Mike Dunn demonstrates gold panning with material dredged from a California riverbed.
Mike Dunn demonstrates gold panning with material dredged from a California riverbed.

Gold prices are up, and California is preparing to allow dredging for gold in rivers and streams. But environmental groups are concerned about the impact to fish habitat.

The original 49ers – the prospectors who scoured the Sierra foothills during California’s Gold Rush – mostly relied on a simple and environmentally friendly piece of equipment: the gold pan.

In Concord, Mike Dunn teaches some of those old panning techniques in a weekly class at his store Gold Pan California.

“See how the gold sits right there? Fan it out a little bit and just lift it out of the water,” he says, swirling a pan in a tub of water.

But today’s prospectors also rely on heavier equipment: the suction dredge. It’s similar to a large floating vacuum.

“You’re in wetsuits moving rocks underwater by hand and vacuuming up the sand and gravels in between… and hopefully some gold,” says Dunn. The heavier material is collected in a sluice box, while the lighter material is released back into the water.

With gold prices topping $1,500 an ounce, a weekend trip can be lucrative.

“My typical take would three quarters of an ounce to an ounce. And this is significant enough income to change most people’s lives for the better,” says Dunn.

But for almost two years, using this equipment has been banned while the state considers the environmental impact on salmon and other fish.

“When the dredgers are going in, they’re stirring up a lot of fine sediment and that may be moving downstream. And the issue there is, when the water is muddy, fish that need to feed visually can’t see their food,” says U.C. Davis biologist Lisa Thompson.

Others are concerned that the suctioning also picks up mercury, adding it back into the river. Scientists say the dredging equipment can actually capture some mercury, smaller particles are re-suspended in the water and travel downstream.

The California Department of Fish and Game has proposed rules to limit when and where the mining can be done. The agency’s Mark Stopher says the limits were written to avoid fish spawning season and rivers with threatened species.

The proposed rules also cap the number of dredging permits at 4,000 and limit the size of the dredging equipment. Public comments can be submitted through May 10.

Calif. Considers New Gold Mining Rules 9 May,2011Lauren Sommer

  • Andria Ventura, Program Manager, Clean Water Action

    The Department of Fish and Game’s proposed regulations allowing suction dredge mining regulations will confound regional water boards’ efforts to address methylmercury in our watersheds and perpetuate Clean Water Act violations. They will further put human health and safety at risk due to increased exposure to mercury in locally caught fish (stirring up the mercury makes it bioavailable), endanger wildlife, contradict tribal and other regulatory authority, and harm the integrity of our waterways and ecosystems. DFG’s narrow interpretation of its regulatory authority will also require duplicative regulatory efforts to prevent the harm done by suction dredge mining practices, wasting resources at a time when the State is struggling economically. In the end, these draft regulations will perpetuate a practice enjoyed by a minority of private interests at great cost to the majority of Californians and the environment.

    • Claudia Wise, usepa retired physical scientist

      I’m sorry Andria but the US public is tiring of hearing the misinformation organizations like yours spread to bring in a paycheck at our citizens expense. Let me guess you are a marketing graduate? Using all incorrect information designed to cause fear for human health and environmental damage to bring in more grant money. Shame on you!
      What is confounding the Regional Water Boards efforts is lack of science to support putting individuals out of business to further regulate the American people. There is no Tribal regulatory authority on our public lands so no duplication of regulatory efforts should be effected. Suction dredgers benefit the waterways they work in by creating refugia for fish to rest in and breaking up compacted sediment to increase future spawning areas for fish. The Regional Water Board themselves did a study on using suction dredges to mitigate mercury from waterways and found that a suction dredge will contain and remove 98% of the mercury from our waters. A Sierra Fund Scientist working on a project with the Nevada Irrigation District wants the public to pony up somewhere upwards of 8 million dollars to remove mercury from Combie reservoir and states in the project proposal that they will disturb 10-15% of the mercury but of course this is in the name of environmental justice. The suction dredgers will remove more for free if they are not regulated out of the water. That is better for the American people in these economically strapped times.
      I would also like to set you straight on another issue…. methylation doesn’t occur to a large extent in rivers and streams because the process is done under anaerobic conditions and need a slew of other factors to occur. In a peer reviewed USEPA study using multiple dredges larger than those allowed under current California regulations researchers found that it was highly unlikely that methylation would occur from suction dredging in these habitats. It is also scientific fact that selenium present in adequate quantities in California will bind with methylmercury protecting fish, wildlife and human health from any effects of mercury toxicity.
      Andria the American people think it’s time for you and other obstructionist environmental groups to go find honest work.

