CRREL REPORT 95-10

Winter Navigation on the Great Lakes

A Review of Environmental Studies

James L. Wuebben, Editor May 1995
Abstract

In 1970, Congress authorized a three-part Great Lakes–St. Lawrence Seaway

Navigation Season Extension Program. It authorized a winter navigation demonstration program, a detailed survey study of season extension feasibility

and a study of insurance rates for shippers. This report provides a review of

numerous environmental and engineering studies conducted as part of the

demonstration and feasibility portions of the program, as well as many environmental studies conducted after the completion of the original program.

Topics include sediment transport, shoreline erosion, shore structure damage, oil and hazardous substance spills, biological effects, ship-induced vibrations and ice control systems.

For conversion of SI units to non-SI units of measurement consult ASTM

Standard E380-93, Standard Practice for Use of the International System

of Units, published by the American Society for Testing and Materials,

1916 Race St., Philadelphia, Pa. 19103.

Cover: The John G. Munsun in the St. Marys River.
CRREL Report 95-10

Winter Navigation on the Great Lakes

A Review of Environmental Studies

James L. Wuebben, Editor May 1995

Prepared for

U.S. ARMY ENGINEER DISTRICT, DETROIT

Approved for public release; distribution is unlimited.

US Army Corps


of Engineers

Cold Regions Research &


Engineering Laboratory
ii

PREFACE

This report was edited by James Wuebben, Research Hydraulic Engineer, Ice Engineering Research Division, Research and Engineering Directorate, U.S. Army Cold Regions Research and Engineering Laboratory. The various sections of the report were

written by other CRREL researchers as follows:

Introduction

Stephen L. DenHartog, formerly of the Ice Engineering Research Division

Sediment Transport, Shoreline Erosion and Shore Structure Damage

James L. Wuebben, Ice Engineering Research Division

Oil and Hazardous Substance Spills

Steven F. Daly, Ice Engineering Research Division

Biological Effects

James L. Wuebben, Ice Engineering Research Division

Vibrations Caused by Ship Traffic

F. Donald Haynes, Ice Engineering Research Division

Bubbler Systems

George D. Ashton, Deputy Director for Research and Engineering

Ice Control Structures

Russell E. Perham, formerly of the Ice Engineering Research Division

Ice Control at Locks

John H. Rand, Research and Engineering Directorate.

This report was prepared for the Detroit District, U.S. Army Corps of Engineers under Intra-Army Reimbursable Order NCE-IA-860127. This literature review summarizes

selected investigations conducted under the Great Lakes–St. Lawrence Seaway Winter

Navigation Demonstration Program, the Navigation Season Extension Feasibility Program and the Extended Season Navigation program under Operation and Maintenance

Authority. It is not meant to be an all-inclusive, state-of-the-art review of the engineering, physical and environmental effects of navigation in winter but rather a comprehensive review of work conducted on the Great Lakes system in support of the season extension programs. While the sections on ice control might be better classified as reviews

of engineering projects rather than environmental studies, they have been included because of their bearing on flow hydraulics, ice characteristics and shipping operations.

The review primarily covers those reports specifically identified by the District for inclusion, but these have been supplemented with additional information when necessary

for completeness.

The contents of this report are not to be used for advertising or promotional purposes. Citation of brand names does not constitute an official endorsement or approval

of the use of such commercial products.
iii

CONTENTS

Page

Preface ................................................................................................................................. ii

Introduction ........................................................................................................................ 1

Sediment transport, shoreline erosion and shore structure damage ......................... 2

Physical effects of commercial navigation in ice ...................................................... 3

Ship waves ..................................................................................................................... 3

Propeller wash ............................................................................................................... 4

Drawdown and surge .................................................................................................. 5

Sediment transport and shoreline erosion ................................................................ 8

Shore structure damage ............................................................................................... 13

Dynamic horizontal ice forces ..................................................................................... 13

Vertical ice forces .......................................................................................................... 15

Field studies of structure damage .............................................................................. 18

Summary ........................................................................................................................ 20

Oil and hazardous substance spills................................................................................. 20

Spill scenarios ................................................................................................................ 21

Identification of probable spill materials .................................................................. 22

Determination of spill probabilities ........................................................................... 22

Identification of spill impacts...................................................................................... 22

Existing contingency plans .......................................................................................... 23

Response capabilities and recovery techniques ....................................................... 23

Modeling oil and hazardous substance spills........................................................... 24

Biological effects ................................................................................................................ 24

Water quality ................................................................................................................. 24

Benthic macroinvertebrates ......................................................................................... 27

Aquatic plants ............................................................................................................... 30

Fish .................................................................................................................................. 31

Birds ................................................................................................................................ 35

Summary ........................................................................................................................ 36

Vibrations caused by ship traffic ..................................................................................... 36

Engineering and environmental effects of heat-transfer bubbler systems................ 38

Environmental effects .................................................................................................. 38

Ice control structures ......................................................................................................... 39

St. Lawrence River ........................................................................................................ 40

Lake Erie ......................................................................................................................... 40

St. Marys River .............................................................................................................. 40

Reference measurements ............................................................................................. 43

Port Huron ..................................................................................................................... 43

Ice control at docks ............................................................................................................ 44

Minimizing ice adhesion to lock walls ...................................................................... 45

Mechanical ice removal................................................................................................ 46

Floating ice control ....................................................................................................... 46

Summary ........................................................................................................................ 47

Literature cited ................................................................................................................... 47

Abstract ............................................................................................................................... 53
iv

ILLUSTRATIONS

Page

Figure

1. The Great Lakes region .......................................................................................... 2

2. Maximum wave heights 100 ft from the sailing line for a variety of

hull forms......................................................................................................... 3

3. Damping of waves at an ice edge ........................................................................ 4

4. Ship-induced water movements .......................................................................... 5

5. Effects on drawdown due to changes in variables from a basic case ............. 7

6. Velocity, water surface elevation and sediment movement measurements

during vessel passage .................................................................................... 9

7. Relation of water level to a shore profile on the St. Marys River .................... 10

8. Horizontal movement of ice against rocks in early winter .............................. 14

9. Spring breakup on the St. Marys River ............................................................... 14

10. Series of finger piers damaged by ice jacking..................................................... 15

11. Aerial view of Johnson’s Point, showing active crack offshore of

structures ......................................................................................................... 16

12. Private dock on the St. Marys River with protective pile clusters................... 16

13. Active crack passing through a damaged dock ................................................. 17

14. Horizontal member of dock in contact with the ice cover ................................ 17

15. Location of test sites on the St. Marys River ....................................................... 36

16. Vibration instrumentation layout ......................................................................... 37

17. Magnitude of vibrations for the Roger Blough passing the Gordon site ....... 37

18. Schematic of a bubbler system .............................................................................. 38

19. Location of the St. Marys River ice control structures....................................... 41

20. Details of the St. Marys River ice boom ............................................................... 42

21. Location of the Port Huron ice control structure ............................................... 44

22. Schematic of an air screen ...................................................................................... 46

TABLES

Table

1. Summary of oil spills on the Great Lakes connecting channels......................... 21

2. Peak loads on the St. Marys River ice boom, 1976 ............................................... 42
INTRODUCTION

In 1970, Congress authorized a three-part Great

Lakes–St. Lawrence Seaway Navigation Season

Extension Program in the Rivers and Harbors Act

of 1970 (PL91-611) and subsequent amendments.

It authorized a demonstration program, a detailed

survey study of season extension feasibility and

a study of ways to provide reasonable insurance

rates to shippers. Since that time, there has been

a series of investigations conducted by the U.S.

Army Corps of Engineers on extending the navigation season on the Great Lakes and St. Lawrence

Seaway system. From 1970 to 1979, with an expenditure of about $21 million, a large number of environmental and engineering studies and demonstrations were completed by the U.S. Army Corps

of Engineers (COE), U.S. Coast Guard (USCG),

St. Lawrence Seaway Development Corporation

(SLSDC), U.S. Fish and Wildlife Service (FWS),

National Oceanic and Atmospheric Administration (NOAA), Maritime Administration (MARAD),

Environmental Protection Agency (EPA) and

others.

The demonstration program was administered

by a Winter Navigation Board, which in turn set

up seven working groups as follows: Ice Information, Ice Navigation, Ice Engineering, Ice Control,

Ice Management, Economic Evaluation, and Environmental Evaluation. Primary organizational

responsibility was handled by the Detroit District, COE. Under the demonstration portion of

the program, the working groups, for example,

developed ice cover reporting and prediction

schemes, conducted studies of fish habitat and

winter shore damage, determined future needs

for icebreakers and harbor improvements, and

found methods to overcome lockage delays due

to ice.

Concurrently a survey study was undertaken

to determine how long a season extension was

feasible and whether it would be the same for all

reaches of the waterway. It soon became clear that

there are three reaches with different problems

that had to be considered separately:

• The St. Lawrence River section of the St.

Lawrence Seaway and the Welland Canal

from Tidewater to Lake Erie;

• The Detroit and St. Clair River portion; and

• The upper lakes including the St. Marys River

and the locks at Sault Ste. Marie.

Six time extensions were considered, ranging

from the status quo (with closure of the Sault Locks

and the St. Lawrence Seaway from late December to early April) to year-round navigation on

the entire system (except for a one-month closure

on the Seaway). An interim feasibility report was

completed in 1977 recommending season extension to 31 January ±2 weeks on the upper Great

Lakes only. This would require very few engineering measures. The final recommendation of

the final demonstration and survey reports (WNB

1979, USACE 1979a) was that, from an engineering and economic standpoint, year-round navigation was feasible on the upper two reaches, and

a two-month closure (from 7 January to 7 March)

would be necessary on the lower reach. The recommended plan projected a total investment cost

of $451 million with a 4.0 benefit-to-cost ratio.

The Office of Management and Budget, in response

to the 1977 interim feasibility report, recommended

that, since the Corps already had authority to

operate the locks and maintain navigation, limited extension be considered under operation and

maintenance authority. Consequently the Detroit

District addressed operation of the locks at Sault

Ste. Marie, Michigan, to 8 January ±1 week in an

October 1979 environmental impact statement

Winter Navigation on the Great Lakes

A Review of Environmental Studies

JAMES L. WUEBBEN, EDITOR
Figure 1. The Great Lakes Region.

Topics covered in this report include sediment

transport, shoreline erosion, shore structure damage, oil and hazardous substance spills, biological effects, ship-induced vibrations, bubbler systems, ice booms and ice control at locks. For the

most part the reports covered are those selected

by the Detroit District for inclusion, but additional

materials have been included as necessary for completeness. In many cases the studies of a particular topic extended over several years, with the

more recent reports including information published in prior years. In those instances, emphasis was placed on the final, comprehensive versions. More detailed and extensive reviews of

methods for dealing with river and lake ice problems can be found in Ashton (1986) and USACE

(1982).

SEDIMENT TRANSPORT,

SHORELINE EROSION AND

SHORE STRUCTURE DAMAGE

In this section, reports dealing with the effects

of extended season navigation on sediment transport, shoreline erosion and shore structure damage are reviewed. As a starting point the physical effects of vessel passage on river hydraulics

are reviewed in some detail since they form a com-

(EIS) and is now operating the locks up to 8 January

±1 week. In 1981 the District began considering

operating the locks to as late as 31 January ±2

weeks. Studies have been conducted since that

time in preparation of an EIS for that proposal. A

draft EIS was completed in 1988 (USACE 1988).

The St. Lawrence Seaway is currently being operated under traditional season guidelines.

This report provides a review of numerous environmental and engineering studies conducted

under the Extended Season Navigation Programs,

including many environmental studies conducted

after the publication of the 1979 Final Survey Report under Operation and Maintenance Authority. These later studies were undertaken to support the preparation of environmental impact statements for extended operation of the lock facilities at Sault Ste Marie, Michigan, to 8 January ±1

week and subsequently 31 January ±2 weeks. The

Survey Study and Demonstration Program covered all U.S. portions of the Great Lakes–

St. Lawrence Seaway System shown in Figure 1.

Most environmental analyses, however, were conducted on the St. Lawrence, Detroit, St. Clair and

St. Marys Rivers, especially the St. Marys, where

the confined waterways were considered to

present the greatest potential for damage. The 8

January ±1 week and 31 January ± 2 weeks program concerned the upper Great Lakes only.

2
rily a function of vessel speed (Gates and Herbich

1977). Figure 2 was developed by Ashton (1974a)

from data presented by Sorenson (1973) for waves

generated by boats with displacements from 3 to

343 tons. These data were derived from measurements in the Oakland Estuary (California) in a

water depth of about 35 ft for various ship speeds.

Although this figure ignores depth and draft effects, there is remarkably little scatter. The figure

serves to show the strong relation between the

maximum wave height 100 ft from the sailing line

Hmax,100 and ship velocity V. In fact, Ofuya (1970),

in his study of ship waves on the Great Lakes

connecting channels, concluded that the essential parameters influencing wave height were ship

speed and distance from the sailing line. He was

unable to factor out the effects of vessel size or

hull geometry due to the small variations caused

by factors other than vessel speed. Ofuya also cited

the results of wave data collection at three sites

on the St. Clair River and one each on the Detroit

and St. Lawrence Rivers. For gauges located in

5–25 ft of water, very few waves were measured

in excess of 0.6 ft, and then only when the speed

limit was significantly exceeded. Further data on

ship-generated, open-water waves on the Great

Lakes connecting channels are presented in the

report by USACE-SLSA (1972).

mon basis for potential damage mechanisms discussed in later sections dealing with specific impacts.

Physical effects of

commercial navigation in ice

Vessel passage through confined waterways

may result in changes in the pattern and magnitude of water motion due to ship-generated waves,

propeller wash, and drawdown and surge. A confined waterway is defined as one in which the

shoreline or bottom is close enough to influence

ship-generated water movements. These changes

in the flow of water can, if large enough, cause

the movement of particulate materials, leading

to erosion of the shoreline and the channel bed,

damage to shoreline structures, increases in turbidity and other chemical and biological effects.

