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Small-Scale Suction Gold DredgingSmall-Scale Suction Gold Dredging

Presented by:Presented by:

Joseph C. Greene, Research BiologistJoseph C. Greene, Research Biologist

Prepared for a Meeting withPrepared for a Meeting with

Oregon State Legislators, Oregon Small-scale Miners, Oregon State Legislators, Oregon Small-scale Miners, and US EPA Region 10 Representativesand US EPA Region 10 Representatives

March 9, 2006March 9, 2006

Oregon House Of Representatives Office Building, Oregon House Of Representatives Office Building, Salem, OregonSalem, Oregon

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Small-Scale Suction Dredging Small-Scale Suction Dredging and the Environmentand the Environment

It is my opinion that the results from scientific It is my opinion that the results from scientific investigations, presented in the Environmental investigations, presented in the Environmental

Impact Reports, prepared by the State of Impact Reports, prepared by the State of California, Clearwater National Forest and California, Clearwater National Forest and Siskiyou National Forest, provide all the Siskiyou National Forest, provide all the

evidence required to support the determination evidence required to support the determination that small-scale suction dredging is that small-scale suction dredging is

de minimisde minimis and impacts from these dredges areand impacts from these dredges are

less than significantless than significant..

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Many people want outdoor settings to be left in Many people want outdoor settings to be left in a natural condition for quiet enjoymenta natural condition for quiet enjoyment. Thus . Thus

suction dredging is perceived as a conflict with these suction dredging is perceived as a conflict with these activities. The noise of the suction dredge engines and activities. The noise of the suction dredge engines and exhaust fumes and the presence of the suction dredge exhaust fumes and the presence of the suction dredge

activities may be the very things many people go activities may be the very things many people go outdoors to escape. outdoors to escape. However, suction dredgers However, suction dredgers

also enjoy the outdoors.also enjoy the outdoors. (CDFG, page V25) (CDFG, page V25)

The “Real” ProblemThe “Real” Problem

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The “Real” ProblemThe “Real” ProblemIt should be noted that suction dredging is

considered a legitimate activity on rivers and streams and suction dredge operators have a

Federally mandated right to operate. Dredgers also have the basic right, of all

citizens, to enjoy and utilize streams as long as their activities are in compliance with the

laws and regulations of the State.

ORS 541.110 provides, “the use of water of lakes and running streams of Oregon for the purpose of developing the mineral resources is declared to be a public and beneficial use and a public necessity.”

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For discussion the following excerpts were taken For discussion the following excerpts were taken from thefrom the

Draft Environmental Impact Report, Adoption of Draft Environmental Impact Report, Adoption of Amended Regulations for Suction Dredge MiningAmended Regulations for Suction Dredge Mining. . 1997. State of California, Dept. of Fish and Game.1997. State of California, Dept. of Fish and Game.

The Conclusions in this report concur with those The Conclusions in this report concur with those found in the Clearwater and Siskiyou National found in the Clearwater and Siskiyou National

Forest Environmental Impact Reports.Forest Environmental Impact Reports.These documents are the culmination of These documents are the culmination of

literature searches for scientific evidence literature searches for scientific evidence regarding the impacts of small-scale suction regarding the impacts of small-scale suction

dredging on the environment and consultations dredging on the environment and consultations with stakeholders and concerned citizens.with stakeholders and concerned citizens.

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Research to Support the Research to Support the Siskiyou National Forest DEIRSiskiyou National Forest DEIRThe SNF engaged Dr. Peter B. Bayley, Dept. Fisheries

& Wildlife, Oregon State University, to conduct a “Cumulative Effects Analysis” on the effects of

suction dredging forest-wideDr. Bayley concluded:

"The statistical analyses 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."

(In other words, if there is an effect, it's so small they can't measure it.)

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Dr. Bayley continued…Dr. Bayley continued…

"The reader is reminded of the effect of scale. 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."

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Dr. Bayley concluded…Dr. Bayley concluded…

"Given that this analysis could not detect an effect averaged over good and bad miners and that a more powerful study would be very expensive, it would seem that public

money would be better spent on encouraging compliance with current

guidelines than on further study."

