The dam was built in response to these pollutants that were contaminating the Sacramento River, the primary water supply for millions of Californians.

[4][5] The dam and reservoir, along with other treatment structures built at and below the mine, have successfully reduced the dry weather pollution of Spring Creek by up to ninety-five percent.

At the very end of the 19th century, Iron Mountain Mine took blames for several fish kills in the Sacramento River.

...release of this waste resulted in virtual elimination of aquatic life in many of the creeks surrounding the Iron Mountain Mine site.

...work is continuing on what is possibly the largest and most difficult acid mine drainage problem in the United States.

Acid mine drainage flowed, unfettered, down Spring Creek directly into the Keswick Reservoir, depositing contaminated sediment and turning a portion of the water a rusty red shade.

Spring Creek Dam was begun in 1961, when a company named Gibbons and Reed was awarded the contract.

The clearing operations began in July of that same year, and the dam was officially dedicated by the Bureau of Reclamation on September 12, 1961.

In 1962, a series of labor strikes impacted communities in the Central Valley, also affecting construction of the dam, which was temporarily halted on May 3 of that year.

Several alternatives were considered for remediating this problem:[12] In 1985, it was found that water seepage into the foundations of the Spring Creek Dam could possibly cause its collapse.

[8] Two years later, in March 1992, an uncontrolled, unexpected spill of acidic water rushed from the dam down Spring Creek.

This spill heavily contaminated the Keswick Reservoir and threatened the water supply of Redding, California.

Despite the fact that the region was suffering from a drought, 77,000 acre-feet (95,000 dam3) of water were released from Shasta Lake, which was only half full, to dilute the pollution.

[10] Spring Creek is a southeast-flowing, 9-mile (14 km) long tributary of the Sacramento River, receiving water from approximately 16 square miles (41 km2) of land.

The stream receives contaminated runoff from the Minnesota Flats Tailing Pile, but is not nearly as polluted or acidic as Spring Creek.

Water from Whiskeytown Lake is diverted through the Spring Creek Tunnel, a conduit roughly 2.4 miles (3.9 km) long and 18.5 feet (5.6 m) in diameter.

[1] – U.S. Bureau of Reclamation, Trinity River Division of the Central Valley Project Spring Creek Reservoir is the artificial lake formed behind the dam.

During the dry season, water from Spring Creek pools in a small, stagnant pond retained behind the dam, depositing contaminated sediment and acidic mine waste in the reservoir space.

Despite this operation strategy, the reservoir was eventually deemed inadequate for the watershed, and can be filled to capacity by a single heavy storm event.

Uncontrollable spills frequently poured into the Sacramento River during floods, through the crest spillway of the dam, which lacks gates.