In addition to these mechanisms, which occur yearround, additional effects during navigation in ice

might occur due to direct movement of ice in contact with vessels, by disruption of stable natural

ice covers, and through interaction of vessel-induced hydraulic effects with the ice cover. The

size and significance of these potential mechanisms depend on a number of local conditions,

such as the bathymetry, water levels, surficial soil

conditions, ice conditions, shore and shore structure composition and geometry, and presence of

other natural agents such as water currents or

waves.

Ship waves

The generation of water waves during vessel

passage is the mode of action most often associated with ship-induced effects in the nearshore

zone. When a ship sails in ice-free open water, a

system of diverging and transverse waves develop.

Diverging waves are those that form the familiar

V-shaped wave pattern starting at the bow of a

ship, while transverse waves form a less noticeable wave train that follows the vessel and is oriented normal to the sailing line.

Due to the decay of the waves as they propagate away from the ship and the interaction between these dissimilar wave sets, the generated

wave heights are a strong function of position.

The location of maximum wave heights, referred

to as cusps, occur where the crests of the two wave

types intersect so that they reinforce each other.

The wave heights at these cusp locations decrease

inversely proportionally to about the cube root

of the distance from the disturbance.

The height of ship-generated waves is primaFigure 2. Maximum wave heights 100 ft from the sailing line for a variety of hull forms. (From Ashton 1974.)

3
Wuebben et al. (1984) analyzed the variation

in ship-generated waves with vessel size on the

St. Marys, St. Clair and Detroit Rivers. For the

44 shoreline sites considered, the waves generated by a 1000-ft vessel traveling at existing speed

limits were calculated to be no more than about

0.5 ft in amplitude at the shoreline. Although

equations are available for predicting ship-generated wave heights and their subsequent decay in open water, none adequately address situations involving shallow water or confined or

irregularly shaped channels accompanied by

complex flow distributions such as those found

in the Great Lakes connecting channels. Without site-specific field data to calibrate and check

the calculated values, any projections made must

be considered approximate. The available theories do, however, clearly show that vessel speed

is by far the most important variable controlling the magnitude of ship waves generated, followed by the distance to the shoreline, which

governs their decay.

During winter ice conditions, the short-period

waves generated by vessel passage are effectively

damped by the ice cover. As part of a study of

the effects of winter navigation on shoreline erosion and structure damage (USACE 1974), continuous measurements of water level variations

during ship passage were collected at several locations on the St. Marys River during periods with

and without an ice cover. These data clearly

showed both wind- and ship-generated waves

during open-water periods, but during periods

with ice covers no waves were detectable.

Figure 3 from Carter et al. (1981) shows the

effect of an ice cover on the height of waves encountering an ice cover. Relative wave amplitude

is defined as the height of a wave passing under

the ice divided by the height of that same wave

under open-water conditions. Based on data given

in USACE (1974) and Ofuya (1970), the wave period for ships on the Great Lakes connecting channels is on the order of 2–4 s. Thus, according to

Figure 3, these ship-generated waves would be

drastically attenuated during navigation in ice

relative to their open-water heights (a 3-ft, 3-s wave

would be reduced to 0.3 ft by a 1.5-ft-thick ice

cover). Further, since these waves decay rapidly

(even in open water) as they propagate from the

ship, these waves are considered to be insignificant and will not be addressed further.

Propeller wash

During vessel passage the bottom and sides

of a channel may be subjected to a propeller-driven

water jet. There has been very little study of sedi1.0

0.8

0.6

0.4

0.2

0 10 20 30

Wave Period (s)

Relative Wave Amplitude

Ice Thickness, 2.0 m

1.0

0.5

0.25

Figure 3. Damping of waves at an ice edge. The water

depth is 10 m. (From Carter et al. 1981.)

ment transport or other effects due to prop wash,

and there were no data available for the Great

Lakes–St. Lawrence Seaway area. Most previous

studies of the damage potential of winter navigation were focused on shoreline and nearshore

effects. As a result, prop wash effects were typically disregarded since they are normally limited

to areas very close to the vessel track.

In a study of the effect of vessel size on shiprelated damage, Wuebben (1983a) selected empirical relations based on their ability to deal with

the variation in propeller jet velocity for locations

with limited depth or lateral confinement. Lacking any calibration data from the Great Lakes system, he was unable to provide site-specific, quantitative predictions, but he did conclude that fully

loaded commercial vessels are easily capable of

scouring the channel bed throughout the dredged

portions of the connecting channels. He also found

that vessel speed was by far the most important

factor determining the magnitude of prop wash,

followed by cross-sectional area and hull geometry. For confined channels, hydraulic interaction

with the channel boundaries requires a higher

propeller thrust to maintain open-water speed,

increasing the damage potential.

Hochstein and Adams (1985b, 1986) modified

their existing prop wash numerical model for application to the St. Marys River by incorporating

appropriate ship and site characteristics and transferring other necessary information from earlier

studies on the Kanawha and Ohio Rivers in West

Virginia and Ohio. They concluded that the effects of prop wash could not be effectively separated from backwater (drawdown) influences, so

they considered both simultaneously. Through a

4
combination of basic theory and empiricism, they

provided a quasi-two-dimensional prediction of

vessel effects. The “quasi” prefix is used since the

two-dimensional predictions are premised on empirically assumed distributions of ambient and

ship-affected velocities. Without collecting appropriate field data (which they recommend), the performance of these assumed distributions in the

complex, dredged channel portions of the river

cannot be accurately assessed. However, the model

has been verified against all available Great Lakes

connecting channel data.*

In their reports Hochstein and Adams have

accounted for the effects of ice in terms of the

added propeller thrust required to maintain speed.

This was accomplished by assuming that the propeller jet velocity for a ship in ice increased as

the square of its equivalent open-water velocity.

In their comparison of the effects of prop wash

for various sizes of vessels traveling at existing

speed limits, they often found that the maximum

effects of lower-class vessels reached a maximum

when their available horsepower was insufficient

to maintain speed. Thus, the largest and most highpowered vessels could induce substantially larger

propeller-induced effects than size alone might

indicate. Quantitative, site-specific predictions of

ship-induced velocity distributions across selected

river cross sections were provided.

Drawdown and surge

When a vessel is in motion, even in deep water, the water level in the vicinity of the ship is

lowered and the ship with it (called vessel squat).

For the same ship this effect increases as the vessel speed increases or as the water depth decreases.

When a ship enters a confined water, there is a

considerable change in flow patterns about the

hull. The water passing beneath the hull must pass

at a faster rate than in deep water, and as a result

there is a pressure drop beneath the vessel, which

increases vessel squat. In a channel that is restricted

laterally, this effect is further exaggerated.

There is, however, another problem associated

with the water level drop caused by the movement of a ship in confined waterways. The water

level drop becomes, in effect, a trough extending

from the ship to the shore and moves along the

channel at the same velocity as the ship. As the

ship size or speed increases, this moving trough

* Personal communications, Don Williams, Detroit District, COE.

Figure 4. Ship-induced water movements. (From Wuebben

et al. 1978a.)

deepens. For the restricted sections of the Great

Lakes channels, this effect might most easily be

envisioned as a channel constriction such as a

bridge pier.

The phenomenon of nearshore drawdown and

surge may be explained in terms of the moving

trough. In sufficiently deep water the moving

trough appears as a fluctuation of the elevation

of the water surface. To an observer in a shallow

or nearshore area where the depressed water level

approaches or reaches the riverbed, the water appears to recede from the shoreline as the ship

passes; this is followed by an uprush and finally

a return to the normal level after the vessel-induced surface waves are damped. To analyze the

mechanics of sediment motion during vessel passage, two-dimensional, near-bottom velocity measurements were collected at a number of locations

along the St. Marys, St. Clair and Detroit Rivers

during periods with and without ice (Alger 1977a,

1978, 1979a, Wuebben et al. 1978a).

An example of these measurements (from

Wuebben et al. 1978a) is presented in Figure 4 to

illustrate the magnitude and complexity of the

situation. The figure presents water velocities under the ice cover during the passage of a 670-ft

ore carrier near Six Mile Point on the St. Marys

River. The observation point was located in about

10 ft of water, and there was an ambient velocity

5
of about 0.3 ft/s. The direction of the near-bottom

water motion rotated 360° during the event, with

velocities in all directions significantly greater than

the ambient downstream current. Numerous other

data sets for the variation of water level and velocity are available in the reports by Alger (1977a,b,

1978, 1979a,b). Nearshore drawdowns of up to 3

ft have been measured on the connecting channels (USACE 1974, Wuebben 1978), but the highest recorded values have been for large vessels

approaching or exceeding the speed limits. A field

study of drawdown and surge on the St. Lawrence

Seaway (Normandeau Associates 1979) documented no drawdown events greater than 2 in.

and felt that no reasonable correlation with vessel parameters was possible.

Ice effects

In a study of the effects of winter navigation

on shoreline erosion and dock damage (USACE

1974), continuous recordings of water level fluctuations were collected at various sites along the

St. Marys River. While the ship- and wind-generated waves were well defined in the open-water recordings, they were undetectable for periods with ice cover, indicating total damping. In

contrast, ship-generated drawdown and surge

were undamped and apparently even enhanced.

From data at an individual site, the authors

were able to get a reasonable correlation between

measured drawdown values and an estimate of

the drag force on a ship hull (USACE 1974). At

one site on the mainland shore of Lake Nicolet,

ship passages were monitored during openwater conditions, early ice (0.3–0.5 ft) and midwinter ice (1–1.3 ft). Although a comparison of

the drawdown and surge among these three conditions is somewhat limited by the relatively few

data points (22) and the scatter inherent in making such measurements, their parameterization

technique indicates that a drawdown of 0.4 ft

during open-water conditions might be increased

by about 40% during periods with ice. The data

did not indicate any clear difference with increasing ice thickness.

Hodek et al. (1986) also examined the effect of

ice on the magnitude of drawdown. Although the

flexure and cracking of an ice cover would dissipate some energy, they felt that the primary effect of an ice cover would be to decrease the area

available for flow and thus increase the magnitude of drawdown. On that basis, smaller cross

sections would be more severely affected by ice

since the same thickness of ice would constitute

a larger percentage of the water area in moreconfined channel reaches. The numerical model

accompanying their report accounts for both a

change in vessel effects with the presence of ice

and with increasing ice thickness. For one example given, a 1-ft open-water drawdown would

be increased as much as 33% for 18 in. of ice. For

the same ice condition, the percentage increase in

drawdown would increase as ship speed increased.

Analysis of drawdown

Most analytical and predictive work on drawdown in the Great Lakes connecting channels has

employed a one-dimensional approach. Although

a multi-dimensional treatment would provide

more detail, especially in regard to water velocities, there are insufficient data to calibrate or validate an expanded treatment. Fortunately field data

(Wuebben et al. 1978a) show that the magnitude

of drawdown is relatively constant over most of

the channel cross section during vessel passage

and that a one-dimensional treatment predicts this

value within acceptable accuracy (Alger 1977a,

Wuebben 1983a, Hodek et al. 1986).

If the channel cross section is not symmetrical

or the ship passes closer to one shore, the onedimensional results can be improved by assuming that no water crosses the sailing line so that

the section may be split into separate pieces for

calculation (Wuebben 1983a, Hodek et al. 1986).

For highly non-uniform flow distributions or complex channel shapes, empirical cross-section shape

factors can also be included, but these are highly

site specific and cannot be reliably transferred elsewhere (Wuebben 1983a). The distribution of velocities and sediment transport potential across

a river cross section cannot be directly considered, however. Previous work has generally used

the existing field database to develop shore and

shore structure damage criteria that can be empirically correlated to one-dimensional modeling

(Wuebben 1981b, 1983a, Wuebben et al. 1984,

Hodek et al. 1986).

Wuebben (1981b, 1983a) and Wuebben et al.

(1984) developed such a one-dimensional treatment to allow an assessment of vessel size on drawdown and resulting sediment transport potential.

For the long, parallel mid-body commercial vessels common on the Great Lakes, vessel length is

relatively insignificant in determining drawdown.

A sensitivity analysis demonstrated that ship velocity is by far the most important variable controlling the magnitude of drawdown. As shown

in Figure 5, a change in vessel speed of 2 ft/s would

6
bidity, an estimate of the surge (increase in water

level) that often follows the drawdown phase, and

an estimate of shore structure damage potential

for basic structural categories were included. They

also found that drawdown is very sensitive to

the position of a vessel within the channel. The

capability to predict the magnitude of the surge

that follows the drawdown phase is important

in evaluating whether an onshore bluff will be

attacked or whether nearshore flooding during

high-water periods will be exacerbated, whereas

the values of turbidity are significant in the potential for biological impacts.

Hochstein and Adams (1985b) adapted a model

that considers drawdown and the effects of propeller wash to the St. Marys River. A subsequent

report (Hochstein and Adams 1986) added treatment of ship-generated waves. Their model is attractive for assessing environmental effects in that

it makes quantitative predictions of the distribution of water velocity, suspended solids and bed

load across a river cross section based on prop

wash, waves and drawdown. The numerical formulation they employed is a quasi-two-dimensional treatment in that it conducts hydraulic calculations in one dimension and then superimposes

assumed distributions for the cross-channel variations of both ambient and ship-influenced flow

variables. While in simple channel shapes this approach may provide useful additional detail, extension to the complex channel shapes and flow

distributions present in the St. Marys River is unbe more significant than a 10-ft change in vessel

beam, vessel draft or channel depth. The basic

case in Figure 5 is a ship with a 25-ft draft and

100-ft beam traveling in a rectangular channel 35

ft deep and 2000 ft wide. The ship velocity relative to the water is 12 ft/s. This corresponds to

the central point on Figure 5.

