There's still gold in them thar rivers, and adventurers still cherish dreams of wealth. These days, though, sifting for gold is more a form of recreation than a business, and the tin pans have mostly been replaced by motorized machines called suction dredges. And the competing claims aren't over who has prospecting rights, but whether this form of mechanized gold hunting is causing irreparable harm to rivers in Northern California and the fish that swim in them.
In 2011, Gov. Jerry Brown signed legislation that imposed a moratorium on the practice until 2016, by which time the state Department of Fish and Game was to adopt regulations that eliminated the potential for significant environmental damage and that set permit fees high enough to cover the state's costs. The regulations adopted last month fall sadly short on both fronts.
Even in the early days, panning for gold wasn't an environmentally clean venture. Gold hunters often used mercury to make it easier to separate out the precious metal. Since then, river flow has entombed the toxic mercury under silt and stone.
Enter the modern suction dredge, which vacuums sand, gravel and stones from the river bottom, then sends it all through a floating sluice where the gold, heavier than the rest of the material, sinks and is trapped, while the remainder is returned to the river. In the process, the dredge unearths the mercury and releases it into the water. In addition, dredging often fills the spaces between river rocks with silt and sand. Those spaces help oxygenate the water and provide habitat for insects that salmon and other fish eat. Dredging also clouds the water with sediment.