certain times during the year, saltwater from San Francisco Bay can move inland during high-tides, making water unusable for irrigation and other industries. As a result, in the interests of creating a sustained, year-round supply of water, as well as controlling salinity of the Central Valley's freshwater, federal legislature for the Central Valley Project (CVP) was passed in 1933.Shasta Dam under construction, June 1942
Today, a system of 20 dams, 500 miles (800 km) of canals, and other mechanisms for water conservation and distribution sustain six of California's 10 most productive agricultural counties. This complex water system also provides fresh water for urban centers like San Francisco. Of the nearly 9,000,000 acre·ft (11,000,000 dam³) of water in its management, the CVP annually delivers 7,000,000 acre·ft (8,600,000 dam³) to these causes. Additionally, the 11 power plants in the region generate 5,600 gigawatt-hours of electricity–enough to provide for approximately two million people. The Central Valley Project also oversees natural preservation efforts, allocating over 1,000,000 acre·ft (1,200,000 dam³) of water annually to conserve fish and wildlife habitats. The CVP also assists in wetland protection efforts. Estimates have shown that the federal government's initial investment of $3 billion has resulted in $300 billion dollars in returned growth of agricultural and other related industries.
 Shasta Division and Shasta Dam
The Shasta division of the Central Valley Project consists of Shasta Dam and Shasta Lake, the Shasta power plant, as well as the Keswick Dam and its power plant. Located ten miles (16 km) north of Redding on the Sacramento River, Shasta Dam is positioned to "catch the headwaters of the network of Central Valley Project waterways and channel the water southward." Shasta Dam is the second-largest dam in the United States, behind the Grand Coulee Dam in Washington. It measures 602 feet (183 m) in height and is 3,460 feet (1,050 m) across. Construction on the dam began in 1938 and finished seven years later in 1945. The dam's spillway is the largest man-made waterfall in the world. In addition, Shasta Lake is the largest man-made reservoir in California, containing about 4,500,000 acre·ft (5,550,000 dam³) of water and consisting of 365 miles (587 km) of shoreline. In total, at least 47 square miles (120 km2) of land are now submerged under the lake.
The area around the region that would later become Shasta Lake was largely unpopulated by Europeans until 1840. However, population was estimated to grow at a staggering rate of 40 percent after the beginning of construction on the dam, and smaller increases have persisted over the years. At the time of the 1990 Census, Shasta County was home to 147,036 people.
In its role of controlling salinity, the dam prohibits water from San Francisco Bay to move inland and damage irrigation efforts. Similarly, in tandem with the Keswick Dam downriver, it operates as a flood control, managing the flow of water from Shasta Lake. The power plant at Shasta Dam has a maximum generating capacity of 676,000 kilowatts, contributing to the 5.6 billion kilowatt-hours of electricity produced by all elements of the Central Valley Project. After concerns about the impact of the dams on wildlife were raised in the 1970s, efforts were made to protect fish habitats on the Sacramento River. As a result, a minimum flow of water is maintained in the Shasta Division, allowing certain species of salmon and other fish to safely maneuver the River as well as offering optimal conditions for spawning.
"Federal and state project planners envisioned Shasta Dam as the key to the Central Valley Project. Shasta would perform several duties for the project, including water storage, to release for irrigation and salinity control in the Delta; flood control, to protect communities along the Sacramento River, long afflicted by flood waters; and power generation."
Further efforts were undertaken at Shasta to provide a Chinook salmon spawning and rearing facility. Water from Shasta Lake provides irrigation for crops in the Sacramento and San Joaquin Valleys valued at an estimated $256 million in 1990, as well as a supplemental area of 460,000 acres (190,000 ha) more of cropland. Finally, Shasta Lake provides recreation such as boating, fishing, swimming, and other water activities. Home sites have also been developed along the shore, as well as resorts that cater to the needs of vacationers