Vessel speed and water velocity are of equal

importance in the calculations, but due to its

greater range of variation, vessel speed is more

significant in practical applications. An increase

in vessel draft is more significant than an equal

increase in beam simply because it geometrically

adds more cross-sectional area to the ship. Similarly, an increase in water depth (with discharge

unchanged) would more than offset the corresponding increase in allowable draft since the

increase in flow area across the river is much larger

than the change in the wetted area of the ship.

The net effect is a decrease in the blockage of the

channel.

Hodek et al. (1986) and Alger and Hodek (1986)

further refined the one-dimensional approach and

developed an interactive, user-friendly program

that could be run on a desktop computer system.

This model allows rapid computation and comparison of various scenarios of fleet mix and site

characteristics. The database for ship effects was

considerably expanded by monitoring hydraulic

conditions at five new sites on the St. Marys River

in addition to those documented under previous

studies. New topics such as vessel-generated turFigure 5. Effects on drawdown due to changes in variables from a basic

case.

7
certain. However, the Hochstein and Adams model

should provide an improved basis for comparison of various vessel frequency scenarios. This

model was subsequently modified by personnel

from the Detroit District to allow input of measured ambient velocity distributions, but the

hydraulic calculations remain one dimensional.

Treating ship effects in two dimensions is important due to significant variation in ship-induced

water velocities across a river cross section. This

variation must be accounted for in predicting magnitudes of sediment transport, turbidity and impacts on biological systems.

Data from a prior study on the Kanawha River

in West Virginia (Hochstein and Adams 1985a)

were compared with predicted values, but the results are not presented in two-dimensional form.

Further, no information is given on river or ship

characteristics or the location of the sampling

points, so the feasibility of transferring velocity

distributions and parameter values developed

there to a Great Lakes connecting channel is unclear. Lacking a complete, two-dimensional set

of field data on the variation of ship-induced water

velocities and sediment movement on the St.

Marys River (which they strongly recommended

obtaining), the performance of the model cannot

be definitely assessed. It was, however, calibrated

against the available data on ship-generated drawdown and waves. The model was also applied to

channels in Duluth–Superior Harbor* and resulted

in predictions of sediment suspension of the same

order of magnitude as the field data of Stortz and

Sydor (1980).

In summary, the major hydraulic effects of vessel passage during periods of ice include propeller wash and drawdown and surge. Ship-induced

waves were found to be quickly damped by an

ice cover and thus unimportant. In contrast, propeller wash and drawdown can be increased due

to the need for greater thrust to overcome the resistance of ice and the reduction of open crosssectional area by the ice. Several models have been

developed for or adapted to the Great Lakes connecting channels for predicting vessel-induced

drawdown, providing both one-dimensional and

two-dimensional predictions. The two-dimensional approach also considers ship waves and

propeller wash effects. These models provide a

capability to develop system-wide predictions of

vessel effects, not only for existing navigation

* Personal communication, Don Williams, Detroit District, COE.

scenarios but more importantly for scenarios considered for possible future implementation where

field documentation is not possible.

Sediment transport

and shoreline erosion

The potential for shore damage due to drawdown is a direct function of the ship-induced

change in hydraulic conditions that can initiate

sediment transport or increase transport rates. For

sediment transport to occur, near-bottom or

nearshore water velocities must overcome a sediment particle’s resistance to motion. Three modes

of transport of granular bottom sediments have

been observed during vessel passage (Wuebben

et al. 1978a). They are

• Bed load, which is typified by a pattern of

slowly migrating sand ripples on the riverbed;

• Saltation load, the movement of individual

grains in a series of small arcs beginning and

ending at the riverbed; and

• Explosive liquefaction, in which bottom sediment is rapidly suspended due to a rapid

change in the soil pore-water pressure gradient.

Bed load is the most commonly observed transport mode, with a progression to saltation and

liquefaction for events with larger, faster ships.

For the cohesive sediments that are widely distributed in the Great Lakes system, disrupted sediments typically go directly into suspension, where

they can remain for extended periods. Hodek et

al. (1986) and Liston and McNabb (1986) made

field measurements of turbidity and light extinction profiles under both ambient and ship-influenced conditions on the St. Marys River. According to Hodek et al. (1986), during open-water

periods, turbidity develops due to wind-driven

waves acting on clay bluffs and the nearshore riverbed. For waves on the order of 6 in. or more

in height, they observed that a high level of turbidity may develop, extending from the shore to

the navigation channel, and no increase in turbidity could be detected during ship passage

during periods of wind-driven waves. In the absence of wind-driven waves, they stated that nearshore turbidity develops with the passage of each

vessel. This topic is discussed further in the section dealing with biological effects.

As discussed previously, a drawdown and

surge event can cause water movements in all directions, so that sediment transported in one direction may be offset during an opposing current.

8
sage presented in Figure 6, so that all transport

should be ship induced. The direction of net transport has been found to be sensitive to the characteristics of a specific site, the vessel direction and

the magnitude of the drawdown event. In this

case the net transport was primarily upstream and

slightly offshore, as indicated by the vector R in

Figure 6.

 Further data on sediment transport during

vessel passage can be found in Alger (1978,

1979a,b) and Hodek et al. (1986). The data analysis by Hodek et al. showed that downbound ships

caused much less sediment transport than

upbound vessels at comparable drawdowns. It

also showed that upbound vessels creating a drawdown of 6 in. or less cause relatively little disturbance. For data indicating net transport, 83% of

upbound ships and 70% of downbound ships

caused net offshore movement.

However, natural currents, a sloping bottom and

the intensity and duration of vessel-generated

currents can combine to cause net transport in

almost any direction. Figure 6 shows velocity and

stage measurements for a vessel passing Nine Mile

Point on the St. Marys River at 10 mph (Alger

1978). In the velocity graph the axes define the

magnitude of water velocity with time, while the

direction of water movement at any particular

time is indicated by the superimposed arrow.

Sediment transport was also measured during that event using an array of four traps oriented in 90° increments. The traps had been set

for a 20-minute period prior to vessel passage,

and no sediment was collected in any of the traps.

On a different date the traps were set during a

period with wind-driven waves of about 1-ft

amplitude, and all traps collected some sediment.

There were no wind waves during the vessel pasFigure 6. Velocity, water surface elevation and sediment movement measurements during vessel passage. (After Alger 1978.)

9
ral and ship-induced hydraulic forces are free to

act on the low bluff on the waters edge during a

high-water period. This bluff is frequently considered to be the shoreline by many property

owners. If the water level were lower, the water

would not act directly against this “shore” but

on the mildly sloping beach below. Persistent

erosive forces might eventually erode back to the

bluff, but in the interim the rate of material loss

would be less since the mild sloping beach would

dissipate the energy more efficiently.

In addition to the lack of predictability for ship

waves discussed earlier, there is almost no information available to examine their ability to

cause sediment movement. Wuebben et al. (1984)

assumed that ship waves were similar to winddriven gravity waves, so that coastal sediment

transport theory could be applied. This assumption is reasonable in deep water, but the validity

of its extension to shallow nearshore zones is uncertain. Wuebben then used information presented

in the Shore Protection Manual (USACERC 1984)

to propose a nearshore wave height of 0.5 ft as a

criterion for the onset of sediment motion. Depending on the depth of nearshore water, lower

wave heights could indeed cause transport, but

due to the oscillatory nature of water movement

in waves, motion does not necessarily imply erosion. In addition, the criterion assumes a sand

bed system, and no information was found to deal

with the cohesive sediments that are widespread

in the Great Lakes system. Since cohesive sediments and materials larger than sand are more

resistant to erosion, any error would be on the

conservative side, and predictions could be tempered with engineering judgment. While this criterion is somewhat arbitrary, it did provide

a useful tool for locating potential damage

sites. However, for winter navigation, shipgenerated waves are of negligible importance because they are nearly immediately

damped by ice.

Hochstein and Adams (1985b) adapted

a model that considers both drawdown and

the effects of propeller wash to the St. Marys

River. They noted that bottom disturbance

is a function of distance from the propeller

axis to the bottom and that disturbances are

greatest in channel bends and reaches where

crosswinds force vessels to crab their sailing line. Using a combination of basic theory

and empiricism, their model produces twodimensional distributions of water velocities. It was then assumed that sediment transFigure 7. Relation of water level to a shore profile on the St.

Marys River. (From Wuebben 1983a.)

Damage criteria

A major problem in setting damage criteria is

in defining levels of ship-induced effects that are

either undesirable or unacceptable. It cannot be

realistically required that ships cause no sediment

motion, even if it were possible to accurately predict the transient, ship-induced threshold of motion in the large, irregularly shaped channels considered. Small sediment dislocations should not

necessarily be considered damaging, particularly

since natural currents, waves, recreational boating and other factors are often more significant.

At the other extreme, ships may cause large

water-level fluctuations and currents that would

cause unacceptable levels of sediment transport,

shoreline erosion and structural damage, as well

as affecting recreation and personal safety. Between these extremes the increase in significance

of ship effects is gradual, so it is difficult to define a precise threshold where the effects become

unacceptable. Any criterion must consider sitespecific conditions of shoreline geometry and composition, vessel speeds and water levels. Predictions of vessel effects are most often premised on

existing speed limits, but if these limits are not

observed, these effects can be severely underestimated. Since drawdown increases as the square

of ship velocity, ship effects can increase rapidly

for small increments above those speed limits. In

contrast, properly developed and enforced speed

limits could effectively eliminate ship-induced

damages.

The water level is another important variable

in determining vessel effects, and it cannot be totally controlled. As shown in Figure 7 for a typical shore profile on the St. Marys River, both natu10
port equations developed for gravity-driven flows

could be applied to these calculated velocity distributions. This assumption may not be strictly

correct but definitely necessary given the state of

the art.

For two sites on the St. Marys River, they predicted velocities, bed loads and suspended sediment concentrations for several vessel classes.

They did not attempt to discriminate between

events causing or not causing a level of unacceptable transport, but they did compare vessel effects in terms of kinetic energy density (one-half

of the square of net ship-induced velocity). It is

not clear how the kinetic energy of individual ship

passages can be summed to provide a season-long

estimate of the potential for sediment movement,

but it is used here to compare the cumulative effects of different fleet mixes and navigation season durations.

In general, they found downbound vessel passage to be more damaging, since ships are typically loaded passing downbound and light passing upbound. In comparing the relative effects

of ships in open water, a continuous broken ice

cover and sheet ice, they concluded that propeller wash effects also increase in that order since

increasing propeller thrust would be required to

maintain speed. They also concluded that the

newer, 1000-ft vessels had a potential for damage four to nine times higher than smaller existing vessels due to higher horsepower, twin propellers and greater possible draft. The lower number represents open-water sailing, the latter with

a solid ice sheet.

In developing a damage criterion for vesselinduced drawdown, Wuebben et al. (1984) adapted non-scouring velocity criteria from the openchannel-flow literature for the various classes of

soils found in the Great Lakes connecting channels. Since drawdown is the ship effect that can

be predicted with the best accuracy, these scour

criteria were then correlated to field data on the

maximum ship-induced velocities caused by given

levels of drawdown. This allowed the use of a

one-dimensional drawdown model to compare

the significance of various channel, vessel size

and speed scenarios and to predict reaches along

the river where the erosion potential was high.

Hodek et al. (1986) based their damage criteria on the level of drawdown and velocity disturbance, the magnitude of surge, soil conditions and

shore geometry. They also indicated that the development of shorefast, grounded ice would serve

as a barrier to shoreline damage. In developing

their criteria, they used data on ship-induced velocities as well as the results of 34 measurements

of directional sediment transport. This allowed

quantitative prediction of net transport and direction for sand-sized materials, but their actual

damage criteria were largely qualitative in nature. Their basis for prediction of cohesive sediment transport is unclear. They classified the potential for damage into three categories. None to

light refers to inconsequential movement, moderate damage implies light transport as bedload,

while severe damage is defined as a condition

where sediment is suspended and soils sustaining shallow-rooted organics may be displaced.

As mentioned earlier, they found little sediment

transport for drawdown events less than 6 in. in

magnitude and concluded that damage could be

effectively minimized by controlling vessel speed

to prevent larger events.

Field studies of shoreline recession

The first field study of shore damage in connection with winter navigation on the Great Lakes

was conducted by the Detroit District on the St.

Marys River beginning in 1972 (USACE 1974). In

that study they measured waves and water level

fluctuations at four sites and repeatedly surveyed

shoreline profiles at 12 sites. They observed no

gouging of shorelines due to ice shoving and instead felt that the shore ice formations served as

protection against damage.

During a survey period from November 1972

to March 1973 they noted little or no change in

the measured shore profiles. A subsequent June

survey indicated some erosion at most sites, with

a maximum recession of about 2.5 ft for two sites

on Lake Nicolet but more typically 0.5 ft or less.

They observed that waves generated by small craft,

particularly cruisers, were generally higher and

apparently more damaging than those generated

by commercial vessels. Sites found to be experiencing significant erosion were near Mission Point,

Frechette Point, Six Mile Point, Nine Mile Point,

the north shore of Neebish Island and upstream

of Johnson’s Point.

Their conclusions were that erosion of the shorelines occurs during the traditional navigation season but is minor during the extended season period. Further, they concluded that less than 5000

ft of shoreline is subject to significant erosion and

that high water levels (which occurred during the

study) are the most significant cause of erosion.

A follow-up study by the consulting firm of

Dalton, Dalton, Little and Newport, Inc. (1975)

11
concluded that about 26,000 ft of shoreline along

the St. Marys River was subject to significant erosion due to all causes. Of this, about 12,000 ft had

been protected in some way, leaving 14,000 ft unprotected. Based on data collected by the Detroit

District, they concluded that waves due to wind

and small boats were far more significant than

waves generated by large ships. They recommended that eroding shorelines should be structurally protected to prevent erosion due to natural causes. They concluded that control of vessel

speed was not important since they considered

the significance of large ship waves to be minor.

