The California Office of Environmental Health Hazard Assessment has issued a safe advisory for any fish caught in Bear River due to elevated levels of mercury.

[3] The Bear River originates at Emigrant Gap, as a tiny stream on the border of Nevada and Placer Counties in the Tahoe National Forest.

The river flows west into the Bear Valley then enters a deep and narrow gorge, passing the community of Dutch Flat.

[4] Below the dam the river flows southwest through the Sierra foothills, past Colfax and Meadow Vista, through Lake Combie and a short but rugged gorge above Garden Bar.

[5] Because the Bear River watershed is at a relatively low elevation compared to other Sierra streams, rainfall, not snowmelt, is the main source of runoff.

Major mining sites in the Bear River basin included You Bet, Red Dog, Dutch Flat, Gold Run, Waloupa, Little York, and Chalk Bluff.

Although nominally two separate projects, the complex system of some 40 reservoirs in the Middle and South Forks of the Yuba and on the upper Bear River is heavily interconnected, and operated as one.

The reservoir stores water for irrigation and hydroelectricity, and serves the important purpose of trapping sediment from early hydraulic mining activity in the upper Bear River basin.

Due to poor economic justifications and opposition from the conservation group, Sierra Watch, local land trusts, ranchers, and the board of supervisors of both Placer and Nevada Counties, the water district dropped the proposed Garden Bar Dam in July 2012.

[29] The "Save the Bear, Stop Centennial" campaign was created in opposition to the proposal by non-profit environmental organizations, the Foothills Water Network and South Yuba River Citizens League (SYRCL),[30] with the support of other community and conservation groups such as Sierra Watch.