NFBR Mining Supplemental EIS Appendix 7A

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Appendix 7A

Effects of Suction Dredging

On Water and Fisheries Resources

In the North Fork Burnt River Minerals Planning Area

The report provides information on the direct, indirect, and cumulative effects of suction 

dredging on water and fisheries resources in the North Fork Burnt River watershed. The water 

resources portion of this report was written by Suzanne Fouty, hydrologist for the Whitman 

Ranger District. The fisheries section was written by written by Suzanne Fouty and reviewed by 

John Quintela, fisheries biologist previously with the Whitman Ranger District and currently 

with the Bureau of Land Management. The fisheries analysis relies on information contained 

within the Water Resources section.

Suzanne Fouty has a Ph.D. in Geography with a specialty in fluvial geomorphology from the 

University of Oregon, a M. S. degree in Geology from the University of Arizona with a specialty 

in geomorphology, and a B.S. degree in Geology from the University of Washington. She has 

worked for the Wallowa-Whitman for six years.

Introduction

A number of miners notified the Forest Service of their intent to suction dredge in streams in the 

North Fork Burnt River (NFBR) watershed by including this activity in their Plans of Operation. 

During the NFBR Supplement analysis, it was determined that the suction dredging activities 

listed in the NFBR Plans do not require approval through a NEPA decision, because if the 

operator’s adhere to the existing Oregon Department of Environmental Quality’s (ODEQ)700-

PM permit (ODEQ), there would be no significant surface disturbance (Finding of Nonsignificant Surface Resource Disturbance, Supplement project file). However, the activity’s 

effects must still be accounted for and disclosed along with the effects of the other mining 

activities being considered in the proposed Plans of Operation. This document serves that 

purpose by capturing the effects of the known suction dredging in the NFBR minerals planning 

area. 

 

To determine these effects, site-specific analyses of streams and stream reaches were necessary. 

Factors examined included channel morphology, water quality, and redband trout and their 

habitat (Appendix 7B). The analysis used a series of questions raised by Harvey and Lisle 

(1998), as well as questions raised in other studies to define potential areas of concern. Channel 

morphology parameters evaluated were stability of the dredge tailings, stability of the channel 

bed, pool characteristics, and abundance and stability of roughness elements (i.e. beaver dams, 

log jams). Water quality parameters evaluated were turbidity, suspended sediment, and stream 

temperature. Fish habitat parameters evaluated were turbidity, suspended sediment, stream 

temperature, spawning gravels, pool habitat, and channel complexity. 
Appendix 7A NFBR Mining Supplemental EIS

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Additionally, several operational factors were considered -- the spatial distribution of suction 

dredging operations, the specific timing of operations, the size of the dredges and hoses, and in 

particular, the terms and conditions of the existing ODEQ 700-PM permit. This existing 700-

PM permit applies only to suction dredges with 30 horsepower or less and an inside diameter 

suction hose of 6-inches or less. All proposed dredge operations in the NFBR Plans fit these 

criteria.

This analysis did not consider other activities associated with suction dredging such as camping, 

firewood collection, trampling of vegetation, trash disposal etc. These activities and their effects 

were evaluated in connection with the other mining activities and operations in the various Plans 

of Operation.

Analysis Area

The analysis area is limited to the specific streams and reaches with proposed suction dredging. 

The analysis is further bounded, relative to the potential impacts on redband trout (a R6 Regional 

Forester’s sensitive species) and their habitat, by the timing of spawning and re-emergence with 

respect to dredging.

The only suction dredging analyzed are those areas indicated in the list of Plans from the 2004 

North Fork Burnt River Mining FEIS that included suction dredging. These Plans are displayed 

in Table A7A-1 and shown geographically on the maps at the end of Chapter 2.

Table A7A-1

Plans of Operation that listed suction dredging as an activity in the 2004 FEIS

Operation 

Name Creek Flow Creek status

Burnt Lode/Placer 

(Karissa site)

NFBR Perennial main stem

Burnt Lode/Placer 

(Cub Creek site)

Cub Perennial. Tributary to NFBR 

*Don Juan 

Lode/Placer

Unnamed tributary Intermittent Tributary to 

Greenhorn Ck.

Dream Chaser 

Placer

NFBR Perennial Main stem

Gimlet Placer Gimlet Perennial? Tributary to Camp 

Ck

Glory B Placer Jackknife Creek Intermittent Tributary to Pinus 

Creek
NFBR Mining Supplemental EIS Appendix 7A

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Operation 

Name Creek Flow Creek status

Gold Busters 

Placer

Plan of Operations map in plan 

signed by the operator on 3/31/05 

showed the operation on both 

Camp and Pinus Creeks. Letter 

from operator dated 2/23/08 with 

corrected map shows that only 

working on Pinus Creek.

Pinus = perennial in this location. 

Long sections are dry downstream

Pinus = Tributary 

to Camp Ck

Jim Bob Placer NFBR Perennial Main stem

*Lucky 7 Placer Gimlet Intermittent Tributary to Camp

Creek

Midas/Lady Bug 

Placer

California Gulch Intermittent. Check Dams in 

California Gulch

Headwater 

tributary

North Fork Placer NFBR Perennial Main stem

Prudent (#9) Placer NFBR Perennial Main stem 

R&RK #2, #3 

Placer

NFBR Perennial Main stem

R&RK #4, #5 

Placer

NFBR Perennial Main stem

Shamrock Placer NFBR Perennial Main stem

Sluice Box Placer NFBR Perennial Main stem

Wild Flower Placer NFBR Perennial Main stem

* Not analyzed since their operators did not continue their operation.

Appendix 7A provides the specific characteristics of the affected streams based on site visits for 

each operation in 2006, 2007, and 2008. 

Information Used

The following information was used to evaluate potential impacts: 

1. Field observations of the channel bed and bank composition, site characteristics and 

stability (Appendix 7B), 

2. Spatial distribution of mining claims with Plans that state suction dredging as one of its 

activities, 

3. Fish type and timing of spawning and emergence, 

4. The timing of the instream work window,
Appendix 7A NFBR Mining Supplemental EIS

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5. Peer-reviewed literature and various reports, 

6. Dredge hose size and distribution of suction dredging activity, and

7. The existing Oregon Department of Environmental Quality’s 700-PM permit 

requirements. 

ODEQ 700-PM permit

The existing ODEQ 700-PM permit replaced the 700-J permit referenced in the 2004 FEIS. This

existing 700-PM permit is due to expire in June, 2010, and the draft of a new 700-PM permit for 

the July, 2010 to December 31, 2014 time period is currently available for public comment. The 

most significant proposed change is the dredge and motor size limitations - proposed to be 

changed to:

1) small suction dredges having an intake nozzle with an inside diameter not exceeding four 

inches and a motor no larger than 16 horsepower,

2) in-water nonmotorized mining equipment used for recovering precious metals or minerals 

from stream bottom sediments.

Recreational hand panning is not required to obtain a permit. 

Dredges larger than this would require an individual, rather than a general, permit from the State 

(www.deq.state.or.us/WQ/wqpermit/mining.htm). This new 700-PM dredge permit is expected 

to be finalized by July, 2010. 

However, it should be noted that the 700-PM permit restrictions and requirements do not replace 

or supersede Federal laws and Forest Service regulations. How the Forest Service regulates 

mining operators on National Forest System lands under the Forest Service’s locatable mineral 

operations regulations at 36 CFR 228 Subpart A remains unchanged. A mining operator 

conducting or proposing to conduct instream suction dredge operations within National Forest 

System lands must be in compliance with 36 CFR 228 Subpart A regulations, whether operating 

under a Notice of Intent or an approved Plan of Operations. The operator is responsible for his 

or her own compliance with all applicable State and Federal laws and regulations. 

