2012 Claudia Wise Letter

Mark Stopher, Senior Policy Advisor

California Department of Fish and Game

601 Locust Street
Redding, CA 96001 [email protected]

March 4, 2012

Subject: Comments re Revisions to Proposed Amendments.
SUCTION DREDGE PERMITTING PROGRAM, Revisions to Proposed Regulations, (Cal. Code Regs., tit. 14, § 228 et seq.), February 17, 2012

Hi Mark,

It makes no sense to me for you to go through all the trouble to convene a public advisory committee and not take into account any of the comments from any of the members with knowledge of suction dredging techniques and related peer reviewed science. You did tell us the first day that the only reason you put the committee together was because you were forced to. Taking any of our expertise into account was then out of the question to expec.t Even so I do have additional comments to add.

In section (g) you reduced the number of permits from 4000 to 1500 and in section (k) reduce the number of dredges working near each other by not allowing operating dredges within 500 feet of each other without any supporting science to dictate such regulations. There have been many scientific studies that have proven that there is no additive effect from multiple dredges working closely even operating simultaneously on the same drainage. Many of the miners on the CDFG PAC stated that it was a safety matter to them to have another dredge close by in case of an emergency. With so much proof that there is no measurable cumulative effect it is irresponsible and possibly negligent as a government agency to cause harm to a miner for no substantial reason.

Cumulative Effects of Suction Dredging

Operation of multiple dredges did not result in cumulative effects (Hassler, 1986). Insignificant cumulative effects have also been reported by Harvey (1982), Harvey (1986) and Huber (1992). All reported no additive effect including on the Yuba River from 40 active dredges on a 6.8 mile stretch (Harvey,1982), and six small dredges (<6 inch nozzle) on a 1.2 mile stretch (Harvey, 1986).

Bailey in 2003, did a thorough review of suction dredge mining of the Illinois valley basin in the Siskiyou National Forest providing a statistical analysis of multiple dredge operations the “analysis did not indicate that suction dredge mining has no effect on the three responses measured, but rather any effect that may exist could not be detected at the commonly used Type I error rate of 0.05.” This means that if there are effects they are so small they could not be measured. He goes on to postulate readers should keep in mind that the effect of scale in regard to suction dredging is so small that only “localized, short term effects of suction dredge mining have been documented in a qualitative sense. However, on the scales occupied by fish populations such local disturbances would need a strong cumulative intensity of many operations to have a measurable effect.”

The Chugach National Forest, Alaska found that, the results from water quality sampling do not indicate any strong cumulative effects from multiple placer mining operations within the sampled drainages. Several suction dredges probably operated simultaneously on the same drainage, but did not affect water quality as evidenced by above and below water sample results (Huber, 1992).

In the recreational mining area of Resurrection Creek, five and six dredges would be operating and not produce any water quality changes (Huber 1992).

• The streams in Alaska have tremendous populations of char, Arctic Grayling, and various species of salmon.

• The environment that sustains these native populations has had intense suction dredging activities that have been ongoing for decades.

• Other problems must be more detrimental to fish and their freshwater habitat. Studies to date have not shown any actual effect on the environment by suction dredging, except for those that are short-term and localized in nature (USACE, 1994). This is an official recognition, by the U. S. Army Corps of Engineers, that below a certain size, the effects of suction dredging are so small and so short-term as to not warrant the regulations being imposed in many cases (USACE, 1994). The U. S. Environmental Protection Agency, has ignored this concept, although numerous studies, including the EPA’s own 1999 study of suction dredging, repeatedly and consistently support the Corps finding de minimus effects (USACE, 1994).

Reports consistently find no actual impact of consequence on the environment, and so almost always fall back to the position that the potential for impact exists (USACE, 1994). The majority of dredge operations studied did not work long periods or disturb large areas of the streambed (Hassler, 1986). The unmodified dredge moved about 2% of the manufacturer’s maximum rating (Griffith, J.S. and D.A. Andrews,1981). When done properly, legal dredging must be allowed by law and environmental effects are acceptable (USDA, 1997).

