In Sacramento, the I Street Bridge had to be raised 20 feet (6.1 m).

As the Yuba River is a tributary of the Sacramento River, much of that debris then found its way to the San Francisco Bay. The mine waste carried by the Yuba River ended up raising the riverbed (by up to 100 feet (30 m) in some cases), causing floods that buried farms east of the town of Marysville with gravel, mud, as well as mercury and arsenic (byproducts of the mining process). Rivers and streams carried the flood of sediment-called slickens-down to the Sacramento Valley.

After the miners extracted gold in long wooden sluices, they dumped the remaining sediment slurry back into the mountain valleys. Mining companies moved from the valley floor into the Sierra Nevada foothills, where miners blasted gravel hillsides with high-pressure jets of water-a process called hydraulic mining. The first Yuba-area miners panned for gold in stream beds in the valley, but within a decade large-scale industrial processes replaced solitary prospectors.

Wild turkeys, deer, ducks, Beavers, herons, bald eagles, Northern river otters and even mountain lions now live in the goldfields. From the air, the goldfields are said to resemble intestines. The goldfields are noted for their otherworldly appearance (a result of gold dredging operations), filled with roughly linear mounds of gravels (called dredge tailing windrows), ravines, streams and turquoise-colored pools of water. In total, more than one billion cubic yards (760 × 10 ^ 6 m 3) of river sediment and lesser hydraulic mining debris was dredged to produce an estimated 5.14 million ounces (146 × 10 ^ 6 g) of gold. Located along the Yuba River approximately 6–12 miles (10–20 km) upstream of the town of Marysville, in Yuba County, the Hammonton dredge field was actively dredged for gold from 1904 to 1968. The Yuba Goldfields, also known as the Hammonton dredge field, is the largest gold dredge field in California.

Gold mining dredges