The existing 700-PM permit does not specify a location or dredge size (i.e. 2 inches, 4 inches, 6 

inches) and is not submitted to the Forest Service. Thus, this discussion of suction dredging 

effects is a minimal effects analysis because the impact of dredging varies as a function of 

dredge size, distribution and number of dredges, stream size, the fineness of the sediments, and 

flow regime (Harvey 1986). However, unless given permission by the miner who has a claim in 
NFBR Mining Supplemental EIS Appendix 7A

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an area, another individual may not suction dredge the portion of the stream that flows through 

the claim. As such, the spacing of mining claims provides zones of limited suction dredging 

activity. Operations are restricted by the State to daylight hours and the particular instream work 

window for each watershed. 

(www.dfw.state.or.us/lands/inwater/Oregon_Guidelines_for_Timing_of_%20InWater2008.pdf). 

In the NFBR watershed the instream work window is July 1 to October 31, based on the presence 

of redband trout. None of the streams in this watershed are Oregon Scenic Waterways or have 

been designated by the State as Essential Salmon Habitat. 

All dredging operations included in this SEIS were proposed to adhere to the terms of the 

existing (expiring) 700-PM permit, and were subsequently evaluated on a site-by site basis 

following Forest Service mining regulations at 36 CFR 228 Subpart A. Only one of the dredging 

proposals rose to the level of needing an authorized Plan of Operations (Burnt Lode/Cub Creek). 

Once ODEQ finalizes on the terms of the new 700-PM, Forest Service will need to verify what 

the dredgers propose to do, and re-evaluate these new dredge proposals as necessary. 

Literature Review 

The peer-reviewed literature on suction dredging impacts is limited and focuses largely on 

impacts to fish, aquatic insects and benthic invertebrates. Channel morphology and water quality 

information was sometimes included because of their influence on the habitat requirements of 

these organisms. When reviewing the literature, dredge size and numbers, channel 

characteristics and study location were noted to place the literature in its proper site context. To 

varying degrees the papers discuss the spatial and temporal extent of the changes. Information 

specifically relevant to understanding and determining the direct, indirect, and cumulative effects 

of suction dredging in the NFBR is presented in the following paragraphs. All literature is 

located in the project file along with a literature summary.

Channel width and sinuosity

Low-flow channel width can be increased and low-flow channel sinuosity decreased by suction 

dredging by removal of gravel/cobble bars. However, the existing 700-PM permit restricts the 

types of channel bars that can be suction dredged, thereby decreasing the extent of impact. 

Dredging is allowed into gravel bars up to 10 feet outside the wet perimeter of the stream 

(Section A.3), but the bar must be devoid of “any rooted vegetation, located either between the 

stream banks and the wet perimeter of the stream or entirely within the wet perimeter of the 

stream” (Definition #4). Because most cobble/gravel bars in this watershed have some 

vegetation, dredging would be largely restricted to the channel bed. Mid-channel bars with 

vegetation would also be excluded from dredging. Therefore, suction dredging has the potential 

to locally decrease low-flow channel sinuosity and increase low-flow channel widths by mining 

unvegetated gravel bars. 
Appendix 7A NFBR Mining Supplemental EIS

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Channel complexity and roughness

Channel complexity and roughness are provided by boulders, log jams, beaver dams, and stream 

bank vegetation. Schedule C.4 of the ODEQ existing 700-PM permit states: “Moving boulders, 

logs, or other natural stream infrastructure within the stream channel as described in Schedule 

A3 is allowed. However, in no case may this infrastructure be removed entirely from the stream 

channel. Removal of infrastructure that extends into the stream channel from the stream bank is 

also prohibited.” Schedule A3 defines the stream channel as the wetted perimeter, or if 

unvegetated gravel bars are present, then the stream channel extends up to 10 feet outside the wet 

perimeter. Only those features that fall within this area may be moved, provided that 

infrastructure is not attached to the bank. Therefore, log jams attached to the stream bank and 

beaver dams would not be disturbed or destabilized because both features are directly attached to 

the stream banks. However, boulders or log jams contained within the channel and not attached 

to the stream banks could be moved. Therefore, suction dredging has the potential to locally 

alter channel complexity and roughness if in-channel boulders and log jams are removed.

Channel bed stability and morphology

Channel bed composition determines channel bed stability and thus the potential for suction 

dredging to alter pool/riffle distributions and characteristics and/or create a knickpoint which 

would might headcut and lead to channel incision. Harvey and Lisle (1999) found that scour and 

fill varied spatially as a function of bed composition and variability in stream flow. Thomas 

(1985) found that deposited sediment increased 10-20 times over background levels immediately 

downstream of a dredge, and then decreased exponentially downstream. His study found that the 

bulk of the sediment stirred up by dredging was redeposited within 6-11 meters, and in one case 

the gravel deposited by the dredge had moved into and filled a pool. Somer and Hassler (1992) 

found increases in sedimentation below dredges on some streams and not others, suggesting the 

role of substrate composition in determining the potential for pool infilling. Therefore, it is 

possible that if a pool exists immediately downstream from a dredging operation, there may be 

some reduction in that particular pool’s depth as a result of infilling by sands and gravels. 

The literature distinguishes between natural riffles and dredge tailings and found that the stability 

of these features differ. The natural riffles have adjusted over time to variable instream flow 

conditions and tend to be stable. The stability of the suction dredge tailings, however, is a 

function of the tailings composition, and its impact on channel bed morphology varies 

accordingly. Thomas (1985) found that gravel tailings are unstable. All the gravels deposited by 

the dredge in his study stream had moved downstream one year after dredging. Somer and 

Hassler (1992) also found that that the “dredge pocket and pile” stream morphology was short 

term, and that the dredge holes and tailings were no longer visible the following summer. In 

contrast, Harvey and Lisle (1998) noted that rocks too large to pass through dredges are 

commonly piled, and that these piles can persist during high flows. These imposed topographic 

high points have the potential to destabilize channels during high flows, depending on site 

characteristics. They also noted that suction dredging may cause natural riffle crests to erode, 

causing upstream pools to become shallower. The potential for natural riffle crests to erode 

depends on the riffle composition and location of the dredging operation with respect to riffle 
NFBR Mining Supplemental EIS Appendix 7A

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crests. Therefore, there is the potential for suction dredging to alter distribution of riffles and 

destabilized channels under certain site conditions.

Stream bank stability

Dredging of stream banks can result in large amount of fines entering the stream, decrease 

stream bank stability, and decrease shade. However, Schedule C.5 of the existing ODEQ 700-

PM permit prohibits dredging of stream banks, undercutting or eroding them or removing 

boulders, rooted vegetation, or embedded woody plants from stream banks. In addition, so long 

as the channel bed composition was resistant to instream scour, a suction dredge pool would not 

be expected to trigger a headcut which, if it happened, would increase stream bank sensitivity to 

instream erosion by increasing bank heights. Therefore, dredging would not destabilize the 

banks and contribute sediment into the creeks, either by removing bank vegetation or 

undercutting the banks. 

Stream Temperature

Current temperature conditions in the NFBR watershed are the result of historic activity which 

resulted in channel incision, widening, and straightening, a lowering of the groundwater table, 

and the removal of riparian woody vegetation. The existing700-PM permit prohibits dredging in 

the stream banks or removing stream side vegetation. Therefore, suction dredging will not alter 

either the actual stream temperatures or their patterns, unless dredging triggers a channel 

headcut. In this case, the increased bank heights, as a result of channel incision, would make the 

stream banks more sensitive to instream erosion and the evolution of a wider channel. The 

increase in channel widths would result in a decrease in water depths for the same discharge and 

thus an increase in stream temperatures. Channel incision would also lead to a lowering of the 

water table, reducing the influx of cooler groundwater base flows into the stream. This would 

also lead to increased stream temperatures and a potential shift from perennial to intermittent 

flow. 