Now, back to the comments published in the Now, back to the comments published in the

California Department of Fish and Game “Draft Environmental Impact Report”.California Department of Fish and Game “Draft Environmental Impact Report”.

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The area or length of river or streambed worked The area or length of river or streambed worked by a single suction dredger as compared to total by a single suction dredger as compared to total river lengthriver length is relatively small compared to the is relatively small compared to the

total available area.total available area.

TheThe average number of hours spent is 5.6 hours average number of hours spent is 5.6 hours per dayper day. . The remaining time is spent working on The remaining time is spent working on equipment and processing dredged materials. equipment and processing dredged materials.

An individual suction dredge operationAn individual suction dredge operation affects a affects a relatively small portion of a stream or riverrelatively small portion of a stream or river. . A A small-scale suction dredge (representing 90-small-scale suction dredge (representing 90-

percent of all suction dredges) may spend a total percent of all suction dredges) may spend a total of 4 to 8 hours per day in the water dredging an of 4 to 8 hours per day in the water dredging an

area from 1 to 10 marea from 1 to 10 m22 (3-33 ft (3-33 ft22).).

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Current regulations on most rivers and streams, Current regulations on most rivers and streams, in conjunction with riparian protective measures,in conjunction with riparian protective measures,

results in a less than significant impact to results in a less than significant impact to channel morphologychannel morphology..

In many of the studies performed on suction In many of the studies performed on suction dredging, potentially adverse impacts to river dredging, potentially adverse impacts to river resources were reported.resources were reported. Effects of increased Effects of increased

turbidity levels and sedimentation, decreases in turbidity levels and sedimentation, decreases in invertebrate populations and re-configuration of invertebrate populations and re-configuration of the streambed were temporary and localizedthe streambed were temporary and localized..

Turbidity and sedimentation levelsTurbidity and sedimentation levels generally generally return to background levels within 20 to 80 m return to background levels within 20 to 80 m

(66-263 ft) below the dredging activities(66-263 ft) below the dredging activities. .

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Suction dredging can have significant short-term and localized adverse impacts on local benthic

invertebrate abundance and community composition. However, over the long-term, the

impacts appear to be less than significant.

Colonies of invertebrates generally re-colonize areas disturbed by suction dredges within a

relatively short period of time ranging from one to two months. Impacts to benthic invertebrate communities, from suction dredging, appear to

be less than significant.

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Effects to benthic and/or invertebrate communities, turbidity and water

quality appear to be less than significant.

They are usually localized and temporary in

duration!

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Effects from elevated levels of turbidity and suspended sediment normally associated with suction dredging as

regulated in the past in California appear to be less than significant with regard to impacts to fish and other river

resources because of the level of turbidity created and the short distance downstream of a suction dredge where

turbidity levels return to normal.

Suction dredging appears to have little direct immediate Suction dredging appears to have little direct immediate physical effect on adult fishes in terms of harm from physical effect on adult fishes in terms of harm from actual entrainment by dredges.actual entrainment by dredges.

ADULTS:

Impacts on Fish

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Yolk Sac Fry:

Entrainment Entrainment can have a significant adverse effectcan have a significant adverse effect on the on the more delicate stages of fish such as the yolk sac fry. more delicate stages of fish such as the yolk sac fry. During this stage the yolk sac can be easily ruptured or During this stage the yolk sac can be easily ruptured or torn from the fish.torn from the fish.

Juveniles:

Impacts on Fish

Entrained through a suction dredge does not appear to have a significant adverse effect on juvenile fish either.

Eggs:

Developing eggs of salmonids are significantly adversely affected by entrainment through suction dredges. The degree of harm may vary depending on species.

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Impacts on Fish

Current law requires that dredging operations must stop or move if redds are present during

a permitted “In Water Work Period”. 

Fish eggs and yolk sac fry are protected by seasonal regulations that keep small-scale

suction dredgers out of the rivers and streams during this season.

