REPORT ON STREAM 

ICE PROCESSES 

Physical and Biological Effects 

and Relationship to Hydroelectric Projects 

Federal Energy Regulatory Commission 

Office of Hydropower Licensing 

Washington, D.C. 

Paper No. DPR-5 

July 1992 
This report was prepared by staff of the Office of Hydropower Licensing, Division of 

Project Review, and does not necessarily reflect the views of other members of the Federal 

Energy Regulatory Commission. 
Report on Stream Ice Processes 

The subject of this report is stream ice formation and its effects on the physical and biological 

environment of high mountain streams. The Federal Energy Regulatory Commission (FERC) 

is interested in this subject because of the potential effects of hydroelectric projects on stream 

ice conditions and the indirect effects on stream biota and ecology. 

The purpose of this report is to provide a summary of information from the available literature 

on stream ice formation and its effects, and to document relationships that exist between stream 

icing and hydropower project operation that might cause biological impacts, such as fish 

mortality. Because this potential for biological impact due to stream icing and hydropower 

project operation exists, some preliminary guidance for evaluating the potential for projectrelated impact is provided in Section 2. 

The report focuses on impacts on small high-gradient streams in the western United States, 

particularly California, Idaho, and Montana. Although the focus is on impacts in the western 

states, experience with ice processes and ecological effects in other areas of the country is 

considered, primarily to expand the limited information base. 

Electronic databases were searched to find literature relevant to stream ice and its effects. 

Besides literature available in standard journal references and resource agency reports and study 

notes, individual scientists and managers experienced with the subject were contacted for their 

personal knowledge and observations. One video tape on stream icing was also reviewed. 

As an aid to FERC and hydroelectric project applicants and owners, a list of questions was 

developed (Section 2) that could be posed and answered to gain insights into whether proposed 

or existing projects might negatively impact ice-related resources. Following these questions is 

discussion on how studies might be conducted and analyzed to further understanding of how a 

proposed hydroelectric project might affect ice processes and their impacts. 

. r /(~ )( ___ ./ 

...,..(.-{ '"!··· ~-~--<.. L(-!Yy 

Dean L. Shumway / 

. 

/f~s.::;~~ Fred E. Springer 

Director, Division of Project Review Director, Office of Hydropower Licensing 

Report on Stream Ice Processes Page i 

Acknowledgements 

The Office of Hydropower Licensing, Federal Energy Regulatory Commission would like 

to thank the many individuals of the firm of EBASCO Environmental Inc. for their dedicated 

research that brought this publication to fruition. We especially thank Mike Prewitt, the Task 

Manager, and Dennis Hanzlick, Tom Cannon, John Knutzen, Scott Urwick, and Leslie Smythe, 

who provided technical input and review. 

Special thanks are extended to the following individuals who played important roles in 

the review and preparation of this document. 

George D. Aston, U.S. Army Corps of Engineers 

John M. Bartholow, U.S. Fish & Wildlife Service 

John S. Blair, Federal Energy Regulatory Commission 

Ken D. Bovee, U.S. Fish & Wildlife Service 

Thomas R. Payne, Thomas R. Payne & Associates 

John D. Ramer, Federal Energy Regulatory Commission 

Michael J. Sale, Oak Ridge National Laboratory 

Dean L. Shumway, Federal Energy Regulatory Commission 

Clair B. Stalnaker, U.S. Fish & Wildlife Service 

Report on Stream Ice Processes Page iii 

CONTENTS 

Director's Introduction 

Acknowledgement 

Section 1. Ice and its Effects on the Physical and Biological 

Environment in Mountain Streams 

1.1 Ice Types and Description on Formation 

1.1.1 Frazil Ice 

1.1.2 Anchor Ice 

1.1.3 Surface Ice 

1.1.4 Snow or Slush Ice 

1.1.5 Aufeis 

1.2 Physical Effects of Ice in Streams 

1.2.1 Physical Effects of Frazil Ice 

1.2.2 Physical Effects of Anchor Ice 

1.2.3 Physical Effects of Surface Ice 

1.2.4 Physical Effects of Snow or Slu~h Ice 

1.3 Biological Effects of Ice in Streams 

1.3.1 Summary of Effects 

1.3.2 Ice and Fish Mortality 

1.3.3 Ice and Aquatic Insects 

1.3.4 Ice and Fish Eggs 

1.3.5 Ice and Fish Habitat 

1.3.6 Snow Cover and Fish Mortality 

1.4 Effects of Hydropower Projects on Stream Ice and 

Subsequent Effect on Aquatic Biota 

1.4.1 Physical Effects on Streams and Stream Icing 

1.4.2 Effects on Aquatic Biota 

Section 2.0 Licensing Considerations 

2.1 Screening Criteria Questions 

2.2 Additional Studies 

2.2.1 Physical 

2.2.2 Biological 

2.2.3 Computer Modeling 

Literature Cited 

Appendix Annotated Bibliography 

Report on Stream Ice Processes 

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CONTENTS CONTINUED 

FIGURES 

Figure 2-1 

Figure 2-2 

TABLES 

Table 2-1 

Page vi 

Screening Criteria Questions 

Additional Data & Studies 

Velocity Conditions Under Which Different Stream Ices May Form 

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Report on Stream Ice Processes 
Report on Stream Ice Processes 

Section 1. Ice and its Effects 

on the Physical and Biological 

Environment in Mountain 

Streams 

This section focuses on the physical 

processes and biological effects of ice in 

small-to-medium sized, high-gradient 

mountain streams. Included are ( 1) a 

description of the types of ice found in 

streams, (2) details of their formation and 

the physical effects of ice, (3) a discussion 

of biological effects of ice, and ( 4) a 

discussion of the potential effects of 

hydropower projects on stream icing and 

subsequent impacts on physical and 

biological regimes. 

1.1 Ice Types and Description of 

Formation 

Commonly recognized types of stream ice 

include frazil ice, anchor ice, surface ice, 

and snow or slush ice. These are 

distinguishable by their characteristics and 

origins, and it is common to find all four 

types present in some combination along any 

mountain stream. Formation processes of 

these ice types are strongly interrelated and 

dependent upon each other. 

1.1.1 Frazil Ice 

Frazil ice can occur in flowing streams in 

winter when stream water temperature falls 

below 0°C. Frazil ice crystals are typically 

0.1 to 1 mm in diameter and may be either 

discoid or needle-shaped (Ashton, 1986). 

Frazil disc concentrations may be up to one 

Repon on Stream Ice Processes 

million discs per cubic meter of water 

(Osterkamp and Gosink, 1982). In high 

concentration, frazil ice may look like an 

underwater snowstorm. 

The process of frazil ice formation and 

production is complex and depends upon 

stream characteristics and environmental 

conditions. An essential condition for 

formation is that the air temperature is 

approximately -10°C or colder, and water is 

supercooled. Supercooling occurs when an 

open water surface that has already been 

cooled to ooc undergoes further heat loss by 

exposure to subfreezing air temperatures. 

Supercooling in streams has been measured 

to be about 0.01 to 0.1 oc below the 

freezing point (Ashton, 1983). If the flow 

velocity is slow, the ice may form a thin 

surface sheet that evolves into a surface 

cover. Above a velocity of approximately 

0.6 meters per second (m/s), the formation 

of a surface ice layer is prevented, and ice 

forms as frazil ice crystals within the water 

body rather than on top (Osterkamp, 1978; 

Ashton, 1988). Ice production continues as 

long as there is continued heat transfer out 

of the water. The production rate depends 

upon the rate of this heat transfer from the 

water to the air. Higher water velocities 

tend to keep frazil ice entrained. As 

velocity decreases, frazil ice will float 

upward and contribute to a surface cover of 

floating ice (Ashton, 1980). Production 

ceases in areas covered by a surface ice 

layer because of the insulating effect of the 

ice cover, but supercooled water may be 

carried beneath a surface ice layer and frazil 

production continued as the heat deficit of 

Page 1 
supercooling is converted to ice (Ashton, 

1991). 

Frazil ice contributes to the further 

accumulation of ice in streams in two ways: 

(1) by growth of individual frazil ice 

crystals and (2) by physical clumping 

together of frazil ice crystals. The most 

important characteristic of frazil ice crystals 

is their tendency to stick readily to anything 

they come in contact with as long as the 

water is supercooled. Frazil ice readily 

adheres to upstream faces of underwater 

structures such as rocks, boulders, 

submerged roots or branches, chains, or 

lines. Once a frazil ice crystal attaches to 

an underwater object, its growth rate, which 

is related positively to the speed of water 

past the crystal, accelerates (Osterkamp, 

1978). In addition, other frazil ice crystals 

stick to the attached ice, leading to an 

accumulation of ice on underwater objects. 

At water velocities less than 0.9 m/s, frazil 

ice crystals tend to clump together and float 

upward. Such agglomerations may be 

carried downstream where they may collect 

in pools to freeze as surface ice. Where 

surface ice already exists, frazil ice may 

accumulate on the upstream edge of an ice 

sheet or the underside of surface ice. 

1.1.2 Anchor Ice 

The accumulation of frazil ice on 

underwater structures is known as anchor 

ice. On stream bottoms, it appears as 

smooth, white pillows. Anchor ice is 

typically a spongy, flocculent mass of ice 

crystals that is more porous than ice that 

forms on the surface. With time, patches of 

anchor ice may grow horizontally and join 

to form a continuous carpet of ice on a 

stream bottom. Maximum anchor ice 

thickness was about 30 centimeters and 

Page 2 

average thickness was about 8 centimeters in 

a Michigan trout stream (Benson, 1955). 

Anchor ice formation is usually highest 

during cold, clear nights, when heat loss 

from the water is greatest. In streams, 

anchor ice occurs most commonly on gravel 

and boulders in riffle areas where flow is 

most turbulent (Benson, 1955). Anchor ice 

seldom forms on substrates of fine sand, 

silt, or clay because (1) the anchor ice can 

lift free before attaining any significant size, 

or (2) streambed heat flow to the water may 

be effectively greater in these areas than 

gravel or rocky areas (Ashton, 1986). 

Wigle (1970) reported temperatures of 0.4 

to 0.5°C at a depth of 10 to 20 centimeters 

below the bottom of the Niagara River, 

while temperatures of the water were 

supercooled, indicating the potential for 

surface heat transfer to water. Anchor ice 

may form on stream beds when turbulence 

is strong enough to transport supercooled 

water to the bottom, where ice crystals may 

attach to the bottom and further grow 

(Ashton, 1986). Anchor ice generally does 

not form when a surface ice cover is present 

(Brown et al., 1953). 

Anchor ice may grow when passing frazil 

crystals are trapped by the rough anchor ice 

surface (Osterkamp and Gosink, 1982) or 

when dislodged anchor ice masses moving 

along the bottom from upstream attach to 

the top of anchor ice patches. 

Daily cycles with anchor ice formation at 

night and breakup during the day 

characterize anchor ice in streams. During 

the day anchor ice tends to break up and 

detach because of higher air temperatures 

and solar radiation (Brown et al., 1953; 

Giltilian et al., 1972; Ashton, 1986). 

Repon on Stream Ice Processes 
Accumulation of anchor k-! on the bottoms 

of streams often leads to formation of ice 

dams, an occurrence often mentioned in the 

literature (e.g., Gilfilian et al., 1972; Brown 

et al., 1953; Benson, 1955; Butler and 

Hawthorne, 1979; Flynn, 1984; Maciolek 

and Needham, 1952). This results in an 

increased stage upstream and decreased 

discharge downstream. Anchor ice growth 

patterns in streams may also form ice 

structures networked by small, 

interconnected water channels and caverns. 

Large buildups of anchor ice may be 

released abruptly after becoming detached 

from the bottom. Floating anchor ice often 

carries bits of substrate material, including 

sand, organic matter, and rocks. 

1.1.3 Surface Ice 

Ice covering the stream surface is termed 

surface ice. It forms on quiescent water in 

a thin, supercooled layer at the surface of 

the water cooled to the freezing point by 

heat loss to the atmosphere. The rate at 

which the thickness of surface ice increases 

is inversely proportional to ice thickness and 

directly proportional to air temperature less 

than ooc. The thicker the ice, the greater 

the resistance to heat loss by water. The 

colder the air temperature, the greater the 

heat loss from water to atmosphere. 

Surface ice formation in small streams is 

more complicated than on strictly quiescent 

water. Surface ice usually occurs in lowvelocity regions such as pool areas or low 

gradient meadow sections of streams. This 

surface ice may be a combination of ice 

formed in place, frazil ice that has 

accumulated at the surface, and anchor ice 

that has lifted and entered a low-velocity 

region of a stream. This combination 

freezes and consolidates into an ice sheet as 

Repon on Stream Ice Processes 

heat continues to be lost. Ice that has 

formed upstream and carried by the flow 

may be swept under the surface ice sheet 

and continue downstream or be captured by 

the rough underside and added to the 

thickness of the ice sheet. Accumulations of 

ice underneath an ice sheet form structures 

known as hanging dams (Osterkamp and 

Gosink, 1982). Ice may also accumulate at 

the upstream edge of an ice sheet and 

contribute to upstream ice cover. Ice dams 

and edges may further slow currents and 

thus contribute to additional surface ice 

formation. 

One of the major influences on the 

formation of surface ice is water velocity. 

Below about 0.2 m/s, surface ice can bridge 

a stream and form an intact ice sheet 

(Ashton, 1988). Between about 0.2 and 0.6 

m/s, ice forms as thin pieces of surface ice. 

Above about 0.6 mls, the ice produced is 

frazil ice, and if the velocity is less than 0.9 

m/s, the frazil ice tends to collect on the 

surface as a layered slush run. Surface ice 

will thus not be found in riffle areas, but in 

slow run areas and pool areas. 

Another source of partial surface ice cover 

is growth from the sides of streams. Ice 

forms in the low-velocity boundaries at the 

edges of streams and may extend to the 

bottom. As the low-velocity boundary 

progresses toward the center of the stream, 

partial ice cover develops. Ice growth 

toward the center of the stream may cease if 

the ice edge encounters high velocities. 

The presence of snow affects ice 

development in streams. When it snows, a 

snow cover may accumulate on surface ice, 

or snow banks adjacent to a stream may 

collapse onto the ice cover. As a result, the 

Page 3 
surface cover may break, be depressed, or 

become thicker with the addition of snow. 

1.1.4 Snow or Slush Ice 

Snow or slush ice is a slushy mixture of 

snow and streamwater. Its origin is snow 

that has fallen into a stream during snowfall 

or as a result of collapsing snow banks 

along a stream. Snow ice behaves much as 

frazil ice on the surface of a stream and may 

contribute to surface ice cover. It is also 

thought that snow may serve as seed crystals 

for the formation of frazil ice in streams 

(Osterkamp, 1978). 

1.1.5 Aufeis 

Aufeis is ice that has formed outside the 

main stream channel from water which has 

overflowed onto existing ice and 

subsequently frozen. This generally occurs 

when a stream has frozen to the bottom, and 

continuing flow from upstream overflows 

and freezes. 

1.2 Physical Effects of Ice in Streams 

1.2.1 Physical Effects of Frazil Ice 

The effects of frazil ice are manifest 

primarily in its contributions to anchor ice 

and surface ice. However, some direct 

effects of frazil ice have been observed. 

Frazil ice that is dispersed throughout the 

water has been observed to increase the flow 

resistance of a stream, reducing maximum 

flow velocity from about 0.5 m/s to 0.4 

mls, and initially increasing the stage by 2 

to 3 centimeters in a 2-meter deep stream 

reach (Osterkamp et al., 1975). 

Gilfilian et al. (1972) reported that growth 

of frazil ice particles resulted in rejection of 

Page 4 

impurities to the water phase, increasing the 

electrical conductivity of the stream water. 

1.2.2 Physical Effects of Anchor Ice 

Anchor ice directly disturbs the bottom of 

streams by dislodging and lifting substrate 

materials such as sand, gravel, insects, and 

organic matter when melting dislodges 

anchor ice. Freezing may penetrate 15 to 

20 centimeters into the substrate, 

consolidating the substrate into an ice/rock 

mass and freezing anything contained in it, 

including fish eggs and fish (Reiser and 

Wesche, 1975; Walsh and Calkins, 1986). 

However, this would only occur to such 

depths due to complete freezing over the 

depth of anchor ice deposits and subsequent 

freezing penetration of the substrate. Direct 

connection via a solid mass to the cold air 

above is required for such deep-freezing 

penetrations (Ashton, 1991). Benson (1955) 

sampled floating ice and found sand, organic 

debris, insects, and one dead trout fry. 

Brown et al. (1953) observed bottom 

organisms floating with anchor ice slush 

mats, but concluded that bottom organism 

abundance was not affected by anchor ice. 

Anchor ice affects the stream by 

redistributing substrate materials, disturbing 

the bottom where the anchor ice is broken 

loose, and dispersing materials into the 

water column (Osterkamp and Gosink, 

1982; Gilfilian et al., 1972). 

The formation of anchor ice dams also 

affects streams. Anchor ice dams may form 

over the course of one night. The 

immediate effect is an abrupt increase in the 

stage of a stream and reduction in discharge, 

due to instream storage. Needham and 

Jones (1959) observed increases in pool 

levels above riffles in Sagehen Creek, 

California of as much as 52 centimeters, 

Report on Stream Ice Processes 
averaging 40 centimeters for 20 episodes 

when anchor ice formed. Gilfilian et aA 

(1972) observed an increase in water level 

from 3 meters to 3. 3 meters in Goldstream 

Creek, Alaska. The corresponding decrease 

in discharge was from 1.3 to 0.6 m3

/s. 

The breakup of anchor ice on sunny days, 

and the subsequent collapse of anchor ice 

dams, leads to surges of water as normal 

stream flow is re-established. Previously 

flooded side channels are rapidly dewatered, 

and the streambed may be scoured by the 

surge of water and entrained ice chunks 

(Maciolek and Needham, 1952; Reimers, 

1957, Butler and Hawthorne, 1979; Walsh 

and Calkins, 1986). 

1.2.3 Physical Effects of Surface Ice 

Surface ice inhibits local formation of frazil 

and anchor ice so that the stream bottom is 

not affected by in situ anchor ice. Surface 

ice also increases flow resistance resulting in 

reduced discharge associated with the 

increased stage. Tsang and Szucs (1972) 

reported a reduction of 25 percent in 

discharge of the Nottawasaga River in 

southwestern Ontario, Canada over 

approximately 3 weeks when surface ice 

cover formed. The corresponding velocity 

decrease was from 37 cm/s to 20 cm/s. The 

river study area was 80 feet wide. With 

locally reduced discharge and flow velocity, 

stage increases upstream because flow 

continues from upstream. The deposition of 

frazil ice beneath surface ice leads to the 

formation of hanging dams, which also 

impedes stream flow and increases the stage 

(Ashton 1986). 

Report on Stream Ice Processes 

1.2.4 Physical Effects of Snow or Slush 

Ice 

Snow or slush ice in streams is physically 

similar to the presence of heavy 

concentrations of frazil ice. Therefore the 

effects are similar to those exerted by frazil 

ice, namely the increase in resistance to 

flow, leading to reduction in flow-velocity 

and increase in stage. 

The collapse of snow banks into a stream, 

which is one of the origins of snow ice, may 

have dramatic effects on the stream, even if 

the presence of snow ice generally appears 

to have minor effects. Nielson et al. (1956) 

reported several instances of snow bank 

collapse into Convict Creek in California. 

Collapses led to abrupt blockages of the 

stream and caused rapid increases in stage 

and flooding of the side channels. Blockage 

dissipated rapidly, leading to dewatering of 

the side channels, and .encouraging water 

and ice surges in the stream. Needham et 

al. (1945) reported similar events and 

subsequent physical effects in earlier studies 

at Convict Creek. 

1.3 Biological Effects oflce in Streams 

Detailing the biological effects of ice in 

streams is complicated because the 

occurrence of ice is accompanied by other 

environmental changes, including cold water 

temperatures, snow, potentially reduced food 

supply, and reduced stream flow relative to 

the warm season. Most published studies 

describe topics, such as migration, habitat 

selection, food abundance, feeding behavior, 

and food assimilation, that relate to fish 

behavior and survival during winter 

conditions. In this section, the focus will be 

on biological observations related to fish and 

PageS 
stream biota that have been directly 

attributed to the presence of ice. 