Turbidity and Suspended Sediment

With respect to potential turbidity plumes, the existing 700-PM permit requires that “suction 

dredges with suction hoses that have an inside diameter of 4 inches or greater must visually 

monitor each day of operation to assure turbidity is not visible beyond 300 feet downstream at 

any time (existing Schedule B.1).” Suction dredges with suction hoses that have an inside 

diameter less than 4 inches do not have to monitor for turbidity (existing Schedule B.2). 

Research examining turbidity plumes found that depending on the amount and type of fines in 

the substrate and the stream gradients, plume distances varied from being non-detectable below a 

dredge or only a few meters in length (Griffith and Andrews 1981), to 80 plus meters (Harvey 

1986), to more than 123 meters downstream (Somer and Hassler 1992). Only Griffith and 

Andrews (1981) identified the percentages or makeup of the fines in the substrate. They found 

that sediment less than 0.5 mm (silt) composed 13 and 18 percent of the substrate on their two 

streams. Sediment less than 4 mm (fine gravel) made up 58% of the material dredged in both 

streams. 
Appendix 7A NFBR Mining Supplemental EIS

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Thomas (1985) found in his study that deposited sediment increased 10-20 times over 

background levels immediately downstream of a dredge, and then decreased exponentially 

downstream. His study found that the bulk of the sediment stirred up by dredging was 

redeposited within 6-11 meters, and in one case the gravel deposited by the dredge had moved 

into and filled a pool. Somer and Hassler (1992) found increased in sedimentation below 

dredges on some streams and not others suggesting the role of substrate composition in 

determining the potential for pool infilling. Harvey and Lisle (1999) found that scour and fill 

varied spatially as a function of bed composition and variability in stream flow. Therefore, there 

is the potential for suction dredging to increase turbidity and suspended sediment in a stream 

depending on the channel bed composition.

Direct/Indirect Effects to Water Resources 

The water resources considered in this analysis are water quality and channel characteristics 

(pools, riffles, sinuosity, roughness, complexity). The site-specific analyses evaluate the impact 

of suction dredging on a given section of stream based on the spatial locations of those Plans of 

Operation. A summary of current stream channel bed and bank conditions where suction 

dredging is proposed is provided when discussing the potential for cumulative effects to channel 

stability, water quality or redband trout and their habitat. More detailed descriptions of current 

conditions can be found in the 2004 FEIS in the Watershed and Soil Resources section (Chapter 

III, pp. 3-39), the Fisheries section (Chapter III, pp. 39 – 68), and Appendix 7B. All operators 

in the plans have indicated that they will be using a 6 inch-or-less suction hose.

Midas/Lady Bug and Glory B

Midas/Lady Bug is located in the headwaters of California Gulch. Glory B is located on 

Jackknife Creek just upstream of the confluence of Pinus and Jackknife Creeks. These 

headwater tributaries were historically placer mined. Old placer tailings line the stream banks,

and the channel banks and bed are composed largely of cobbles and thus resistant to instream 

erosion. Silts and clays in the channel bed are expected to be low, with the dominant fine 

sediment being sands and gravels. Flow is seasonal and the streams are dry by mid-late summer. 

The section of Pinus Creek below its confluence with Jackknife Creek also has intermittent flow 

and has been historically mined. Fish are not present. Channel bars are absent and the channels 

are straight.

Seasonal flow restricts the period when suction dredging would occur. Any turbidity generated 

during operations would be short-term and not make it 300 feet before flows go subsurface. The 

temporally and spatially limited seasonal flow prevents any surface hydrologic connection 

between flows in these areas with channels downstream that have a surface hydrologic 

connection to streams with perennial flow. For these reasons, suction dredging at these two 

operations would not affect channel stability, water quality, or redband trout and their habitat 

either on site or downstream. Therefore, suction dredging will not alter channel form and 

sinuosity, channel complexity and roughness, stream bank stability, channel bed stability and 

morphology and water quality in these stream reaches.
NFBR Mining Supplemental EIS Appendix 7A

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Gimlet Placer

Gimlet Creek is a tributary to Camp Creek. The mining operation is more than 2 miles upstream 

of the confluence of Gimlet Creek with Camp Creek. Gimlet Creek, below Gimlet Placer and to 

the confluence with Camp Creek, is incised, widened and straightened, and has long reaches 

which have only intermittent flow. The limited silt and clay prevents long turbidity plumes or 

increased suspended sediment for any distance, and the low flow results in sands and gravels 

settling out within a short distance (less than 50 feet) (Griffith and Andrews 1981; Thomas 

1985). In addition, Gimlet Creek has long sections that are dry during the dredging season 

downstream of the operation. As a result there is no surface hydrologic connection between the 

operation and reaches of Gimlet Creek that have perennial flow, or Camp Creek. For these 

reasons, suction dredging at this operation would not affect channel stability, water quality, or 

redband trout and their habitat either on site or downstream. Therefore, suction dredging will not 

alter channel form and sinuosity, channel complexity and roughness, stream bank stability, 

channel bed stability and morphology and water quality in this stream reach.

Cub Creek

Cub Creek is a tributary to the NFBR and flows through a narrow valley composed of fine 

sediment. Cub Creek is narrow (less than 7 feet) and has fine-grained stream banks. The 

channel bed contains a high percentage of silt and sands with some cobbles. Complexity and 

roughness are limited to a few boulders and downed woody material. Riparian woody vegetation 

is limited along the stream. Large amounts of fine sediment are entering the creek due to bank 

trampling by domestic livestock. Flow is low, but perennial in this section. It is unknown if fish 

are present. This proposed section of stream does not appear to have been historically placer 

mined. Dredging on Cub Creek would occur upstream of its confluence with the NFBR.

 

The composition of the channel bed (high percentage of fines) and stream banks fine-grained 

sediments) increases the possibility that suction dredging could trigger the development of a 

headcut. Headcuts once established often lead to the rapid channel incision as the headcut 

migrates upstream. As the channel incises, there is a drop in the groundwater table and a shift in 

vegetation type to more drought-tolerant species. The speed at which channel morphology and 

stream character can change as a result of channel incision varies as a function of channel bed 

and bank characteristics and is well-documented in the literature (Bryan 1927, Bryan 1928a, 

Bryan 1928b, Cottom and Stewart 1940, Schaffer 1941, Cooke and Reeves 1976, Shankman and 

Pugh 1992, Fouty 2003). The ability of suction dredging, specifically, to alter channel 

morphology has been noted by Harvey (1986) on a tributary with a large percentage of fines. He 

observed that 15 meters of a stream were channelized and riffles transformed into exposed gravel 

bars as the result of a 10-day operation of one dredge.

The high percentage of fines in the channel bed and channel banks and the low flows on Cub 

Creek may result in the turbidity plume generated by suction dredging to persist longer than that 

generated by suction dredging in the NFBR. If the channel begins incising and/or undercutting 

its banks, the plume would persist even after dredging ceased. Depending on the amount of 

dredging, the Cub Creek plume may be visible in the NFBR just downstream of the confluence 
Appendix 7A NFBR Mining Supplemental EIS

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of Cub Creek and the NFBR. In addition, it is possible that the turbidity would span Cub Creek 

because the channel is narrow. 