Subsequently the U.S. Army Cold Regions Research and Engineering Laboratory began a series of studies of the influence of ship passage on

sediment transport and shoreline erosion extending over several years (Alger 1977a,b, 1978, 1979a,

1980, 1981, Gatto 1978, 1980a,b, 1982, Hodek et

al. 1986, Wuebben 1978, 1981a,b,c, 1983a,b,

Wuebben et al. 1978a,b, 1984). These studies ranged

from field documentation to numerical modeling of the physical effects of vessel passage on

shoreline and shore structure stability.

The reports by Alger provide data from repeated surveys of shore profiles from 1977 to 1981

along the St. Marys, St. Clair and Detroit Rivers.

Ten sites received detailed monitoring over a period of years, with multiple profiles at each site.

Supplementary observations included documentation of ice conditions and water levels and velocities during ship passage. The maximum recorded shoreline recession documented over a oneyear interval was somewhat less than 4 ft, and

for the full period from 1976 to 1981 the maximum recession was about 8 ft for a site on the St.

Marys River, but most sites showed little or no

change over the full period of study. Although

he found that large vessel passage can produce

large hydraulic effects and cause sediment transport, based on these studies, Alger found no evidence of an increased potential for ship-induced

erosion due to the presence of ice.

On the St. Marys River, Wuebben (1981a,c,

1983b) reported the results of shore and shore structure monitoring during two winter periods with

essentially no commercial shipping. During the

period from 15 January to 24 March 1980 there

were only eight passages (all by icebreakers), and

from 31 December 1980 to 24 March 1981 there

were nine passages (all icebreakers except for one

tanker). Under the program, shoreline profiles

were repeatedly surveyed throughout the two

winters to detect any change due to natural agents.

Three river areas monitored during years with

winter navigation were selected for detailed observation during the closed period. One site experiencing minor erosion over the course of several years showed no measurable change during

the entire period bracketing both closed seasons.

A second site previously exhibiting bluff recession on the order of 1.5 ft per year continued to

recede at about the same rate through the period

of study. Of the total bluff recession recorded at

this site from 1976 to 1981, the maximum recession was 8 ft, with an average of about 5 ft.

The third site, despite an apparent potential

for damage, had not experienced meaningful erosion during previous years of winter navigation.

During the 1980 closed season, however, significant shoreline recession was noted at five of seven

profiles at the site (0.5–2 ft). Over the 1980-81 closed

season, this site again showed little change, suggesting that the temporary increase in erosion may

have been due to the relatively high water levels

during 1979-80, which allowed water forces to

act directly on the low bluffs at the water’s edge.

The shore at one of the profile locations had been

structurally protected during the study period.

During the 1980-81 closed period no further

changes were noted. The data collected during

extended season navigation (Alger 1977a,b, 1978,

1979a) and the limited observations during periods closed to navigation do not provide evidence

of increased erosion due to navigation in ice on

the St. Marys River.

Gatto (1978, 1980a,b, 1982) reviewed the shoreline characteristics and historic shoreline recession rates for the St. Marys, St. Clair and Detroit

Rivers. Most of this information has been incorporated into the final 1982 report. The specific

objectives were to document bank conditions and

erosion sites along the rivers, to monitor and compare the amounts of winter and summer bank

recession and change, and to estimate the amount

of recession that occurred prior to winter navigation. An analysis of historical air photos showed

that bank recession was active prior to winter

navigation along the St. Marys, St. Clair and Detroit Rivers and was active without winter navigation on the St. Lawrence River.

An extensive field program was conducted to

inventory shoreline characteristics in terms of soil

types, shore geometry and the presence and type

of vegetation and shore protection structures

(Gatto 1982). Three hundred and forty-five miles

of river shoreline were observed and photographed at least twice yearly from 1977 through

12
channels and harbors. Further, structures designed

for commercial use are typically able to withstand

forces in excess of those generated by the above

mechanisms. This leaves privately owned structures, such as docks, boathouses, boat hoists, etc.,

as the structures most likely to experience damage. The majority of these private structures are

of lightweight construction sufficient to serve their

summertime function but not necessarily engineered to withstand the load potential of winter

ice.

Ice conditions within the Great Lakes system,

even without winter shipping, have always subjected these small structures to forces capable of

damage, but over time, construction techniques

evolved to provide structures that were generally

competent to withstand the local ice conditions.

The degree to which the shore structures of the

Great Lakes system may be damaged by ice varies

greatly according to the manner of ice action. Winter navigation, by disrupting the normal ice cover

characteristics, may aggravate any natural ice-related damage. Ice effects on structures typically

fall into one of the following categories:

• Static ice forces, which arise from a structure in contact with an ice sheet subject to

thermal expansion and contraction or steady

wind or water drag forces;

• Dynamic horizontal ice forces, which arise

from ice sheets or floes that move against a

structure due to water currents or wind; or

• Vertical ice forces, which arise from a change

in water level and require the adhesion of

floating ice to structures.

For small structures within the connecting channels, dynamic horizontal and vertical forces are

typically the critical modes of ice action.

Dynamic horizontal ice forces

Depending on the size and strength of an ice

floe, the horizontal force exerted on a structure

may depend on the strength of an ice sheet and

its failure mode (bending, crushing or shear) or

the magnitude of the force driving the ice sheet

(wind or water current). With a vertical pile or

structure face, failure of the ice sheet usually occurs by crushing. Current Association of State

Highway Transportation Officials standards employ a crushing strength of ice of 400 psi, while

the Canadian bridge design code provides for

“effective ice strength” values ranging from 100

to 400 psi. Thus, if there is sufficient driving force

for the ice sheet, a pile subjected to horizontal ice

loads would have to be strong indeed.

1980, with any visible signs of recent erosion noted.

Banks were found to be eroding along 21.5 miles

(6.2%). The erosion along approximately 15 of the

21.5 miles (70%) was occurring along reaches not

bordering winter navigation channels. The results

of the twice-yearly surveys did not conclusively

indicate whether or not winter bank erosion was

more or less than that occurring during the summer. Along most of the reaches, the degree of erosion appeared to remain the same over the winter and summer.

On the St. Lawrence Seaway a study was conducted to determine the nature and extent, if any,

of shoreline erosion during the winter season to

serve as a database in the event that the navigation season was extended there (Palm 1977a,b,

Palm and Cutter 1978). They developed a classification system to define the potential for shoreline erodibility based on soil type, slope, vegetation and potential for ice action. They estimated

that 28.6 miles of shoreline could be impacted by

an extended navigation season, or 7% of the shoreline length evaluated. Of 8250 ft considered to

have a potential for high impact, 6200 ft was classed

as highly erodible. They also monitored 12 shoreline sites to document any ongoing erosion. Although some slumping of bluffs was noted, no

general recession of the shore profiles was evident during the winter season.

In summary, although various analyses of vessel

effects have concluded that there is a potential

for shoreline erosion, field surveys and reviews

of historical records have not supported that conclusion. For the most part, erosion rates due to

any cause have been minor, and a comparison of

erosion rates during years with and without winter

navigation shows no appreciable difference. Both

one- and two-dimensional models have been developed to examine sediment transport caused

by drawdown and surge, and the two-dimensional

treatment also considers propeller-induced transport. All of these models have a strong empirical

component due to the complexities of vessel effects and their interaction with details of the river

channel geometry and flow.

Shore structure damage

Damage to shore structures can occur due to

water currents, water level fluctuations or ice action, either alone or in combination with vessel

traffic. Since ship effects extend over a limited

area surrounding the ship, the potential for vessel-related damage is primarily limited to areas

near the shipping tracks, such as the connecting

13
Figure 9. Spring breakup on the St. Marys River. Note the large floating ice

masses in the foreground.

Figure 8. Horizontal movement of ice against rocks in early winter.

vately owned structures are often contained within

a band of shore-fast ice that can provide effective

protection (Hodek et al. 1986). Rather, they may

break up or dislodge ice, allowing it to be moved

by natural water currents, waves or winds against

a structure. Since the St. Clair River is typically

ice-free over much of its length, ship passage

through the natural ice arch on Lake Huron has

Damage due to horizontal forces can occur naturally during the unstable early ice period (Fig. 8)

or during ice cover breakup events (Fig. 9). Ships

do not typically transfer forces to a structure

through the ice, unless they come very close to

shore, since any forces imparted to the ice cover

are rapidly distributed through the ice, rendering point loads quite small. Further, small pri14
Figure 10. Series of finger piers damaged by ice jacking.

lifts the pile from the soil, and the void under the

bottom tip of the pile fills in. When the water level

drops, the weight of the ice is supported by the

skin friction and point bearing of the pile. Since

the pile is not driven into the soil as easily as it is

pulled out, if the water level continues to drop,

the ice will break and the ice sheet will drop relative to the pile. The ice may then refreeze to the

pile but at a lower position on the pile. This process occurs in cycles throughout the winter, gradually “jacking” the pile completely out of the soil.

Figure 10 shows a series of finger piers damaged

by ice jacking.

With moderate water level fluctuations of sufficient frequency, cracks in the ice sheet around

structures may not refreeze, and a permanently

open, active crack may result (Fig. 11). This crack

may serve as a vertical force release mechanism.

One method of structure protection that takes advantage of this concept is to surround a structure

with pile clusters, as in Figure 12, that resist uplift and force an active crack to form around it. If

the crack passes through a dock, if the water level

fluctuations are large or infrequent, this protective mechanism is lost (Fig. 13).

If piles resist uplifting, continuing water level

fluctuations may cause the ice to break around

the pile, and an accumulation of ice rubble may

develop. These accumulations can develop to the

point where they damage the horizontal members of a dock. Docks can also be damaged if the

the potential to cause damage if it destroys the

arch, causing an ice run. However, this arch has

also been disrupted naturally during periods with

high winds. Vessels could also influence horizontal

ice loading if they generate significant drawdown

and surge, since the associated water movements

can exert drag forces on the underside of an ice

cover, leading to horizontal forces on an ice-bound

structure.

Vertical ice forces

A major source of damage is the vertical movement of an ice sheet. On any large body of water

the water level constantly fluctuates. Coastal variations are primarily due to tides, while on large

lakes, barometric pressure fluctuations, wind setup, runoff and seiche action contribute. During

periods of open water the normal fluctuations are

relatively harmless. In conjunction with an ice

sheet that is firmly attached to the structures, these

fluctuations can exert large vertical forces through

the floating ice cover. For the confined channel

areas of the Great Lakes, the drawdown and surge

generated by vessel passage can be a major factor.

The structures that typically suffer the most

damage are light-duty pile-supported piers, such

as those constructed for pleasure boaters. Designed

for summer activity, the support piles have very

little skin friction resistance to an upward force.

When the water level rises, the buoyant ice sheet

15
Figure 12. Private dock on the St. Marys River with protective pile clusters.

Figure 11. Aerial view of Johnson’s Point, showing active crack offshore of structures.

16
He discounted propeller wash as a damage mechanism due to its remoteness from most private shore

structures, and ship waves were considered insignificant during periods with an ice cover because they are efficiently damped by ice. This left

drawdown as the major vessel effect contributing to shore structure damage and then only for

periods with ice. His criterion for the onset of

damage potential was a drawdown in excess of 1

Figure 14. Horizontal member of dock in contact with the ice cover.

Figure 13. Active crack passing through a damaged dock.

water level is high enough so that the ice surface

contacts the cross members; then the ice can act

directly on the superstructure, as shown in Figure 14. Further discussion of the modes of ice action

on structures and illustrative photographs can be

found in Wuebben (1983b).

Wuebben (1981b,1983a) and Wuebben et al.

(1984) evaluated the effects of vessel passage on

shore structure damage in terms of vessel size.

17
ft, but actual damage estimates would have to be

augmented by an analysis of structural integrity

on a site-by-site basis. The 1-ft criterion was only

meant to define river areas where reasonably well

built structures could be exposed to damaging

ship effects and to compare the damage potential of various fleet mixes.

In forming their estimate of the potential for

vessel-related structural damage, Hodek et al.

(1986) considered both vertical and horizontal

dynamic loadings. For the areas of St. Marys River

considered in the report, they felt that dynamic

horizontal loadings would be small for cases with

a continuous ice sheet (such as those that commonly occur during the extended season). If vessel passage were sufficient to break the ice cover

into individual pans (as documented in USACE

1974), the potential for damage by horizontal forces

would increase. For vertical ice forces, they felt

that gravity structures, such as rock-filled timber cribs, would not be damaged by vertical forces.

The rest of their analysis was limited to uplift forces

on vertical piles. They concluded that all piles,

unless properly engineered and installed, will be

subjected to tensile loads in excess of their capacity and will eventually move upward.

Field studies of

structure damage

The first field study of shore structure damage during winter navigation was conducted by

the Detroit District on the St. Marys River beginning in 1972 (USACE 1974). They selected several docks in two reaches of the river for monitoring: near Six Mile Point on Lake Nicolet and

Johnson’s Point on Neebish Island. Some of the

docks monitored were pile supported, while others

were constructed with rock-filled timber cribs or

steel piling. Monitoring was limited to visual

observations and photographs. Their conclusions

were that water level fluctuations and ice floes

can cause structural damage and that navigation

in ice can be a contributing factor.

The pile-supported portions of structures were

found to be the most susceptible to damage, but

even timber crib structures were not immune. Jacking of finger piers due to vertical ice forces induced by natural water level fluctuations and

drawdown was common, and several structures

were damaged as the result of differential ice movements along active cracks that passed through

them. Water levels were high enough that some

structures were damaged by ice in contact with

the horizontal members of the superstructure.

Some structures were observed to sustain damage during icebreaking operations when the ice

cover was so violently disrupted that chunks of

ice were thrown against them. While most damage was minor, three of the docking structures

monitored had portions substantially destroyed,

and a boat house was so severely damaged during the opening of navigation in March that it

later collapsed.

In that study (USACE 1974) arrays of survey

stakes were laid out at six sites to monitor ice

movement in the offshore direction. At one site

the ice was found to have moved as much as 30 ft

offshore over a period of 40 days, but typical ice

movements were on the order of 10 ft or less. Some

lateral movement was also observed at three sites.