1.3.1 Summary of Effects 

A variety of real and hypothesized effects 

occur to stream aquatic organisms from ice 

formation. Documented effects of anchor 

ice formation include fish and invertebrate 

stranding, fish egg displacement, and 

invertebrate displacement. Other effects that 

are thought to be caused by anchor ice 

formation include direct fish mortality, 

insect mortality, fish stress leading to poor 

condition, gravel displacement, and in situ 

egg mortality. Surface ice formation has 

been found to kill benthic insects at the 

point where the ice contacts the stream 

bottom. 

1.3.2 Ice and Fish Mortality 

Butler and Hawthorne (1979) observed daily 

cycles of formation and deterioration of 

anchor ice in Sagehen Creek, California, 

which caused flooding and subsequent 

dewatering of side channels. They reported 

that fish and other aquatic organisms that 

had entered flooded side channels were 

trapped as the disappearance of anchor ice 

allowed water to drain from the overflow 

areas. Direct fish mortality was not 

observed, but the report implied that the 

result was death of fish and aquatic insects. 

The authors stated that "heavy mortality 

may occur in the fish population as well as 

in the feed represented by aquatic insects" 

when conditions cause daily cycles of 

flooding and dewatering. Dead fish were 

shown being recovered in scenes from a film 

made by the authors documenting the 

occurrence and effects of anchor ice. 

Page 6 

Maciolek and Needham (1952) conducted 

studies on the effects of winter conditions on 

trout and trout food in Convict Creek, 

California. They reported only one event 

where after three days of low temperatures, 

63 trout were found stranded and dead on 

rocks in a flood-control bypass. Daily 

freezing and incomplete thawing of 

subsurface ice had progressively reduced 

water flow in the bypass. When water 

ceased to flow into the bypass due to ice 

blockage, fish were stranded as water in the 

bypass drained into the porous substrate. 

While this event was associated with 

artificial structures in the stream, the authors 

reported that other dead trout were observed 

several days later in similar situations, some 

in natural side channels as far as 1.5 miles 

upstream of the experiment station. 

Tack (1938) reported about 100 of several 

thousand small rainbow trout in a hatchery 

pond in Germany died as a result of 

suffocation because of ice crystals in their 

mouths and gills. Larger fish in an adjacent 

pond suffered no corresponding mortality. 

The event was caused by frazil ice produced 

when very cold temperatures accompanied 

high winds causing water turbulence and 

preventing a stable surface ice layer from 

forming. 

Calkins (1989) reported that salmonid 

species hide in the substrate during winter. 

This would make them vulnerable to 

accumulations of anchor ice over areas in 

which the fish are "hibernating" (Stalnaker, 

1992). 

1.3.3 Ice and Aquatic Insects 

Stream ice may contribute to aquatic insect 

mortality. Logan (1963) observed dead 

insects frozen in ice at the edges of Bridger 

Report on Stream Ice Processes 
Creek, Montana. Surface ice that began 

forming at the stream edges froze all the 

way to the bottom, entrapping and killing a 

small number of insects (9 were observed). 

Brown et al. (1953) also reported insect 

mortality when surface ice froze next to the 

shore. Logan concluded that surface ice 

cover, other than the small losses described 

above, had no significant effect on the 

abundance of bottom organisms. 

Anchor ice indirectly causes dislodging of 

benthic organisms and dispersion in the 

water column. Maciolek and Needham 

(1952) observed that insects were dislodged 

and carried downstream when the collapse 

of anchor ice obstructions led to short-term 

events of increased flow of water and 

entrained ice that scoured the bottom. They 

noted that dislodged insects were generally 

alive and that the greatest numbers 

corresponded with high-flow events. 

Benson (1955) found that insects collected in 

anchor ice, both frozen to the bottom and 

drifting in the flow were alive. The 

population densities of insects were 

approximately the same, an average of 10 

organisms per square foot of ice, whether 

the anchor ice was collected from the 

bottom or was drifting. Two implications 

are that anchor ice released from the bottom 

directly transports insects into the water 

column and that insects survive being frozen 

in an anchor ice substrate. 

Butler and Hawthorne (1979) surmised that 

insect mortality would accompany fish 

mortality due to stranding in side channels 

after collapse of anchor ice dams led to 

dewatering of side channels in Sagehen 

Creek. They did not actually report finding 

dead insects. 

Report on Stream Ice Processes 

Reimers (1957) contended that snow 

bridging and/or surface ice cover affected 

bottom organisms and trout food abundance. 

His studies indicated that bottom organism 

abundance was 21.4 1bs/acre in mid-April 

1952 in Convict Creek, California following 

a winter with harsher conditions than 

normal. The five-year average of 225 Mayto-September samples was 109 lbs/acre of 

bottom organisms. An average of 12 

bottom samples taken in late April 1952 a 

week after the steam had begun to clear 

yielded a value of 32.4 lb/acre of bottom 

organisms, a slight improvement on the 

value of 21.4 lb/acre obtained 12 days 

earlier. Reimers contended that extended 

periods of ice cover produced extended 

periods of reduced light, which in tum led 

to reduction in bottom organism abundance. 

1.3.4 Ice and Fish E~:~:s 

Fish eggs ~e deposited in the gravels of 

stream beds and may be susceptible to ice 

influences. Maciolek and Needham (1952) 

observed that two fish stomachs each 

contained two trout eggs. The authors 

speculated that the "action of ice in 

disturbing spawning gravels may have freed 

these eggs in the current," but suggested that 

the general scarcity of fish eggs in fish 

stomachs indicated only slight disturbance of 

spawning beds. Reiser and Wesche (1975) 

conducted experiments in the Laramie 

River, Wyoming. Boxes of 100 brown trout 

eggs were placed 15 to 18 em deep in riffle 

areas with water depth of 6 to 36 em. Upon 

removal in March, only 1 percent of the 

eggs were found to have survived. Three of 

20 boxes were completely frozen, even 

though buried 15 em in the substrate beneath 

12 to 20 em of flowing water. Reiser and 

Wesche concluded that extremely low water 

temperature and in situ freezing of redds 

Page 7 
were the two main factors contributing to 

egg mortality. Thus, eggs of all spawning 

salmonids may be jeopardized by ice in 

streams. 

1.3.5 Ice and Fish Habitat 

Direct effects of stream ice on fish were 

presented in Section 1.3.1. Ice in streams 

may affect fish survival indirectly by 

altering fish habitat. That is, if the result of 

ice presence in a stream is forcing fish into 

harsher environmental conditions than would 

be encountered in the absence of ice, then 

one potential consequence is relatively 

higher fish mortality. No studies were 

found that quantified or even isolated effects 

of habitat alteration by ice. However, it is 

possible that such effects .do exist. 

Bovee et al. (1978) presented figures 

showing surface ice cover profiles at three 

transects across the Tongue River in 

southeast Montana. In none of the figures 

was ice shown contacting the bottom. It is 

estimated (based on the figures) that surface 

ice excluded approximately 50 percent of the 

stream habitat. The authors hypothesized 

that presence of the ice cover would alter 

the flow velocity characteristics of the river, 

either creating, destroying, or simply redistributing specific velocity habitat. There 

was no mention of direct effects on fish. 

Johnson et al. (1982) found that surface ice 

contiguous with the shore excluded up to 60 

percent of the cross-sectional area of 

Wagonhound Creek in Wyoming. Flow 

velocity and mean depth were subsequently 

affected. It follows that if brown trout were 

present and preferred areas of slow, deep 

water, then they would be forced to move or 

remain and endure less preferable habitat 

conditions. 

Page 8 

Chisholm et al. (1987) similarly found that 

extensive surface ice excluded between 40 

and 70 percent of the habitat in a stream in 

the Snowy Range in Wyoming. Tracking 

studies conducted by Chisholm et al. (1987) 

showed that brook trout generally selected 

low velocity conditions (less than 15 cm/s), 

deeper water (30 to 107 em deep), but not 

substrate type. Presumably, these fish 

would migrate if habitat exclusion by 

surface ice (or by anchor ice) altered 

velocity and depth distributions in the 

stream. 

Using underwater time-lapse photography, 

Butler and Hawthorne (1979) observed that 

fish habitat was obliterated by anchor ice, 

and fish appeared to lose orientation and 

swim aimlessly through caverns of anchor 

ice. 

1.3.6 Snow Cover and Fish Mortality 

Another source of winter fish mortality is 

the collapse of snow cover into streams. 

Such events are not caused by ice in 

streams, but may still be an important 

consideration in connection with overwinter 

fish survival. Needham et al. (1945) 

reported several hundred dead fish beneath 

a snow mass that had collapsed into the 

stream below a hatchery. Similarly, Nielson 

et al. (1956) attributed severe trout mortality 

(80 to 90 percent) in Convict Creek, 

California during winter to the periodic 

collapse of snow and ice overburden into the 

stream. Fish were said to have been killed 

in any of three ways: (1) crushed or 

suffocated directly beneath the collapsed 

mass; (2) suffocated throughout the length of 

stream dewatered downstream of a collapse; 

or (3) left stranded under the snow when the 

ponded area upstream of the snow barrier 

receded. 

Repon on Stream Ice Processes 
It is apparent from the literature that 

observations of direct effects of ice on fish 

are few. The published studies indicate that 

ice can kill fish directly and destroy fish 

habitat, but do not support hypotheses that 

ice represents a significant fish population 

limiting factor. 

1.4 Effects of Hydropower Projects on 

Stream Ice and Subsequent Effect 

on Aquatic Biota 

This section discusses the potential effects of 

hydropower projects on physical stream 

processes and stream biota. No known 

studies have directly assessed physical and 

biological conditions in mountain streams 

before and after hydropower projects were 

constructed. In the absence of specific 

studies, it is only possible to discuss 

potential, rather than observed, effects of 

hydropower projects on ice and its effects. 

The method used in the following discussion 

relies upon combining knowledge gained 

from studies and observations with 

information concerning the general nature of 

hydropower projects and the ways in which 

they are known to affect factors which relate 

to ice formation. 

1.4.1 Physical Effects on Streams and 

Stream Icine 

Ice characteristics are largely dependent on 

whether a hydropower project has a storage 

reservoir, or simply diverts water from a 

bypassed reach. In a project with a storage 

reservoir, water velocity in the reservoir is 

reduced relative to the stream, and water 

depth is increased. In reservoirs, the 

surface area to volume ratio is decreased, 

resulting in a reduced rate of heat loss. 

Because of this reduced rate of heat loss in 

a reservoir relative to the stream, heat will 

Repon on Stream Ice Processes 

be retained. Wintertime reservoir water 

temperatures and their discharges are thus 

typically higher than those in uncontrolled 

streams. Since the average residence time 

of water in a run of river (R-0-R) project 

pool is less than that for a project which 

stores water for later release, the change in 

water temperature between inflow and 

outflow will be less for an R-0-R project. 

Because of the quiescent nature of a 

reservoir, surface ice will likely form in 

cold, mountain settings. The surface ice 

serves as an insulating blanket for reservoir 

heat loss, especially if covered by snow. 

The exception is when a reservoir impounds 

a relatively warm spring, and pooling 

increases transit time and exposure to cold 

air, thus increasing heat loss to the 

atmosphere. 

Stream discharge is affected through storage 

and release of water. High mountain stream 

flow normally decreases through the winter 

as precipitation is tied up as snow and ice. 

A store and release hydropower project with 

sufficient storage will always change the 

downstream discharge pattern, with seasonal 

shifts varying by the load characteristic, and 

yearly hydrology of the area. This is in 

contrast to a R-0-R project where operation 

does not alter stream discharge except in the 

bypassed reach, where present. Discharge 

changes may cause ice buildup in dewatered 

margins of the stream because of alternating 

cycles of increased and decreased discharge 

that cause stream stage to fluctuate. Ice 

may also form outside the main stream 

channel from overflow of water onto 

existing ice and subsequent freezing. This 

ice is called aufeis. No documentation of 

aufeis formation due to hydropower plant 

operation in small streams was found, 

although Gilfilian et a/. (1972) reported 

Page 9 
stream ice and aufeis accumulation of about 

2 meters due to anchor-ice-caused stage 

fluctuations in Goldstream Creek, Alaska. 

In the case of hydropower projects with 

little or no storage, temperature is rarely 

affected when the diversion channel is open 

to the atmosphere. Heat may be retained to 

some degree if the diversion is a closed 

conduit, and, if it is underground, heat may 

be added to the water by conduction from 

the soil through the pipe walls. 

Flow in the bypassed reach is reduced by 

the amount of water diverted through the 

diversion channel, and this reduced flow 

leads to reduced stage and velocity. If the 

bypassed reach has relatively vertical sides, 

little or no side-channel dewatering will 

occur. Because exposed stream surface area 

changes little in this scenario, heat flux will 

change little. However, the reduction in 

velocity that accompanies reduced discharge 

will likely lower the potential for frazil ice 

formation. If the reduction of velocity is to 

a value that is less than 0.6 m/s 

approximately, frazil ice production may 

cease entirely and surface ice may form. 

If the bypassed reach is shallow with gently 

sloping bottom lateral! y, or if the channel is 

braided, then reduction in stage will cause 

dewatering of some of the streambed, 

exposing it to freezing air temperatures. In 

extreme cases of stage reduction, the depth 

of water remaining may be small enough 

that the stream may freeze to the bottom, 

and additional flow would spread on top of 

the ice and laterally, adding to the volume 

of the frozen stream. Gill and Kershaw 

(1979) observed this type of ice buildup at 

riffle points along the upper Tsichu River in 

northwest Canada. 

Page JO 

If the hydropower project has a spillway 

exposed to the atmosphere, the increase in 

surface area and resultant increases in heat 

loss may cause the production of frazil ice. 

1.4.2 Effects on Aquatic Biota 

No documented studies of the effects of 

hydropower projects on aquatic biota in 

small, high-gradient mountain streams were 

found. Predicting biological effects 

becomes a matter of posing physical 

contingencies and determining the probable 

biological consequences. Since there is no 

source of specific studies of stream biology 

before and after hydropower project 

installation, predictions involve inference 

from published biological observations in 

mountain streams under winter icing 

conditions combined with potential physical 

effects of hydropower projects on ice 

conditions. Therefore, the following 

discussion draws upon observational 

biological information from Section 1.3 and 

projection of effects of hydropower projects 

on stream ice regimes. 

In the case of a hydropower project with 

storage, effects on stream biota both in the 

reservoir and downstream can be beneficial 

at least in terms of water temperature and 

ice. In a reservoir in which water 

temperatures are increased relative to free 

stream flow, fish are not subjected to as low 

temperatures as in the free-flowing stream. 

In addition, water temperatures are more 

stable, and water velocities are lower than in 

free-flowing streams, which are desirable 

fish winter habitat features. Below the 

reservoir, the effects of increased 

temperature usually extend some distance 

downstream of the project, locally 

maintaining a greater amount of habitat by 

inhibiting ice formation and encroachment. 

Report on Stream Ice Processes 
The overall effects are increases in the 

amount and desirability of fish habitat, and 

possibly increased survival rates. 

When a hydropower project has a long 

buried pipe diversion, a relative temperature 

increase may occur in the stream below the 

powerhouse from the acquired ground 

heating or lack of heat loss to the 

atmosphere that can occur in the stream. 

This temperature increase would reduce the 

formation of ice in the reach below the 

powerhouse increasing available habitat. 

When the reservoir temperature is colder 

than free-flowing streams, such as when 

spring flows dominate the inflowing stream, 

there is the beneficial effect of quiescent 

water, stable temperatures, and surface ice 

formation in the reservoir. However, the 

colder reservoir water may increase local ice 

accumulation where it rejoins the stream 

channel and produce habitat loss comparable 

or worse than free-flowing conditions. 

Since flow fluctuations from daily freezing 

and thawing of anchor ice have been 

observed to affect fish mortality in natural 

settings (Section 1.3), fluctuations in flow 

caused by hydropower project operation 

could affect fish as well. If the facility is 

operated so that extensive areas of solid ice 

form in and adjacent to the stream channel, 

fish mortality could be high. For example, 

peaking to meet variation in power demand 

can cause side channel areas to either dry up 

or freeze solid as flow levels drop causing 

mortality for fish residing in these areas. 

These low velocity areas may be used for 

overwintering fish, particularly for youngof-the-year fish. Gradually increasing flow 

during the winter can cause ice to form on 

top of ice. Extensive icing outside the main 

stream channel can damage riparian habitat 

adjacent to the stream (e.g., ice damage to 

Repon on Stream Ice Processes 

bushes and trees), which may not directly 

affect fish, but might affect terrestrial 

animals that use that habitat either in cold or 

warm seasons. 

Reduced water velocity and turbulence could 

result in less frazil ice production and, thus, 

less anchor ice accumulation on the bottom 

of the bypassed or downstream reach. Less 

anchor ice generally means reduced 

disruption of bottom substrate and less 

extreme fluctuations in stage, discharge, and 

velocity. Thus, flow reductions could result 

in winter habitat improvement for fish, their 

eggs, and insects that use the substrate for 

cover. Fish would be less likely to be 

stranded by rapid dewatering of side 

channels filled and drained by anchor ice 

dam formation and collapse. Reduction in 

flow surges caused by anchor ice dam 

collapse would also mean reduced scouring 

of the bottom substrate, which could wash 

out eggs, flsh, and insects. 

Hydropower projects would not be expected 

to have any additional effect on ice if the 

bypassed reach was narrow enough that the 

snow bridged and covered a significant 

portion of the stream. Snow bridging has 

been reported over streams 3 meters to 5 

meters wide (Nielson et al., 1956; Needham 

and Jones, 1959). In this case, snow cover 

would insulate the stream and prevent or 

slow down the cooling of water eliminating 

local formation of frazil and anchor ice. 

However, if stage in the bypassed reach 

fluctuated so that the snow cover collapsed, 

fish would be trapped and either suffocated 

or crushed (Needham et al., 1945; Nielson 

et al., 1956). Eggs and organisms in the 

substrate would not be directly affected by 

the collapse, but would likely be endangered 

by high speed scour that occurs when the 

Page 11 
water backed up by the collapse is suddenly 

released as the snow dam fails. 

Predicting the effects of hydropower projects 

on aquatic biota will ultimately require 

combining observations of the physical and 

biological effects of stream ice in natural 

settings with projections of how the facility 

will modify stream conditions. Some 

suggestions for determining the potential 

physical and biological effects of 

hydropower projects related to stream icing 

and recommendations for potential studies 

follow in Section 2. 

Section 2. 

Considerations 

Licensing 

This section provides guidance for 

evaluating potential site-specific impacts of 

proposed hydroelectric projects on stream 

ice formation and aquatic organisms in 

small, high-gradient mountain streams. The 

information and guidance is provided to 

assist both applicants and PERC staff in 

evaluating the potential for project-related 

ice problems and in addressing those 

problems during the pre-filing period. 

The section is presented in two sections. 

The first section presents a set of 

recommended questions to determine 

whether or not stream ice formation is a 

potential problem for a specific proposed 

project. The second section details 

additional studies which might be useful to 

evaluate the potential impact, if any, of a 

proposed hydropower project on stream ice 

formation and aquatic organisms. 

As before, this section is focused on small, 

high-gradient mountain streams in the 

western United States. Different 

Page 12 

considerations would apply for larger 

streams or those at lower elevations or in 

other parts of the country. Physical and 

biological processes related to ice in those 

areas would be quite different from those in 

the regions described in this report. 

2.1 Screening Criteria Questions 

These questions are meant to identify 

whether ice might be problematic at a 

particular hydropower project. These 

questions can be answered with a minimum 

of on-site observational data and are 

proposed as initial screening criteria. It is 

recommended that the screening be applied 

during Stage I consultation to determine 

whether further studies might be necessary 

in Stage II. Questions are arranged in a 

dichotomous key with responses to each 

question level resulting in direction to a 

subsequent question (Figure 2-1). 

QUESTION NO. 1 

Is there currently a population of important 

fish in the stream reach in which flow will 

be reduced or augmented by project 

operations? 

If NO, it can be concluded that project 

operation will not have negative biological 

effects even if stream icing conditions are 

made worse by the project. 

If YES or UNKNOWN, continue to 

Question No. 2. 

QUESTION NO. 2 

Does the location of the proposed project lie 

above 6, 000 ft elevation in the Rocky 

Mountains or the Sierra Mountains, or 

Report on Stream Ice Processes 
Are Salmonid 

Fish Present in NO ~ the Stream? 

YES OP. 'f.;NKNOWN 

"0 

Is the Elevation Higher / 

than 6,000 ft (Sierras 

and Rockies), or 

4,000 ft (Cascades)? 

