Settlement of the basin began about 1844. In 1848, discovery of gold near the present site of Coloma precipitated a great influx of gold seekers from all parts of the country. At the height of the gold rush, the American River foothill area was one of the most populous in the State. Early miners quickly recognized the potential of riverflows to help in dredging, panning, and sluicing for gold. Diversion dams began appearing on the river in the 1850's. As mining activities declined, two of the dams were used to divert water for use in suburban Sacramento areas and remained in use until the completion of Folsom Dam in 1955. In December 1964, the last of those early diversion dams was breached by floodwaters. Currently general public tours of the dam are on indefinite hold.