In connection with some of their recordings of

water level fluctuations, they also measured the

relative motion of the ice sheets on either side of

an active crack. These data indicated that the offshore ice sheet could move at least several tenths

of a foot offshore during vessel passage (apparently in response to the drawdown-induced movement of water) and that the ice cover did not fully

return to its original horizontal position when the

water returned to its prior elevation.

It is postulated here that this mechanism results in a gradual horizontal jacking of the ice

cover towards the navigation channel, since the

water in the open shore crack can partially or

totally refreeze before the next ship passage. Starting from this new position the next event will

leave the offshore ice sheet slightly farther from

its original location. Repeated cyclings of this

backing process could lead to the large horizontal motions recorded over the winter season and

lead to increased ice volumes in the vessel track.

If the crack were to pass through a structure, this

horizontal jacking could incrementally pull the

structures apart.

A follow-up study by the consulting firm of

Dalton, Dalton, Little and Newport, Inc. (1975)

concluded that although ship passage during icecovered conditions can contribute to structure

damage, a major factor is the inadequate design

and construction of many structures on the river.

They concluded that control of vessel speed was

not important since they considered ship-generated waves to be of minimal importance. Instead,

they recommended improved structural design

to withstand natural forces and consideration of

removable, floating structures.

Carey (1980) reviewed the potential for winter-navigation-related shore structure damage on

18
the St. Marys, St. Clair and Detroit Rivers using

aerial photos, Corps of Engineers permit data and

site visits. He estimated the total value of private

shoreline structures at that time to be on the order of $18 million (1976 dollars). A probabilistic

approach was employed that consisted of characterizing the ice conditions, on a reach-by-reach

basis, that occur naturally and under several

schemes of winter navigation. On the basis of these

ice conditions and the channel characteristics

within each reach, two probability estimates were

made: the probability of the occurrence of ice

damage and its probable severity. Damage values were calculated in terms of replacement cost.

Although the results of this study are hard to

summarize since they provide maximum potential damage costs as a function of various levels

of probability, it was concluded that there was a

90% probability that the annual ice damage costs

for the three rivers should not exceed $1.275 million without navigation, $2.28 million with the

traditional season (navigation to December 15th)

and $3.05 million with year-round navigation. If

damage mitigation measures were implemented,

it was felt that these year-round damages could

be reduced to $1.65 million.

On the St. Marys River, Wuebben (1981a,c,

1983b) reported the results of shore structure monitoring during two winter periods with essentially

no commercial shipping. During the period from

15 January to 24 March 1980 there were only eight

passages (all by icebreakers), and from 31 December 1980 to 24 March 1981 there were nine passages (all icebreakers except for one tanker). Under the program, docks were repeatedly observed

and photographed throughout the two winters,

and four river areas were selected for detailed

monitoring based on a high potential for damage during years with winter navigation. At these

sites, points on the structures were repeatedly surveyed to document any displacement of their components.

Visits immediately following the close of navigation showed some damage due to both horizontal and vertical forces, but their condition at

that time was used as a basis for future comparisons. No structural displacements were measured

in either closed season, except for one dock that

was documented to have had piles uplifted a maximum of 5 in. following the passage of a convoy

of one tanker and four icebreakers on 3 March

1981. Apparently the natural water level variations were not sufficient to cause noticeable damage during either period. Hodek et al. (1986) noted

that very slow water level variations due to longterm seasonal changes may result in such low

loading rates that plastic deformation within the

ice or at the ice/structure interface can occur. This

will result in very low vertical forces being applied to the structure.

In addition, ice conditions were monitored at

several sites. In contrast to periods with navigation in ice, active, shore-parallel cracks were largely

absent. During the 1979-80 closed period one site

had a grounded crack only during a survey in

late January, and a second site showed an active

crack only during a survey in late February. During the 1980-81 field season, no active cracks were

observed. Arrays of pins were set in the ice across

active cracks evident at the close of the navigation season, but no measurable changes in the

relative locations of these pins were detected during the closed season, except near the dock experiencing uplift in March. At this location the shore

parallel crack opened 1.5 in., but no lateral movement was noted. Apparently the water level fluctuations during these two field seasons were not

large or frequent enough to develop the continuous, open, shore-parallel cracks evident during

all previous field seasons with navigation in ice.

On the St. Lawrence Seaway a study was conducted to determine the nature and extent of any

damage to shore structures during the winter season to serve as a database in the event that the

navigation season was extended there (Palm

1977a,b, Palm and Cutter 1978). As part of that

study they inventoried 5675 structures within the

U.S. portion of the seaway and categorized them

according to function, type of construction, historical and cultural significance, and potential for

damage due to ice.

Damage potential criteria were based on the

distance from the navigation channel, the presence of sharp turns and the conditions of an individual structure. Structures closer than 300 yards

from the channel or near turns sharper than 10°

were considered susceptible to damage. Structure

types included both shore protection measures

and facilities for recreational boating. Overall they

determined that 3247 should not be impacted, 135

might require minor additional maintenance, 177

could be subject to moderate damage and 54 could

be severely impacted. Of 26 historic or culturally

significant structures, 4 were considered susceptible to damage.

They also conducted repeated surveys of 18

structures to check for any vertical or horizontal

displacement. During the first winter season 6 of

19
found to be more resistant but not immune to

damage. Improved structure designs and proper

control of vessel speed could minimize damages.

Summary

Although various analyses of vessel effects have

concluded that there is a potential for shoreline

erosion, field surveys and reviews of historical

records have not supported that conclusion. For

the most part, erosion rates due to any cause have

been minor, and a comparison of erosion rates

during years with and without winter navigation

shows no clear trend. High water levels, however, have been associated with periods of increased shoreline recession. There is a definite

potential for sediment transport during vessel

passage, and it appears that this material is often

transported offshore towards the channel. Since

ambient sediment transport in the connecting

channels is quite low, this would constitute a

permanent (though apparently small) net loss of

soil from the nearshore zone. The transport could

also have biological ramifications through increases in suspended solids and turbidity; these

topics will be discussed later.

Information from periods without navigation

revealed little or no ice-related damage to even

poorly constructed structures. There was a documented potential for damage to private shore structures due to vessel passage in ice, particularly the

light-duty pile-supported docks constructed by

recreational boaters. Because there are thousands

of these structures on the connecting channels,

the previous damage estimates have run into

millions of dollars. Well-designed structures were

found to be significantly more resistant to damage but not immune. However, numerous studies cited in the text have pointed out the strong

relation between the magnitude of vessel effects

and vessel speeds. Speed limits developed with

regard to sediment transport and dock damage

could essentially eliminate measurable damage.

In most cases existing limits were found adequate.

OIL AND HAZARDOUS

SUBSTANCE SPILLS

Spills of oil or hazardous substances from transiting vessels during the season extension program represent a potential adverse impact to the

environment. Because of the combination of cold

weather and ice, spills in winter present additional

difficulties in tracking, recovery and mitigation.

Because of this, the potential for spills during exthe 12 docks monitored were determined to have

been displaced vertically and/or horizontally, but

most displacements were on the order of 0.1 ft

with a maximum of 0.2 ft. Although it was stated

that the measurements were accurate to 0.001 ft,

the reported displacements may actually reflect

only the true accuracy of the survey. It is particularly interesting to note that all recorded vertical

displacements indicated that the structures were

sinking as the winter progressed. This is contrary

to the typically reported lifting or “jacking” of

pile structures by vertical ice forces.

During 1978, their second winter season, 8 of

the 18 structures monitored during the first season showed vertical and/or horizontal displacements in excess of 0.1 ft at one or more locations.

Of six additional structures monitored during the

second season only, five exhibited measurable

movement. Structures not experiencing damage

were supported by concrete or substantial timber cribs. Of the docks experiencing displacement,

one was pile supported and the remainder were

timber cribs. For the survey points monitored on

these docks, 109 displacements in excess of 0.1 ft

were recorded. For events with vertical displacement, 13 were up and 19 were down. For horizontal motion events, 6 displacements were onshore and 20 were offshore; 26 were upriver and

22 were downriver. The maximum vertical displacements were about 0.6 ft and occurred in both

directions. The maximum horizontal displacement

was 0.9 ft onshore and 1.8 ft downstream. One

incident of total destruction was cited, but no

description of cause was provided.

In summary, there is a documented potential

for shore structure damage due to vessel passage

in ice. While little or no damage was observed

during periods without winter navigation, extensive damage or complete destruction of a number of structures was documented on the St. Marys

River during the demonstration program. Because

it is necessary to consider details of construction

techniques, ice conditions, ship passage characteristics and site layouts, quantitatively predicting damage for the thousands of privately owned

structures on the Great Lakes connecting channels is a nearly impossible task. The most comprehensive analysis conducted so far relied on

probabilistic estimates of damages based on broad

categories of structure types, their values and ice

conditions in the general area. Lightly constructed,

pile-supported structures were found to be most

susceptible to damage. More substantial pile structures or other designs (such as timber cribs) were

20
tended season navigation has been extensively

analyzed during the past 15 years. This analysis

was undertaken even though actual spills were

unknown during the demonstration program; indeed, spills in general are quite rare in the Great

Lakes at any time of year. In addition, the general operational assessment is that spills in winter are unlikely for the following reasons:

• When vessel traffic continues through an extended season, tracks are established by preceding ships, so the risk of collision or

grounding is less.

• Vessels moving through ice are not able to

move at high rates of speed; they are not

able to move out of their tracks with ease;

and when they do start to get out of the track,

it is relatively easy to stop them because of

the friction effect of ice.

• There are fewer vessels operating and they

generally operate with an escort when they

are in difficult waters.

• With lake waters covered or largely covered

by ice, the effects of wind and waves are

considerably reduced, and ice between ships

tends to serve as a buffer to keep vessels

away from danger.

Even with the excellent record of low spill occurrence and the positive operational assessment

given above, nearly all aspects of potential spills

associated with the extended season navigation

have been addressed in a series of reports. Ironically the excellent record of spills has been the

greatest hindrance to the advancement of knowledge on tracking and forecasting spills in ice, the

development of recovery techniques and the assessment of spill impacts. Given this, the Coast

Guard, in cooperation with many local, state and

federal agencies, has a number of contingency

plans, with equipment and personnel in place,

to respond to potential spills. The ability to forecast spill movement in the connecting channels

during winter conditions was greatly improved

recently, with the development of a comprehensive computer model that can quickly and accurately forecast spill movement (Shen et al. 1986).

The following section is a summary of the work

done to assess the potential of spills, the probable impacts and the response capabilities. In each

case only a summary is given; the original reports

contain more information and greater detail.

Spill scenarios

Spills from vessels can be divided into spills

due to accidents, operational spills and spills during loading and unloading. An operational spill

occurs during a transfer of fuel or as a result of a

malfunction of a fueling system. An accidental

spill would be the “result of collision with ice,

other vessel or obstacle, grounding or accidental

spillage in transfer operations” (USCG 1973) and

is thought most likely to occur from a “vessel illequipped to navigate ice identified as the older

ships in the Great Lakes fleet” (USCG 1973). Hull

damage caused by ice crushing a drifting or

moored and swinging ship against a large landbound ice sheet is also a possibility (Shulze et al.

1982). However, due to double-hulled construction, the presence of a forward cofferdam in the

bow, and the aft location of the fuel tanks, it is

thought that substantial damage to the hull must

occur before a spill would occur (Shulze et al. 1982).

A tabulation of spills from ships is available

for the St. Marys River and Whitefish Bay for the

years 1974–1979 (Shulze et al. 1982) and the St.

Clair River, Lake St. Clair and the Detroit River

for the years 1974–1981 (Shulze and Horne 1982).

There were no ship spills resulting from accidents

in the St. Marys River or Whitefish Bay during

this period. There were three spills that resulted

from collisions on the Detroit River during the

period covered. The average spill amount was 8

gal., and 84% of the spill material was recovered.

There were no spills on the St. Clair River or Lake

St. Clair due to accidents during the study period. A summary of all spills reported for the entire

period is provided in Table 1.

Table 1. Summary of oil spills on the Great Lakes connecting channels.

 Operational spills Accidental spills

Study Avg. Avg.

River system period Number amount (gal.) Number amount (gal.)

St. Marys 1974–1979 11 81 0 0

St. Clair River 1974–1981 7 15 0 0

and Lake St. Clair

Detroit River 1974–1981 34 67 3 8

21
Identification of

probable spill materials

The frequency and amount of substances

shipped through the St. Lawrence Seaway Development Corporation (SLSDC) locks in 1977

(Nicholson and Dixon 1979) and the St. Clair–

Detroit River System (SCDRS) for the period 1974–

1979 (Shulze and Horne 1982) have been tabulated.

By far the largest amount of potential spill material is oil and petroleum products. The majority of this is residual fuel oil (also called number

6 and Bunker C) on all the systems studied. Also,

refined fuels, mostly gasoline and fuel oil, are

extensively transported. Residual fuel oil is not

thought likely to spill in winter because of its high

viscosity. At low ambient air temperatures, residual fuel is nearly solid (Shulze and Horne 1982),

with the consistency of toothpaste (USCG 1973).

The potentially hazardous substances shipped

are approximately 10% of the volume of petroleum products on the Detroit River and 32% of

the volume of petroleum products on the St. Clair

River. Approximately 85% of the potentially hazardous substances on the St. Clair and 70% on

the Detroit River are basic chemicals and chemical products (Shulze and Horne 1982). In many

cases these are a bulk cargo and are not likely to

spill, and many are not necessarily hazardous if

they are released in the water. Potentially toxic

chemicals such as insecticides and disinfectants

make up only 0.4% of the chemicals shipped.

Determination of

spill probabilities

The probability of a spill on the St. Marys River

and the SCDRS has been calculated for various

options of the Extended Season Navigation Program (Schulze and Horne 1982, Schulze et al. 1982).