YES 

Does the Project 

Operate During 

the Winter? 

YES 

Does the Project 

Have a Diversion 

Reach? 

YES 

NO -[> 

\.. 

/ ""' 

' 

Collect Additional Data 

and Conduct Additional 

Studies (Figure 2-2) 

No Need to """"'~ 

Consider Stream 

Icing Impacts ..... 

Stream Icing ""' 

Will Not Be a 

Problem 

Stream Icing 

Will Usually Not 

Be a Problem 

_.... 

Does the Project 

Have a Storage 

Reservoir? 

YES 

/ "" 

\... 

No Alteration of 

Ice Regime is 

Expected 

Figure 2-1 

Report on Stream Ice Processes 

Screening Criteria Questions 

Page 13 
above 4,000 ft elevation in the Cascade 

Mountains? 

If NO, stream icing is not a potential 

consideration at this location. 

If YES, continue to Question No. 3. 

QUESTION NO. 3 

Will the project operate during the winter 

months when stream icing may be expected 

to occur? 

If NO, operation will not affect stream 

icing, except in rare or unforseen situations. 

If YES, continue to Question No. 4. 

QUESTION NO. 4 

Will the project diven water from a reach of 

stream that provides overwintering habitat 

for imponant fish? 

If NO, project design and operation still 

require consideration. Continue to Question 

No.5. 

If YES, there is a potential that the project 

might impact fish through alteration of the 

present stream icing patterns. Additional 

information is required to evaluate that 

possibility and to quantify the effects. 

Insights may be gained from additional 

studies. 

QUESTION NO. 5 

Does the project create storage in the form 

of a reservoir? 

Page 14 

If NO, it can be concluded that, since there 

is no diversion and no storage, stream ice 

formation will not be significantly affected. 

If YES, then there is the possibility that the 

project will modify the existing stream ice 

regime. Ice process changes may result 

either from reservoir effects on water 

temperature or from operations that create 

stream flow fluctuations. Additional 

information may be required to evaluate and 

quantify the possible effects. 

2.2 Additional Studies 

If answers to the foregoing questions 

indicate that studies might be required, this 

section provides guidance on such studies. 

It is important to note that extensive data 

collection efforts strictly to evaluate ice 

formation, unlike temperature simulations, 

may not provide answers at the level of 

confidence necessary for hydraulic 

evaluations or habitat. Figure 2-2 presents 

a schematic summary of recommended 

additional data and studies. 

2.2.1 Physical 

The primary objective of physical data 

collection is to obtain information which 

pertains to elements related to ice formation. 

Channel geometry data such as longitudinal 

distance, width, depth, average gradient, 

and substrate type all relate to ice formation, 

but provide little predictive value. 

Predictive capabilities may be obtained by 

conducting measurements at a series of 

transects across the stream channel, similar 

to those obtained for hydraulic simulation 

modeling. Such data are very often 

collected for conducting the U.S. Fish and 

Wildlife Service lnstream Flow Incremental 

Methodology (IFIM) analyses. The IFIM is 

Repon on Stream Ice Processes 
Collect 

Stream 

Data 

- Bevetion 

- Streem Morphology 

- Gredient 

-Flow Rete 

- Weter Tempereture 

- Groundweter 

Inflow 

- Present Ice 

Accumuletion 

I 

Search for 

~.-. Previous 

Observations 

ADDITIONAL DATA 

COLLECTION AND STUDIES 

I 

Collect 

Meteorological 

Data 

- Air Tempereture 

-Winds 

-Cloud Cover 

-Snow 

Accumuletion 

Collect 

Biological 

Data 

- Mejor Species 

- Stending Rsh 

Populetion 

- A veileble Hebitet 

- Hebitet Usege 

Petterns 

'\.. Project-ySecific 

~ Data ... Set 

--.. 

1 

Plant 

Design I 

Operation 

- Amount of Diversion 

- Length of Diversion 

Chennel 

- Type of Diversion 

Chennel 

- Weter Tempereture 

Modificetions 

- Spillwey Use 

- Flow Fluctuetions 

Modeling 

Studies 

- Modificetion of Flow Rete, 

Stege, end Hebitet 

- Modificetion of Streem 

~ 7 Tempereture 

-Reservoir Temperetures 

end Surfece Ice 

Information Formetion 

Synthesis 

r '··· .··. '"' ·'·:,'Evah,Jation of'·· .. '., - · Potenti<W ,·.· ,.·,,·•· - ------~ ... ~,,., l,hp~cts 11<..._::.------ ~'·'''., ,,.~ 

Figure 2-2 Additional Data & Studies 

Report on Stream Ice Processes Page 15 
a simulation model-based assessment 

technique which combines predicted depth, 

velocity, and substrate conditions with fish 

preferences, to evaluate preferred fish 

habitat for flows associated with various 

project operations. The IFIM is routinely 

used on evaluations of proposed hydropower 

projects in the western states. It would be 

wise to evaluate any IFIM study plans in 

terms of both fishery and ice predictions in 

the many cases where IFIM is required. 

The IFIM analysis requires both pre- and 

with-project monthly discharge patterns, 

which will be valuable in ice simulations or 

evaluations. 

In addition to IFIM hydraulic and habitat 

data bases, stream temperature data would 

be required for those winter periods when 

freezing might occur. As before, stream 

temperature data alone does not provide 

predictive capabilities, and a temperature 

simulation model or technique would 

probably be required to predict stream 

temperatures expected under project 

operations. Such models require, in 

addition to hydraulic data as needed for 

IFIM applications, water temperature 

measurements and meteorological data. 

These data should include daily air 

temperature time series with as short a 

sampling interval as possible. An effort 

should be made to correlate on-site 

temperature measurements with data from 

the nearest available permanent recording 

station, such as an airport. Local wind data 

should be collected because winds increase 

heat loss rates from water and blow snow 

into streams. Statistics regarding incidence 

and persistence of cloud cover should also 

be determined from existing local weather 

records. Data should include typical snow 

depths and seasonal patterns of snow 

accumulation in the project area. Site visits 

Page 16 

and documentation of field observations of 

ice conditions would be useful. Another 

useful statistic is the number of clear, sunny 

days during seasonal stream ice formation. 

Anchor ice forms at night, but often 

detaches from the substrate in response to 

sunshine the following day. 

Groundwater inflows, if any, within and 

upstream of the affected reach should be 

identified. These data would most 

conveniently be gathered in conjunction with 

stream morphology surveys. Methods 

include physical observation of inflow or 

examination of temperature patterns along 

the stream channel. 

Observations of existing winter ice and snow 

conditions on the stream are important for 

establishing baseline data. Such 

observations can be obtained by on-site 

observers or possibly by aircraft 

photographic overflights. These 

observations should be planned when ice 

formation is most likely to occur; however, 

direct observations may be expensive and 

hazardous to obtain, so these factors should 

be considered before proceeding with direct 

observations. 

Ultimately, physical data would be used 

with hydraulic simulation techniques to 

determine at which discharges frazil and 

anchor ice might form, given the generally 

known water velocities which favor their 

development. The data from Ashton (1988) 

and repeated in Table 2-1 may be used as a 

general guide to how project-related velocity 

would relate to various ice processes given 

suitably cold climate conditions. In this 

way, model results would aid in 

characterizing the stream areas which meet 

certain ice formation standards or criteria. 

Use of computer simulations is discussed in 

Report on Stream Ice Processes 
TABLE 2-1 

Velocity Conditions Under Which 

Different Stream Ices May Fono !/ 

< 0.2 

0.2- 0.6 

> 0.6 

0.6-0.9 

> 0.9 

Ice That May Fonn 

Intact Sheet Ice 

Thin Pieces of Sheet Ice 

Frazil 

Layered Frazil and Slush 

Well Mixed Frazil 

!1 Given suitably cold climate conditions. 

more detail in section 2.2.3. Detailed data 

and simulation models, however, should be 

used only to gain insights into the general 

directions of project-related ice changes. 

Predictive precision regarding ice formation 

and its subsequent effect is not at the level 

expected for hydraulic or stream temperature 

simulations. 

2.2.2 Biolo~:ical 

Information about the fish populations is 

generally required of all applicants. At a 

minimum, species composition should be 

determined and fish populations estimated 

(see Figure 2-2). If possible, studies should 

be conducted to determine current 

overwinter fish mortality in the affected 

stream reach and approximately .25 mile 

upstream and downstream. 

Biological surveys should determine the 

amount and types of habitat available to fish 

in summer and winter. In conjunction with 

any winter surveys, estimates of the amount 

of habitat excluded by ice should also be 

estimated. Additionally, the presence or 

absence of coarse substrate and evidence of 

fish overwintering in the substrate would be 

useful information. 

Repon on Stream Ice Processes 

2.2.3 Computer Modelin& 

As discussed previously, some insights may 

be gained into ice formation by use of 

computer simulations of stream hydraulics 

and temperatures. Frazil, surface, and 

anchor ice formation are products of three 

primary physical factors: 

(1) Water temperature- obviously, ice 

cannot form if water temperature is 

above 0°C, so it is critical to know 

if and when that temperature is 

reached. 

(2) Water velocity and turbulence -

Frazil ice exists in or below areas of 

turbulence, surface ice forms in 

lower water velocity (less than 0.2 

m/s), and anchor ice forms in higher 

velocity water. 

(3) Meteorology - As discussed, cloud 

cover, windspeed, snow cover, and 

air temperature are related 

formations of the various ice types. 

Also, long- and short-wave radiation 

is a significant determinant of both 

stream water temperature and ice 

formation. 

Ideally, a hydroelectric project applicant, 

given the potential for ice formation at the 

proposed project site, would want to 

determine whether the project operation 

would create or increase ice problems. 

Simulation modeling data could provide 

some insight into this question in the 

following fashion. 

Three basic data or information sets would 

be developed. These would be: 

(1) Hydraulic data to predict stream 

velocity (for use in determining 

flow travel time), wetted width (for 

Page 17 
(2) 

detennining insolated area), and 

depth - These factors are used either 

directly to evaluate the ice formation 

potential or indirectly as inputs to the 

water temperature model described 

below. 

Water temperature modeling - In 

most instances, a water temperature 

model would be required to 

determine temperatures below a 

diversion or return point or below a 

storage reservoir release. In the 

former cases, the model would be 

used to determine changes in 

temperature resulting from 

dewatering the bypassed reach. 

Normally, during winter, such 

discharge decreases would not result 

in changes in either when, seasonally 

or where the ooc would be reached. 

Use of a model in such situations 

would only be required if discharge 

reduction was large (greater than 70 

percent relative to pre-project flows) 

and/ or if the bypassed reach was 

exceptional! y long (greater than 1 

mile). In the latter case, temperature 

modeling relative to storage releases 

would be required, particularly if the 

storage reservoir were large enough 

to cause temperature stratification. 

Even with small reservoirs, however, 

enough thermal energy may be 

stored to cause significant changes 

from pre-project conditions. 

Temperature models normally 

require hydraulic data (wetted width, 

travel time, depth) across the range 

of discharges to be simulated. They 

also require meteorologic data 

including cloud cover, shade factor, 

long- and short-wave radiation, air 

Page 18 

temperature, and day-length relative 

to canyon locations, if any. Stream 

temperature models are typically 

steady-state, that is, they predict 

temperature within stream reaches at 

time steps no shorter than the travel 

time of water through the stream 

reach. Temperatures can be 

predicted for steady conditions of all 

input factors except temperature and 

discharge, which would vary 

according to the need to simulate 

existing temperatures and discharges 

or those related to alternative project 

configurations or operations. 

(3) Climatic or weather-related 

infonnation - Some of the data in 

this area are the same as those 

collected for water temperature 

modeling, specifically, cloud cover, 

and air temperature. In addition, 

information on snow depth and 

frequency is required. These data 

are used to determine the frequency 

of periods when there are extremely 

cold temperatures (less than -15 °C) 

with low snow accumulations and 

clear nights. Collectively, these 

situations would cause anchor icing 

if stream velocity were sufficient. 

Generally, such simulation modeling results 

would be used to determine such conditions 

as the following: 

(1) When with-project discharges 

would be low enough to cause 

complete freezing - Here, stream 

depth of less than 0.5 feet with low 

velocities (less than 0.1 fps), 

extremely cold air temperatures, and 

little snow cover could freeze the 

stream solid. However, such flows 

Report on Stream Ice Processes 
(2) 

(3) 

would probably not be permitted 

initially because of their low fish 

habitat. Complete freezing of the 

entire stream is apparently a very 

rare occurrence in streams which 

naturally sustain fish populations. 

When surface ice might form -

Surface ice forms when frazil ice is 

generated from very cold air 

temperatures (<-l5°C) but water 

velocity is low (simple channel 

geometry and less than 0.2 m/s 

water velocity). 

When anchor ice might form -

Here, project velocities would have 

to exceed 0.6 m/s and would be of 

concern only if velocities were 

significantly less in the existing 

condition. Also, in association with 

augmented winter flows, there would 

need to be clear nights and extremely 

cold air temperatures. 

For non-storage hydro projects with 

diversions, the most reasonable outcome 

related to ice would be complete freezing or 

increased surface ice formation resulting 

from reduced depth and/or velocity. From 

a quantitative modeling perspective, these is 

no way to accountably predict whether a 

stream will or will not freeze completely or 

create surface ice due to the discharge 

changes associated with a hydroelectric 

project. Using hydraulic models in 

association with some climatic information, 

it is possible to generally evaluate whether 

the dewatering will be so extreme as to 

cause concern. 

If the proposed project had storage, it would 

be necessary to model both the internal 

reservoir temperature regime and the 

Report on Stream Ice Processes 

resulting regime in the downstream affected 

reaches. If warmer water than pre-project 

were to be released, the stream temperature 

model could be used to determine the point 

downstream at which freezing might begin. 

The model would also be useful in 

simulating the stream temperature relative to 

the monthly discharges associated with the 

proposed operating alternatives. In all 

cases, one could determine the downstream 

point of potential freezing (0°C water 

temperature) and the water velocities 

associated with monthly discharges. Surface 

or anchor icing conditions could be 

generally predicted, again using the water 

velocity and temperature information derived 

from the hydraulic and temperature 

simulation models. 

To summarize stream ice modeling 

approaches, effects of a hydroelectric project 

on stream icing regimes can only be 

predicted thmugh a combination of stream 

temperature simulations, hydraulic 

modeling, and climatic information. 

Obviously, if the temperature simulations 

indicate that project releases would be 

warmer than 0 o C, all modeling can be 

ceased and a "no-effect" conclusion reached. 

Therefore, temperature simulation modeling 

should be used as the primary tool for 

screening. If temperature simulation 

modeling predicts that stream temperatures 

will reach ooc in a bypassed stream reach, 

in a diversion channel, or below a storage 

reservoir, then hydraulic modeling in 

combination with climate data should be 

used to predict whether stream velocities 

and temperatures will be suitable for ice 

formation and what type of ice would form. 

In all cases, as stated earlier, ice processes 

and conditions are not as predictable and 

quantifiable as stream temperatures, depths, 

Page 19 
and velocities. Hydroelectric project 

applicants may gain insights into the 

directions of ice changes, but only through 

careful project operation and monitoring will 

the exact effects of ice be known. 

Generally, however, studies and case 

histories indicate that the usual project 

operations licensed in small, high-gradient 

western streams, would not create physical 

change great enough to warrant concern for 

ice problems other than the initial concerns 

for fish habitat preservation. 

Page 20 Report on Stream Ice Processes 
Literature Cited 

Ashton, G.D. 1991. Letter dated November 5 to J. Blair (FERC). 

Ashton, G.D. 1988. Falls river anchor ice study. Letter report. April 7, 1988. 

Ashton, G.D. 1986. River and lake ice engineering. Water Resources Publications. Printed 

by Book Crafters, Inc., Chelsea, Michigan. 485 pp. 

Ashton, G.D. 1983. Frazil ice. In: Theory of Dispersed Multiphase Flow. Academic Press. 

pp. 271-289. 

Ashton, G.D. 1980. Freshwater Ice Growth, Motion, and Decay. In: Dynamics of Snow and 

Ice Masses. Academic Press. 

Benson, N.G. 1955. Observations on anchor ice in a Michigan trout stream. Ecology. 

36:529-530. 

Bovee, K., J. Gore, and Dr. A. Silverman. 1978. Field testing and adaptation of a 

methodology to measure "in-stream" values in the Tongue river, northern great plains 

(NGP) region. Montana University, Missoula, Montana. 

Brown, C.J.D., W.O. Clothier, and W. Alvord. 1953. Observations on ice conditions and 

bottom organisms in the West Gallatin River, Montana. In: Proceedings of the Montana 

Academy of Sciences. 13:21-27. 

Butler, R.L. and V.M. Hawthorne. 1979. Anchor ice, its formation and effects on aquatic life. 

Science in Agriculture. 26(2). 

Calkins, D.J. 1989. Winter habitats of Atlantic salmon, brook trout, brown trout and rainbow 

trout. A literature review. Special Report 89-34. U.S. Army Corps of Engineers, Cold 

Regions Research and Engineering Laboratory. Hanover, New Hampshire. 

Chisholm, I.M., W.A. Hubert, and T.A. Wesche. 1987. Winter stream conditions and use of 

habitat by brook trout in high-elevation Wyoming streams. Transactions of the American 

Fisheries Society. 116: 176-184. 

Flynn, J.W. 1984. Authority, background and guidelines for department recommendations on 

winter flows for small hydro development. Montana Dept. of Fish, Wildlife and Parks. 

Repon on Stream Ice Processes Page 21 
Gilfilian, R.E., W.L. Kline, T.E. Osterkamp, and C.S. Benson. 1972. Ice formation in a 

small Alaskan stream. In: The role of snow and ice in hydrology. Proceedings of the 

Banff Symposium, September 1972. 1:505-513. 

Gill, D., and G.P. Kershaw. 1979. Ecological role of river icings in the Tsichu river valley, 

Northwest Territories, Canada. In: Snow and Ice Symposium on the Canberra 

Assembly, International Union of Geology and Geophysics, Canberra, Australia. 

Johnson, L.S., T.A. Wesche, D.L. Wichers, and J.A. Gore. 1982. Instream salmonid habitat 

exclusion by ice-cover. Project No. B-038-WYO. Water Resources Research Institute, 

University of Wyoming, Laramie, Wyoming. 

Logan, S.M. 1963. Winter observations on bottom organisms and trout in Bridger Creek, 

Montana. Transactions of American Fisheries Society. 92:140-145. 

Maciolek, J.A., and P.R. Needham. 1952. Ecological effect of winter conditions on trout and 

trout foods in Convict Creek, California. Transactions of the American Fisheries 

Society. 18:202-217. . 

Needham, P.R., J.W. Moffett, and D.W. Slater. 1945. Fluctuations in wild brown trout 

populations in Convict Creek, California. Journal of Wildlife Management. 9:9-25. 

Needham, P.R., and A.C. Jones. 1959. Flow, temperature, solar radiation, and ice in relation 

to activities of fishes in Sagehen Creek, California. Ecology. 40:465-474. 

Nielson, R.S., N. Reimers, and H.D. Kennedy. 1956. A six-year study of the survival and 

vitality of hatchery-reared rainbow trout of catchable size in Convict Creek, California. 

California Fish and Game. 42:5-6. 

Osterkamp, T.E. 1978. Frazil ice formation: A review. Journal of the Hydraulic Division, 

American Society of Civil Engineers. 104:1239-1255. 

Osterkamp, T.E., and J.P. Gosink. 1982. Ice cover development on interior Alaska streams. 

Geophysical Institute, University of Alaska, Fairbanks, Alaska. 

Osterkamp, T.E., R.E. Gilfilian, and C.S. Benson. 1975. Observations of stage, discharge, 

pH, and electrical conductivity' during periods of ice formation in a small subarctic 

stream. Water Resources Research. 2:268-272. 

Reimers, N. 1957. Some aspects of the relation between stream foods and trout survival. 

California Fish and Game. 43-69. 

Reiser, D.W., and T.A. Wesche. 1975. In situ freezing as a cause of mortality in brown trout 

eggs. The Progressive Fish-Culturist 41(2):58-60. 

Page 22 Repon on Stream Ice Processes 
Stalnaker, C. 1992. Letter dated January 29 to J. Blair (PERC). 

Tack, E. 1938. Trout mortality from the formation of suspended ice crystals. FishereiZeitung. 41:42 (Reviewed in Progressive Fish-Culturist 1937-38). 