Potential for channel incision and stream bank undercutting or erosion as a result of suction 

dredging is restricted to Cub Creek because of the fine grained composition of its bed and banks 

(silts, sands, and gravels). However, suction dredging on Cub Creek would be monitored as part 

of the Forest Service’s annual mining inspections. If undercutting or stream bank erosion occurs 

as a result of suction dredging, the operator would be in violation of the existing State 700-PM 

permit (Schedules C.3, C.5, and C.7) and dredging would be stopped until resource issues were 

addressed. 

Schedule C.3 states: The permittee must provide a safe passage for fish around and through the 

active mining area if the stream was historically or is currently inhabited by native migratory 

fish. 

If the channel incises and/or widens the groundwater table would drop and portion of the stream 

could go dry. As a result, the fish would not be able to move around and through the active 

mining area. 

Schedule C.5 states: Dredging stream banks is not allowed under this permit. Undercutting or 

eroding stream banks and remove or disturbance of boulders, rooted vegetation, or embedded 

woody plans from stream banks is prohibited.

Suction dredging on this creek has the potential to trigger a headcut. A channel headcut would 

lead to 1) channel straightening, 2) undercutting of stream banks, 3) channel widening, 4) 

increased turbidity, 5) increased suspended sediment, 6) increased stream temperatures as the 

groundwater table dropped, and 7) sections of stream shifting from perennial to intermittent flow 

as base flows contributed by groundwater decreased. 

Schedule C.7 states: Suction dredging activity must not result in the formation of organic or 

inorganic deposits that are harmful to fish or other aquatic life as required in OAR 340-041-

0007 (13). 

The increased sediment loads created from channel incision and stream bank erosion would bury 

spawning gravels located downstream resulting in the formation of inorganic deposits that are 

harmful to fish or other aquatic life.

North Fork Burnt River suite

Operations on the NFBR are bounded by the confluence of Cub Creek and the NFBR on the 

upstream end, and the confluence of Patrick Creek and the NFBR on the downstream end. Flow 

on the NFBR is perennial and redband trout are present. The NFBR is 303 (d) listed for stream 

temperature and sedimentation (embeddedness). The distance between the ten individual 

operations varies from 660 feet to more than 6100 feet (Figure 1). 
NFBR Mining Supplemental EIS Appendix 7A

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The stream banks of the NFBR are composed of fine sediment (sand, silt, and clay) overlying a 

layer of cobble/gravels/fines. Stream bank characteristics vary. In places the banks are vertical, 

exceed five feet in height, are unvegetated and are therefore easily eroded during high spring 

flows. Point bars are present in the channel with the amount of bar vegetation varying from site 

to site. Bars are typically composed of cobbles, gravels, and sand. The channel beds are 

dominated by cobbles, with sands and gravels in the spaces in between. High percentages of silt 

and clay are restricted to behind the beaver dams within the NFBR, and along the margins of the 

stream where banks have failed. Coarse woody material exists in the form of occasional log 

jams and beaver dams. The NFBR was historically placer mined and the channel is wide, 

incised, and straightened. Water depths were measured in reaches with and without newly 

formed beaver dams in late fall 2007 (project). In two reaches without beaver dams, the average 

water depths were 0.8 to 1 foot deep, with a few deep pools related to historic mining activity or 

log jams. When beaver dams were present, the average water depth was 1.7 feet, almost twice 

the average depth found in reaches without beaver dams. Stream temperatures exceed ODEQ’s 

temperature standard of 68*F. Wetted widths measured in the three reaches ranged from 7 to 

more than 25 feet wide. The channel bed is composed of cobbles and very coarse gravels and is 

well armored. The coarseness of the channel bed makes the bed highly stable and resistant to 

channel scour.

Cobbles dominate the NFBR channel bed. The coarseness of the channel bed material makes the 

bed resistant to instream scour and limits the development of pools. This has resulted in a 

relatively smooth channel bed topography, as reflected in limited variation in water depths in the 

two reaches that did not have beaver dams surveyed in Fall 2007. The greater variability in 

channel bed topography in Reach 4 compared to Reach 2 is the result of stable pools created by 

past mining activity and scour around in-channel woody material. In 2007, Reaches 1 and 3 

contained beaver dams and displayed much greater variability in channel bed topography and 

water depths. 

Pools created by suction dredging would not result in the development of a headcut and channel 

incision because the dominance of cobbles has created a channel bed resistant to scour. The 

coarse channel bed material also makes the bed resistant to instream erosion, even if dredging is 

near a riffle crest. The depth of a pool immediately downstream of the suction dredging may be 

affected depending on the amount of sand and gravel disturbed by dredging. Therefore, it is 

possible that if a pool exists immediately downstream from a dredging operation that there may 

be some reduction in that particular pool’s depth as a result of infilling by sands and gravels. 

Suction dredge tailings composed largely of gravels are expected to be transitory and remolded 

or removed by high flows (Harvey and Lisle 1998). Tailing composed of cobbles are expected 

to more stable with limited remolding during high flows. While the cobble tailings may persist, 

the overall coarseness of the channel bed material and the width of the channel (7-25 feet) 

minimize the potential for the topographic high points to destabilize the channel bed or banks 

during high flows. Therefore, there is only a short-term (one season) alteration of the channel 

bed on channel bed stability and morphology as a result of suction dredging. 

Channel complexity and roughness is provided by log jams, beaver dams, and boulders. 

Removal of any of these features that are embedded into the stream bank is prohibited by 

existing ODEQ 700-PM permit, Schedules C.4 and C.5. Boulders or log jams not embedded in 
Appendix 7A NFBR Mining Supplemental EIS

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the stream can be moved and therefore, suction dredging would result in a small reduction in 

channel complexity and roughness. However, the protection of the larger features (beaver dams, 

log jams embedded into the bank, stream bank vegetation) from disturbance means that the effect 

on channel complexity and roughness would be minimal.

Turbidity plumes from the NFBR operations are expected to be much less than 300 feet in length 

for the following reasons. First, the silt/clay component in the substrate of the NFBR is expected 

to be low because the stream was historically placer mined with large equipment, which would 

have flushed the silt/clays downstream. Any large quantities of silt/clay in the stream are now 

limited to along the margins of the channels where banks are eroding, or behind beaver dams or 

bank-embedded log jams. Activity should not occur in these areas according to the existing 700-

PM permit. However, disturbance of in-channel log jams could result in a local, seasonal plume 

depending on the type of sediments trapped behind the jams. Second, the summer wetted widths 

range from 7 to more than 25 feet, based on measurements taken in fall 2007. In contrast, the 

inside diameter suction hose is no greater than six inches. The nozzle size limits the amount of 

channel bed that can be mobilized at any one time. Therefore, the plume would be very limited 

in width. Finally, even if all ten operators were suction dredging at the same time, the distances 

between operations closest to each other vary from 660 feet to 6100 feet or more of stream 

(Figure 1) and plumes would not overlap. Therefore, there would be a short-term increase in 

turbidity as a result of suction dredging, but limited in length and width.

Suspended sediment in the NFBR would only increase locally as a result of suction dredging. 

Cobbles dominate the NFBR channel bed with silts, sands and gravels in the spaces in between. 

Dredging in streambeds in which sand is the dominant interstitial fine sediment is unlikely to 

yield suspended concentrations. Sand and gravel are usually deposited immediately downstream 

(Harvey and Lisle 1998). Based on the amount of historic placer mining that occurred in this 

stream, sands and gravels are expected to be the dominant interstitial fine sediment. Any change 

in suspended sediment concentrations would therefore be local and immeasurable, except 

perhaps immediately below the dredge. 

Stream temperatures on the NFBR would not be altered by suction dredging because dredging 

would not alter the factors that control stream temperatures. 