The probability of a spill is determined by summing the product of the probability of an accident and the probability of a spill, given that an

accident has occurred, for all the possible accidents. The accidents assumed to be possible were

grounding, collision, collision with ice and, for

the SCDRS, grounding in ice. For each river system the probability for each type of accident was

determined by compiling the accident record and

the number of vessel transits. The probability of

a spill given an accident was determined by examining the records from tank ships for all of the

Great Lakes. It was felt that tank ships represented

the principal threat for a spill.

The probability of a spill during the extended

season was quite low in all cases. Generally the

probability was an order of magnitude less than

the probability of a spill in the normal season, in

part due to the lower frequency of shipping. However, it was found that there was an increased

risk of a spill per transit during the extended season

period of 1.5–3 times the normal season. In Lake

St. Clair it was found to be five times the normal

risk. This increased risk was largely due to operating in ice.

The likely spill size in the extended season was

determined by summing the products of the average spill size resulting from an accident and

the probability of a spill from each accident type.

It was found that the likely additional discharge

of oil during the extended season is small and,

for the St Marys River, generally less than an

operational spill during the normal season. Because of the limitation of data that are available,

it was not possible to compute an expected value

of spill size for the SCDRS.

Identification of spill impacts

To date, the potential impacts of an oil or hazardous substance spill associated with extending

the navigation season have been discussed

(USACE 1979a, Baca et al. 1986). Actual data describing impacts of spills in the Great Lakes are

scarce, reflecting the relatively minor nature of

spills in the Great Lakes.

The general effects of a spill on an aquatic environment could vary by impact and degree. These

include:

• Direct kill of organisms through coating and

asphyxiation;

• Direct kill through contact poisoning of organisms;

• Direct kill through exposure to water-soluble

toxic components of oil at some distance in

space and time from the accident;

• Destruction of the generally more sensitive

species;

• Destruction of the generally more sensitive

juvenile forms of organisms;

• Incorporation of sublethal amounts of oil and

oil products into organisms, resulting in reduced resistance to infection and other

stresses (the principle cause of death in birds

surviving the immediate exposure to oil);

• Destruction of food values through the incorporation of oil and oil products into fisheries resources; and

22
• Incorporation of carcinogens into aquatic

food chain and human food resources.

Oil and greases could have a devastating effect upon waterfowl as well as upon life within

the water; the problems for waterfowl are compounded by low water temperatures. Therefore,

of the living resources, waterfowl appear to be

potentially the most vulnerable to the effects of

an oil spillage. However, few waterfowl are present

during the extended season navigation period

except on the Detroit River (Davis and Erwin 1982).

The specific impacts of spills on the freshwater environment have been summarized

based on laboratory and field studies and on

observations during four actual spills (Baca et

al. 1986). None of the observed spills were in

the Great Lakes. The impacts were summarized

as follows:

• Algae. Phytoplankton was relatively unaffected by spilled oil except in certain laboratory cultures and in exposures to certain

components of oils. Filamentous and benthic

algae showed some impacts but were generally resistant or recovered quickly. Bluegreen algae frequently increased following

spills.

• Macrophyte vegetation. Submerged species

or the submerged portions of emergent species were generally not impacted. However,

emergent species or those at the edge of the

water (typically marsh) were affected or

killed by surface oiling.

• Invertebrates. Results of laboratory studies

established toxicity levels, but impacts in real

spills have been minimal or short-lived. The

most impacted groups have been insects

moving at the air/water interface.

• Fish. Toxicity studies have established levels, and field experience shows serious impacts caused by spills in some cases. Larvae and fry have generally been more sensitive than adults. Tainting of flesh in adults

is another impact. Oiling of lines and gear

and impacts on ice fishing are other factors

to consider relative to fisheries.

• Birds. Historically the most noticeable impacts have been on this group. Toxic effects

can be through ingestion, absorption or transfer to eggs and chicks. Surficial oiling has

been most deleterious, causing problems

with heat regulation and buoyancy.

• Mammals. Similar to birds, impacts are related to surface oiling, which causes a loss

in insulative properties of the fur. Mortality can also be caused by ingestion.

Existing contingency plans

A comprehensive review of the existing contingency plans has been published (Nicholson and

Dixon 1979). The contingency plans for cleaning

up oil spills in the Great Lakes exist on the international (joint Canada–United States), national,

regional, subregional and state levels. The U.S.

plan was developed by the Council on Environmental Quality, the regional and subregional plans

by the U.S. Coast Guard, and the state plans by

the individual state agencies responsible for natural resources. Generally all the plans detailed the

five cleanup phases of discovery and notification;

evaluation and initiation of action; containment

and countermeasures; cleanup, mitigation and disposal; and documentation and cost recovery

(Nicholson and Dixon 1979). However, very few

of the plans contained any winter cleanup information, the exceptions being the Coast Guard

subregional plan for Sault Ste. Marie and the New

York plan.

Response capabilities

and recovery techniques

The Coast Guard has developed a number of

contingency plans for spill cleanup and containment. The response time is said to be on the order of a few hours, and equipment is available

for various types of oil spills. A good description

of the organizational structure of the response capabilities for the Great Lakes is available (USACE

1979a). However, the presence of ice and cold

weather may seriously hamper all major phases

of oil spill mitigation. As no major spill has resulted from winter navigation, there is no practical experience available to guide us in assessing

the extent to which cold weather and ice will seriously interfere with recovery operations. The

only recourse at this point seems to be to gather

all information on oil spill recovery from other

locations (such as the Arctic) and through laboratory and controlled field experiments, and suggest how this may be relevant to the season extension program.

Several good summaries of techniques of wintertime oil recovery are available (USCG 1973,

Nicholson and Dixon 1979, USACE 1979a). These

summaries divide the techniques into responses

for spills in water, on ice or under ice. Generally

spills in water are handled if possible with the

23
same techniques as during the open-water season, with the acknowledgment that access may

be difficult and that floating ice may interfere with

operations. Absorbing agents, skimming by

vacuum, skimming by pumping or burning, and

herding agents have been proposed. Oil spills on

ice are rare. Burning has been proposed, and if

the ice is strong enough, scraping by large machinery may be possible. Little is known about

the behavior of oil beneath ice; this type of spill

would probably be the most difficult to deal with.

It is known that the oil collects in pockets beneath

the ice; pumping the oil out of these pockets, driving out the oil with compressed air, and deploying booms through the ice (if it is thin) or under

the ice (if thick) have been suggested.

Alaska Clean Seas, a nonprofit organization

sponsored by 15 oil companies, is devoted to oil

spill response in most offshore areas of Alaska.

This organization has sponsored research and

development of better oil spill cleanup equipment

and techniques, much of it for use in ice-covered

waters. In addition, it provides manuals, training and equipment for oil spill containment, disposal and mitigation. This organization could be

a resource in improving the response capabilities and recovery techniques in the Great Lakes

during the extended season navigation periods.

Modeling oil and

hazardous substance spills

The ability to model and forecast the transport of oil and hazardous substance spills is necessary to speed up response to spills and to adequately and expeditiously deploy existing equipment. The ability to model oil and hazardous

substance spills depends intimately on the understanding of the many processes that affect spills.

These processes include advection by wind and

water currents; weathering of the material by

evaporation and dissolution; mechanical spreading of the material by viscous, tension and gravity forces; and interaction of the material with the

shoreline. In addition the ability to model movement in open-water and ice-covered conditions

can significantly improve response and deployment in winter. A recent development in modeling (Shen et al. 1986) has provided a state-of-theart model that incorporates the above considerations. The model is specifically developed for

the St. Marys River, the St. Clair River, Lake St.

Clair and the Detroit River. Available on mainframe or desktop computer, the model should be

valuable for real-time response to a spill or to

provide planning capabilities for spill response.

BIOLOGICAL EFFECTS

This section reviews the available documentation on the potential ecological effects of extended season navigation on the Great Lakes

system. Most of the work has centered on the St.

Marys River, where an ice cover is normally present

in winter, effects on the river ice regime due to

winter navigation have been most apparent and

the potential for damage would seem the greatest. Further, significant navigation already occurs

in winter on the St. Clair and Detroit Rivers independent of any season-extension activities. Virtually all of the studies have taken place since

1979, and only one of those years included navigation on the St. Marys River significantly beyond

the traditional season. Data in other years were

collected to provide baseline information for

comparison. Topics considered include water quality, benthic invertebrates, aquatic plants, fish,

waterfowl and raptorial birds.

Water quality

Liston and McNabb (1986) collected baseline

water quality data at seven stations in both shipping and non-shipping channels along the St.

Marys River during periods without winter navigation. Variables considered include temperature,

pH, dissolved oxygen, turbidity and sedimentation rates.

Temperature, pH and dissolved oxygen were

not considered subject to impact by winter navigation. Turbidity was a more significant concern

because of the biological importance of water clarity and light penetration for photosynthesis. Further, turbidity can directly impact invertebrates

and fish by fouling gill mechanisms, which in turn

can affect circulation, respiration, excretion and

salt balance. Turbidity levels sufficient to harm

invertebrates and fish were not expected to occur on the St. Marys River, with or without extended season shipping, especially considering

the rapid flushing rates in the river. Lake Nicolet,

for example, undergoes about 1.3 volume exchanges daily. From their studies, however, Liston

and McNabb concluded that slight increases in

turbidity can limit the outer depth limits of submerged macrophyte growth and affect species

composition.

24
Turbidity was generally lower during periods

of winter ice than for open-water conditions. Winter means were between 0.5 and 2.3 NTU, while

summer means ranged from 1.3 to 45.5 NTU with

no vessel traffic.* During open water, ambient

turbidities generally decreased from shallow zones

out to the navigation channel and increased with

distance downriver due to tributary inputs and

broad expanses of shallow water subject to winddriven wave action. Turbidity measurements during open-water vessel passages showed no values in excess of 11.8 NTU at any of their sites,

which is within the range of natural variation.

Winter sedimentation rates without the presence

of navigation ranged from 53 to 2400 mg/day·m2,

with a median value of about 962. The mean particle size from all samples was estimated to be

between 50 and 60 μm.

Sletten (1986) conducted a two-year study of

the water quality effects of extended season operations on the SCDRS. Included were documentation of background water quality, sedimentation rate data and water quality variations with

time during vessel passages. The background

water quality information was primarily summarized from existing databases supplemented by

a limited amount of data collection. The primary

emphasis in the analysis of these data was to locate extreme values of total suspended solids and

turbidity for comparison with vessel passage

events. Other variables examined were pH, temperature and dissolved oxygen. Average turbidities were found to vary from 8.7 JTU in the winter to 7.3 in the summer, but temporal variations

within a season were large. Mean values of suspended solids, pH and dissolved oxygen did not

vary significantly between seasons.

Baseline sedimentation rate data were also collected by Sletten (1986) at two sites on each river

in shallow, off-channel areas. Samplers were typically placed at each site monthly from December

or January through March in both years. All samplers were collected simultaneously the following April, and the amount of sedimentation between deployment of each sampler could be estimated incrementally. Most stations indicated a

trend of increasing sedimentation rates with time

from January through March, but no explanations

were given. Average rates during the entire sampling period ranged from 94 to 483 mg/day·m2,

with a median of 310 and a maximum measurement of 850 at one site during 8 March to 9 April

1985.

Ship passages were monitored at two sites, one

on each river. The Detroit River site had 24 passages sampled, equally split between field trips

in August 1983 and April, August and December

1984. The St. Clair River site had 18 passages

sampled, evenly split between the three 1984 field

trips. April and December were considered winter, while the August trips constituted summer.

Water samples were collected at intervals following

the passage of the bow for periods of 30 or 60 minutes, providing a time record of water quality variations. Although levels of turbidity and suspended solids were found to vary following vessel passage, all maximum values recorded were significantly less than natural variations in background

levels. No significant correlations between ship size,

speed or season of passage, and measured changes

in water quality parameters were detected.

Possible reasons cited for the lack of any correlations were that none exist, that correlations

exist but are too complex for analysis, and that

the samplers were not located properly. However,

Sletten used linear regression with single ship variables (draft, displacement or speed) to examine

correlation. Correlation on this basis would require equal effects for large and small ships if they

traveled at the same speed, or equal effects for a

single ship traveling at different speeds. A lumped

parameter reflecting both ship speed and size

would be more appropriate. Further, the data show

that the elapsed time from ship passage to the

maximum recorded parameter values ranged as

high as 60 minutes, which was the maximum

period of sample collection. While vessel passage

effects can persist for a relatively long time, it is

curious that maximum values were often found

as much as an hour after the event, probably indicating other causes. Hodek et al. (1986) found

that spatial variations in turbidity were large, even

under ambient conditions on the St. Marys River,

and that the maximum levels of ship-generated

turbidity were near the shoreline. Sletten’s sampling was conducted at the edge of the navigation channel, where Hodek’s observations showed

* In the discussions that follow, turbidities are expressed

in both Jackson Turbidity Units (JTU) and Nephelometric Turbidity Units (NTU) in order to retain the units

employed by the authors of the reports under review.

Although these units are roughly equivalent, turbidity readings are influenced to some degree by the measurement technique and the characteristics of the material in suspension. For the purposes of this report,

however, it should be possible to consider these units

equivalent.

25
the least change and where fluctuations due to

other causes would be more significant.

A study by Gleason et al. (n.d.) examined sedimentation rates on the St. Marys River by placing nine samplers at three locations: one in a channel closed to winter navigation and two along

active channels. Sedimentation data were collected

between 7 and 27 March. The samplers were left

in place during breakup, but five were lost and

only two retained usable samples. Their analysis

of the data at one site indicated an increase in

sedimentation with vessel traffic, although rates

were low (averaging 1.3 mg/day in their 18.5-

cm2 sampler area). A second site showed no relation between sedimentation rates and vessel passage, perhaps due to high natural turbidity. The

third site, which had the highest sedimentation

average at 11.1 mg/day, showed a correlation with

vessel passage. Further, sedimentation rates were

found to decrease with increasing distance from

the channel.