Tsang, G., and L. Szucs. 1972. Field experiments of winter flow in natural rivers. The role 

of snow and ice in hydrology. Proceedings of the Banff Symposium, September 1972. 

1:772-785. 

Walsh, M., and D. Calkins. 1986. River ice and salmonids. 4th workshop on hydraulics of 

river ice, Montreal. U.S. Army Corps of Engineers, Cold Regions Research and 

Engineering Laboratory. 

Wigle, J.E. 1970. Investigations into frazil, bottom ice, and surface ice formation in the 

Niagara River. Proceedings of the International Association for Hydraulic Research Ice 

Symposium 1970. Reykjavik. 

Report on Stream Ice Processes Page 23 

Appendix - Annotated Bibliography 

Report on Stream lee Processes 

Annotated Bibliography 

Arden, R.S., and T.E. Wigle. 1972. Dynamics of ice formation in the upper Niagara 

River. The role of snow and ice in hydrology. Proceedings of the Banff Symposium, 

Alberta, Canada, September 1972, World Meteorological Organization; Geneva. 

LOCATION OF STUDY: 

ANCHOR ICE, 

FRAZIL ICE, 

ICE FORMATION 

Upper Niagara River between Lake Erie and Niagara Falls, New York. 

STREAM CHARACTERISTICS: 

0.8 to 3.0 m/s velocity; no others given. 

HYDROELECTRIC PRQJECT EFFECTS: 

Reduction of flow in the 24 kilometer-long bypass reach. 

PHYSICAL EFFECTS OF ICE: 

A stationary ice cover could not develop because of high velocities that prevent initiation of the bridging 

process, ice control procedures, and a boom that eliminates ice inflow from Lake Erie. Frazil ice forms 

rapidly in supercooled water near the surface under clear skies. Surface ice production increases as the 

water column cools, and the area of surface ice increases. Surface ice continuously moves with the river 

flow. Formation of anchor ice causes a sudden flow reduction of 20 to 30 percent during night hours. 

Flow slowly increases during daylight hours. The prime condition for anchor ice formation is a rocky 

or gravelly bottom. 

BIOLOGICAL EFFECTS OF ICE: 

None discussed. 

COMMENTS: 

None. 

Repon on Stream Ice Processes 
Annotated Bibliography 

Ashton, G.D. 1989. Effect of Toston dam on upstream ice conditions. Special Report 89-

16. U.S. Army Corps of Engineers, Cold Regions Research and Engineering Laboratory, 

Hanover, New Hampshire. 

WCATION OF STQDY: 

ICE MODELING, 

RIVER ICE 

Missouri River upstream of Toston Dam in Montana; elevation approximately 3,950 feet. 

STREAM CHARACTERISTICS: 

2,000 to 5,000 cfs. 

HYDROELECTRIC PROJECT EFFECTS: N/A 

PHYSICAL EFFECTS OF ICE: 

This report presents results of a modeling study to predict effects of ice after raising the height of Toston 

Dam. In general, ice will increase water levels upstream slightly higher than if ice were not present. 

The physical setting is not applicable to the present project concerning small, high-gradient streams. 

BIOWGICAL EFFECTS OF ICE: N/ A 

COMMENTS: 

None. 

Repon on Stream Ice Processes 
Annotated Bibliography 

Ashton, G.D. 1988. Falls river anchor ice study. Letter report to Mr. Grant Durtschi, 

Environmental Energy Company, Driggs, Idaho. April 7, 1988. 6 pp. 

WCATION OF STQDY: 

Falls River; Eastern Idaho, east of Marysville. 

STREAM CHARACTERISTICS: 

300-400 cfs in winter; 200 feet wide; 1.1 feet deep; slopes of 0.004 to 0.008. 

HYDROELECTRIC PRQJECT EFFECTS: 

Diversions of flow through power generation facilities will reduce flow to 160 cfs in the reach between 

diversion and return points. There is no anticipated effect on the hydroelectric project by ice. 

PHXSICAL EFFECTS OF ICE: 

It is unlikely that frazil ice or anchor ice formation rate will be signifieantly affected in the diverted reach 

as long as the open water area remains approximately constant. There is an increased tendency for 

formation of floating ice cover at reduced flow rates. 

BIOLQGICAL EFFECTS OF ICE: 

Not discussed. 

COMMENTS: 

This paper discusses characteristics of frazil and anchor ice and factors that influence their production. 

It informally assesses the effects of river diversion on frazil and anchor ice production in the diverted 

reach. 

Repon on Stream Ice Processes 
Annotated Bibliography 

Ashton, G.D. 1987. River ice problems, where are we? A review. International Union 

of Geodesy and Geophysics. Vancouver, British Columbia, Canada. August 12, 1987. 

WCATION OF STUDY: N/A 

STREAM CHARACTERISTICS: N/A 

HYDROELECTRIC PROJECT EFFECTS: N/ A 

PHYSICAL EFFECTS OF ICE: N/ A 

BIOWGICAL EFFECTS OF ICE: N/A 

COMMENTS: 

This paper summarizes major problems associated with river ice and discusses the state of knowledge of 

the various processes and phenomena that are involved with those problems. There is general discussion 

of ice formation, evolution, and deterioration and relation of ice to environmental and ecological systems, 

in-river structures, navigation, and hydropower. No specific study site is discussed. 

Repon on Stream Ice Processes 
Annotated Bibliography 

Ashton, G.D. 1986. River and lake ice engineering. Water Resources Publications. 

Littleton, Colorado. 504 pp. 

WCATION OF STQDY: N/A 

STREAM CHARACTERISTICS: N/A 

RIVER ICE, 

LAKE "ICE 

HYDROELECTRIC PROJECT EFFECTS: N/ A 

PHYSICAL EFFECTS OF ICE: N/A 

BIOWGICAL EFFECTS OF ICE: N/A 

COMMENTS: 

This is a general reference text for ice .on rivers and lakes. It presents technical discussions of ice types 

and processes. It is not site oriented. Presentations are often theoretical, and the text covers a wide 

variety of topics associated with ice in rivers and lakes. 

Report on Stream Ice Processes 
Annotated Bibliography 

Ashton, G.D. 1983. Frazil ice. In: Theory of Dispersed Multiphase Flow. Academic 

Press, New York. pp. 271-289. 

LOCATION OF STUDY: N/A 

STREAM CHARACTERISTICS: N/ A 

HYDROELECTRIC PROJECT EFFECTS: N/A 

PHYSICAL EFFECTS OF ICE: N/A 

BIQLOGICAL EFFECTS OF ICE: N/A 

COMMENTS: 

This is an informational paper that discusses physical characteristics of frazil ice and processes associated 

with its formation and transport in rivers and streams. No specific studies are included and it is not 

oriented toward evaluation of effects of frazil ice on streams. 

Repon on Stream Ice Processes 
Annotated Bibliography 

Ashton, G.D. 1980. Freshwater ice growth, motion, and decay. In: Dynamics of Snow 

and Ice Masses (S.C. Colbeck, Ed.), Academic Press, New York. pp. 261-304. 

WCATION OF STQDY: N/A 

STREAM CHARACTERISTICS: N/A 

RIVER ICE, 

LAKE ICE 

HYDROELECTRIC PROJECT EFFECTS: N/A 

PHYSICAL EFFECTS OF ICE: N/A 

BIOLOGICAL EFFECTS OF ICE: N/A 

COMMENTS: 

This paper gives a general review of freshwater ice growth, motion, and decay for river and lake ice. 

The emphasis is on river ice. It presents equations governing energy budgets for ice formation, growth, 

and decay. In addition, it discusses ice jams and physical break-up of ice cover. This paper does not 

discuss aspects of a particular river or stream. 

Repon on Stream Ice Processes 
Annotated Bibliography 

Ashton, G.D. 1979. River ice. American Scientist. 67:38-45. 

LOCATION OF STQDY: N/A 

STREAM CHARACTERISTICS: N/ A 

HYDROELECTRIC PROJECT EFFECTS: N/ A 

PHYSICAL EFFECTS OF ICE: N/A 

BIOLOGICAL EFFECTS OF ICE: N/A 

COMMENTS: 

This is a general reference paper on river ice. It does not concern a particular study or location. It 

describes physical processes of ice formation, growth, and deterioration on rivers. It does not include 

specific discussions of surface ice, anchor ice, or frazil ice. 

Repon on Stream Ice Processes 
Annotated Bibliography 

Barnes, H.T. 1928. Ice Engineering. Renouf Publishing Co., Montreal, Canada. April 

1928. 366 pp. 

ICE FORMATION 

WCATION OF STQDY: N/A 

STREAM CHARACTERISTICS: N/A 

HYDROELECTRIC PROJECT EFFECTS: N/A 

PHYSICAL EFFECTS OF ICE: N/A 

BIOWGICAL EFFECTS OF ICE: N/ A 

COMMENTS: 

This is one of the early references that discusses various aspects of ice formation in streams, river, and 

lakes. Much ofthe content has been either confirmed or superseded by more recent studies. It is included 

for completeness. 

Repon on Stream Ice Processes 
Annotated Bibliography 

Barton, D.R., and W.D. Taylor. 1985. Dimensions of riparian buffer strips required to 

maintain trout habitat in southern Ontario streams. North American journal of Fisheries 

Management. 5:364-378. 

WCATION OF STUDY: 

TROUT 

TEMPERATURE 

Thirty eight streams in southern Ontario, Canada. 

STREAM CHARACTERISTICS: 

All but one of the streams had typical weekly maximum temperatures less than 22°C. All the streams 

had stable flow regimes and low concentrations of fine suspended solids. 

HYDROELECTRIC PROJECT EFFECTS: N/A 

PHYSICAL EFFECTS OF ICE: N/A 

BIOWGICAL EFFECTS OF ICE: 

The paper describes the relationships between riparian land use, fish composition (mainly trout), and 

stream parameters such as: temperature, suspended solids, and discharge variability. Results indicated 

that temperature is indeed the most significant factor determining the presence or absence of resident trout 

in southern Ontario streams. Turbidity and discharge stability also contribute but to a lesser degree. It 

was concluded that these stream parameters can be controlled to a certain extent by establishing or 

maintaining forested riparian buffer strips along stream banks. 

COMMENTS: 

Repon on Stream Ice Processes 
Annotated Bibliography 

Benson, N.G. 1955. Observations of anchor ice in a Michigan trout stream. Ecology. 

36:529-530. 

WCATION OF STQDY: 

Pidgeon River, Otsego County, Michigan. 

STREAM CHARACTERISTICS: 

Average winter flow is 40 cfs; depth 6 to 24 inches; contains brown trout, rainbow trout. 

HYDROELECTRIC PROJECT E~CTS: N/A 

PHYSICAL EFFECTS OF ICE: 

Anchor ice formed during clear nights when air temperature fell below -15.6°C and was observed on 5 

days during the study interval. Anchor ice formed primarily in fast-flowing, turbulent stream bed 

sections. The mean thickness of anchor ice was about 2 inches, reaching a maximum of 7 inches. 

Usually, anchor ice lifted by 10 a.m. and floated downstream. Stream flow decreased gradually during 

anchor ice formation. When ice loosened, large amounts of stored water were released, abruptly 

increasing flow volume. These flow surges produced no observable stream bed scouring. Samples of 

lifted ice contained sand, gravel, organic debris, and organisms. 

BIOWGICAL EFFECTS OF ICE: 

All insects found in the drifting ice were alive. One egg sac trout fry was found dead. It was speculated 

that the fry could have been vulnerable during emergence if ice scour occurred, but that eggs would not 

be affected because of the short duration of the ice on the stream bottom, usually less than 12 hours. 

Surface ice prevented formation of anchor ice during much of the year. Observed flooding effects were 

much less than normal spring flows. Trout that were observed were not feeding and were in poor 

condition. Ice could apparently dislodge benthic insects, but the number was too small to depopulate the 

stream bottom. 

COMMENTS: 

No direct harmful effects of anchor ice on fish were observed. All insects that were drifting in the ice 

were alive, and the ice only carried small amounts of sand from the bottom. Number of insects lost from 

drift would be small. Only minor flooding was observed due to ice formation. 

Repon on Stream Ice Processes 
Annotated Bibliography 

Bjornn, T.C. 1971. Trout and salmon movements up two Idaho streams related to 

temperature, food, stream flows, cover and population density. Transactions of the 

American Fisheries Management. 5:364-378. 

WCATION OF STUDY: 

SALMONID 

MIGRATION 

FACTORS 

Lemhi River and Big Springs Cree, eastern Idaho. 

STREAM CHARACTERISTICS: 

The Lemhi River falls an average of 6. 7 m/km, is 90.3 km long, has a maximum water level fluctuation 

of 0.61 m, and discharges 3.4 to 4.0 m3/s. Big Springs Creek is 8 km long, has a maximum water level 

fluctuation of 0.85 m, and discharges 0.8-1.0 m3/s. Daily water temperature fluctuations ranged from 

none to more than 14 oc in the summer. During the summer, daily temperatures ranged from a minimum 

of 7-13°C to a maximum of 23.9°C. 

HYDROELECTRIC PROJECT EFFECTS: N/ A 

PHYSICAL EFFECTS OF ICE: 

Ice was present in the streams during the winter. Effects were not discussed. 

BIOLOGICAL EFFECTS OF ICE: 

The study concluded that age I chinook salmon and age II or III steelhead trout migrate seaward in the 

spring. Downstream migration also occurred during the fall, winter and spring by pre-smolt and non 

anadromous fish. 

COMMENTS: 

In this study, both field experiments and laboratory experiments were conducted and them compared in 

an effort to determine which factors cause or influence fish migratory movements. 

Report on Stream Ice Processes 
Annotated Bibliography 

Bjornn, T.D., andJ. Mallet. 1964. Movements of planted and wild trout in an Idaho river 

system. Transactions of the American Fisheries Society. 93:70-76. 

LOCATION OF STUDY: 

SLUSH ICE, 

ICE JAMS 

Upper Salmon River and Middle Fork of the Salmon River, Idaho. 

STREAM CHARACTERISTICS: 

Both streams are found in the mountains at elevations of up to 11,000 feet. These streams mostly flow 

through steepsided canyons and occasionally through narrow valleys. Mean discharge of the upper 

Salmon River is 1881 cfs and 1484 cfs for the Middle Fork of the Salmon River. 

HYDROELECTRIC PROmCT EFFECTS: N/A 

PHYSICAL EFFECTS OF ICE: 

Not discussed. 

BIOWGICAL EFFECTS OF ICE: 

Both cutthroat trout and Dolly Varden followed the same movement patterns, upstream in the spring and 

early summer, and downstream in the fall and winter. 

COMMENTS: 

During the winter it is not uncommon to find slush ice and ice jams extending for many miles along both 

streams. 

Report on Stream Ice Processes 
Annotated Bibliography 

Bovee, K., J. Gore, and Dr. A. Silverman. 1978. Field testing and adaptation of a 

methodology to measure "in-stream" values in the Tongue River, Northern Great Plains 

(NGP) region. Montana University, Missoula, Montana. 

LOCATION OF STQDY: 

Tongue River, southeast Montana. 

STREAM CHARACTERISTICS: 

RIVER ICE, 

ICE THICKNESS vs. 

FLOW 

Medium size river, average width 50 meters, average discharge 45 m3/s with a width to depth ratio of 

50 to 1, contains cool water fisheries. 

HYDROELECTRIC PRQJECT EFFECTS: N/A 

PHYSICAL EFFECTS OF ICE: 

The paper first presents a general background of ice types and their formation. In the discussion of 

observations, a regression relation between current velocity and ice thickness was given, and the relation 

was quoted as significant at the 1 percent level. During early stages of surface ice formation, thickness 

of the ice sheet was fairly uniform. As thickening continued, the rate was faster in low velocity areas 

than in high velocity areas. Frazil ice and anchor ice were not observed. 

BIOWGICAL EFFECTS OF ICE: 

The authors hypothesized that the formation of surface ice would have its greatest impact on organisms, 

particularly insects, living in shallow water areas that are susceptible to freezing all the way to the 

bottom. A change in velocity is characteristic in certain areas of the increased roughness of the ice, 

which may affect organisms that are tied to a specific velocity. Generally, velocity would decrease in 

the shallowest areas and increase in the thalweg areas as ice formation progressed, given that discharge 

would not change appreciably with freeze-up. Application of the regression relation developed by the 

authors indicated that the greater the flow, the smaller the amount of bottom that would be frozen. 

COMMENTS: 

None. 

Report on Stream Ice Processes 
Annotated Bibliography 

Brown, C.J .D., W .D. Clothier, and W. Alvord. 1953. Observations of ice conditions and 

bottom organisms in the West Gallatin river, Montana. Proceedings of the Montana 

Academy of Sciences. 13:21-27. 

WCATION OF STQDY: 

ANCHOR ICE, 

BOTTOM ORGANISMS 

West Gallatin River, Gallatin County, Montana. 

STREAM CHARACTERISTICS: 

150-300 feet wide. 

HYDROELECTRIC PROJECT EFFECTS: N/A 

PHYSICAL EFFECTS OF ICE: 

Both anchor ice and surface ice were observed at three stations in the study area. Observations indicated 

that anchor ice first seeded on upstream faces of rocks in riffle areas and was thickest and most extensive 

in riffle areas. Anchor ice formed during nighttime at subfreezing air temperatures and generally broke 

free and floated downstream during daytime, when incident solar radiation penetrated to the stream 

bottom. Aquatic organisms were seen floating along with the ice on several occasions, but no large 

stones were observed being lifted and carried away by the ice. Where surface ice formed, no anchor ice 

was found below except at the extreme outer edge. Floating slush ice often packed below the surface ice 

and froze to the underside. 

BIOWGICAL EFFECTS OF ICE: 

Bottom organisms were observed floating with the anchor ice slush mats. Bottom organism abundance 

did not appear affected by anchor ice. Areas not observed to have anchor ice had a density of 3.43 m/s 

per sample. Areas with anchor ice observed on different occasions had densities from 3.47 m/s per 

sample to 4. 75 m/s per sample. Organisms were found dead in sheet ice near the shore. They tested 

the ability of organisms to survive in freezing water in a can. They found that if any water at all were 

present in the can, most organisms would remain alive. 

COMMENTS: 

They found no apparent detrimental effect of anchor ice on bottom organisms. This was apparently 

because water in which organisms can live fills space between ice crystals. Apparently shore ice is the 

most damaging to benthic insects as they freeze in the ice when it contacts the bottom. 

Repon on Stream Ice Processes 
Annotated Bibliography 

Butler, R.L., and V.M. Hawthorne. 1979. Anchor ice, its formation and effects on 

aquatic life. Science in Agriculture. 26(2). 

LOCATION OF STQDY: 

Pennsylvania (unidentified) and a film from Sagehen Creek, California. 

STREAM CHARACTERISTICS: N/ A 

HYDROELECTRIC PROJECT EFFECTS: N/A 

PHYSICAL EFFECTS OF ICE: 

This article presents findings of a study of formation and biological effects of anchor ice in Sagehen 

Creek near Truckee, California. Anchor ice formation may temporarily alter stream bed configuration, 

form subsurface dams, and affect stream bed conditions. It repeats statements in the source document 

to the effect that anchor ice can be "very destructive to aquatic organisms". 

BIOLOGICAL EFFECTS OF ICE: 

Fish were observed swimming "aimlessly" through caverns of ice when anchor ice formed and the stream 

flooded. Fish and insects were caught in off-channel areas where they were trapped by the nightly 

flooding. Referred to a film "Trout Streams in Winter" that could be obtained. Greatest risks were due 

to low snow cover and very cold temperatures. 

COMMENTS: 

Report on Stream Ice Processes 
Annotated Bibliography 

Calkins, D.J. 1989. Winter habitats of Atlantic salmon, brook trout, brown trout and 

rainbow trout. A literature review. Special Report 89-34. U.S. Army Corps Cold Regions 

Research and Engineering Laboratory, Hanover, New Hampshire. 

WCATION OF STUDY: N/A 

STREAM CHARACTERISTICS: N/A 

FLOATING ICE, 

ANCHOR ICE 

HYDROELECTRIC PROJECT EFFECTS: N/ A 

PHYSICAL EFFECTS OF ICE: 

Paper summarizes winter ice effect on streams. In streams that had floating ice, temperatures were near 

ooc, and if the temperature rose to 0.2 o or 0.3 oc the ice would melt in the stream. Supercooled water 

in rivers with ice cover may enter gravel beds, but is less likely to enter river beds with fine sediment. 