Summary of Potential Direct/Indirect Effects to Water Resources

The potential effects to water resources from suction dredging listed in the Plans of Operations 

are summarized in Table 2. Of the 14 operations (15 sites) only the Burnt Lode/Placer on Cub 

Creek was identified as a site where suction dredging could influence channel bed and bank 

stability and thus water quality and fisheries habitat. 

Cumulative Effects to Water Resources

The beneficial cumulative effects of proposed suction dredging on water resources (water quality 

and channel morphology) in the NFBR watershed are 1) a local reduction in channel 
NFBR Mining Supplemental EIS Appendix 7A

13

embeddedness, 2) a local increase in a source of spawning gravel material, and 3) creation of 

short-term local pool habitat during the summer. Except in the case of Cub Creek, increases in 

turbidity and/or suspended sediment are localized, short-term (limited to actual time of 

operation), and non-measurable except in close proximity to the dredge. 

The negative cumulative effects of suction dredging are restricted to Burnt Lode/Placer site on 

Cub Creek, where the creek has the potential to incise and create a sustained turbidity plume and 

increased suspended sediment. The turbidity on Cub Creek may make it to NFBR. However, 

any plume that enters the NFBR from Cub Creek is expected to be non-measurable less than 100 

feet downstream of the confluence because the flows on Cub Creek are low compared to those 

on the NFBR. The potential for headcutting is the greatest concern because of its subsequent 

impacts to the groundwater table, vegetation, and channel sinuosity. Unlike increased turbidity, 

headcutting does not cease once suction dredging has stopped, but would continue until it 

reached a section of stream which was bedrock controlled, or well-armored by cobbles or roots. 

However, as stated above under Direct/Indirect Effects, suction dredging on Cub Creek (Burnt 

Lode/Placer) would be monitored as part of the Forest Service’s annual mining inspections. If 

channel incision and/or bank failure is observed, then suction dredging would be in violation of 

the existing State 700-PM permit and dredging would be stopped until resource issues were 

addressed. 
Appendix 7A NFBR Mining Supplemental EIS

14

Table A7A-2. 

Sites identified in Plans of Operation where suction dredging is proposed. 

(Shaded boxes indicate areas of potential concerns to water resources)

Operation Creek Flow/Fish 

Status

Channel 

sinuosity

Channel 

complexity 

and 

roughness

Channel bed 

stability and 

morphology

Stream 

bank 

stability

Stream 

Temp

Turbidity Suspended 

Sediment

Burnt Lode/ 

Placer (Cub 

Creek)

Cub 

Creek

Perennial in 

this section. 

Unknown if 

fish-bearing.

Potential for 

bank 

undercutting and 

channel 

straightening as a 

result of the 

development and 

migration of a 

headcut. Also 

potential increase 

in gravel tailings. 

No impact 

because very 

little channel 

complexity at 

present. 

Potential for 

channel 

incision and 

development 

and 

migration of 

a headcut.

Potential for 

bank 

undercutting 

as a result of 

the 

development 

and 

migration of 

a headcut.

Potential for 

an increase 

in stream 

temperatures 

and shift 

from 

perennial to 

intermittent 

flow as 

channel 

incised and 

stream banks 

erode.

Potential for 

increased 

turbidity that 

extends the 

width of the 

stream and 

continues after 

dredging 

ceases as a 

result of 

dredging 

causing 

channel bed 

and bank 

instability.

Potential for 

increased 

suspended 

and bedload 

sediment 

movement 

because of 

channel 

headcutting 

and bank 

erosion.

Burnt Lode/ 

Placer 

(Karissa)

NFBR Perennial/

Fish-bearing

Potential to 

locally alter 

developing lowflow channel 

sinuosity and 

channel 

narrowing by 

mining gravel 

bars Restricted to 

places with 

unvegetated 

channel bars. 

Potential to 

locally reduce 

complexity 

and roughness. 

Changes 

restricted to 

moving 

roughness 

features 

contained 

within the 

stream channel 

but not those 

which extend 

into the stream 

bank (i.e. 

beaver dams, 

Short-term 

(1-2 seasons) 

pool 

development 

depending on 

the amount of 

bedload 

moving. 

Short-term 

gravel 

tailings 

which will be 

remobilized 

during spring 

high flows. 

Cobble 

tailings may 

No impact No impact Plume will be 

< 300 feet in 

length and 

much less in 

width than the 

width of the 

wetted 

channel.

No WQ 

concerns. 

Low 

concentration

s in channel 

bed because 

creek has 

been 

historically 

mined. 
NFBR Mining Supplemental EIS Appendix 7A

15

15

Operation Creek Flow/Fish 

Status

Channel 

sinuosity

Channel 

complexity 

and 

roughness

Channel bed 

stability and 

morphology

Stream 

bank 

stability

Stream 

Temp

Turbidity Suspended 

Sediment

log jams). persist for a 

couple of 

seasons. No 

headcutting 

expected due 

to cobbledominated 

channel bed.

Dream 

Chaser 

Placer

NFBR Perennial/

Fish-bearing

Localized impact 

to low-flow 

channel. See 

Burnt 

Lode/Placer 

(NFBR sites).

Possible 

localized 

impact. See 

Burnt 

Lode/Placer 

(NFBR sites). 

Short-term 

localized 

impact. See 

Burnt 

Lode/Placer 

(NFBR site).

No impact No impact Same as Burnt 

Lode/Placer 

(NFBR site).

No WQ 

concerns. 

See Burnt 

Lode/Placer 

(NFBR site).

Gimlet 

Placer

Gimlet 

Creek

Intermittent/ 

Non-fish 

bearing

No impact No impact No concerns. 

No changes 

in channel 

stability 

because bed 

is cobbledominated. 

Pools and 

tailings likely 

to persist 

because 

limited flow. 

No 

headcutting 

expected 

because 

channel bed 

resistant to 

instream 

erosion and 

flow low.

No impact No impact None. Stream 

goes 

subsurface 

below site.

No WQ 

concerns. 

See Burnt 

Lode/Placer 

(NFBR site).

Glory B Jackknif Intermittent/ No impact No impact. No concerns. No impact No impact None. Flow No WQ 
Appendix 7A NFBR Mining Supplemental EIS

16

Operation Creek Flow/Fish 

Status

Channel 

sinuosity

Channel 

complexity 

and 

roughness

Channel bed 

stability and 

morphology

Stream 

bank 

stability

Stream 

Temp

Turbidity Suspended 

Sediment

Placer e Creek Non-fish 

bearing

See Gimlet 

Placer.

seasonal and 

goes 

subsurface 

below site.

concerns. 

See Burnt 

Lode/Placer 

(NFBR site)

Gold 

Busters 

Placer

Pinus 

Creek

Intermittent/ 

Non-fish 

bearing

No impact No impact No concerns. 

See Gimlet 

Placer.

No impact No impact None. Flow in 

this area may 

be perennial 

but stream 

goes 

subsurface 

below site.

No WQ 

concerns. 

See Burnt 

Lode/Placer 

(NFBR site)

Jim Bob 

Placer

NFBR Perennial/

Fish-bearing

Localized impact 

to low-flow 

channel. See 

Burnt 

Lode/Placer 

(NFBR sites).

Possible 

localized 

impact. See 

Burnt 

Lode/Placer 

(NFBR sites). 

Short-term 

localized 

impact. See 

Burnt 

Lode/Placer 

(NFBR site).

No impact No impact Same as Burnt 

Lode/Placer 

(NFBR site).

No WQ 

concerns. 

See Burnt 

Lode/Placer 

(NFBR site).

Midas/Lady 

Bug Placer

Californi

a Gulch

Intermittent/ 

Non-fish 

bearing

No impact No impact No concerns. 