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Dredge piles do not appear to occupy a significant Dredge piles do not appear to occupy a significant portion of the available spawning habitat so that portion of the available spawning habitat so that

dredge pile impacts are expected to be dredge pile impacts are expected to be

less than significantless than significant

Impacts on Spawning Gravel

Most of the effects related to turbidity and sedimentation, and the disturbance of spawning gravels reported were temporary and localized,

and therefore, represented impacts considered less than significant.

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Impacts on Spawning Gravel

Once tailing piles are dispersed by high stream flows they do make up a component

of the suitable spawning substrate.

Approximately 60 salmonid redds were observed in a study on Canyon Creek, CA.

None of the redds were found within dredge tailing piles.

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Salmonids do not spawn in this type of coarse overburden

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TurbidityTurbidity

It has been asserted that salmon were not affected by elevated turbidity but studies have stated that salmonid growth was reduced at 25

NTU but not below.

Turbidity caused by suction dredging is highly variable. Suction dredging bedrock pockets

containing only sand and gravel causes virtually no change in turbidity whereas suction dredging clay deposits causes very noticeable turbidity.

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Flood Stage, Klamath River above Portuguese Creek, 2006Flood Stage, Klamath River above Portuguese Creek, 2006

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Klamath River water: The left vial was allowed to settled for 24-hours, the right vial was Klamath River water: The left vial was allowed to settled for 24-hours, the right vial was shaken to re-suspend the particulates. The sample was measured at 656 NTU.shaken to re-suspend the particulates. The sample was measured at 656 NTU.

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People with agendas

often don’t put facts in perspective

and blur the difference

between facts and speculation

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Turbidity plumes, usually, do not cover wide areas of the stream and they are not continuous or consistent in sediment content

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TurbidityTurbidityEffects of the levels of turbidity and

suspended sediment normally associated with suction dredging appear

less than significant

with regard to the health or physiology of adult and juvenile salmonids, particularly when one considers that turbidity levels

return to normal levels on an average of 20-80 m (66-263 ft.) below the suction dredge.

Also, natural levels of turbidity may be higher than levels of turbidity caused by suction dredging during certain times of the year.

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Notice the switch in plume turbidity density. Now the distant Notice the switch in plume turbidity density. Now the distant dredge plume is lower in suspend material concentrationdredge plume is lower in suspend material concentration

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United States Department of Agriculture Forest Service Siskiyou National Forest, 200 NE Greenfield Road, Grants Pass, OR  97526-0242

Reply to: 2800 Date: October 16, 1995

Subject: A comparison of stream materials moved by mining suction dredge operations to the natural sediment yield rates

To: The Record

…”There are 1,092,302 acres on the Siskiyou National Forest. Using a factor of 0.33 cubic yards per acre per year times 1,092,302 acres will produce a very conservative estimate that 331,000 cubic yards of material move each year from natural causes compared to the 2413 cubic yards that was moved by suction dredge mining operations in 1995 on the Siskiyou. This would be a movement rate by suction dredge mining that equals about 0.7% of natural rates.”

MICHAEL F. COOLEY, Recreation, Lands and Minerals Staff Officer, Siskiyou National Forest

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Constructing a nice deep hole for fish habitat while producing an almost imperceptible turbidity plume

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Fish FeedingFish FeedingFish have been observed feeding in turbid plumes

created by suction dredging. Stern (1988) observed young steelhead feeding on dislodged

invertebrates in turbid dredge plumes, even though clear water was available nearby.

Cutthroat and rainbow trout have also been observed feeding.

The effects of suction dredging on the feeding of fish appears to be less than significant.

Although invertebrate populations are negatively affected by suction dredging, the impacts are

localized and short-term.

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Fish feeding below outfall from a small-scale suction gold dredge Fish feeding below outfall from a small-scale suction gold dredge sluice boxsluice box

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Behavior and DistributionBehavior and Distribution

Studies in Canyon Creek, Butte Creek, and the North Fork American River, CA did not indicate

a difference in fish distribution or density below or above suction dredging sites.