Also noted was how flow depth in a stream will increase as ice cover occurs on the stream due to the 

resulting roughness increase, even occurring with floating ice cover. Anchor and slush ice may occupy 

60 to 80 percent of a stream cross-section in small streams. This may ultimately develop into surface 

ice. 

BIOLOGICAL EFFECTS OF ICE: 

This is a literature summary of winter habitat uses by several species of salmon and trout relating 

specifically to velocity, depth, and substrate. Presented is a summary of literature on habitat uses by life 

stage. 

COMMENTS: 

The paper presents little specific discussion of the effects of ice on fish other than citing past general 

literature about its importance. Concentrated on focal point habitat uses in the winter by various species. 

Report on Stream Ice Processes 
Annotated Bibliography 

Carstens, T. 1966. Experiments with supercooling and ice formation in flowing water. 

Geophysical Publications. 26:1-18. 

WCATION OF STUDY: N/A 

ICE FORMATION, 

HEAT TRANSPORT 

STREAM CHARACTERISTICS: N/A 

HYDROELECTRIC PROJECT EFFECTS: N/A 

PHYSICAL EFFECTS OF ICE: 

See comments. 

BIOWGICAL EFFECTS OF ICE: N/ A 

COMMENTS: 

The paper describes cold-room experiments to investigate supercooling of water as a function of heat flux 

across the water/air interface and heat transport from the interior of the water mass to the surface. The 

experiments were made in response to the practical problem of icing of intakes in rivers with an ice 

regime. No study location or specific river was mentioned. Experimental results were compared with 

theoretical predictions or were used to formulate empirical parameterization of processes involved in frazil 

ice production and fate. The paper provides a good laboratory reference for examining frazil ice in 

natural settings. 

Report on Stream Ice Processes 
• 

Annotated Bibliography 

Chisholm, I.M. 1985. Winter stream conditions and brook trout habitat use on the snowy 

range, Wyoming. Master's Thesis, University of Wyoming, Laramie, Wyoming. 113 pp. 

WCATION OF STUDY: 

STREAM ICE, 

TROUT WINTER 

HABITAT 

Albany County, Wyoming, tributaries to the Little Laramie River; two streams elevation 2,993 to 3,205 

meters and reaches below this elevation, nine reaches at 2,280 to 2,068 meters. 

STREAM CHARACTERISTICS: 

Of the upper sites, most are second order with gradients ranging from 0.39 to 1.35 percent. Average 

daily flow during the winter ranges from 0.01 to 0.11 m3/s. One stream had an average of 0.58 m3/s. 

Minimum winter flow was less than 0.01 m3/s. The nine additional lower elevation sites had gradients 

ranging from 0.2 to 4.3 percent. These streams were third to fifth order. 

HYDROELECTRIC PROJECT EFFECTS: N/A 

PHYSICAL EFFECTS OF ICE: 

Surface ice physically excluded little stream habitat. No ice was observed at 3,205 meters elevation, and 

little at 3,150 and 3,120 meters. Maximum thickness of ice at these elevations was 16 centimeters, and 

it occurred only near the bank at pool edges. Ice was most extensive at 2,993 meters elevation, where 

the maximum thickness was 24 centimeters. Generally, the deepest snow was found at the highest 

elevations. Ice thickness was inversely correlated with snow depth. Riffles had the highest proportion 

of depth covered with ice. Surface ice diminished through the winter, persisting at edges of the stream 

and often separated from the water by an air gap. Habitat exclusion by surface ice increased with 

decreasing elevation. Surface ice covered from 40 percent to about 70 percent of the total cross-sectional 

area at elevations below 2,800 meters. Anchor and frazil ice were observed at only 3 of 13 sites. At 

elevations greater than 2,990 meters, anchor ice, slush, or surface ice did not impede the flow. 

BIOWGICAL EFFECTS OF ICE: 

Five of seven tagged fish moved downstream in 1983-84 with an average distance of 0 to 306 meters. 

During 1984-85, fish movement ranged from 33 to 342 meters, the mean of 163 meters. Fish generally 

moved to low gradient habitats in pools, typically with velocities less than 15 centimeters per second. 

During 1984-85, six fish moved from high gradient areas (1.6 to 6.8 percent) to a beaver pond. Most 

fish selected water 30 to 46 centimeters and 60 to 76 centimeters deep. 

Repon on Stream Ice Processes 
Annotated Bibliography 

Chisholm, I.M., W .A. Hubert, and T .A. Wesche. 1987. Winter stream conditions and use 

of habitat by brook trout in high-elevation Wyoming streams. Transactions of the 

American Fisheries Society. 116:176-184. 

LOCATION OF STUDY: 

STREAM ICE, 

TROUT WINTER 

HABITAT 

Several tributaries to the Laramie River, Albany County, Wyoming; on the east slope of the snowy range. 

Four study reaches at high elevation; 2,993 to 3,205 meters and nine study reaches at low elevation at 

2,280 to 2,868 meters. 

STREAM CHARACTERISTICS: 

Most low slope at 1.5 percent, some up to 4 percent; mean width 2.2 to 5.1 meters; winter flow less than 

0.5 m3/s. Stream order mostly two and some three, mostly brook trout. 

HYDROELECTRIC PROJECT EFFECTS: N/A 

PHYSICAL EFFECTS OF ICE: 

Surface ice physically excluded little stream habitat. No ice was observed at 3,205 meters elevation, and 

little at 3,150 and 3,120 meters. Maximum thickness of ice at these elevations was 16 centimeters, and 

it occurred only near the bank at pool edges. Ice was most extensive at 2,993 meters elevation, where 

the maximum thickness was 24 centimeters. Generally, the deepest snow was found at the highest 

elevations. Ice thickness was inversely correlated with snow depth. Riffles had the highest proportion 

of depth covered with ice. Surface ice diminished through the winter, persisting at edges of the stream 

and often separated from the water by an air gap. Habitat exclusion by surface ice increased with 

decreasing elevation. Surface ice covered from 40 percent to about 70 percent of the total cross-sectional 

area at elevations below 2,800 meters. Anchor and frazil ice were observed at only 3 of 13 sites. At 

elevations greater than 2,990 meters, anchor ice, slush, or surface ice did not impede the flow. 

BIOLOGICAL EFFECTS OF ICE: 

Seven brook trout were monitored with radio tags. In streams with elevations greater than 2,900 meters, 

fish actively moved between pools. Net movement distance averaged 96 meters, and ranged from 0 to 

206 meters. Five of the fish moved downstream to low gradient reaches. The next year, six of eight 

fish moved downstream an average distance of 163 meters. Preferred winter habitats were primarily 

pools with velocities less than 15 centimeters per second, often beaver ponds. Fish were usually found 

in water 30 to 107 centimeters deep. The authors concluded that in the region of elevations greater than 

2,900 meters, water withdrawal would not compound the loss of habitat from freezing or surface ice. 

Repon on Stream Ice Processes 
Annotated Bibliography 

However, at lower elevations, habitat loss would be worse from withdrawal because of the exclusion of 

habitat by surface ice. 

COMMENTS: 

The article suggests that snow cover and channel shape play a major role in the ice formation and 

potential loss of winter habitat for trout. The major loss of habitat was in riffle areas, and pools were 

the most selected habitat area by fish. There was no determination of whether or not changes in flow 

would increase the proportion of habitat loss. In areas with snow, loss is proportional to flow change. 

In ice areas, habitat loss is greater than the reduction of flow would suggest. 

Repon on Stream Ice Processes 
Annotated Bibliography 

Cunjak, R.A. 1988. Physiological consequences of overwintering in streams: the cost of 

acclimatization? Canadian Journal of Fisheries Aquatic Sciences. 45:443-452. 

LOCATION OF STUDY: 

Credit River, Ontario, Canada. 

STREAM CHARACTERISTICS: 

TROUT 

ACCLIMATIZATION 

Five separate reaches were studied: three characterized as main channel and two smaller tributaries as 

spring creek tributaries. Spring creeks had 0 to 9 percent ice cover during the year, while the main 

channel sections had ice cover ranging from 22 to 39 percent of the surface. Winter discharge ranged 

from 0.4 to 2.2 m3/s in the main channel sections and 0.7 to 0.4 m3/s in the tributary sections. One of 

the spring creeks had a fairly low slope and sand and gravel as the main substrate, while some of the 

main channel sections had high gradient with boulder substrates. 

HYDROELECTRIC PROJECT EFFECTS: N/A 

PHYSICAL EFFECTS OF ICE: 

Not discussed. 

BIOLOGICAL EFFECTS OF ICE: 

In two types of trout habitat, spring creeks and main channels, trout energy reserves were depleted 

rapidly from late summer to early winter, with the general depletion in biological characteristics of the 

brook trout being similar in both the springs creeks and the main channel reaches. Condition factors of 

all fish decreased significantly from August to the November/December period. In the coldest streams, 

there was also a decrease in the number of fish in March. The implication is that a decrease in 

temperature from fall to winter was more stressful to the fish than the rising spring temperature. 

COMMENTS: 

While anchor ice was not mentioned, there was significant surface ice on the main channel streams. 

There was no significant difference in condition factor between fish in spring creeks with little surface 

ice and those in colder main channel sections with heavy ice cover. This suggests that ice conditions may 

not play a major role in winter survival of trout in streams. 

Report on Stream Ice Processes 
Annotated Bibliography 

Cunjak, R.A., R.A. Curry, and G. Power. 1987. Seasonal energy budget of brook trout 

in streams: implications of a possible deficit in early winter. Transactions of the American 

Fisheries Society. 116:817-828. 

LOCATION OF STUDY: 

Credit River, 30 km west of Toronto; Calendon site, gradient 0.31 percent; Spring Tributary, gradient 

not measured; Black Creek, gradient 0.67 percent. 

STREAM CHARACTERISTICS: 

Calendon, 2.2 cfs in winter; Spring Tributary, 0.08 cfs in winter; Black Creek, 0.39 cfs in winter. 

HYDROELECTRIC PROJECT EFFECTS: N/ A 

PHYSICAL EFFECTS OF ICE: N/A 

BIOLOGICAL EFFECTS OF ICE: 

See comments. 

COMMENTS: 

This study mentions no ice or ice effects; it presents the results of studies of fish metabolism. Although 

brook trout continued to feed throughout the winter, their condition declined markedly from late summer 

to early winter, and remained low until spring. It appeared that low winter temperatures restricted the 

rate of food intake, which thereby limited energy intake. This restriction was believed to be responsible 

for the metabolic deficit condition when minimal costs of maintenance metabolism could not be offset by 

energy intake. Where groundwater minimized temperature fluctuations, winter deficits only occurred in 

reproductively spent brook trout. 

Report on Stream Ice Processes 
Annotated Bibliography 

Cunjak, R.A., and G. Power. 1987. The feeding and energetics of stream-resident trout 

in winter. Journal of Fisheries Biology. 31:493-511. 

WCATION OF STQDY: 

Credit River, Ontario, Canada. 

STREAM CHARACTERISTICS: 

TROUT WINTER 

FEEDING 

This main river is a fifth order stream that drains directly into Lake Ontario. Two tributaries to this 

stream were studied: the North Branch, which has a gradient of 1.6 percent and discharge of 1.6 to 2.2 

cubic meters per second, and the West Branch which has a discharge of 0.4 to 0.6 cubic meters per 

second. Brook and brown trout are the dominant species. 

HYDROELECTRIC PROJECT EFFECTS: N/A 

PHYSICAL EFFECTS OF ICE: 

The North Branch has anchor ice forming infrequently and has average surface ice cover of 22 percent. 

The West Branch is cooler and has a surface ice cover of 39 percent. It generally freezes sooner and 

thaws later than the North Branch. 

BIOLOGICAL EFFECTS OF ICE: 

Active feeding was observed in the winter as indicated by fish stomachs greater than 70 percent full. 

North Branch stomachs were fuller than those of theW est Branch, which had more severe ice conditions 

in the winter. Brown and brook trout had similar diets in all areas. The condition factor of fish 

decreased from late summer to early winter, including immature fish of both species. Consumption of 

food was similar among all seasons studied; late summer, early winter, late winter and spring, indicating 

that fish actively feed in the winter. Lower feeding in West Branch was a function of lesser quantity of 

food available. Even though fish actually take in food in the winter, food assimilation may not be 

sufficient for requirements in the colder part of the year, resulting in poor condition factor. Fish were 

not able to digest enough food, even if their stomachs were full, to meet the energy needs in the early 

winter (November). The colder stream, West Branch, had a greater early winter deficiency in food 

intake. It also had a greater deficiency in later winter (March), possibly because of lower food 

availability. Colder winter climate in the West Branch retarded insect emergence, which reduced food 

supply. 

Report on Stream Ice Processes 
Annotated Bibliography 

COMMENTS: 

Direct effect of ice was not discussed. Colder temperatures in the lower productivity stream appeared to 

increase winter energy deficiencies for trout. Although trout actively fed through the winter, they 

continued to lose condition factor. Because of the cold temperature, they could not assimilate the quantity 

of food needed. The implications are that even with sufficient food supply, fish in cold streams cannot 

obtain energy requirements needed to maintain condition factor. 

Report on Stream Ice Processes 
Annotated Bibliography 

Cunjak, R.A., and G. Power. 1986. Winter habitat utilization by stream resident brook 

trout and brown trout. Canadian Journal of Fisheries and Aquatic Sciences. 43:1970-1981. 

LOCATION OF STUDY: 

TROUT WINTER 

HABITAT 

UTILIZATION 

Upper Credit River, Ontario, Canada; drains into Lake Ontario. 

STREAM CHARACTERISTICS: 

The mainstream is a fifth order stream. Shoreline vegetation includes cedar, hardwoods, and hemlock. 

Major species are brook trout and brown trout with some rainbow. Three streams were sampled. 

Calendon, with a winter discharge of 1.6 to 2.2 m3/sec, and having surface ice along its edges from 

November to mid-March, was the first stream. Anchor ice forms in exposed riffles and runs, but is not 

common. The surface ice covers about 24 percent of the stream surface mostly occurring along the 

shallow margins and regions less than 20 centimeters deep. The mean width is 12 meters. The second 

stream sampled was Spring Tributary, which is a second order stream. It has groundwater inflow of .07 

cubic meters per second, no ice formations, and a mean width of 5 meters. The third stream was North 

Branch, which is just below the spring tributary. It has a high gradient of 16 meters per kilometer and 

similar discharge to Calendon. It has a mean width of 9 meters. It has more frequent anchor ice than 

Calendon, and surface ice covers about 22 percent of the stream. 

HYDROELECTRIC PROJECT EFFECTS: N/A 

PHYSICAL EFFECTS OF ICE: 

None described. 

BIOLOGICAL EFFECTS OF ICE: 

Fish were more commonly found in aggregations in the winter than in the summer. Aggregation behavior 

increased as the temperature dropped from 5.5 to 0.1 oc. The majority of these aggregations offish, 18 

of 19, were facing or in tributaries with groundwater flow having temperatures of 2 to 6°C. 

Aggregations of fish were found in deeper, slower water more often in the winter than in the summer. 

Some of the trout were found in the bottom rubble when the temperature was less than 5°C. Fish fed 

less in the winter than in the summer. During the winter, fish were rarely observed in the high velocity 

areas. Most were found in pools, runs, and margins. Most fish, 50 to 60 percent, were found resting 

on the bottom in the winter. Generally, fish were not found over-wintering within the substrate. Fish 

may have migrated to more suitable pool habitat as winter commenced. Aggregation increased with 

Repon on Stream Ice Processes 
Annotated Bibliography 

reduced temperature because feeding occurred less. Optimal habitat may become more limited with 

reduced flow and increased ice cover. Large trout still stayed in the deep pools. 

COMMENTS: 

Direct ice effects on fish were not discussed. These streams apparently did not have extensive ice 

conditions: Fish were observed to aggregate in the winter, using low velocity areas as temperature 

decreased. It was speculated that low-velocity cover habitat may be the major habitat requirement in the 

winter, and food becomes less important. 

Repon on Stream Ice Processes 
Annotated Bibliography 

Ettema, R., M.F. Karim, and J.F. Kennedy. 1984. Frazil ice formation. CRREL Report 

84-18. U.S. Army Corps of Engineers. Cold Regions Research and Engineering 

Laboratory, Hanover, New Hampshire. 

WCATION OF STQDY: N/A 

STREAM CHARACTERISTICS: N/A 

HYDROELECTRIC PROJECT EFFECTS: N/A 

PHYSICAL EFFECTS OF ICE: N/A 

BIOLOGICAL EFFECTS OF ICE: N/A 

COMMENTS: 

This paper discusses frazil ice formation, particularly in relation to turbulence and water temperature. 

It presents both analytical and experimental investigations and associated findings with respect to frazil 

ice formation. Rate and quantity of frazil ice formation increases with both increasing turbulence 

intensity and decreasing water temperature. The extent of initial supercooling of water is also an 

important factor. 

Report on Stream Ice Processes 
Annotated Bibliography 

Ferguson, H.L., and H.F. Cork. 1972. Regression equations relating ice conditions in the 

upper Niagara river to meteorological variables. The role of snow and ice in hydrology. 

Proceedings of the Banff Symposium, Alberta, Canada. September 1972. World 

Meteorological Organization; Geneva. 2:1314-1327. 

LOCATION OF STUQY: 

RIVER ICE, 

ICE MODELING 

Upper Niagara River between Lake Erie and Niagara Falls, New York. 

STREAM CHARACTERISTICS: 

None given, but flow retardation of 30,000 cfs is mentioned. This is a large river. 

HYDROELECTRIC PROJECT EFFECTS: 

Ice production affects the amount of water available for power generation. 

PHYSICAL EFFECTS OF ICE: 

The work involved relating water temperature and meteorological variability to ice formation on the river. 

As much as 85 percent of the variance in ice flow and 80 percent of the variance in stream flow 

retardation by anchor ice formation were explained. 

BIOLOGICAL EFFECTS OF ICE: 

Not discussed. 

COMMENTS: 

This paper is useful for its investigation of individual terms of the thermal energy balance equation for 

the river expressed in a simple manner. The equation is applicable to icing of streams of all sizes, even 

though the importance of individual terms may vary. 

Report on Stream Ice Processes 
Annotated Bibliography 

Flynn, J. W. 1984. Authority, background and guidelines for department 

recommendations on winter flows for small hydro development. Montana Department of 

Fish, Wildlife and Parks. 

LOCATION OF STUDY: N/A 

STREAM ICE, 

FISH MORTALITY 

STREAM CHARACTERISTICS: N/A 

HYDROELECTRIC PROJECT EFFECTS: N/A 

PHYSICAL EFFECTS OF ICE: N/A 

BIOLOGICAL EFFECTS OF ICE: N/A 

COMMENTS: 

This document presents a literature review of the ice effects on fish, particularly in Montana streams, 

where stream flow is 76 percent snow melt. The stream flow typically averages 1.4 to 2.1 percent of 

the annual flow during November to March. No flow withdrawals were recommended during the winter 

months for protection of fisheries. Fish mortality in the Gallatin River was 53 percent in the winter and 

17 percent in the summer. Mortality for the Madison River was 9 to 50 percent in the winter and 9 to 

33 percent in the summer. Cited literature indicated that the primary causes of winter mortality were the 

collapse of snow banks and bridges and the dewatering of side channels. Fish may be active in the winter 

but do not feed as extensively as in warmer seasons. Habitat uses are different in the winter than 

summer. Major conclusions presented, but not substantiated or quantified by specific studies are (1) 

anchor ice is a severe detriment to fish survival in winter, (2) flow reductions will lead to the worsening 

of stream ice conditions, in particular, the increased formation of anchor ice, and (3) increased flow will 

provide protection against freeze-ups. Many of the conclusions regarding cause-and-effect of ice 

conditions and biological and physical aspects of the stream appear to be speculative. 

Report on Stream Ice Processes 

• 
Annotated Bibliography 

Gilfilian, R.E., W.L. Kline, T.E. Osterklamp, and C.S. Benson. 1972. Ice formation in 

a small Alaskan stream. The role of snow and ice in hydrology, Proceedings of the Banff 

Symposium, September 1972. 1:505-513. 

WCATION OF STQDY: 

ICE FORMATION, 

FRAZIL ICE, 

ANCHOR ICE 

Goldstream Creek, near Fairbanks, Alaska; elevation not given. 

STREAM CHARACTERISTICS: 

0.6 m/s mean velocity; 8 m wide; 0.6 m deep; gradient 0.12 percent. 