See Gimlet 

Placer.

No impact No impact None. Flow 

seasonal and 

goes 

subsurface 

below site 

No WQ 

concerns. 

See Burnt 

Lode/Placer 

(NFBR site)

North Fork 

Placer

NFBR Perennial/

Fish-bearing

Localized impact 

to low-flow 

channel. See 

Burnt 

Lode/Placer 

(NFBR sites).

Possible 

localized 

impact. See 

Burnt 

Lode/Placer 

(NFBR sites). 

Short-term 

localized 

impact. See 

Burnt 

Lode/Placer 

(NFBR site).

No impact No impact Same as Burnt 

Lode/Placer 

(NFBR site).

No WQ 

concerns. 

See Burnt 

Lode/Placer 

(NFBR site).

Prudent 

(#9) Placer

NFBR Perennial/

Fish-bearing

Localized impact 

to low-flow 

channel. See 

Burnt 

Lode/Placer 

(NFBR sites).

Possible 

localized 

impact. See 

Burnt 

Lode/Placer 

(NFBR sites). 

Short-term 

localized 

impact. See 

Burnt 

Lode/Placer 

(NFBR site).

No impact No impact Same as Burnt 

Lode/Placer 

(NFBR site).

No WQ 

concerns. 

See Burnt 

Lode/Placer 

(NFBR site).

R&RK #2 

#3 Placer

NFBR Perennial/

Fish-bearing

Localized impact 

to low-flow 

Possible 

localized 

Short-term 

localized 

No impact No impact Same as Burnt 

Lode/Placer 

No WQ 

concerns. 
NFBR Mining Supplemental EIS Appendix 7A

17

17

Operation Creek Flow/Fish 

Status

Channel 

sinuosity

Channel 

complexity 

and 

roughness

Channel bed 

stability and 

morphology

Stream 

bank 

stability

Stream 

Temp

Turbidity Suspended 

Sediment

channel. See 

Burnt 

Lode/Placer 

(NFBR sites).

impact. See 

Burnt 

Lode/Placer 

(NFBR sites). 

impact. See 

Burnt 

Lode/Placer 

(NFBR site).

(NFBR site). See Burnt 

Lode/Placer 

(NFBR site)

R&RK #4 

#5 Placer

NFBR Perennial/

Fish-bearing

Localized impact 

to low-flow 

channel. See 

Burnt 

Lode/Placer 

(NFBR sites).

Possible 

localized 

impact. See 

Burnt 

Lode/Placer 

(NFBR sites). 

Short-term 

localized 

impact. See 

Burnt 

Lode/Placer 

(NFBR site).

No impact No impact Same as Burnt 

Lode/Placer 

(NFBR site).

No WQ 

concerns. 

See Burnt 

Lode/Placer 

(NFBR site).

Shamrock 

Placer

NFBR Perennial/

Fish-bearing

Localized impact 

to low-flow 

channel. See 

Burnt 

Lode/Placer 

(NFBR sites).

Possible 

localized 

impact. See 

Burnt 

Lode/Placer 

(NFBR sites). 

Short-term 

localized 

impact. See 

Burnt 

Lode/Placer 

(NFBR site).

No impact No impact Same as Burnt 

Lode/Placer 

(NFBR site).

No WQ 

concerns. 

See Burnt 

Lode/Placer 

(NFBR site).

Sluice Box NFBR Perennial/

Fish-bearing

Localized impact 

to low-flow 

channel. See 

Burnt 

Lode/Placer 

(NFBR sites).

Possible 

localized 

impact. See 

Burnt 

Lode/Placer 

(NFBR sites). 

Short-term 

localized 

impact. See 

Burnt 

Lode/Placer 

(NFBR site).

No impact No impact Same as Burnt 

Lode/Placer 

(NFBR site).

No WQ 

concerns. 

See Burnt 

Lode/Placer 

(NFBR site).

Wildflower 

Placer

NFBR Perennial/

Fish-bearing

Localized impact 

to low-flow 

channel. See 

Burnt 

Lode/Placer 

(NFBR sites).

Possible 

localized 

impact. See 

Burnt 

Lode/Placer 

(NFBR sites). 

Short-term 

localized 

impact. See 

Burnt 

Lode/Placer 

(NFBR site).

No impact No impact Same as Burnt 

Lode/Placer 

(NFBR site).

No WQ 

concerns. 

See Burnt 

Lode/Placer 

(NFBR site).
Appendix 7A NFBR Mining Supplemental EIS

18

Direct and Indirect Effects to Fisheries

The instream work window for the NFBR watershed is July 1 to October 31. Redband trout are 

present and they typically spawn in March, April, and May and emerge in June and July 

(Quintela, pers. com. 4/18/08). For the purposes of this analysis, redband trout are assumed to 

be present in all perennial streams. Redband trout are assumed to be absent in intermittent 

streams or streams that have large section(s) of channel that are dry during the summer 

downstream of the mining site. 

Operations that were located on sections of channel that carry only intermittent flow and are nonfish bearing are Gimlet Placer (Gimlet Creek), Glory B Placer (Jackknife Creek), Gold Busters 

Placer (Pinus Creek), and Midas/Lady Bug Placer (California Gulch). Therefore, these creeks 

and Operations will not be discussed further. The discussion below is limited to operations on 

the NFBR and Cub Creek, which are perennial streams. 

Spawning Gravels

Suction dredge tailings can become focal points of spawning depending on the abundance of 

natural riffles in a stream channel (Harvey and Lisle 1999). The large amount of historic mining 

and channel changes in the NFBR watershed has resulted in the streams having limited spawning 

gravels. Therefore, the timing of spawning is key when evaluating the potential impact of suction 

dredging on redband trout. Redband trout typically spawn in March, April, and May and emerge 

in June and July (Quintela, pers. com. 4/18/08). 

The tailings piles created during the summer in the NFBR would vary in their composition from 

piles dominated by cobbles to piles dominated by gravels and sands. The piles composed of 

gravels and sands are expected to be remolded or removed by the high flows in the spring 

(Thomas 1985). As a result, gravel-dominated tailings would not be available in the spring as 

potential spawning gravels, which is when the redband trout spawn. The tailings piles dominated 

by cobbles might persist into the spring but would not be conducive to spawning. Therefore, 

suction dredging would not impact redband trout survival as it pertains to spawning and 

emergence in NFBR.

The channel bed of Cub Creek is a mix of fines and gravels. The low flow conditions on Cub 

Creek mean that any gravel tailings might not be remolded or removed by high spring flows to 

the same degree as those in the NFBR. This is not a concern at this site because redband trout 

typically spawn in March, April, and May and emerge in June and July (Quintela, pers. com. 

4/18/08) and the redds would not be washed out prior to emergence. However, bank trampling 

by livestock and their removal of riparian woody vegetation, which stabilizes the streambanks, is 

contributing to increased suspended and bedload sediment in the channel. This sediment input 

would likely bury spawning gravels generated by suction dredging and suffocate eggs. The 

bedload and suspended sediments input from bank trampling would increase if suction dredging 

triggered channel incision and bank undercutting. However, impacts to fisheries triggered by 

suction dredging would be in violation of the existing State 700-PM permit (Schedule C.5, C.7) 

and dredging would be stopped until resource issues were addressed. Therefore, while it is 

possible that suction dredging may result in an increase in spawning sites, the beneficial 

alteration would likely end up a negative for redband trout because of livestock impacts even if 

dredging does not alter bed and bank stability. 
NFBR Mining Supplemental EIS Appendix 7A

19

 

Pools

The NFBR channel bed is dominated by embedded cobbles making the channel beds highly 

resistant to erosion. As a result pool habitat is limited. Some exceptions exist where historic inchannel mining and in-channel woody material have created some deep and stable pools. It is 

possible that suction dredging, in the process of deepening pools or creating new pools, may 

intersect cooler subsurface flows (Harvey and Lisle 1998), thereby creating temporary, seasonal 

refugia for fish both in terms of habitat and improved stream temperature conditions. Therefore, 

suction dredging would result in a localized increase in pool habitat which may or may not 

persist, depending on the amount of bedload that moves during the high spring flows. 