Stern (1988) reported that suction dredging did not appear to influence the behavior of adult spring-run salmonids in their summer holding

areas.

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Behavior and DistributionBehavior and Distribution

Abandoned dredge holes can provide holding and resting areas for fish. Stern (1988) observed

young steelhead in active and abandoned dredge holes in Canyon Creek.

Suction dredge operators report adult salmon and steelhead moving into dredge holes

overnight. Dredge holes often provide thermal and deeper water habitat for fish and some

dredge holes in the Scott River, CA have held more juvenile salmonids than adjacent habitats.

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Benefits to the Benefits to the EnvironmentEnvironment

Small-scale suction dredge miners remove lead shot, fishing sinkers, bullets and other metals

and fragments from streams and rivers.

Removal of these materials by suction dredgers is considered a benefit to the environment.

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Intention of CongressIntention of Congress"The development of information which describes "The development of information which describes the relationship of pollutants to water quality is the relationship of pollutants to water quality is essential for carrying out the objective of the essential for carrying out the objective of the Clean Water Act.  This information, known as Clean Water Act.  This information, known as criteria, is required under Section 304(a) to be criteria, is required under Section 304(a) to be developed and published by the Administrator developed and published by the Administrator and issued to the states and public.and issued to the states and public.    Criteria to Criteria to be developed in this section should draw upon be developed in this section should draw upon the bestthe best scientific knowledgescientific knowledge on the subject, on the subject, including information, if any, from the National including information, if any, from the National Academy of Sciences, the U.S Geological Survey Academy of Sciences, the U.S Geological Survey in the Department of Interior, scholarly literature, in the Department of Interior, scholarly literature, academic experts, and other sources.”academic experts, and other sources.”

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Establishing Effects of Establishing Effects of PollutantsPollutants

““Criteria establish the effects of pollutants on Criteria establish the effects of pollutants on health or welfare, receiving water ecosystems and health or welfare, receiving water ecosystems and man, man, and identify the natural chemical, physical and identify the natural chemical, physical and biological integrityand biological integrity of the Nation's waters.” of the Nation's waters.”

““The concentration and dispersal of pollutants and The concentration and dispersal of pollutants and their by products through biological, physical and their by products through biological, physical and chemical processes and any related changes in the chemical processes and any related changes in the

diversity, productivity, or stability of receiving diversity, productivity, or stability of receiving water ecosystems water ecosystems would be part of the information would be part of the information

providedprovided”.”.

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Natural Integrity of WatersNatural Integrity of Waters

……may be determined:may be determined:

Partially by consultation of Partially by consultation of historical recordshistorical records on species composition;on species composition;

Partially from Partially from ecological studiesecological studies of the area of the area or comparable habitats; and,or comparable habitats; and,

Partially from Partially from modeling studiesmodeling studies which make which make estimations of the balanced natural ecosystem estimations of the balanced natural ecosystem based on available information.based on available information.

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USEPA Fact SheetUSEPA Fact SheetJanuary 14, 2000

On Nov. 18, 1996, EPA and the two environmental groups entered into a settlement agreement to

resolve the challenge to the general permit. The proposed permit sets conditions on the discharge

- or release – of pollutants from the operation into waters of the United States.

The settlement agreement required EPA to complete two studies related to the impact of placer mining on the natural environment in Alaska. One was to address the discharge of

metals by placer mining operations and the other was to address the impact of suction dredge

mining.

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FINAL REPORT Submitted June 1999FINAL REPORT Submitted June 1999

Prepared For:Prepared For: US Environmental Protection AgencyUS Environmental Protection Agency

Region 10Region 10Seattle, WashingtonSeattle, Washington

  Prepared By:Prepared By:

Aaron M. Prussian, Todd V. Royer, and G. Wayne Minshall Aaron M. Prussian, Todd V. Royer, and G. Wayne Minshall Department of Biological SciencesDepartment of Biological Sciences