Yes, there was No actual impact of consequence to the environment and without regulating the timing of the activity or the dredge nozzle size (section k). The regulations for both should not be changed from the previous 1994 permit regulations. Also in section K you attempt to regulate the storage and use of fuel, oil. These are expensive commodities that a miner would be very careful to conserve and protect. Being required to store them such a long distance away is not only a nuisance to get your work done but unsafe. Having a containment system close at hand in all circumstances would be the best practice. Attaching some type of rig to capture the full capacity of fuel is not even available to my knowledge and is not necessary. A drip pad could easily be rigged up to catch any accidental over flow.

Section (k) implies that silt and clay material should not be disturbed but again there is no evidence that this is a significant problem. Duration, intensity and mixing zone are the primary factors to consider.


Persistent long term sediment sources have been shown to be the most detrimental to fish and fish habitat with low gradient streams being more vulnerable to irreversible clogging than high gradient streams (Chamberlin 1982). There is evidence suggesting that most western United States salmonids have evolved in systems that periodically experience short-term (days to weeks) elevated TSS/turbidity events (winter runoff, spring storms and floods) and are adapted to periodically elevated TSS exposures without adverse effects. (CH2M Hill 2000). Experiments of Dr. Griffin have shown that young fish live well up to 30 days in good water mixed with an amount of natural soil materials from two to three times as large as the extreme load of the materials contributed to the Rogue River by maximum conditions produced by placer mining (Ward 1938).

Newcombe and Jensen 1996, pointed to several important factors that must be considered when studying the effects of TSS on fish. The frequency and duration of the exposure, not just the TSS concentration, must be considered. They cautioned that adverse effects can become more pronounced with increased TSS concentrations and longer exposure durations in aquatic systems where elevated TSS conditions occur infrequently. In a system where elevated TSS conditions occur more frequently, fish can become acclimated to higher TSS levels and adverse affects can be less pronounced or nullified Newcombe (2003). Moyle’s observation in 1982 showed support for this theory indicating that “fish and invertebrates apparently, were not highly sensitive to dredging in general, probably because streams studied naturally have substantial seasonal and annual fluctuations in flow, turbidity, and (on a local scale) substrate.”

The California Department of Fish and Game (CDFG) had it right when they presented their findings at the CDFG PAC meetings that the regulation of 6 hours a day does not imply. CDFG regulations should reflect scientific finding in preparing the SEIR… turbidity created from suction dredge operations have insignificant impact on water quality is not a concern as part of the current or proposed permit requirements (Stopher, 2010).

Small scale suction dredging effects are less than significant, miners can employ the following three best management practices (BMP) to ensure there is no detrimental effect to fish. This could further aid in reducing any effects and improving water quality.

1) The duration of a turbidity plume within a 24-hour work period (Time in stream);

2) The intensity of the plume or degree of exposure [measured in Turbidity units (NTU)]; and,

3) Short term exceedance of water quality limits created by allowing an adequate mixing zone.

It takes approximately 24-hours, according to the studies cited above, for minor effects in fish to occur at turbidity levels most frequently identified. Mining occurs over short time periods of less than 24 hours (limited duration). Taking into account results of numerous scientific journal articles (which show suction dredging does comply with being below the recognized exposure threshold of 30 NTU at 500 feet), regulating turbidity based simply on duration of an in-stream work period makes sense. As previously stated the easiest approach would be to limit duration of in-stream suction dredging to the 1994 regulations allowing 1/2 hour after sunrise to sunset. The miners would be able to comply and still more than adequately meet water quality criteria not detrimental to fish and regulating compliance would not be cost prohibitive.

Suction dredging is the Best Management Practice which includes many benefits to the environment and should be allowed without restrictive and unnecessary regulations. Miners I have talked with are open to improving the environments they work in and they do as they remove mercury, lead, and trash from our waterways that no other group of citizens can accomplish. Excavations from dredging operations can result in temporarily formed pools or deepen existing pools which may improve fish habitat. Deep scour may intersect subsurface flow creating pockets of cool water during summer which can provide important habitat for fish (Nielsen, 1994), especially in California where cold water refugia is at a premium.

I think that it is always important when defining new regulations that will effect so many to remember the fact that many individuals depend on suction dredge mining as their only income and for many more it is a necessary supplement to their income. According to the bulk of research out there suction dredge mining is insignificant and can produce beneficial results if allowed. Over regulation is not proactive regulation it is just wrong.


Claudia Wise

U.S.EPA, Retired
Physical Scientist/Chemist

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