They concluded that winter navigation can increase sedimentation rates over ambient conditions, but that natural sedimentation during spring

breakup also causes sedimentation rates equaling or exceeding those due to navigation. They

cited sedimentation rates on a channel with significant navigation being 50 times greater than

at their control site, but the large difference in

site conditions (and thus natural sedimentation

rates) makes the comparison of questionable validity. The authors did not find significant spawning areas in the St. Marys, nor did they demonstrate or discuss the effects of sedimentation rates

on coregonine eggs.

Hodek et al. (1986) conducted a field investigation of ship-generated turbidity on the St. Marys

River. They provided the results of 95 measurements of turbidity and 85 light extinction profiles under both ambient and ship-influenced conditions. Unfortunately there were no vessel passages during sampling periods with an ice cover.

Ambient turbidities during open-water conditions

were typically in the range of 5–30 JTU, although

numerous points were higher and the maximum

reading was 380. Measurements during open-water vessel passages typically ranged from 6 to 30

JTU, with a maximum of 53. This information has

been incorporated into the database of their numerical model of the physical effects of vessel

passage, which primarily deals with sediment

transport and shoreline erosion potential. However, it was not directly incorporated into the

numerical calculation scheme.

They found that a common source of turbidity was the clay shorelines common along the river

and that wind-driven waves of 6 in. or more in

height could generate a high level of turbidity

extending from the shore to the navigation channel. Under those conditions, no effect of vessel

passage could be discerned. Several of the sites

used to monitor other vessel effects examined in

their study were sufficiently turbid throughout

all field periods that it was impossible to see the

riverbed. Their major findings were:

• The nearshore zones have more turbidity

than the navigation channel, both with an

ice cover and no vessel traffic and with openwater and vessel passages.

• Navigation channel turbidity was less in

March than in May or June.

• In general, near-shore turbidity decreased

with the removal of the ice cover.

• The turbidity in offshore areas of Lake

Munuscong (but away from the channel) was

least with an ice cover and most in June.

• Sites on Lake Nicolet showed a decrease in

turbidity after ice-out.

• The Charlotte River is a major contributor

of sediments causing turbidity.

Finally, vessel-induced turbidity was observed to

be slight near the channel and highest near the

shore, indicating that ship waves and drawdown

and surge were generally more significant than

propeller wash.

Poe et al. (1980) also measured light extinction on the St. Marys River during the winter of

1978-79 during a period with winter navigation.

They chose two river areas for study, and they

selected what they considered to be high- and lowimpact data collection sites within each of these

areas based on a perceived difference in the potential for vessel passage effects. The basis for

determining the level of vessel impact potential

is not clear, nor are differences in site conditions

apart from vessel effects explained.

All measurements were collected during or immediately following vessel passage except for

those made during March. Observations in March

had no vessel passages and were considered as a

“control” condition. All measurements were taken

through the ice, but by the April field period the

ice cover had become fragmented. They found

that light penetration was generally lower in February than in March or April and that light penetration was greater at their low-impact sites than

at the high ones.

Based on records of ship passage they felt vessel

26
traffic may have been responsible for the higher

turbidity in February, but only one site was monitored during February, and all March and April

measurements (except one) were collected at three

other sites. It is questionable whether a comparison of samples collected at different sites on different dates can be used to infer navigation-induced turbidity. Further, the single March “control” measurement taken at the same site as the

February measurements was less than the maximum light penetration recorded during February.

They also suggested that the greater light penetration at their low-impact sites supported the

claim of ship-induced turbidity. However, their

data from their March control period show this

same relation between sites, suggesting natural

variations may have contributed. Further, since

Hodek et al. (1986) found turbidity levels to vary

significantly with location (even for essentially

simultaneous samples at a single site), drawing

conclusions on ship effects by direct comparison

of turbidity levels at sites more than 3000 ft apart

is tenuous. Interestingly penetration was greater

in April than in March despite heavier vessel traffic.

They felt that this may be due to the fragmentation of the solid ice cover in April.

Benthic macroinvertebrates

Liston and McNabb (1986) sampled benthic

macroinvertebrates on the St. Marys River during two years without winter navigation (1982

and 1983). A total of 670 samples were analyzed

to estimate the populations occurring at selected

sites along the river. Total benthic invertebrate

abundance was generally high throughout the

river, ranging from 21 to 64,278 organisms per

square meter, with a median between 7,000 and

8,000. Abundance was almost always less in the

navigation channel (the median was less than 1,000

per square meter) than at other locations. Further, abundance was about three times greater on

the western shore than on the eastern shore. This

was considered to be a reflection of a lower energy environment there due to prevailing winds

from the west.

A total of 162 taxa were identified, with 118

taxa within the vegetated littoral zone and 41 taxa

unique to that zone. Organisms characterizing the

littoral zone include odonates, lepidopterans, coleopterans and nonchironomid dipterans. Both

herbivores and predators were well represented.

At offshore sites, 120 taxa were identified, of which

42 were unique. Organisms characterizing that

zone include mollusks, trichopterans and chironomids. Omnivores were the most common functional group at offshore sites. Within the navigation channel, only 37 taxa were collected. None

were unique or dominant. It was stated that extended season navigation could impact benthic

invertebrates through loss of food and cover if

aquatic macrophytes are damaged, through increased turbidity or sedimentation, or by causing direct contact with ice. This in turn would

affect the abundance of food available to fish.

However, no evidence of damage to aquatic macrophytes was cited, and no basis for hypothesis

was provided.

During the winter of 1974-75, the Great Lakes

Fisheries Laboratory conducted a field study of

the macrobenthos in the Lake Nicolet portion of

the St. Marys River to assess what, if any, effects

could be attributed to navigation in ice (Hiltunen

1979). Results from the sampling sites were also

compared against control sites in the West Neebish

channel, which was closed to winter navigation.

Although the winter of 1974-75 had the largest

number of vessel transits and greatest tonnage

shipped beyond the traditional navigation season, Hiltunen found no significant decline in the

population densities of any macrozoobenthos or

macrophytes in either test or control site areas.

Poe et al. (1980) sampled fish, benthic macroinvertebrate populations and drift at four sites

on the St. Marys River as part of the 1978-79 Environmental Evaluation Work Group effort. Too

few fish and eggs were sampled to examine the

effects of vessel passage on fish distribution or

abundance. Their results indicated no decrease

in the density of benthic macroinvertebrates due

to vessel-related disturbances, but they mentioned

that their data were subject to some statistical uncertainty. Examination of their drift net records

led them to conclude that only in February could

an “unequivocal demonstration” be made of the

effects of vessel passage. At other times vessel

passage was too frequent to gather backgroundlevel data for comparison. Although they noted

that the available data were not sufficient to assess the significance of vessel-induced drift, they

nonetheless postulated that if an increase in transport were to occur it could indicate a net loss of

energy (biomass) in the system.

Poe and Edsall (1982) conducted a follow-up

study of vessel-induced drift on the St. Marys River

during the period from January through May 1980.

Their objective was to determine how the composition and amount of drift varied between the

following conditions: ice covered with vessel traf27
fic; ice covered without traffic; and ice free with

traffic. However, they were unable to obtain additional data for ice-covered conditions with vessel

traffic. Their major conclusions include:

• Macroinvertebrate drift was less for ice-covered conditions without vessel traffic than

for open-water conditions with traffic.

• The average density and biomass of macroinvertebrate drift was higher in the navigation channel than in nearby littoral waters.

• The amount of macrophyte drift for icecovered conditions without vessel traffic was

less than that found during the 1979 study

(Poe et al. 1980) for ice-covered conditions

with vessel traffic.

• Zooplankton biomass was higher in the navigation channel than in littoral waters.

• Detrital biomass was higher in the channel

than adjacent littoral waters for three out of

four locations sampled.

They concluded that drift rates for all components were considerably higher when there

was navigation in ice than when there was ice

and no navigation or when there was navigation in open water. They also concluded that navigation in ice can cause considerable amounts

of detritus, macrophytes, zooplankton and macroinvertebrates to be transported out of the system. While they noted that the significance of

these losses could not be addressed with available data, they felt that it was important that

the losses would occur at a time when production reaches an annual minimum.

Jude et al. (1986) examined benthic drift at three

sites on the lower St. Marys River during 1985,

including Frechette Point, lower Lake Nicolet and

Point Aux Frenes. In addition to collecting consecutive samples over approximate 12-hour time

increments during one winter and one summer

field period, they also collected a series of fiveminute samples during the passage of vessels during the summer. During the study a total of 71

taxa were identified. Drift densities during both

winter and summer were found to be significantly

greater (900–2200%) at night than during the day

for all comparisons except at Frechette Point in

summer. At all sites the number of taxa collected

was greatest at night regardless of the season.

While the study of benthic density and diversity by Liston and McNabb (1986) found lesser

benthic densities along the eastern shore, which

they attributed to greater scouring of the bed by

waves driven by prevailing winds from the west,

Jude et al. found a general lack of benthic drift

density differences across the river. They did note

such a trend at one site, Frechette Point, but this

was only during the winter field period when wind

waves would not be active due to the ice cover.

Consistently greater drift densities at Frechette

Point than at the other two sites were attributed

to higher ambient water velocities there.

When comparing their data to the earlier studies

of Poe and Edsall (1982) at Frechette Point, they

found that their winter, under-ice drift density

was 2000% greater (989 vs. 47/1000 m3) than in

that earlier study. Similarly the 1985 summer measurements showed a drift density 2600% greater

(1659 vs. 64/1000 m3). While they cited annual

biological variations and slight variations in seasonal sampling times as a partial cause, they felt

that the disagreement was primarily due to differences in sampler mesh sizes. There was also

disagreement between the two studies as to the

variation of drift density with depth. While Poe

and Edsall found that drift density decreased from

the surface to the bottom, Jude et al. found drift

densities to increase with depth. The cause of this

disparity was considered unexplainable, but seasonal biological variations and slight differences

in sampling dates were again cited as possible

contributors.

Jude et al. (1986) considered it highly probable that vessel passage could result in increased

benthic drift, and based on visual observations

they speculated that upbound vessels would have

the greatest impact on drift density. In reviewing

their data, however, they were unable to demonstrate detectable increases in the density of drifting benthos due to vessel traffic. Noting the windy

conditions prevalent during data collection, they

concluded that ship passage had not significantly

altered the already disturbed system.

While considering the distance that disrupted

benthos might be expected to travel in the St. Marys

River before resettlement, Jude et al. speculated

that a great proportion resettle within a short distance, with only a small fraction consumed or

destroyed by drifting activity. Since the period

of ship disturbance is very short-lived in comparison with wind events, which could last for

hours or days, they concluded that ship-induced

drift would resettle more quickly than windinduced drift. On that basis they felt that drift

induced by windy weather has a greater overall,

river-wide effect on drift than individual, though

frequent, ice-free ship passages. They did not

collect data for ship passages in ice.

Based on their review of the field data of Poe

28
et al. (1980) for ship passage in ice, Jude et al.

(1986) disagreed with the conclusion that there

would be a considerable increase in drift density

for ship passages in ice. While they agreed that

the data collected during February 1979 for periods with and without vessel passages showed

significant ship-induced drift, they noted that it

is the only documented occurrence known to exist.

Due to increased levels of ship traffic during field

periods subsequent to the one in January, no data

could be collected to represent the without-shipping case for those later data sets.

In arriving at their conclusion that ship passage in ice would increase drift rates in general,

Poe et al. (1980) and Poe and Edson (1982) pointed

out that drift catch per unit time was roughly equal

for field periods in March and April 1979, even

though there were only four vessel passages while

drift nets were deployed in March and 22 while

nets were deployed in April. Since water flow rates

and temperatures were comparable for the two

periods and limnological conditions that affect

catch were considered little changed, they concluded in the 1980 report that greater drift rates

occur with ship passage in solid ice than for ship

passage under floe ice (broken ice) conditions. In

their 1982 report, Poe et al. expanded this conclusion to state that drift rates were considerably

higher for vessel passages with an ice cover than

for ice-covered conditions without navigation or

ice-free conditions with navigation.

Jude et al. (1986), however, were not convinced

that the apparent ship-induced drift pulse continue to be evident with additional ship passages.

They instead interpreted the data to indicate that

ship passage through ice may cause a pulsed increase in drift density during some events (January data), while at other times (March data) it may

cause little apparent effect. Further, they felt that

short, ship-induced pulses of benthic drift in winter may not be subject to predation as severe as

at other times due to generally lower metabolic

rates. However, they were concerned about any

additional loss of benthic populations at a time

when numbers and productivity are minimal, and

about disruption or loss of preferred habitat. They

postulated that ship-generated drawdown and

surge during spring breakup may result in ice

floes disrupting the bed through direct contact.

However, no documentation or observations were

cited to support this proposed mechanism for

increased drift rates.

In view of several years of year-round navigation under the demonstration program and the

presence of reasonable benthic densities and production rates, Jude et al. concluded that the effects of winter shipping have been minimal. However, they felt that the available ship passage data

and the observation that previous shipping did

not appear to detrimentally affect the benthos is

not a sufficient basis on which to forecast the future.

Gleason et al. (1979) studied the loss of benthos

through nearshore, shore-parallel cracks along the

St. Marys River. A system of one or more of these

cracks can form due to water level fluctuations

large enough to fail the ice cover in flexure. The

first crack generally forms at the offshore limit of

shore-fast grounded ice, and other offshore cracks

have sometimes occurred at sharp changes in river

bathymetry. With frequent water level fluctuations these cracks may not have time to refreeze,

leading to open or active cracks persisting throughout the winter. For large, fast-moving ships it has

been observed that the associated drawdown and

surge can be large enough to cause water, sediment, vegetation and even small fish to be sprayed

through these nearshore cracks (Wuebben 1978).

