Shasta Dam

Shasta Dam, also known before its construction as Kennett Dam, is a massive concrete arch-gravity dam across the Sacramento River in Northern California. Standing 602 feet high, it is the eighth-tallest dam in the United States. The dam creates Shasta Lake, the largest reservoir in California, which can store about 4,500,000 acre-feet of water. Shasta Lake helps with storing water for the future, controlling floods, producing electricity, and keeping salty water from moving into the river.

People first thought about building Shasta Dam in 1919 to help manage water for California's main farming area, the Central Valley. The project was approved in the 1930s but faced problems because of the Great Depression. It became a federal project led by the Bureau of Reclamation. Construction began in 1937 under Chief Engineer Frank Crowe and provided jobs for many people. The dam was finished in 1945, 26 months earlier than planned. When it was done, it was the second-tallest dam in the United States after Hoover and was seen as a amazing achievement in engineering.

Even before it was officially opened, Shasta Dam helped provide electricity to factories in California during World War II. Today, it remains important for managing water in the state. However, the dam has changed the environment of the Sacramento River and covered lands that were sacred to Native American tribes. Recently, people have discussed raising the dam to store more water and make more electricity. This could help reduce carbon emissions, but it is opposed by tribes and groups that protect fish because it could harm river flows and endangered species.

History

In the late 1800s, many people moved to California’s Central Valley to farm because the land was rich and the weather was nice. The Sacramento River flows through this area and brings lots of water, but most of it comes in the winter, leaving very little in the summer. This caused problems for farms, especially when salty water from the Pacific Ocean would mix into the river.

To fix this, people suggested building a big dam on the Sacramento River near a place called Kennett. The dam would store water for use in dry months, help control floods, and give more water to farms. In 1931, a plan called the State Water Plan was made, which included this dam and canals to bring water to other dry areas.

Because of the Great Depression, California needed help paying for the project. In 1935, President Franklin Delano Roosevelt approved the Central Valley Project as part of programs to create jobs. The dam was built by experts who had worked on the famous Hoover Dam.

Construction

The Shasta Dam was officially named on September 12, 1937, in a small town called Kennett. Congress gave $12 million for the project. The dam was built in a deep canyon near Kennett. The winning bid for building the dam came from Pacific Constructors Inc.

Construction began with digging out bedrock to make space for the dam’s foundations. Roads and railroads were moved to make way for the rising waters of Shasta Lake. A new town called Toyon was built to house workers and officials.

Construction started on a channel to move water aside so the dam’s foundations could be built. A very long conveyor belt was used to bring sand and gravel from Redding to the dam site.

Once the foundations were ready, workers began pouring concrete for the main dam. A special system of towers and cables moved concrete buckets quickly to the workers.

Building the main dam began in July 1940. Thousands of workers poured concrete into large blocks to form the dam. In December 1941, Japan attacked Pearl Harbor, and the United States entered World War II. This caused a shortage of workers, so many women and high school students helped build the dam. The dam provided important electricity for factories during the war.

When the tunnel was ready, the river was moved through it, allowing work on the middle part of the dam. The spillways were finished in the summer of 1943.

Water began to fill behind the dam in February 1944. The last bucket of concrete was poured on January 2, 1945. When finished, Shasta Dam was the second tallest dam in the world and the highest structure in California.

Design and operations

Shasta Dam helps control flooding and store water for dry seasons, which is very important for farming in the Sacramento Valley and for boats traveling on the Sacramento River. It also keeps enough fresh water in the Sacramento-San Joaquin Delta so it can be used for other areas. Another big job of the dam is to make electricity. It can make 676 megawatts of power using five big machines called turbines.

The dam is very tall, standing 602 feet above its base. It is also very long, stretching 3,460 feet. It has special valves that let out extra water during floods, and a big concrete area called a spillway that helps manage the water flow. The dam creates a large lake called Shasta Lake, which is the biggest man-made lake in California. This lake stores a lot of water and is fed by several rivers and streams.

Future expansion

In the 1990s, water shortages in California's Central Valley led to ideas about making Shasta Dam taller. The dam could be raised in three ways: a little bit, a medium amount, or a lot. The smallest raise would just add a wall on top. The bigger raises would need new buildings and could cover bridges and towns. The biggest raise would triple the amount of water the lake could hold.

Some people don't want the dam made taller. They say it would cover important places for fish and Native American traditions. They also think it might not save much water and could cost too much money. Work has started on studies to see how the raise would affect the environment, and some land has been bought to make it possible. In 2020, plans were shared to greatly increase how much water Shasta Lake could hold.

Potential geologic hazards

Plans for changing Shasta Dam note that several natural dangers could happen nearby. These include earthquakes from fault zones, volcanic eruptions from mountains like Mount Shasta and Mount Lassen, mudflows, snow avalanches, land sliding, and a wave effect in lakes called seiches. The closest fault zone is about 27 miles south of the dam and could cause a big earthquake.

Criticism

Ecological effects

The Shasta Dam has greatly affected Pacific salmon in the Sacramento River. When the dam was built in 1943, it blocked salmon from reaching their spawning grounds upstream. This loss of habitat has hurt salmon populations. The dam also changed the temperature of the river water, which is harmful to salmon and other fish like steelhead and trout.

To help the salmon, a fish hatchery was built in 1942. In 1991, a special device was added to the dam to control water temperature, which has helped improve conditions for fish.

Wintu lands

The land now covered by Shasta Lake was home to the Winnemem Wintu people. Most of their land was flooded when the dam was built, leaving only a small part along the McCloud River. Many important cultural and sacred sites are now underwater. The Winnemem Wintu are not officially recognized by the U.S. government, and they have been fighting to protect their remaining land and traditions.

Tours and recreation

The Shasta Dam offers guided tours all year, lasting two to three hours. These tours include a long elevator ride down to the base of the dam and visits to its inner areas and power station. Shasta Lake, which the dam creates, covers a large area and is surrounded by the Shasta-Trinity National Forest. The lake is a favorite spot for many activities, including boating, fishing, swimming, and water sports. Visitors can also enjoy hiking, picnics, biking, and camping near the lake, with many places to stay and play around the area.

Shasta Dam on January 6, 2006