Cub Creek channel has very few pools and suction dredging could be beneficial in creating more 

pools if it does not trigger a headcut. However, the high percentage of fines in the bed and the 

lack of channel bed armoring raises the possibility of channel incision could occur. This would 

alter the character of this stream and result in degraded habitat conditions. 

Habitat Complexity

Streams in this watershed have widened, incised, and straightened, and features creating channel 

complexity are limited. Schedule C.4 of the existing ODEQ 700-PM permit states: “Moving 

boulders, logs, or other natural stream infrastructure within the stream channel as described in 

Schedule A3 is allowed. However, in no case may this infrastructure be removed entirely from 

the stream channel. Removal of infrastructure that extends into the stream channel from the 

stream bank is also prohibited.” Schedule A3 defines the stream channel as the wetted 

perimeter, or if unvegetated gravel bars are present, then the stream channel extends up to 10 feet 

outside the wet perimeter. Only those features that fall within this area may be moved, provided 

that infrastructure is not attached to the bank. Therefore, log jams and beaver dams, key 

elements in creating habitat complexity, would not be disturbed or destabilized because both 

features are directly attached to the stream banks. 

The Schedule C.4 restriction applies to the following operations: North Fork Placer, Prudent 

(#9), R&RK 2&3, Wildflower (beaver dams), and Sluice Box (log jams). The protection of log 

jams and beaver dams means that key habitat elements for fish are protected. However, inchannel logs, boulders, and unvegetated gravel bars could be moved resulting in a local reduction 

of habitat complexity. As a result parts of the NFBR could see a local reduction in habitat 

complexity as a result of suction dredging. Cub Creek has little to no habitat complexity at 

present and therefore suction dredging would not alter this parameter.

Stream Temperature

The U.S. Forest Service has limited stream temperature data for the NFBR watershed. Based on 

the available data, the perennial streams are above ODEQ temperature standard of 68*F, at least 

some years. The elevated stream temperatures are the result of historic land use activity which 

led to channel incision, widening and straightening and a lowering of the groundwater table 

(USDA 1995). 
Appendix 7A NFBR Mining Supplemental EIS

20

The existing ODEQ 700-PM permit (Schedule C.5) prohibits undercutting or eroding stream or 

removing of stream bank vegetation, woody plants or boulders embedded in the bank, and thus 

indirectly channel incision. As long as the terms and conditions of the existing 700-PM permit 

are adhered to, suction dredging would not alter streamside shade, stream discharge, 

groundwater recharge, base flows, channel bed or bank stability, or channel widths – all factors 

that influence stream temperature. On the NFBR, it is possible that suction dredging may 

intersect cooler subsurface flows in the process of deepening pools or creating new pools, 

(Harvey and Lisle 1998), thereby creating temporary, seasonal refugia for fish. Given the small 

size of Cub Creek, the pools created by suction dredging may not intercept groundwater and 

would therefore not influence stream temperatures. 

Turbidity

The potential for an increase in turbidity during the summer when fish are already stressed by 

elevated stream temperatures was evaluated and found to be low on the NFBR for three reasons. 

First, most of the streams channels evaluated have been historically placer mined during which 

time much of the silt/clays were flushed downstream. Therefore, any large quantities of silt/clay 

in these historically mined streams are now limited to the margins of the channels where banks 

are eroding, or behind beaver dams in most creeks where suction dredging is proposed. The 

existing ODEQ 700-PM permit prohibits disturbing beaver dams or log jams or working in 

stream banks. These restrictions, if adhered to, eliminate the concern that suction dredging 

would destabilize these features and cause increased turbidity downstream of the operation. 

Second, the summer wetted widths in the NFBR varies from 7 to more than 25 feet, based on 

measurements taken in 2006 and 2007. In contrast, the inside diameter suction hose is less than 

six inches, which limits the amount of channel bed that can be mobilized at any one time. 

Therefore, the plume would be very limited in width at any one time. The remaining streams 

where suction dredging is proposed are separated from perennial streams 

Finally, the operations are spatially separated from each other (Figure 1) which eliminates the 

potential for overlapping plumes. Therefore, the turbidity plumes from these operations are 

expected to be well within the requirements of the existing 700-PM permit and much less than 

300 feet in length andwidth. This would leave ample areas of undisturbed water for the fish to 

hold, feed, and migrate in.

Cub Creek is the exception to the above discussion. Cub Creek does not appear to have been 

historically mined. Channel widths are narrow (less than ten feet wide) and the banks are fine 

grained and heavily trampled, resulting in an increase in silts in the channel bed. In addition, 

flows are low during the summer. Therefore, the turbidity plume may persist for a longer 

distance in Cub Creek and there may be a small plume of cloudy water in the NFBR just 

downstream of its confluence with the NFBR. It is uncertain if there are fish in Cub Creek, but if 

they are present, suction dredging could have an impact on fish as the turbidity plume may span 

the entire channel width and length.
NFBR Mining Supplemental EIS Appendix 7A

21

Suspended Sediment

Cobbles dominate the NFBR channel bed with silts, sands and gravels in the spaces in between. 

Dredging in streambeds in which sand is the dominant interstitial fine sediment is unlikely to 

yield suspended concentrations. Sand and gravel are usually deposited immediately downstream 

(Harvey and Lisle 1998). Thomas (1985) found that suspended sediment returned to ambient 

levels at 30.5 meters downstream of the dredge (measured during worst-case scenario). The bulk 

of the sediment stirred up by dredging was re-deposited within 6-11 meters. In contrast, Somer 

and Hassler (1992) found that suspended sediment in their stream did not return to background 

levels 113 meters downstream from the dredge. However, the authors note that the sediment in 

their stream was displaced farther downstream than results in Thomas (1985) because of the 

steeper gradient and the high proportion of fines released in the overburden. 

Based on the amount of historic placer mining that occurred in the NFBR, sands and gravels are 

expected to be the dominant interstitial fine sediment. Any change in suspended sediment 

concentrations would therefore be local and immeasurable, except immediately below the 

dredge. In the case of Cub Creek, movement of suspended sediment as a result of suction 

dredging may persist because 1) there is a much greater amount of fines in the channel bed, 2) 

bank trampling and the removal of riparian woody vegetation by livestock results in the banks 

are actively contributing fines to the creek, and 3) the pools created by the dredge could trigger a 

headcut. All of these increase suspended sediment and bedload inputs. However, a suction 

dredging-generated headcut and bank undercutting would be in violation of the existing 700 PM 

permit (Schedule C.5) and dredging would be stopped until resource issues were addressed. 

Summary of Potential Direct/Indirect Effects to Fisheries

The potential direct and indirect effects to fisheries, as a result of suction dredging in the sections 

of streams where the Plans of Operation indicated activity, are summarized in Table 3. Only 

minor changes are expected on the NFBR and none of these changes are detrimental to fisheries. 

The dredging of pools may provide a short-term benefit to fish or fish habitat by intersecting 

cooler groundwater and thereby creating summer refugia. The gravel tailings may also provide a 

benefit because they would be remolded by the spring high flow and may provide additional 

spawning sites in the spring. In addition, dredging may locally break up the armored channel 

bed and permit the stream to create additional scour pools. 