      • Brett Lauble

        Ditto! Thank you Claudia for stating the facts. There is so much mis-information out there on dredging. Scientific study after study has shown no harm to fish. Obviously Lisa Thompson has not left her office to see what a river looks like in the winter. By her comment, all the fish would starve by the time I put my dredge in the water. Ask a salmon fisherman, the best time to catch fish is in sediment filled water after a big storm.

        The fact is, nets and hooks kill fish, NOT dredges!

  • mike

    Claudia Wise said it better than I could have ever said.

    I sent out a note on this and the public meetings to my gold prospecting list. I hope that some people will take action and go speak up.

  • Ed Treece

    Several years ago I came across a website that contains a ton of information about studies done on the effects of dredging. I don’t know the background of the site but it appears to be a mining company based in Alaska that has pulled together a database of studies covering many years on dredging at many locations. I am assuming these are legitimate studies but a few calls to the agencies named would quickly verify legitimacy. They were done by, to name a few, The Washington State Department of Ecology, the US Environmental Protection Agency, the US Dept of the Interior, The U.S. Geological Survey, the U.S. Army Corps of Engineers and many others. I hope you would agree these are organizations with a huge amount of credibility and after you read the studies, I think you will agree that none of them found an adverse effect on the environment or fish from dredging. Several of them include detailed scientific measurements, charts and graphs etc to support the conclusions by people with “Dr.” in front of their names. While I am not a scientist, they look impressive to me and I think they would be extremely hard to refute or disprove. Not only did they conclude it was not harmful, some of them concluded that dredging is actually beneficial to the environment and fish – specifically to spawning salmon.

    The website is at this link:


    It appears the California DFG study reached the exact opposite conclusion of the studies listed at the website and before someone decides to limit dredging, I think they have a moral if not a legal obligation to explain why their results are right and all the others are wrong. In fact, with all the extremely competent studies out there, I find it hard to understand how DFG justifies spending the money and man hours I assume they spent on a study – unless it is a case of “Not Invented Here” mentality. I think they had a politically correct conclusion in mind before they started their study and it was not supported by any of the existing ones so they chose to ignore them.

    I sent DFG essentially this email six weeks ago and asked these questions and got no reply. I also sent it to the Sacramento Bee and got no reply. I didn’t expect them to reply because they can’t without reversing their entire approach.

  • Andria Ventura, Program Manager, Clean Water Action

    For the record, I was not a marketing major, my facts were supported by the Dept. of Fish and Game’s own study, and research findings by mining companies with a vested interest should be taken with a healthy grain of salt. Also, if selenium addressed the methylmercury situation, the state would not be finding the latter in such high levels in fish that people and wildlife are consuming.

    As for what the people of California want, well I guess it depends on who you speak to. If it is the minority of suction dredge miners in the state, they don’t want regulations on these practices. As for our 85,000 members, they want this practice stopped.

  • Brett Lauble

    Mercury is a natural occurring element in our rivers. Even the cleanest rivers that have no history of mining will have some mercury levels found in fish. Sure some of the amounts have been increased by past mining, but the only effect todays equipment has is to collect it.

  • Michael Hesseltine

    It is so dissapointing that the environmentalists continue to demonize small scale recreational dredging with misinformation and lies. Despite all the studies showing the benefits of recreational dredging to our streams. Far more mercury is released into our state waterways by high spring runoffs and the natural erosion caused by summer forest fires and thunderstorms than any 100 dredgers could ever release.