HYDROELECTRIC PROJECT EFFECTS: N/A 

PHYSICAL EFFECTS OF ICE: 

The presence of frazil ice and the subsequent formation of anchor ice modified the streamflow and 

changed the physical characteristics of the stream. Lifting and transport of anchor ice resulted in rapid 

redistribution of sediment. Supercooling of the stream led to immediate frazil ice formation, and if 

sustained for a few hours or more, abundant anchor ice formed on the bottom. Border ice also formed 

and grew slowly toward the center of the stream. Flow discharge decreased and stream level increased 

in response to anchor ice formation. 

BIOWGICAL EFFECTS OF ICE: 

Not discussed. 

COMMENTS: 

Report on Stream Ice Processes 
Annotated Bibliography 

Gill, D., and G.P. Kershaw. 1979. Ecological role of river icings in the Tsichu river 

valley, Northwest Territories, Canada. In: Snow and Ice Symposium on the Camberra 

Assembly, International Union of Geology and Geophysics, Canberra, Australia. 

LOCATION OF STUDY: 

Upper Tsichu River, NW Canada, 15 to 20 km east of Macmillan Pass, on the border between Northwest 

Territories and the Yukon; elevation 1,300 to 1,400 m. 

STREAM CHARACTERISTICS: 

None are given, other than it being described as a high-gradient stream with numerous riffles over 

bedrock outcrops. 

HYDROELECTRIC PROJECT EFFECTS: N/A 

PHYSICAL EFFECTS OF ICE: 

Total freeze-up of the stream forces water to overflow outside the stream channel and freeze. Snow cover 

is incorporated into the ice, creating a virtually snow-free corridor. This type of icing only occurs in 

regions of very long cold winters. This is an extreme example of stream icing and may not be directly 

applicable to the present scope. 

BIOLOGICAL EFFECTS OF ICE: 

Willows line the banks and moose use the clear river channel from icing as a route for feeding on the 

willows. Moose were not found to over-winter in the area unless icing occurred. They noted moose kills 

by wolves that had forced the moose out of the river channel into the higher snow where they could not 

escape. 

COMMENTS: 

This relates to larger, colder streams but it does imply that surface ice can provide habitat for some 

important terrestrial species. 

Report on Stream Ice Processes 
Annotated Bibliography 

Hoyt, W.G. 1913. The effects of ice on stream flow. Water Supply Paper 337, U.S. 

Geological Survey. 77 pp. 

WCATION OF STUDY: N/A 

STREAM CHARACTERISTICS: N/A 

STREAM ICE, 

STREAM FLOW 

HYDROELECTRIC PROJECT EFFECTS: N/A 

PHYSICAL EFFECTS OF ICE: N/A 

BIOLOGICAL EFFECTS OF ICE: N/ A 

COMMENTS: 

This is one of the earliest published manuscripts that concerns ice in streams. It draws upon observations 

of ice at many different locations, and provides descriptions of the effects of ice on stream flow 

characteristics. It includes brief descriptions of frazil and anchor ice and details of their formation as 

understood at the time. It also discusses the effects of surface ice cover on flow velocity. In general, 

the presence of ice increases the river stage. The documentation of ice and flow conditions at several 

locations makes this paper an important source of historical information. The technical content has been 

greatly supplemented by subsequent studies, so that more recent literature should be consulted for details 

of ice types and processes in streams. 

Report on Stream Ice Processes 
Annotated Bibliography 

Hillman, T.W., and J.S. Griffith. 1987. Summer and winter habitat selection by juvenile 

chinook salmon in a highly sedimented Idaho stream. Transactions of the American 

Fasheries Society. 116:185-1195. 

LOCATION OF STUDY: 

= t<£vw6~[)s . 

FISH WINTER 

HABITAT 

Red River, which is tributary to the south fork of the Clearwater River in Idaho. 

STREAM CHARACTERISTICS: 

The study area is a low gradient stream of 1 to 2 percent meandering through a meadow, major species 

include chinook and steelhead. 

HYDROELECTRIC PROJECT EFFECTS: N/A 

PHYSICAL EFFECTS OF ICE: 

No winter studies were conducted beyond November. 

BIOLOGICAL EFFECTS OF ICE: 

Fish migrated out of the region in fall and winter with density declining approximately 80 percent from 

August to November. With the inclusion of cobble into these reaches and selected areas, the population' 

only declined 57 percent. Summer habitat used by chinook was pools and glides. They are often found 

over sand and gravel. Fish were often found in aggregations. In the winter, fish moved to the lateral 

scour pools and into shallower water than used during the summer and were usually not found in pools. 

They used bank sedges for cover. Trout migration occurred in the late fall when temperatures dropped 

from go to 4°C. They suggested that the major cause of out migration was lack of suitable habitat in the 

reach. 

COMMENTS: 

There was no discussion of ice in this region. The results indicate a large out-migration of chinook in 

the fall as temperature approach 4 oc or about 80 percent of those typically rearing in the stream. Large 

cobble improved habitat quality and reduced out-migration of chinook. 

Report on Stream Ice Processes 
Annotated Bibliography 

Hunt, R.L. 1969. Overwinter survival of wild fingerling brook trout in Lawrence Creek, 

Wisconsin, Journal of Fisheries Research Board of Canada. 26:1473-1483. 

WCATION OF STUDY: 

Lawrence Creek, Wisconsin. 

STREAM CHARACTERISTICS: 

TROUT WINTER 

SURVIVAL 

Not indicated, but stream temperature typically decreases to ooc between 5 and 10 days per year. 

HYDROELECTRIC PROJECT EFFECTS: N/A 

PHYSICAL EFFECTS OF ICE: 

Not discussed. 

BIOLOGICAL EFFECTS OF ICE: 

Over-winter survival ranged from 35 to 73 percent, with a mean of 54 percent for fingerling brook trout. 

Two factors significantly correlated with survival were fish size and air temperature. Generally, survival 

rate increased with increasing fish size and decreased with decreasing air temperature. Generally, the 

larger the number of days during December, January, and February with air temperatures greater than 

4.5°C, the greater the survival of over-wintering fingerling brook trout. 

COMMENTS: 

This paper does not discuss ice effects directly. It reports that low air temperatures are directly correlated 

with winter mortality. 

Repon on Stream Ice Processes 
Annotated Bibliography 

Johnson, L.S., T.A. Wesche, D.L. Wichers, and J.A. Gore. 1982. lnstream salmonid 

habitat exclusion by ice cover. Project No. B-038-WYO. Water Resources Research 

Institute, University of Wyoming, Laramie, Wyoming. 

LOCATION OF STUDY: 

STREAM ICE, 

HABITAT EXCLUSION 

Wagon Home Creek, Carbon County, Wyoming 

STREAM CHARACTERISTICS: 

Fifteen to 45 feet wide; elevation 7,420 feet; typical riffle-pool-run; mean velocity of 0.254 ft/s in 

September. September mean discharge ranges from 2.59 to 7.7 cfs; it contains ice cover after November. 

Riparian vegetation is willow, rose, cottonwood, and adjacent grazed land. 

HYDROELECTRIC PROJECT EFFECTS: N/A 

PHYSICAL EFFECTS OF ICE: 

Regression formulas were developed that related percent habitat excluded by ice with length of day, 

degree days of frost, mean water depth, and mean water velocity for riffle, run and pool areas. No 

specific physical effects of ice formation at the study area were described. In riffle areas, percent habitat 

excluded was positively correlated with length of day and negatively with degree days of frost, average 

depth, and average velocity. In run areas, percent habitat excluded was positively correlated with degree 

days of frost and negatively with length of day, average depth, and average velocity. In pool areas, 

percent habitat was positively correlated with degree days of frost and average depth, and negatively with 

length of day and average velocity. Measurements began on January 15 and continued to March 25. Ice 

thickness decreased as the study progressed. At the start of the study, about 60 to 70 percent of all three 

stream habitats were excluded, including runs, riffles, and pools. The greatest percentage increase in 

habitat over time was in riffles and runs, while pools were the last to regain most of their habitat. 

Velocity was not correlated with ice thickness, because surface ice formed from the shore out and not 

from frazil ice. 

BIOLOGICAL EFFECTS OF ICE: 

Not discussed. 

COMMENTS: 

These regression formulas did not produce accurate predictions when tested in another stream (Chisholm 

et al. 1987). 

Repon on Stream Ice Processes 
Annotated Bibliography 

List, R., and L.A. Barrie. 1972. Heat losses and synoptic patterns relating to frazil ice 

production in the Niagara river. The role of snow and ice in hydrology, Proceedings of the 

Banff Symposium, Alberta, Canada. September 1972. World Meteorological 

Organization, Geneva. 2:1328-1338. 

<. KE:vwoR.os v 

FRAZIL ICE 

LOCATION OF STUDY: 

Upper Niagara River, New York. 

STREAM CHARACTERISTICS: 

None mentioned; this is a large river. 

HYDROELECTRIC PROJECT EFFECTS: 

Not discussed. 

PHYSICAL EFFECTS OF ICE: 

This paper describes relationships between frazil ice production and synoptic weather patterns and 

investigates the heat exchange between the river and the atmosphere. Empirical heat transfer equations 

were developed. A surface ice cover did not form because of high turbulence intensities, and no ice 

advents in from Lake Erie. Therefore, virtually all ice production was due to frazil ice. 

BIOLOGICAL EFFECTS OF ICE: 

Not discussed. 

COMMENTS: 

Report on Stream Ice Processes 
Annotated Bibliography 

Logan, S.M. 1963. Winter observations of bottom organisms and trout in Bridger Creek, 

Montana. Transactions of American Fisheries Society. 92:140-145. 

LOCATION OF STUDY: 

••••••••••••••••••···•••••••••••K:E\'Wolios t•••••••••••••••••·•· 

STREAM WINTER 

BIOLOGY 

Bridger Creek, Southwest Montana. Five miles northeast of Bozeman. 

STREAM CHARACTERISTICS: 

Seventeen feet wide with a mean depth of 15 inches, numerous riffles and a few deep pools, 14 inches 

of snow in the winter. Bank conditions of willow and brush associated with fir and aspen. Rainbow is 

the most abundant trout. 

HYDROELECTRIC PROJECT EFFECTS: N/ A 

PHYSICAL EFFECTS OF ICE: 

Only surface and anchor ice were found in this study. Surface ice ranged from 2.5 to 4.5 inches thick. 

Surface ice disturbed the stream bed at edges of the channel, killing some limnephilids. Anchor ice dams 

did not form because of the presence of surface ice cover. Therefore, the study area did not experience 

sudden changes because of water surges released by collapsing anchor ice dams. 

BIOLOGICAL EFFECTS OF ICE: 

Water temperature had no effect on benthic organism abundance (November:285 organisms per square 

foot; May:104). Surface ice was common from November through March. There was no difference in 

the abundance of benthic insects under the ice cover and in open water. They noted that dead insects 

were observed where ice froze all the way to the bottom. Ice cover appeared to have no effect on 

abundance of bottom organisms, and bottom organisms only decreased during the high spring flows. No 

increase in drift was correlated with surface ice formation. Trout abundance from October 21 to April 

decreased to 9.6 percent. Approximately 62 percent were left on November 21. Greater than 50 percent 

of all marked fish recovered were within 150 feet of their original location. Downstream and upstream 

movements were similar; 38 percent upstream and 27 percent downstream. In spring, summer, and fall, 

fish were mostly in the pools, while in the winter, fish were under ice near the edges of the stream. 

COMMENTS: 

The only impact from ice was the freezing of insects along the shore where ice had frozen to the bank. 

Little anchor ice was found, and no increase in insect drift occurred where ice drift was observed. 

Greater than 90 percent of the fish moved less than 400 feet during the winter. Apparently, mortalities 

greater than 90 percent occurred in the original marked population of rainbows that were more than 7 

inches long. 

Report on Stream Ice Processes 
Annotated Bibliography 

Maciolek, J.A., and P.R. Needham. 1952. Ecological effect of winter conditions on trout 

and trout foods in Convict Creek, California. Transactions of the American Fisheries 

Society. 18:202-217. 

WCATION OF STVDY: 

STREAM ICE, 

STREAM WINTER 

BIOLOGY 

Convict Creek, Mono County, California. On the east slope of the Sierra Nevada mountains. Elevation 

7,200 feet. 

STREAM CHARACTERISTICS: 

Natural stream is 10 feet wide. This stream is divided into four 1/4-mile-long channels. Willows and 

meadows grow along the stream. Snow usually is present in the area from 2-4 feet deep in the winter. 

Flow during the period was 8-23 cfs for the whole stream. During the study, only two cold periods 

occurred during which ice formed on the stream. The stream contains mostly wild brown trout, with a 

few rainbow. 

HYDROELECTRIC PROJECT EFFECTS: N/ A 

PHYSICAL EFFECTS OF ICE: 

Surface ice formed over quiescent pools and along stream edges in riffle areas. Frazil ice and anchor 

ice formation were also observed at the edges. Surface ice indirectly caused disturbance of stream banks 

and bottom when water surges broke it loose. Frazil ice contributed to clogging the main channel. 

Anchor ice formed during cold, cloudless nights, appearing first at the downstream ends of pools, second 

in riffles, and lastly on the bottoms of pools. Anchor ice blocked water flow into side channels and 

caused gradual decreases in flow volume through the nighttime hours. Subsequent breaking free of 

anchor ice with increased incident solar radiation on the following days liberated water and scoured the 

stream. Only small amounts of bottom material were lifted by anchor ice. 

BIOLOGICAL EFFECTS OF ICE: 

Sheet ice was used for cover by trout in the creek. On one occasion when frazil ice formed because high 

winds blew ice into the stream, the stream left its banks, but no adverse effect on trout was observed. 

The surge of water from melting anchor ice caused stream bed scour, dislodging benthic organisms. This 

dislodging of benthic organisms supplied food to the fish. Trout were seen to be active during the 

daytime. Biomass of insects in the riffles was higher in the winter than in the summer. Trout were 

observed feeding only during periods following peak flows when insect drift was highest. During drift 

net studies only infrequently were trout eggs observed, indicating little disturbance of the bottom from 

Repon on Stream Ice Processes 
Annotated Bibliography 

anchor ice, particularly red areas. Sixty-three fish were found stranded in side channels after three days 

of cold weather, which caused reduced flows from freezing. This was the only direct source of winter 

mortality observed. Some fish were observed in poor and dying conditions (7 brown trout and 4 rainbow 

trout) but never during freezing weather. Trout generally did well in the winter after some initial 

detriments occurred. Later, ice provided cover and dislodgement of food sources. 

COMMENTS: 

The only observed direct mortality was from stranding of fish in the side channel. Some fish eggs may 

have been dislodged during scour from anchor ice. Ice provided cover, and melting dislodged benthic 

insects that fish could feed upon. Anchor ice commonly formed at night and melted daily. 

Report on Stream Ice Processes 
Annotated Bibliography 

Marcus, M.D., L.E. Noel, and M.K. Young. 1990. Rating salmonid habitat research 

needs in the central Rocky Mountains. Fisheries. 15(5):14-18. 

LOCATION OF STUPY: N/A 

1 )/ / xE'YWoR.os················ 

SALMONID HABITAT 

STREAM CHARACTERISTICS: N/ A 

HYDROELECTRIC PROJECT EFFECTS: N/A 

PHYSICAL EFFECTS OF ICE: N/ A 

BIOLOGICAL EFFECTS OF ICE: N/ A 

COMMENTS: 

This article, through a survey, evaluated the research needs for streams in the central Rocky Mountains. 

State and federal agencies in this region were asked to rank 50 specific questions concerning the 

importance of fisheries habitat for future management research needs. The second highest ranked 

question was: "Define the determinates of winter habitat that are critical to the over-winter survival of 

some salmonid fisheries." This indicates that winter habitat area is of major interest to resource 

managers. It also suggests very little information is currently available on cold winter habitat uses by 

salmonids in the Rocky Mountains. 

Report on Stream Ice Processes 
Annotated Bibliography 

Marsh, P., and T.D. Prowse. 1987. Water temperature and heat flux at the base of river 

ice covers. Cold Regions Science & Technology. 14:33-SO. 

LOCATION OF STUDY: 

l<:EY"WoR.ns, 

RIVER ICE, 

ICE MODELING 

Laird River near its confluence with the Mackenzie River near Fort Simpson, N.W.T., Canada; no 

elevation given. 

STREAM CHARACTERISTICS: 

Annual mean 9,200 cfs; 700 m wide; 2 m deep; 0.037 percent slope. 

HYDROELECTRIC PROJECT EFFECTS: N/A 

PHYSICAL EFFECTS OF ICE: N/A 

BIOLOGICAL EFFECTS OF ICE: N/A 

COMMENTS: 

This study does not concern small high-gradient streams. It is useful as a reference comparison of 

methods for calculating heat transfer coefficients, and thus heat flux, at the base of river ice covers. 

Comparisons showed it is essential to consider ice roughness and to measure water temperature to a high 

degree of accuracy. The Colburn analogy method for calculating heat transfer coefficients agreed best 

with that using a temperature decay approach. 

Repon on Stream Ice Processes 
Annotated Bibliography 

Martin, S. 1981. Frazil ice in rivers and oceans. Annual Review of Fluid Mechanics. 

13:379-397. 

FRAZIL ICE 

LOCATION OF STUDY: N/A 

STREAM CHARACTERISTICS: N/ A 

HYDROELECTRIC PROJECT EFFECTS: N/A 

PHYSICAL EFFECTS OF ICE: N/A 

BIOLOGICAL EFFECTS OF ICE: N/A 

COMMENTS: 

This is a review paper concerning frazil ice and describes general aspects of frazil ice formation, 

characteristics, and fate. It also provides several references for previous models of frazil ice production. 

No specific studies are included. 

Repon on Stream Ice Processes 
Annotated Bibliography 

Morrill, C.F., and T.C. Bjornn. 1972. Migration response of juvenile chinook salmon to 

substrates and temperatures. Research Sediment Completion Report, Project A-028-IDA. 

Water Resources Research Institute. University of Idaho, Moscow, Idaho. 

SALMON MIGRATION 

WCATION OF STUDY: 

Hayden Creek, an artificial stream channel on the Lemhi River, Idaho. 

STREAM CHARACTERISTICS: 

None given. 

HYDROELECTRIC PROJECT EFFECTS: N/A 

PHYSICAL EFFECTS OF ICE: N/ A 

BIOLOGICAL EFFECTS OF ICE: N/A 

COMMENTS: 

Ice was not discussed. However, the results regarding fish movements during periods of declining water 

temperature may be peripherally related to fish condition and distribution in streams that are subject to 

icing. 

Studies were conducted to assess the effects of temperature and substrate size on out-migration of zeroage spring chinook. It was found that few fish left the artificial channels of suitable substrate, that is, 

large rocks 1S to 4S centimeters in diameter, and were present independent of temperature. Generally, 

more fish out-migrated in streams of poor substrate than in streams with good substrate; poor substrates 

being rocks of 1.6 centimeters or smaller in size. Out-migration began as temperatures dropped from 

10° to S°C. In some cases with poor substrate, out-migration increased as temperature dropped below 

S°C. In studies with constant temperature and poor substrate, fewer fish out-migrated, but as temperature 

dropped, out-migration increased. It was concluded that suitable substrate in the fall reduced outmigration, but that some out-migration will still occur even when suitable substrate is present for zero-age 

chinook. Fish tended to go into the substrate when temperatures were less than S to 7°C. 

Repon on Stream Ice Processes 
Annotated Bibliography 

Needham, P.R., J.W. Moffett, and D.W. Slater. 1945. Fluctuations in wild brown trout 

populations in Convict Creek, California. Journal of Wildlife Management. 9:9-25. 

WCATION OF STUPY: 

TROUT WINTER 

SURVIVAL 

Convict Creek, Mono County, California. East slope of the Sierra Nevada mountains. Elevation 7,200 

feet. 

STREAM CHARACTERISTICS: 

Twelve feet wide with willows, aspen, and grass. 

HYDROELECTRIC PROJECT EFFECTS: N/A 

PHYSICAL EFFECTS OF ICE: 

Not discussed. 

BIOLOGICAL EFFECTS OF ICE: 

The only biological effect of ice or snow was the collapse of a hanging snow bank below a nearby 

hatchery. Several hundred first-year fish were found dead beneath the snow mass. The authors stated 

that smaller losses were "common," but did not elaborate. Regarding first-year trout mortality, the 

authors believed that severe winter conditions exert the primary influence on growth and survival. 