Idaho State UniversityIdaho State UniversityPocatello, Idaho Pocatello, Idaho 

Impact of Suction Dredging on Water Quality, Impact of Suction Dredging on Water Quality, Benthic Habitat, and Biota in the Fortymile River, Benthic Habitat, and Biota in the Fortymile River, Resurrection Creek, and Chatanika River, AlaskaResurrection Creek, and Chatanika River, Alaska

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Alaska Study SummaryAlaska Study Summary

The report described the results of research into The report described the results of research into the effects of commercial and small-scale suction the effects of commercial and small-scale suction dredging on the water quality, habitat, and biota dredging on the water quality, habitat, and biota

of Fortymile River, Resurrection Creek and the of Fortymile River, Resurrection Creek and the Chatanika River, Alaska. Chatanika River, Alaska.

Focus of the work on Fortymile River was on an 8-inch suction dredge located on the main

stem and a 10-inch suction dredge located on the South Fork.

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Alaska Study SummaryAlaska Study Summary

Water chemistry measured on Fortymile River showed the primary effects of suction dredging were increased turbidity, total filterable solids, and Cu and Zn concentrations downstream of

the dredge.

The results from this sampling revealed a relatively intense, but localized, decline in

water clarity during the time the dredge was operating. These variables returned to

upstream levels within 80-160 m (263-524 ft.) downstream of the dredge.

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Alaska Study SummaryAlaska Study SummaryCross-sectional profiles indicate that theCross-sectional profiles indicate that the impact impact of the dredge piles relative to the width of theof the dredge piles relative to the width of the

FortymileFortymile River was small.River was small.

Macroinvertebrate abundance and diversity were greatly reduced in the first 10 m (33 ft.) below the dredge but returned to values seen at the

reference site by 80 to 160 m (263-524 ft.) downstream of the dredge.

One year after dredging on the main stem and South Fork of Fortymile River, recovery of macro-invertebrate diversity appeared to be substantial.

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Alaska Study SummaryAlaska Study SummaryThe second component of this project is to The second component of this project is to examine the effects of small-scale suction examine the effects of small-scale suction dredging on smaller streams in Alaska. dredging on smaller streams in Alaska.

Sampling was conducted on Resurrection Creek and on the Chatanika River, Alaska.

The results from Resurrection Creek showed that there was no difference in the macro-

invertebrate communities between the mining area and the locations downstream of the

mining area, in terms of macroinvertebrate density, taxa richness, EPT richness, or food

resources.

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Alaska Study SummaryAlaska Study Summary

Results from the Chatanika River showed slight downstream decreases in macroinvertebrate

density, but all other measures remained similar to those of the reference area.

In general, the results are in agreement with other studies that have found only localized

reductions in macroinvertebrate abundance in relation to small-scale suction dredging.

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USEPA Fact SheetUSEPA Fact SheetJanuary 14, 2000

The U.S. Environmental Protection Agency (EPA)Plans To Issue A Wastewater Discharge Permit To:

Alaska Mechanical Placer Miners

This will also serve as a notice of a

FINDING OF NO SIGNIFICANT IMPACT

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USEPA Fact SheetUSEPA Fact SheetJanuary 14, 2000

The environmental groups believed that the suction dredge report (40-mile River, Resurrection

Creek, and Chatanika River) did not address all of the required elements as set out in the 1996

settlement agreement.

To avoid further litigation over the general permits, EPA and the environmental groups entered into another settlement agreement.

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The EPA had chosen to flex its legal muscle where The EPA had chosen to flex its legal muscle where scientific data does not justify their actions. Other scientific data does not justify their actions. Other

Federal Agencies have stated the following:Federal Agencies have stated the following:

“. . . For decades, suction dredging has been essentially unmanaged. Its effects were considered insignificant and its consequences immeasurable.” (Siskiyou National Forest Draft Environmental Impact Statement).

And, the U.S. Army Corps of Engineers stated, “To regulate against a potential for harm, where none has been shown to exist, is unjustifiable and must be challenged."

4646Presented by Joseph C. Greene, Research Biologist (March 9, 2006 in Salem, Oregon)Presented by Joseph C. Greene, Research Biologist (March 9, 2006 in Salem, Oregon)