    This is nothing more than another environmental witch hunt. Once they close all the roads in the forest to ATV’ers, and have the recreational dredgers and out of the way, then the will be coming for YOU FISHERMEN! And don’t think that idea is so far fetched. President Obama already has several people in his cabinet (Cass Sussman & Van Jones) who think animals should have the same rights as humans and that recreational fishing should be done away with all together.

    The environmentalist movement has no desire for “multi-use” on our public lands.

  • Ed Treece

    Andria, your post does what liberals do constantly. It mis states the facts and then tries to sell your conclusions as fact. You wrote: “research findings by mining companies with a vested interest should be taken with a healthy grain of salt.” I wrote that these studies were posted at a mining company web site BUT they were done by: “to name a few, The Washington State Department of Ecology, the US Environmental Protection Agency, the US Dept of the Interior, The U.S. Geological Survey, the U.S. Army Corps of Engineers and many others. I hope you would agree these are organizations with a huge amount of credibility” Go back and reread the post and click on the link and look at some of the studies before you write them off as being done by a mining company and therefore meaningless. Do you want to imply that the US EPA study, Dept of Interior, etc were all lies?

  • Michael Hesseltine

    Dear Ed,
    Thank you for your factual and informed reply to Andria’s post. However, please try to remember that a good environmentalist will never let something as trivial as “facts” and “truth” get in the way of their idealogical agenda.

    It doesn’t matter how many studies have found that dredging has no harmful impact on fish habitats, and that modern dredges remove 98% of the mercury that is sucked into the dredge, the environmentalists have lumped us into the same category as large mining operations in which nothing we do will ever sit right by them.

    Comparing small scale recreational dredgers to large scale miners is kind of like trying to compare the person who takes a toke or two of pot once in awhile, to a hard core meth addict!

    The two “in both situations” aren’t fair (or honest) comparisons.

    I truly wish that environmentalist would be OPEN MINDED enough to see that recreational dredgers “aren’t the enemy” and that we can both co-exist without harming the environment.

  • Joe Michal

    It’s time to put environmentalist in concentration camps!

  • Michael Hesseltine

    Well Joe, I think your comments might be a bit extreme, however, it makes me scratch my head to wonder why any good environmentalist would be adverse to a practice (dredging) that removes 98% of the harmful mercury in our rivers! If someone came up with a device that removed 98% of harmful ozone or 98% of carbon monoxide, wouldn’t environmentalists be jumping up and down celebrating? Yet here we have an activity that removes 98% of the harmful mercury from our California waterways “FOR FREE”………..let me repeat that again….”FOR FREE”!!, and all the environmentalists can think to do is fight us! It just doesn’t make sense and defies logic.

    It really makes you wonder if environmentalists such as the “Sierra Fund” can really think for themselves….or if all they can do is march like sheep to the lies and misinformation of their leaders. I thought liberals were suppose to be smarter!?…..It sure makes you wonder sometimes.

  • Ed Treece

    Michael, I think most enviromnentalists are well meaning but poorly informed people who are being led and manipulated by a small group of very bad people with very bad motives. The ultimate objective is to destroy the country from within. It’s called the Cloward and Piven strategy and it explains much of what has happened in the last 50 years…like shutting down farming because of a three inch fish, the delta smelt or not wanting to remove 98% of the mercury from streams at no cost to the government while benefitting the environment (according to the studies I linked above) and a lot of other things. If you are not familiar with it, do a Google search on Cloward and Piven and get ready to be disgusted. Check out this article and the links it contains. http://www.americanthinker.com/2009/11/clowardpiven_government.html


Lauren Sommer

Lauren is a radio reporter covering environment, water, and energy for KQED Science. As part of her day job, she has scaled Sierra Nevada peaks, run from charging elephant seals, and desperately tried to get her sea legs – all in pursuit of good radio. Her work has appeared on Marketplace, Living on Earth, Science Friday and NPR’s Morning Edition and All Things Considered. You can find her on Twitter at @lesommer.

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