According to their observations, overwinter losses of all trout, regardless of size, were 60 percent. 

COMMENTS: 

This study is directed toward gathering information regarding patterns and causes of changes in trout 

populations, and ice effects are not discussed directly, but mentioned in "severe winter conditions." This 

article is useful in combination with other studies at Convict Creek. 

Repon on Stream Ice Processes 
Annotated Bibliography 

Needham, P.R., and A.C. Jones, 1959. Flow, temperature, solar radiation, and ice in 

relation to activities of rashes in Sagehen Creek, California. Ecology. 40:465-474. 

LOCATION OF STUDY: 

KEY"WoWos 

STREAM ICE, 

WINTER FISH 

ACTIVITY 

Sagehen Creek, California. Tributary to Little Truckee river located on the California-Nevada line. 

Elevation 6,337 feet. 

STREAM CHARACTERISTICS: 

Fifteen feet wide; flow ranging from 50 cfs in the spring to 2 cfs in September; forested along the banks 

with pine and fir. Average snow is 44 inches deep. Severe winter from mid-December to the end of 

March. Contains rainbow, cutthroat, and brown trout. 

HYDROELECTRIC PROJECT EFFECTS: N/ A 

PHYSICAL EFFECTS OF ICE: 

Physical factors (temperature) leading to ice formation were discussed. Groundwater inflow moderates 

temperature in the winter. When the weather is stormy, the creek temperature may be well below 

groundwater temperature. Anchor ice first appeared in riffles and sometimes accumulated, creating ice 

dams. The influence of the slightly elevated temperatures of groundwater inflow prohibited anchor ice 

formation within 500 yards downstream of the groundwater entrance. Anchor ice was found in the open 

regions of meadows where no trees or groundwater upwelling occurred. Anchor ice formed between 

-9°F and l2°F. It occurred once at 26°F after a high windstorm blew snow into the stream. Anchor 

ice was more prevalent in December than in January through March, possibly because of increased 

insulation from snow during the latter period. Whenever the temperature was less than 0°F, anchor ice 

formed. Formation of anchor ice caused the stream level to rise an average 1.3 feet at a gaged pool. 

The average flow at this time was 3.5 cfs. 

BIOLOGICAL EFFECTS OF ICE: 

Trout were observed to feed at 32 o and 33 °F in the winter when frazil ice was floating down the stream. 

There was no directly observed mortality of fish. In the daytime, fish were observed near shelter 

(overhanging banks, root wads), and more were seen out in the stream at night. At night, trout 

maintained close contact with the substrate, often with fins touching the bottom. Bottom organisms were 

apparently abundant and active in the winter. 

Repon on Stream Ice Processes 
Annotated Bibliography 

COMMENTS: 

No loss of fish due to ice was documented, although substantial periods of anchor ice occurred. Anchor 

ice caused substantial increase in stream elevation and some drop of flow, (not quantified). Anchor ice 

dislodged benthic organisms that were thought to increase food for fish. Fish actively fed in the winter 

even at 32 9F with frazil ice in the water. Speculation was that dewatering of streambed areas due to ice 

jams and ice in riffle areas could affect fish, but no such effects were actually observed. Frazil ice can 

form in streams although the temperature is not very cold if high winds blow in substantial quantities of 

snow. 

Repon on Stream Ice Processes 
Annotated Bibliography 

Needham, P.R., and D.W. Slater. 1944. Survival of hatchery-reared brown and rainbow 

trout as affected by wild trout populations. Journal of Wildlife Management. 8(5):22-36. 

LOCATION OF STUQY: 

Convict Creek, north of Bishop, California; elevation 7,200 ft. 

STREAM CHARACTERISTICS: 

2 cfs; 12 ft. wide; 2 percent grades. 

HYDROELECTRIC PROJECT EFFECTS: N/ A 

PHYSICAL EFFECTS OF ICE: 

Anchor ice formed on the bottom of riffle areas, and snow blown into the water drifted against the anchor 

ice, forming dams. Water levels rose up to 2 or 3 feet, forming pools upstream of the dams. Pools 

would freeze over. Sunlight on following days caused melting and breakup, usually removing all ice 

formed the previous night. Snow banks broke off into the water occasionally, covering bottom and fish. 

BIOLOGICAL EFFECTS OF ICE: 

COMMENTS: 

Repon on Stream lee Processes 
Annotated Bibliography 

Nielson, R.S., N. Reimers, and H.D. Kennedy. 1956. A six-year study of the survival and 

vitality of hatchery-reared rainbow trout of catchable size in Convict Creek, California. 

California Fash and Game. 42:5-6. 

WCATION OF STUDY: 

·.· X.• ·····K£YWORDs••••••••·>·····•·· .. ······ 

TROUT WINTER 

SURVIVAL 

Convict Creek, Mono County, 35 miles north of Bishop, California. 

STREAM CHARACTERISTICS: N/ A 

HYDROELECTRIC PROJECT EFFECTS: N/A 

PHYSICAL EFFECTS OF ICE: 

Heavy snow collapsed into the stream: (1) crushing/suffocating fish; (2) suffocating fish throughout the 

dewatered length of the stream; and (3) stranding fish when elevated water levels receded. Snow cover 

inhibited formation of anchor ice. 

BIOLOGICAL EFFECTS OF ICE: 

Mortality is high in small streams for wild trout as well as for hatchery trout. In winters when conditions 

are extreme and protracted, mortality is exceptionally high and more drastic among hatchery-reared trout 

than among wild trout. 

COMMENTS: 

None. 

Repon on Stream Ice Processes 
Annotated Bibliography 

Osterkamp, T.E. 1978. Frazil ice formation: A review. Journal of the Hydraulic Division, 

American Society of Civil Engineers. 104:1239-1255. 

1t£two«os / 

FRAZIL ICE 

WCATION OF STUDY: N/A 

STREAM CHARACTERISTICS: N/ A 

HYDROELECTRIC PROJECT EFFECTS: N/ A 

PHYSICAL EFFECTS OF ICE: 

See comments. 

BIOWGICAL EFFECTS OF ICE: N/A 

COMMENTS: 

As the title indicates, this is a review article; no specific study or study location is mentioned. The article 

covers supercooling of water leading to frazil ice formation, the nucleation process that initiates 

formation, physical properties of frazil ice, the growth rate of frazil ice crystals, and the quantification 

of frazil ice production. It combines information from previous sources with basic mathematical 

descriptions of thermodynamic processes. One notable result is that frazil ice crystal growth rate is 

proportional to the square root of velocity of supercooled water flowing past it. Thus, the relative 

velocity between suspended ice crystals and water may only be a few centimeters per second. However, 

the relative velocity becomes equal to the mean flow velocity as soon as the crystal becomes attached to 

some stationary point, and the result is a striking increase in growth rate of the crystaL Accumulation 

and growth of frazil ice on submerged objects may thus occur rapidly once the process has begun. 

Report on Stream Ice Processes 
Annotated Bibliography 

Osterkamp, T.E., R.E. Gilfilian, and C.S. Benson. 1975. Observations of stage, 

discharge, Ph, and electrical conductivity during periods of ice formation in a small subarctic stream. Water Resources Research. 2:268-272. 

WCATION OF STUDY: 

Goldstream Creek near Fairbanks, Alaska. 

STREAM CHARACTERISTICS: 

FRAZIL ICE, 

ANCHOR ICE 

0.5 cfs; 8 m wide; 0.6 m deep; gradient is 0.12 percent. 

HYDROELECTRIC PROJECT EFFECTS: N/ A 

PHYSICAL EFFECTS OF ICE: 

Frazil ice suspended in the stream flow reduced velocity profiles and increased the stage. Anchor ice and 

border ice formation decreased discharge during two episodes of .underwater ice production by 31 and 

55 percent, respectively. Ice formation reduced flow by storing water in the form of ice and causing 

upstream water storage by flow obstruction. 

BIOWGICAL EFFECTS OF ICE: N/A 

COMMENTS: 

None. 

Repon on Stream lee Processes 
Annotated Bibliography 

Osterkamp, T.E., and J.P. Gosink. 1982. Ice cover development on interior Alaska 

streams. Geophysical Institute, University of Alaska, Fairbanks, Alaska. 

WCATION OF STUDY: 

Yukon River, Goldstream Creek, Tanana River. 

STREAM CHARACTERISTICS: 

None included. 

HYDROELECTRIC PROJECT EFFECTS: N/ A 

PHYSICAL EFFECTS OF ICE: 

See comments. 

BIOLOGICAL EFFECTS OF ICE: 

Not discussed. 

'OMMENTS: 

This is a very good background paper on ice in streams. It presents a thorough discussion of ice types, 

the physical processes associated with their formation and growth, and factors that influence their 

formation and growth. This paper also includes photographs illustrating various observations concerning 

stream ice. It does not present results of particular studies, but reviews and clarifies physical aspects of 

ice in streams and the associated processes. 

Repon on Stream Ice Processes 
Annotated Bibliography 

Pariset, E., and R. Hausser. 1961. Frazil ice and now temperature under ice covers. The 

Engineering Journal (Canada) EIC. January 1961. pp. 46-49. 

LOCATION OF STUDY: N/A 

··················•·•·••• l<:EvwoR.os••n••••<n••••··· 

FRAZIL ICE 

STREAM CHARACTERISTICS: N/A 

HYDROELECTRIC PROJECT EFFECTS: N/A 

PHYSICAL EFFECTS OF ICE: 

See comments. 

BIOLOGICAL EFFECTS OF ICE: N/A 

COMMENTS: 

This paper is a combination of theoretical and empirical investigations into alleviating the problem of 

frazil ice accumulation on intakes in rivers subject to icing. There is no specific, related field study. It 

examines frazil ice formation, transport, deposition, and sticking properties as well as water temperature 

variations under river ice covers. While some general physical parameters and descriptions of ice 

processes may apply to any type of supercooled flow, the work and results presented are primarily aimed 

at very large river systems. 

Repon on Stream lee Processes 
Annotated Bibliography 

Pariset, E., R. Hausser, and A. Gagnon. 1966. Fonnation or ice covers and ice jams in 

rivers. Journal or the Hydraulics Division, American Society or Civil Engineers, pp. 1-23. 

LOCATION OF STUDY: N/A 

STREAM CHARACTERISTICS: N/A 

xexwoR.t>~ 

SURF ACE ICE, 

ICE JAMS 

HYDROELECTRIC PROJECT EFFECTS: N/A 

PHYSICAL EFFECTS OF ICE: N/ A 

BIOLOGICAL EFFECTS OF ICE: 

Not discussed. 

COMMENTS: 

This paper presents a theoretical analysis of ice cover formation and thickening on large rivers. 

It may be a useful source of parameters that relate to ice freeze-up processes. 

Report on Stream Ice Processes 
Annotated Bibliography 

Platts, W .S., and R.L. Nelson. 1989. Stream canopy and its relationship to salmonid 

biomass in the intermountain west. North American Journal of Fisheries Management. 

9:446-457. 

WCATION OF STUDY: 

SALMONID 

PRODUCTIVITY 

Seventeen study areas were selected in the northern Rocky Mountains and the Great Basin of the western 

U.S., specifically Idaho, Nevada, and Utah. 

STREAM CHARACTERISTICS: 

All streams studied generally had high temperatures during the summer and cold temperatures (high 

potential for heavy icing) during the winter. 

HYDROELECTRIC PROJECT EFFECTS: N/A 

PHYSICAL EFFECTS OF ICE: 

Not discussed. 

BIOLOGICAL EFFECTS OF ICE: 

Stream canopy conditions studied were: canopy density, light intensity, unobstructed sun arc, and average 

daily thermal input in both grazed and ungrazed habitat. Results showed that thermal input can be a 

potential measurement index of salmonid productivity in some riparian habitats. 

COMMENTS: 

Purpose of study was to investigate possible relationships between stream (riparian overstory) canopy 

conditions, salmonid biomass, and livestock grazing. 

Repon on Stream Ice Processes 
Annotated Bibliography 

Reichmuth, D.R., D.D. Findorff, and M.J. Leaverton. 1988. Evaluation of the potential 

for anchor ice formation along a reach of the Falls River, Idaho. Revised April 22, 1988. 

Geomax. P.C. Bozeman, Montana. 

LOCATION OF STQDY: 

FRAZIL ICE, 

ANCHOR ICE 

Falls River, Eastern Idaho, Fremont County, east of Marysville. 

STREAM CHARACTERISTICS: 

300-400 cfs in winter; 200 feet wide; 1.1 feet deep; slopes of 0.004 to 0.008. 

HYDROELECTRIC PROJECT EFFECTS: 

Proposed diversion would reduce winter flows in the bypassed reach to approximately 160 cfs. Ice 

formation will not affect hydro project. 

PHYSICAL EFFECTS OF ICE: 

As long as the area of open water remains approximately constant, the formation rate of frazil ice and 

anchor ice will not increase due to reduced flow in the bypassed reach. Reduced flow may increase 

production of surface ice cover and reduce production of frazil ice and anchor ice. 

BIOLOGICAL EFFECTS OF ICE: 

Not discussed. 

COMMENTS: 

None. 

Repon on Stream Ice Processes 
Annotated Bibliography 

Reimers, N. 1963. Body condition, water temperature, and over-winter survival of 

hatchery-reared trout in Convict Creek, California. Transactions of the American Fisheries 

Society. 92:39-46. 

.. . .......................... . KevwbR.os 

TROUT MORTALITY 

WCATION OF STUDY: 

Convict Creek, California; elevation 7,200 feet; discharge 5 to 15 cfs. 

STREAM CHARACTERISTICS: N/A 

HYDROELECTRIC PROJECT EFFECTS: N/ A 

PHYSICAL EFFECTS OF ICE: 

Not discussed. 

BIOWGICAL EFFECTS OF ICE: 

The summer survival of catchable size, hatchery trout from August to November averaged 87 percent, 

ranging from 70 to 97 percent. Winter survival (November through May) of these hatchery trout ranged 

from 2.8 to 69 percent, with an average of 27 percent. Mortality generally increased by month through 

the winter as fish condition factors decrea.c;ed. No sudden increase in mortality occurred that would 

indicate catastrophic events. The author mentioned that the same mortality was not observed in wild fish, 

but did not provide references or study results. 

COMMENTS: 

This article does not directly address causes of winter mortality other than the loss of condition factor. 

No catastrophic mortalities were observed during the winter. However, winter conditions were average 

or better than average in this region during the study. Catastrophic events such as side channel 

dewatering and snow bridge collapse may not generally occur under these environmental conditions. 

Report on Stream Ice Processes 
Annotated Bibliography 

Reimers, N. 1957. Some aspects of the relation between stream foods and trout survival. 

California Fish and Game. 43-69. 

WCATION OF STUDY: 

!d::Y\Vorms 

TROUT WINTER 

SURVIVAL, 

STREAM ICE 

Convict Creek, Mono County, California; elevation 7,200 feet. 

STREAM CHARACTERISTICS: 

6 to 15 feet wide; bottom gravel and rubble; long riffles; few deep pools; about 2 percent grade. 

HYDROELECTRIC PROJECT EFFECTS: N/A 

PHYSICAL EFFECTS OF ICE: 

Anchor ice and slush ice were observed. Slush ice was likely a combination of wetted snow, frazil ice, 

and refloated anchor ice. Anchor ice formation produced ice dams that caused fluctuations in flow by 

water backing up behind dams and then being released suddenly as the dams collapsed. The result was 

deterioration of stream bottom habitat by exposing areas to partial drying, freezing, and rewatering. 

Snow and ice bridged the creek, and occasional collapses due to weight of the cover filled the channel, 

forming backwaters. Snow bridges also caused periods of darkness up to 4 months long in the stream 

bed below. Surges of refloated anchor ice, slush ice, and released water scoured the bottom of the creek 

episodically. Radical changes in flow were judged more harmful to bottom dwelling populations than 

partial snow and ice cover. The importance of physical abrasion of fish by slush and ice was noted. 

BIOWGICAL EFFECTS OF ICE: 

In the darkness under snow bridges, the stream bottom became devoid of algal growth, which reduced 

the population of larger bottom organisms that serve as food for fish. Scouring of the bottom by surges 

of water and slush and disruption of the bottom by formation and dissipation of anchor ice also reduced 

bottom-dwelling populations. Formation and dissipation of anchor ice set bottom-dwelling organisms 

adrift in the stream, where they became more accessible to fish for food. Comparison of observations 

from two different years with different snow and ice conditions led the author to surmise (recognizing 

the statistical limitations of observations) that "populations of bottom-dwelling organisms are apparently 

harmed less by partial snow and ice cover than by repeated exposure to the radical changes in flow that 

accompany subsurface ice action." The total effect of ice and snow is a gradual depletion of available 

trout food through the winter. 

Controlled starvation experiments were conducted in a hatchery trough exposed to the gamut of winter 

ice conditions versus one subjected only to surface ice formation, and in open stream versus pond 

Repon on Stream Ice Processes 
Annotated Bibliography 

environment. The results suggested that physical factors such as abrasion by slush and ice, crushing or 

suffocation beneath collapsed snow and ice bridges, and stranding by fluctuations in flow were major 

influences on winter trout survival. Of secondary effect was quantity of food, and experiments indicated 

that assimilation rate rather than food quantity controls trout nourishment in water near the freezing point. 

The overall conclusion is that the physical effects of water conditions are more important than food 

regarding overwinter losses of catchable-size trout. 

COMMENTS: 

This paper is based upon direct observations and a sequence of controlled exposure and starvation 

experiments. Results are presented in a detailed and straightforward manner, making this a useful 

information source concerning trout survival in small streams that are subject to snow and ice effects in 

winter. 

Repon on Stream lee Processes 
Annotated Bibliography 

Reiser, D.W., and T.A. Wesche. 1975. In situ freezing as a cause of mortality in brown 

trout eggs. The Progressive Fish-Culturist 41(2):58-60. 

WCATION OF STUDY: 

TROUT EGG 

MORTALITY 

Laramie River, Wyoming; 35 km west of Laramie. 

STREAM CHARACTERISTICS: 

Transition zone between steep gradient and low gradient meandering section. Average discharge is 2.8 

m3/s, during the study it was 1.4 m3/s. 

HYDROELECTRIC PROJECT EFFECTS: N/ A 

PHYSICAL EFFECTS OF ICE: 

In an 80-ft.-long study area of the river, sheet ice completely covered the pool area and anchor ice 

covered the substrate in the riffle area. No frazil ice was observed. Intra-gravel ice formed and 

contributed to trout egg mortality is a controlled experiment. 

BIOLOGICAL EFFECTS OF ICE: 

Brown trout eggs were placed 15 to 18 centimeters deep in riffle areas in water depth of 6 to 36 

centimeters, with a 31 centimeter mean depth. Upon removal in March, only one percent of the eggs 

survived. Three of the twenty samples were complete} y frozen. The author suggested that gravel freezes 

due to the slow movement of supercooled water through the substrate. These results suggest that freezing 

of the substrate occurs to a depth of 12 to 20 centimeters even in the absence of frazil ice. This freezing 

may cause high mortality among fish eggs buried in the substrate. 

COMMENTS: 

Assuming that temperatures increase enough that substrate freezing does not occur after approximately 

March or April, then it can be inferred that egg/sac fry of fall/winter spawning salmonids may face 

greater risk of freezing mortality than for spring-spawning salmonids. 

Repon on Stream Ice Processes 
Annotated Bibliography 

Santeford, H.S., G.R. Alger, and J.A. Stark. 1986. Ice in streams--its fonnation and 

effects on flow. US Geological Survey Report 86-4209. Lansing, Michigan. 

WCATION OF STUDY: 

···•·········•· .> !cE:vwoR.os•• i•· r••••··· 

STREAM ICE, 

ICE MODELING 

Sturgeon River near Sidnew, Sturgeon River near Nahma Junction, Red Cedar· River near Williamston, 

all in Michigan. 

STREAM CHARACTERISTICS: 

30 to 100 cfs; 65 to 100ft. wide; 1 to 10ft. deep; moderate slope. 