Unlike the NFBR, Cub Creek is more sensitive to channel changes as a result of suction dredging 

because of its channel bed and bank characteristics and the low flows, and there is the potential 

for an impact to fisheries. However, impacts to fisheries triggered by suction dredging would be 

in violation of the existing State 700-PM permit (Schedule C.3., C.5, C.7) and dredging would 

be stopped until resource issues were addressed. 
Appendix 7A NFBR Mining Supplemental 

EIS

22

Table A7A-3

Sites identified in Plans of Operation where suction dredging is proposed and summary of potential impacts to Fisheries.

(Shades boxes indicate areas of concern to fisheries)

Operation Creek Flow/Fish 

Status

Spawning Gravels Pools Habitat 

Complexity 

(i.e. log jams, 

instream 

wood, beaver 

dams)

Stream 

Temperature

Turbidity Suspended 

Sediment

Burnt Lode/ 

Placer 

Cub 

Creek

Perennial in 

this section. 

Unknown if 

fish-bearing.

Local increase in 

spawning gravels. 

The low flows may 

result in spawning 

gravels (tailings) 

persisting for several 

seasons. However, 

continued inputs of 

bank sediments due 

to trampling have 

the potential to bury 

these spawning 

gravels and any 

eggs.

Local 

increase in 

pool 

habitat. 

The pools 

could 

persist for a 

number of 

seasons due 

to low 

flows.

No impact to 

channel 

complexity 

because the 

creek has very 

little 

complexity at 

present.

Pools could become 

knickpoints leading 

to headcuts, channel 

incision, a lowering 

of the water table and 

the temperatures 

increasing and/or the 

flow changing from 

perennial to 

intermittent.

Potential for 

increased 

turbidity 

because of high 

percentage of 

fines in channel 

bed and along 

the channel 

margins and the 

limited flow.

Potential for 

increase 

because of 

high 

percentage of 

fines in 

channel bed 

and along the 

channel 

margins.

Burnt Lode/ 

Placer 

(Karissa)

NFBR Perennial/

Fish-bearing

Local, 1 season 

increase in spawning 

gravels

Local, 1-2 

season 

increase in 

pool habitat

Minimal 

reduction

No change Local, and 

minor increase 

during 

operation 

Local, and 

minor increase 

during 

operation 

Dream 

Chaser 

Placer

NFBR Perennial/

Fish-bearing

Local, 1 season 

increase in spawning 

gravels

Local, 1-2 

season 

increase in 

pool habitat

Minimal 

reduction

No change Local, and 

minor increase 

during 

operation 

Local, and 

minor increase 

during 

operation 

Gimlet 

Placer

Gimlet 

Creek

Intermittent/ 

Non-fish 

bearing

N/A N/A N/A N/A N/A N/A

Glory B 

Placer

Jackknife 

Creek

Intermittent/ 

Non-fish 

bearing

N/A N/A N/A N/A N/A N/A

Gold 

Busters 

Pinus 

Creek

Intermittent/ 

Non-fish 

N/A N/A N/A N/A N/A N/A
NFBR Mining Supplemental EIS Appendix 7A

23

Operation Creek Flow/Fish 

Status

Spawning Gravels Pools Habitat 

Complexity 

(i.e. log jams, 

instream 

wood, beaver 

dams)

Stream 

Temperature

Turbidity Suspended 

Sediment

Placer bearing

Jim Bob 

Placer

NFBR Perennial/

Fish-bearing

Local, 1 season 

increase in spawning 

gravels

Local, 1-2 

season 

increase in 

pool habitat

Minimal 

reduction

No change Local, and 

minor increase 

during 

operation 

Local, and 

minor increase 

during 

operation 

Midas/Lady 

Bug Placer

California 

Gulch

Intermittent/ 

Non-fish 

bearing

N/A N/A N/A N/A N/A N/A

North Fork 

Placer

NFBR Perennial/

Fish-bearing

Local, 1 season 

increase in spawning 

gravels

Local, 1-2 

season 

increase in 

pool habitat

Minimal 

reduction

No change Local, and 

minor increase 

during 

operation 

Local, and 

minor increase 

during 

operation 

Prudent (#9) 

Placer

NFBR Perennial/

Fish-bearing

Local, 1 season 

increase in spawning 

gravels

Local, 1-2 

season 

increase in 

pool habitat

Minimal 

reduction

No change Local, and 

minor increase 

during 

operation 

Local, and 

minor increase 

during 

operation 

R&RK #2 

#3 Placer

NFBR Perennial/

Fish-bearing

Local, 1 season 

increase in spawning 

gravels

Local, 1-2 

season 

increase in 

pool habitat

Minimal 

reduction

No change Local, and 

minor increase 

during 

operation 

Local, and 

minor increase 

during 

operation 

R&RK #4 

#5 Placer

NFBR Perennial/

Fish-bearing

Local, 1 season 

increase in spawning 

gravels

Local, 1-2 

season 

increase in 

pool habitat

Minimal 

reduction

No change Local, and 

minor increase 

during 

operation 

Local, and 

minor increase 

during 

operation 

Shamrock 

Placer

NFBR Perennial/

Fish-bearing

Local, 1 season 

increase in spawning 

gravels

Local, 1-2 

season 

increase in 

pool habitat

Minimal 

reduction

No change Local, and 

minor increase 

during 

operation 

Local, and 

minor increase 

during 

operation 

Sluice Box NFBR Perennial/

Fish-bearing

Local, 1 season 

increase in spawning 

gravels

Local, 1-2 

season 

increase in 

pool habitat

Minimal 

reduction

No change Local, and 

minor increase 

during 

operation 

Local, and 

minor increase 

during 

operation 

Wildflower 

Placer

NFBR Perennial/

Fish-bearing

Local, 1 season 

increase in spawning 

Local, 1-2 

season 

Minimal 

reduction

No change Local, and 

minor increase 

Local, and 

minor increase 
Appendix 7A NFBR Mining Supplemental 

EIS

24

Operation Creek Flow/Fish 

Status

Spawning Gravels Pools Habitat 

Complexity 

(i.e. log jams, 

instream 

wood, beaver 

dams)

Stream 

Temperature

Turbidity Suspended 

Sediment

gravels increase in 

pool habitat

during 

operation 

during 

operation 
NFBR Mining Supplemental EIS Appendix 7A

25

Cumulative Effects

There is the potential for short-term improved pool and spawning habitat in the NFBR. 

However, the overall cumulative effect of suction dredging on fisheries habitat conditions and 

fisheries in NFBR is limited to one to two seasons. Turbidity increases would not be channel 

spanning and would be non-measurable within a few 100 feet at most downstream of the dredge. 

There is the potential for short-term improved pool and spawning habitat in Cub Creek. There is 

also the potential for spawning gravels to be buried by sediment inputs from trampled and 

eroding stream banks. Turbidity on this creek would likely be channel spanning because it is 

narrow and flows low. 

Determination of Effect to Redband Trout

Based on the above fisheries analysis, suction dredging may impact individuals or habitat but 

will not likely contribute to a trend towards federal listing or loss of viability to the population or 

species for two reasons. First,on the NFBR, suction dredging may improve pool habitat and 

increase spawning gravels. Second, on Cub Creek there is the possibility for an increase in 

spawning gravels that may result in increased spawning if fish are present. There are, however, 

concerns about increased turbidity, increased suspended sediment, buried spawning gravels, and 

the potential for headcutting and channel incision. The concern about having newly generated 

spawning gravels buried is the result of the continued input of fine grained bank sediment into 

the channel due to bank trampling and removal of riparian woody vegetation by livestock which 

both directly and indirectly contributed on bank failures.