HYDROELECTRIC PROJECT EFFECTS: N/A 

PHYSICAL EFFECTS OF ICE: 

Formation of surface ice cover over an open channel changed the water-surface profile and the stagedischarge relation. Extent of the change depended upon the nature and location of the ice cover relative 

to the measurement site. Where elevation controlled stage and discharge, floating ice cover had no effect 

on the flow. Elevation controls include those features that generally act as weirs. Other such features 

are inlets or outlets from lakes or reservoirs, adverse slopes, and major channel constrictions. Where 

resistance dominated, the stage-discharge relation was a function of geometry, ice roughness, and buoyant 

displacement of ice. Resistance controls are features, such as channel roughness or an ice cover, that 

produce frictional resistance to flow. No frazil ice or anchor ice were observed in the study or 

considered in the development of an analytical model relating ice-covered profile to open-water profile 

and stage to discharge. 

BIOWGICAL EFFECTS OF ICE: 

Not discussed. 

COMMENTS: 

None. 

Report on Stream Ice Processes 
Annotated Bibliography 

Scarnecchia, D.L., and E.P. Bergersen. 1987. Trout production and standing crop in 

Colorado's small streams, as related to environmental features. North American Journal 

of Fisheries Management. 7:315-330. 

LOCATION OF STUDY: 

Ten small streams in northern Colorado; elevations ranging from 2,146 to 3,139 m. 

STREAM CHARACTERISTICS: 

Stream order one to three; width 1.5 to 4. 7 m; containing brook, brown, and mostly cutthroat trout; 

discharges ranges from 0.01 to 0.14 m3/s in the summer. 

HYDROELECTRIC PROJECT EFFECTS: N/A 

PHYSICAL EFFECTS OF ICE: N/A 

BIOWGICAL EFFECTS OF ICE: 

The studies correlated specific factors to trout production and biomass. Elevation had the highest single 

correlation to trout production and biomass, that is, the greater the elevation, the lower the trout 

production and biomass. The next most important factors were conductivity, alkalinity, hardness, and 

substrate diversity. It was concluded that elevation had the best correlation with production because only 

streams with good habitat were included. Lower elevation streams that may have had less suitable trout 

habitat were not used. The step-wise model, after elevation was entered, found that stream width-to-depth 

ratio was the most important in predicting trout production. 

COMMENTS: 

Stream ice effects were not assessed. The fact that lower production occurs at the higher elevations 

suggests that longer, colder winters, independent of the possibility of increased snow cover, which 

reduces ice cover (as indicated in other articles), may result in poor production. Although not stated, it 

is expected that the winters would be longer at higher elevations than at the lower elevations. 

Repon on Stream Ice Processes 
Annotated Bibliography 

Schaefer, V.J. 1950. The fonnation of frazil and anchor ice in cold water. Transactions 

of the American Geophysical Union. 31:885-893. 

WCATION OF STUQY: 

FRAZIL ICE, 

ANCHOR ICE 

No formal study was made, although informal observations were made at North Creek, Mohawk River, 

and Cutler River in New York; elevation was not given. 

STREAM CHARACTERISTICS: 

None given. 

HYDROELECTRIC PROJECT EFFECTS: 

Frazil ice collected on intake trash racks, with potential to shut down the powerplant within an interval 

of about 1 hour. 

PHYSICAL EFFECTS OF ICE: 

The author describes observations of frazil and anchor ice formation. Frazil ice formed in supercooled 

water in turbulent areas. It collected on underwater objects such as rocks, chains, bars, or plants. The 

author distinguished between accumulations of frazil ice on the bottom and the formation of anchor ice. 

This distinction is no longer held in more recent literature. 

BIOWGICAL EFFECTS OF ICE: 

None presented. 

COMMENTS: 

This is largely anecdotal information in which the observations are generally consistent with contemporary 

studies. 

Repon on Stream Ice Processes 
Annotated Bibliography 

Schrader, W. C. 1989. Trout mortality, movements, and habitat selection during winter 

in south Willow Creek, Montana. Master's Thesis, Montana State University, Bozeman, 

Montana. 

LOCATION OF SfUDY: 

STREAM ICE, 

TROUT WINTER 

BEHAVIOR 

South Willow Creek, Gallatin County, Montana. Tributary to Jeffery River southwest Montana. 

STREAM CHARACTERISTICS: 

Average slope 4 percent; elevation 1,829 meters; third order stream; small high gradient. There were 

three study sections. The lower had a width of 6.9 meters, the middle had a width of 6.6 meters and 

both had a slope of 4 percent, consisting of rapids and cascades. The upper section had an average width 

of 6.9 meters and a low gradient of 1.2 percent, mostly riffles and some pools. Substrate was mostly 

boulders greater than 256 millimeters, and the lower and middle sections were cobble from 65 to 256 

millimeters in the upper section. The banks consisted mainly of willows and alders with some pine and 

fir. Mostly rainbow trout were present. Discharge during the year ranged from 0.4 to 11 m3/s. Winter 

discharge was less than 0.5 m3/s. 

HYDROELECTRIC PROJECT EFFECTS: N/ A 

PHYSICAL EFFECTS OF ICE: 

Anchor ice was common in the upper and lower sections when air temperatures were less than -18°C. 

It never occurred in the middle section. Surface ice was common in the middle section from October to 

April, although this was not quantified. 

BIOLOGICAL EFFECTS OF ICE: 

Average winter abundance of rainbow trout decreased 32 percent and standing crop 30 percent from fall 

to spring. Fifteen rainbow trout longer than 225 millimeters were radio tagged. Movement during the 

winter averaged 114 meters but was 65 meters when adjusted for direction. Lowest section had some 

fish movement upstream, while movement in the others was both directions along the streams. Of five 

fish released in pools greater than 1 meter deep, four remained in these pools all winter. Of fish released 

into pools less than 0.5 meters deep no number given in the thesis, probably 5 or 6, only one remained. 

Fish preferred the deepest water with cover habitat. Fifty percent of the fish in the upper section and 80 

percent of the fish in the lower and middle sections used pools, particularly high-quality pools. Ice was 

only observed being used for cover twice. The thesis presented a summary of winter mortality from 

other studies, in which mortality ranged from 46 to 97 percent. Condition of fish remained good, and 

Report on Stream Ice Processes 
Annotated Bibliography 

fish were observed feeding in the winter on insects dislodged by anchor ice. Absolute and relative 

mortalities of fish were similar in the upper and lower sections, which had sporadic and extensive anchor 

ice, to mortalities in the middle section, which did not have anchor ice presumably because of the 

presence of surface ice. Catastrophic mortality from snow and ice events may not be as important as 

earlier thought, and that snow and ice disturbance may in fact be beneficial. Greater than 90 percent of 

all tagged fish recovered were in the original marked section of the stream, indicating little winter 

movement. · 

COMMENTS: 

This study was designed to determine winter habitat use in a future small-hydro diversion reach. Ice 

conditions were not quantified, but there were no differences in winter mortality between regions with 

extensive anchor ice and those areas without anchor ice. Movement of large rainbow trout was limited 

in the winter, with preferred habitat being pools greater than 0.5 meters deep with cover. Ice was rarely 

used as cover. Mortality in this study was low, at 32 percent, relative to other winter mortality studies 

quoted in the thesis. 

Report on Stream Ice Processes 
Annotated Bibliography 

Smith, R., and Dr. J. Griffith. Researchers find greatest enemy of Idaho rash: it's winter. 

WCATION OF STUDY: 

Henry's Fork River, Idaho. 

STREAM CHARACTERISTICS: 

None provided. 

J{EY\Voms 

TROUT WINTER 

BEHAVIOR 

HYDROELECTRIC PROJECT EFFECTS: N/A 

PHYSICAL EFFECTS OF ICE: 

Not discussed. 

BIOWGICAL EFFECTS OF ICE: 

Concealment cover is needed in the winter. Rainbow trout select habitat with a velocity range of 0 to 

6 centimeters per second near high-velocity areas. As concealment cover decreases in the winter (loss 

of macrophytes), juvenile rainbow abundance decreased. Fish moved from 1.5 kilometers downstream 

to .85 kilometers upstream in winter, in response to the loss of shoreline habitat as water level dropped. 

Caged fish studies showed that fish condition and water temperature were major factors influencing fish 

survival. Generally, the colder the water in the winter, the greater the condition factor that fish needed 

in the fall for them to survive through winter. 

COMMENTS: 

This article was received from FERC with insufficient information to identify the source citation details. 

Repon on Stream Ice Processes 
Annotated Bibliography 

Tack, E. 1938. Trout mortality from the formation of suspended ice crystals. FJShereiZeitung. 41:42 (Reviewed in Progressive Fish-Culturist 1937-38). 

WCATION OF STUDY: 

Hatchery Pond, Germany. 

STREAM CHARACTERISTICS: N/ A 

HYDROELECTRIC PROJECT EFFECTS: N/A 

PHYSICAL EFFECTS OF ICE: 

High wind coupled with freezing temperatures caused ice crystals to be mixed homogeneously in the 

water of a hatchery pond. Surface ice could not form. 

BIOWGICAL EFFECTS OF ICE: 

Out of several thousand rainbow trout fingerlings in a pond beset by an overnight freeze accompanied 

by high winds, about 100 died. Fish examined immediately after death showed mouths and gills plugged 

with small masses of ice sufficient to cause asphyxiation. Larger fish (no size quoted) in a neighboring 

pond subject to the same conditions experienced no difficulty from the ice crystals. 

COMMENTS: 

Study indicates fish can die directly from ice crystals in water. 

Report on Stream Ice Processes 
Annotated Bibliography 

Tsang, G., and L. Szucs. 1972. Field experiments of winter flow in natural rivers. The 

role of snow and ice in hydrology. Proceedings of the Banff Symposium, Alberta, Canada, 

September 1972. World Meteorological Organization; Geneva. 1:772-785. 

WCATION OF STVDY: 

RIVER ICE, 

FRAZIL ICE, 

ANCHOR ICE 

Nottawasaga River, southwestern Ontario, Canada and Peace River, Alberta, Canada. 

STREAM CHARACTERISTICS: 

230 cfs. minimum; 80ft. wide. 

HYDROELECTRIC PROJECT EFFECTS: N/ A 

PHYSICAL EFFECTS OF ICE: 

Channel resistance increased as surface ice cover increased. The result was an increase in stage and 

d~crease in flow velocity and volume. Ice formed first at the edges of the rivers and progressed toward 

the center. Decreasing water temperatures led to frazil ice production, which then froze onto the border 

ice and contributed to ice coverage. Most frazil ice formed during night and in early morning. No 

anchor ice was observed. Ice cover thickened through accretion of frazil ice produced upstream, 

accumulation and freezing of precipitation on top of the ice, and continued freezing of water to the bottom 

surface of the ice. Development of the ice cover caused very active lateral sediment transport as a result 

of changing velocity profiles. Ice cover breakup began with moderating temperature and progressed 

quickly over the course of a week. Discharge increased from 230 cfs to 700 cfs. 

BIOLOGICAL EFFECTS OF ICE: 

Not discussed. 

COMMENTS: 

None. 

Repon on Stream Ice Processes 
Annotated Bibliography 

Walsh, M., and D. Calkins. 1986. River ice and salmonids. 4th workshop on hydraulics 

of river ice, Montreal. U.S. Army Corps of Engineers, Cold Regions Research and 

Engineering Laboratory, Hanover, New Hampshire. 

WCATION OF STUDY: N/A 

R.Evwokos< 

RIVER ICE, 

SALMONID WINTER 

MORTALITY 

STREAM CHARACTERISTICS: N/ A 

HYDROELECTRIC PROJECT EFFECTS: N/A 

PHYSICAL EFFECTS OF ICE: 

This is a review article that draws upon previously published studies. It presents a useful 

qualitative/quantitative discussion of stages of ice formation and growth in streams. Major points are that 

freeze-up may lead to ice occupying up to 70 percent of the stream cross section; frazil ice deposited 

underneath an ice cover appears to accelerate growth of the solid ice sheet; fraziling may extend 

approximately into the bottom substrate; and ice jams can cause the stage in shallow streams to rise up 

to 1m. 

BIOLOGICAL EFFECTS OF ICE: 

See comments. 

COMMENTS: 

This article presents a literature summary of the effects of river ice on habitat of Atlantic salmon. The 

authors indicate four factors that were detrimental to over-winter survival: (1) crowding of juveniles from 

ice reduced habitat areas, (2) migration caused from overcrowding, (3) solid ice growth into the substrate, 

and (4) high velocity during ice cover breakup. Atlantic salmon juveniles move into the substrate in the 

winter below cobble and boulders up to 15 centimeters deep in the substrate. Low winter air 

temperatures and low winter discharge reduce egg-to-fry survival of Atlantic salmon. Frazil ice, in 

combination with surface ice, will increase freezing to the bottom. Freezing to the bottom may be the 

major problem for survival. Factors that inhibit ice growth into the substrate include snow cover and air 

voids from water level drops, geothermal heat, and high friction energy. Snow bridging is a form of 

insulation that is more common on narrow streams. For over-wintering Atlantic salmon, cover such as 

boulders is of primary importance, as these fish often penetrate into the substrate. Exact mechanisms of 

over-winter mortalities have not been defined, but key factors are stream depth and flow volume. 

Repon on Stream Ice Processes 
Annotated Bibliography 

Wankiewicz, A. 1984. Analysis of winter heat now in an ice-covered Arctic stream., 

Canadian Journal of Civil Engineering. 11:430-443. 

:: ~~¥\VoR.os 

ICE MODELING 

LOCATION OF STUDY: 

Caribou Creek near Inuvik, N.W.T., Canada; elevation not given. 

STREAM CHARACTERISTICS: 

0.5 cfs; width typically 6 m; depth typically 0.4 m; gradient not given. 

HYDROELECTRIC PRQJECT EFFECTS: N/A 

PHYSICAL EFFECTS OF ICE: N/A 

BIOLOGICAL EFFECTS OF ICE: N/ A 

COMMENTS: 

This paper is not directly applicable to small high-gradient streams. It also contains no discussion of 

biological effects. The paper presents a model of channel ice growth in the stream and a comparison of 

model results with observations. It may be useful as a source of modeling techniques and parameters for 

heat transfer processes associated with ice formation in flowing streams. 

Report on Stream Ice Processes 
Annotated Bibliography 

Wichers, D.L. 1978. Telemetric detennination or salmonid winter microhabitat occupation 

and movement in ice-covered streams. Master's Thesis, University or Wyoming, Laramie, 

Wyoming. 

LOCATION OF STUDY: 

SALMONID WINTER 

BEHAVIOR 

Albany County, Laramie River near Jehn, Wyoming. 

STREAM CHARACTERISTICS: 

Discharge range from a maximum daily discharge of 4,200 cfs to a minimum of 5.6 cfs and in the 

winter, is near 32 cfs. Ice cover persists from late November through February. Elevation is 7, 739 feet, 

banks contain willow, alder and grass, and hayfields are common. Contains good brown trout 

populations. 

HYDROELECTRIC PROJECT EFFECTS: N/A 

PHYSICAL EFFECTS OF ICE: 

Details of ice formation were not recorded during this study. Relative to ice-free conditions, the presence 

of ice reduced volume flow by about 4 percent, decreased water depth by 17 percent, and increased flow 

speed by 25 percent. 

BIOLOGICAL EFFECTS OF ICE: 

Sixteen brown trout, in excess of 11.5 inches long, were tagged and tracked from late fall into the winter 

for a period of no more than three months. Of all brown trout studied during the summer, 36 percent 

used water greater than 1.5 ft. deep, preferring low velocity regions less than 0.5 feet per second. After 

ice cover, the fish used low velocity regions, but preferred shallower water 0.55 to 0.99 feet deep. The 

fish apparently used ice as cover in the winter. Average ice thickness where most fish were often found 

was 1.34 feet. Majority of movement in September, October, and November was upstream, possibly 

based on spawning runs. As temperature cooled, movement decreased. Fish that were collected from 

other regions and moved tended to migrate back to their original region. Average distance moved by fish 

was 700 feet, with a maximum of 1,900 feet. The fish used rubble and ice for cover during the winter. 

COMMENTS: 

This study was done on a stream of medium size, moderate slope, and mostly covered with ice. It did 

not address anchor ice, as it was not a problem in this area. 

Repon on Stream Ice Processes 
Annotated Bibliography 

Wichers, D.L., T.A. Wesche, L.S., and Johnson, J.A. Gore. 1982. Two techniques for 

locating and sampling brown trout microhabitat under complete ice cover. Water 

Resources Research Institute Report 83. University of Idaho, Moscow, Idaho. 

WCATION OF STUDY: 

STREAM CHARACTERISTICS: 

COMPLETE ICE 

COVER 

HYDROELECTRIC PROJECT EffECTS: 

PHYSICAL EFFECTS OF ICE: 

BIOLOGICAL EFFECTS OF ICE: 

COMMENTS: 

The information contained in this paper re-iterates the findings presented in Wichers, D.L. 1978. 

Telemetric determination of salmonid winter microhabitat occupation and movement in ice covered 

streams. Masters Thesis, University of Wyoming, Laramie, Wyoming. Refer to that citation for 

annotations. 

Report on Stream lee Processes 
Annotated Bibliography 

Wigle, J .E. 1970. Investigations into frazil, bottom ice, and surface ice fonnation in the 

Niagara River. Proceedings of the International Association for Hydraulic Research Ice 

Symposium 1970, Reykjavik, Iceland. 

LOCATION OF STUDY: 

: , kEv}wolU)s . :,:,::-

FRAZIL ICE, 

ANCHOR ICE 

Upper Niagara River between Lake Erie and Niagara Falls. 

STREAM CHARACTERISTICS: 

190,000 cfs; average depth is 12 feet; no other data were given. 

HYDROELECTRIC PROJECT EFFECTS: None 

PHYSICAL EFFECTS OF ICE: 

This river is definitely not a small, high-gradient system. However, the paper does present results of 

observations which showed that frazil and anchor ice did not form on sandy bottom, but only on rocky 

substrate. Frazil ice formation and flocculation were also observed. 

BIOWGICAL EFFECTS OF ICE: N/ A 

COMMENTS: 

None. 

Report on Stream Ice Processes 
Annotated Bibliography 

Williams, G.P. 1972. A case history of forecasting frazil ice. The role of snow and ice in 

hydrology. Proceedings of the Banff Symposium, Alberta, Canada. September 1972. 

World Meteorological Organization; Geneva. 2:1212-1223. 

LOCATION OF STUDY: 

FRAZIL ICE, 

ICE FORECASTING 

Ottawa River, between Ottawa, Ontario and Hull, Quebec, Canada. 

STREAM CHARACTERISTICS: 

None given, this is a large river system. 

HYDROELECTRIC PROJECT EFFECTS: 

Frazil ice collection on intakes affects operation. 

PHYSICAL EFFECTS OF ICE: 

Rate of heat loss at a given site gives an indication of potential magnitude of frazil ice formation. For 

this study, frazil ice was a problem when water was at or very near the freezing point and heat loss 

averaged more than 30 cal/cm2 per hour over the preceding 12-hour period. Convective heat loss was 

the most important factor affecting frazil ice formation, but long-wave and short-wave radiation and 

evaporation exerted strong influence, depending on weather conditions. Heat exchanges were greater in 

early fall, when the area of open water was greater relative to spring breakup. This meant that in fall, 

the winter temperature decreased faster than it increased in spring. Water temperatures in early fall were 

still above freezing. 

BIOLOGICAL EFFECTS OF ICE: 

Not discussed. 

COMMENTS: 

None. 

Report on Stream Ice Processes 
Annotated Bibliography 

No author listed. No date, but literature as recent as 1984 is cited. Effects of winter 

conditions on fish life of eastern sierra streams of Inyo and Mono Counties. California 

Department of Fish and Game. 

WCATION OF S'fUDY: 

No study was made. 

STREAM CHARACTERISTICS: N/A 

STREAM ICE, 

WINTER FISH 

MORTALITY 

HYDROELECTRIC PROJECT EFfECTS: N/A 

PHYSICAL EFFECTS OF ICE: N/ A 

BIOWGICAL EFFECTS OF ICE: N/A 

COMMENTS: 

This is a literature review concerning effects of winter conditions on streams and associated biological 

populations. It does not describe studies actually carried out in streams in Inyo and Mono counties, 

California, but rather infers probable effects on the basis of published findings from other studies. Major 

causes of winter mortality were speculated to be snow bank/bridge collapse and scouring and dewatering 

caused by anchor ice. The data presented did not support directly that anchor ice is the direct cause of 

mortality. This document is a good summary of the behavior of trout in winter and the alleged effects 

that occur in trout populations during winter. 

This article is Attachment A of a document originated by the California Department of Fish and Game. 

The article was received from FERC with insufficient information to identify the source citation details. 

Repon on Stream Ice Processes