At three sites Gleason et al. (1979) monitored

fluctuations in the elevation of the ice surface during ship passage, sampled the quantity and composition of materials washed through a crack, and

collected dredged samples of bed material to define site characteristics. During the study period,

24 recorded ship-induced ice level fluctuations

ranged from 2.8 to 72.5 cm. Twenty samples were

retrieved from events causing material to pass

through the active cracks. Of these, there were

only five that contained benthic organisms, and

they were collected during the three vessel passages causing the largest recorded vertical ice displacements.

The most abundant organisms found in the bed

samples were snails at 45%, followed by dipterans at 17%, annelids at 17% and pelecypods at

12.4%. The most abundant in the crack samples

were dipterans (75%), followed by annelids (15%)

and ostracods (10%). From the bottom sample data

the average benthic density was 9593 organisms

per square meter, while the 20 crack samples

yielded a total of 21 organisms. This yield of about

one organism per vessel passage was extrapolated

to 10 organisms per meter of crack per vessel passage, or about 0.1% of the existing benthos population along the vessel track.

They concluded that there was a correlation

between the magnitude of vessel-induced fluctuation in ice elevation and benthic loss to the ice

29
surface but that it was not a continuous relation.

Rather, large events caused dislocation onto the

ice, while events below some threshold did not.

They felt that vessels transiting within existing

speed limits should cause little damage to benthic

populations. Loss of benthos to the ice surface

was considered insignificant in comparison with

total annual mortality due to all causes.

Hudson et al. (1986) examined the distribution and abundance of macrozoobenthos, aquatic

macrophytes and juvenile fishes during the 1983

and 1984 open-water seasons in the SCDRS. A

total of 756 benthic samples were collected along

21 transects. The diversity of macrozoobenthos

was highest in the upper Detroit River, with 101

taxa, and lowest in Lake St. Clair, where 65 were

recorded. Elsewhere, 98 taxa were identified in

the upper St. Clair River, 95 in the lower St. Clair

River, and 80 in the lower Detroit River.

Hudson et al. (1986) concluded that the benthic

communities observed in their study did not exhibit obvious ill effects from existing levels of winter navigation. However, winter vessel traffic had

already occurred for many years, and there was

no truly unaffected baseline from which to judge

prior effects. A major ice jam on the St. Clair River

in 1984 did, however, afford an opportunity to

examine conditions representing perhaps a worstcase scenario of winter ecosystem disruption by

ice. While the St. Clair and Detroit Rivers normally

remain nearly ice free, this jam persisted for three

weeks, from late April into early May, and included

significant ship traffic and icebreaking operations.

Macrozoobenthos populations appeared to be

the most adversely affected of the three groups

examined in their study. Densities of ten taxa and

total biomass were lower in 1984 than in 1983,

and most declines occurred in the lower St. Clair

River. It is not known whether these declines were

due to ice scour, lower temperatures or some other

factor or combination of factors. If the low densities had not recovered by the fall of 1984, it might

have seemed reasonable to postulate that the ice

jam had caused long-term damage. However, most

of the affected taxa had recovered by the fall of

1984 to levels equaling or exceeding those in the

fall of 1983, and the remaining taxa were within

30% of the fall 1983 values.

Aquatic plants

Liston and McNabb (1986) examined aquatic

plants and primary productivity on the St. Marys

River. Composition, distribution, biomass and productivity were found to be typical of oligotrophic

systems of the upper Great Lakes. The major species of phytoplankton were diatoms, but their biomass was low (on the order of 1 mg/m3 based on

chlorophyll a). Submersed macrophyte communities were simple in species composition, with

three species dominating: Chara globularis (charophyte), Isoetes riparia (quillwort) and Nitella flexilis

(charophyte). The maximum annual biomass of

submersed stands ranged from 10 to 70 g/m2 (ashfree dry weight). Extensive emergent wetlands

were well developed in shore zones that were

protected from waves, currents and shifting sand.

Emergent wetlands were dominated by Scirpus

acutus (hardstem bullrush) at 64% of the areas

mapped, followed by secondary dominants

Sparganium eurycarpum (bur reed) at 16% and

Eleocharis smallii (spikerush) at 13%.

Submersed and emergent plant communities

varied little in species composition, location, size

and annual maximum biomass from year to year

during the period of study. Submersed plant communities were 5–10 times more productive and

emergent wetlands 300 times more productive than

phytoplankton, indicating their importance in the

food chains of the St. Marys River.

Aerial photographs revealed evidence of emergent wetland erosion at some locations in Lake

Nicolet, but its cause was not readily apparent.

Apparently dead rootstocks of emergent plants

were evident in shallow water offshore of existing emergent stands. Ground surveys found these

to be relics of previous bulrush stands in some

locations. Liston and McNabb (1986) felt that

patterns of vegetation and channels in the adjacent emergent stands supported the conclusion

that erosion was occurring. The rate of erosion

was not determined, however, since it was too

slow to be measured from the photographs. At

other sites along the Lake Nicolet shoreline, the

outer fringe of the wetland had apparently undergone little change for over 30 years. Further,

scuba observations and collections and Ponar

dredge sampling have shown that the location

and species of submerged macrophytes in the St.

Marys River tended to be stable from year to year.

Further studies of the wetlands by personnel

of the Detroit District, COE, using photointerpretation of historical aerial photographs has indicated a correlation between the outer boundary of wetlands and water levels.* It is question-

* Personal communication, Don Williams, Detroit District, COE.

30
able whether the sediments were actually eroding, and the outer boundaries of the wetlands were

probably responding to increases in water levels.

Both submersed plant communities and emergent wetlands occurred on clay sediments, leading Liston and McNabb to suggest that their destruction could lead to increased turbidity in the

river. It might also be argued that the clays are

more stable than sands, allowing colonization by

plants. Periods of winter ice were identified as a

time of potential damage to the rootstocks of

emergent vegetation. Possible mechanisms include

vertical movement of an ice cover frozen to the

bed during water level fluctuations and scouring by moving ice floes during ice cover breakup.

Jude et al. (1986) found no strong seasonal differences in the occurrence of macrophytes in their

St. Marys River drift samples (48% of all samples

in winter, 57% in summer). However, only six macrophytic taxa were collected in winter compared

with 10 in the summer. At one site, Frechette Point,

macrophytes were both more frequent and more

diverse in summer (89%, nine taxa) than in winter (77%, five taxa). In addition, the dominant

plants were found to change seasonally at Frechette Point and Point Aux Frenes.

Hudson et al. (1986) sampled aquatic macrophytes in the Detroit and St. Clair Rivers during

the open-water seasons of 1983 and 1984. Using

a Ponar grab sampler they collected a total of 18

taxa of submersed macrophytes on the St. Clair

River and 19 on the Detroit River. The average

depths at which submersed plants were retrieved

varied only between 6 and 8 ft for all sites, despite wide ranges in light transmission and water velocity. Mean light transmission varied from

a low of 2% measured on the Detroit River to 86%

at a site on the St. Clair River. Near-bottom water

velocities ranged from essentially still water to

2.5 ft/s. Light transmission was typically two to

three times greater and water velocities two times

greater in the St. Clair River than in the Detroit

River.

Hudson et al. (1986) concluded that the aquatic

plant communities observed in their study did

not exhibit obvious ill effects from existing levels of winter navigation. However, winter vessel

traffic had occurred for many years, and there

was no truly unaffected baseline from which to

judge prior effects.

As discussed in the section on benthos, however, a major ice jam on the St. Clair River in 1984

afforded an opportunity to examine conditions

representing perhaps a worst-case scenario from

disruption of the community by ice. The distribution and occurrence of aquatic macrophyte taxa

changed little over this period. Plant bed development was delayed in the St. Clair River and at

Belle Isle in 1984, but by September the beds were

little different than in 1983. There were significant differences in biomass between the two years,

but there were no consistent differences between

locations or months. No impacts on submersed

macrophytes could be attributed to the jam, except perhaps for delayed development due to

lower water temperatures.

Fish

Gleason et al. (n.d.) documented conditions

at potential coregonine (lake whitefish and lake

herring) spawning grounds as part of the Environmental Evaluation Working Group studies

during the winter of 1978-79. There was concern

that winter navigation could adversely affect incubating eggs due to excessive sedimentation,

localized current alterations and dislocation. Their

objectives were to identify spawning areas, determine species composition by sampling eggs,

quantify the rate of sedimentation, and determine

the composition of sediments in those areas. Their

literature review generally indicated that sedimentation can adversely affect spawning grounds,

but opinions in the literature often conflicted,

perhaps due to a lack of quantification of mortality vs. sedimentation rates. It was also unclear

whether coregonines have a “home” spawning

ground, which could make individual sites important.

Nine potential spawning areas were identified,

but attempts to sample eggs were unsuccessful.

Sampling included visual searches by divers and

dredging of areas thought to have a high potential as spawning beds. A single egg was recovered at one site, and “several” at a second site.

None of the areas were conclusively shown to be

spawning areas. However, the authors felt that

the lack of success may have been due to low initial egg populations, high predation rates, dislocation of eggs by water currents, or inability to

locate discrete spawning areas. It was recommended that future attempts take place during

or immediately following spawning, along with

sampling of fish at the sites.

Liston and McNabb (1986) sampled fish populations in the St. Marys River during years without winter navigation past December (1982-83)

with the objective of providing baseline information for analyzing the effects of winter naviga31
tion. Larval, juvenile and adult life stages were

examined at seven sites, with sampling locations

at each site ranging from the navigation channel

to nearshore zones. There were 896 samples of

ichthyoplankton collected during the summers

of 1982 and 1983, which yielded nearly 30,000

larvae of 34 taxa. The density of fish larvae and

the number of taxa were generally greatest in the

upper littoral zone and lowest in the channel.

Rainbow smelt, cyprinid, yellow perch and emerald shiner larvae dominated the samples, reflecting their dominance as adults. Thirty-four taxa

were identified, though not all were found each

year, with temperature cited as a possible cause

for differences. They also provided detailed descriptions of spatial and temporal distributions

for the dominant taxa sampled.

Some 140,000 fish of 64 taxa were collected using

trap nets, trawls and gill nets (Liston and McNabb

1986). They also tagged 14,946 fish, of which 42

were recovered, to document their movements.

The shallow littoral zone was dominated annually by emerald shiners, spottail shiners, mimic

shiners, bluntnose minnows, yellow perch and

white suckers, though brown bullheads, rainbow

smelt, gizzard shad and black crappies were also

prominent during the warmer year of 1983. The

demersal, offshore community was dominated by

several small forage fish: trout-perch, spottail

shiners, johnny darters, ninespine sticklebacks,

yellow perch, mottled sculpins and mimic shiners. Top piscivores dominant in the river were

northern pike and walleyes, followed by smallmouth and rock bass. Lake herring were a dominant species in the deeper, offshore areas. Shannon–Weaver diversity indices ranged from 1.4 to

2.8, with mid-river diversity the greatest at 2.4–

2.8. Cold-water species such as salmonids were

more prevalent in upstream areas, while downstream areas had both warm-water species such

as centrarchids and cyprinids and cold-water species such as lake whitefish.

Liston and McNabb (1986) also made a significant effort, based on gill net sampling, to define the winter fish community. Almost half of

the total samples were taken during winter, most

from late January to mid-March. While open-water

gill net sampling collected 6354 fish of 37 species, the winter catch consisted of 1904 fish of 19

species. The summer catch was dominated by lake

herring (27%), followed by white suckers (18%),

northern pike (11.4%), rainbow smelt (10%), yellow perch (9.7%), walleyes (9.5%) and rock bass

(4.6%). In contrast, the winter catch consisted

primarily of lake herring (49%), white suckers

(17%), northern pike (12%), yellow perch (6%) and

both walleye and rainbow smelt (5%).

The yellow perch catch was considered meager in winter, perhaps due to their generally lower

mobility. Significantly, more fish were collected

nearshore than near the channel, which is contrary to claims that they move into deeper water

areas of the St. Marys during winter. Most yellow perch were found to be in good condition,

but there was a moderate level of parasitization,

which Liston and McNabb speculated could be

increased if the fish were to be further stressed.

The number of white suckers sampled was considerably lower in winter than during open water, and it was felt that their movements are very

restricted during that time. More suckers and

northern pike were found near the shore than near

the channel.

There was no significant difference in catch per

unit effort between nearchannel and nearshore

areas for walleyes, lake herring or rainbow smelt

sampled in winter. The catch per unit effort (CPE)

was greater during summer for walleyes and rainbow smelt but less during summer for herring.

The peak CPE for herring occurred during fall

spawning activities. While other fish were captured during the winter period, their numbers

were insufficient for comparison. For example,

only one brown bullhead and three rock bass were

collected in winter gill nets, all at the same station. Other smaller fish were collected only incidentally (or not at all) in the gill net samplings.

The authors noted that the effects of winter

navigation on fish populations are limited to conjecture. They cited potential changes due to direct mortality, alterations in suspended solids and

alterations of macrophyte beds. For substantial

direct mortalities to occur, fish would have to be

concentrated in or near the shipping channels and

exacerbated by low winter metabolic rates. This

does not appear to be the case on the St. Marys

River. From their studies on the SCDRS, Haas et

al. (1985) concluded that fish concentrations are

substantially reduced in the vicinity of the navigation channel during winter and that fish that

remain near the channel seek out adjacent marshes

and channels as overwintering sites. There has

been no documentation of extended season navigation effects on macrophyte beds, but Liston and

McNabb have speculated that they might be adversely affected by scour or excessive sedimentation. Such scour or sedimentation processes have

not been documented, however. Hudson et al.

32
(1986) were able to compare the extent of macrophyte beds in the SCDRS before and after a massive ice jam in April 1984. Little change was noted

in macrophyte beds due to this severe ice event,

as noted earlier.

The potential effects of suspended solids included siltation of spawning beds, decreased productivity, reduced food availability, clogging of

gills, reduced respiration and changes in behavior. Liston and McNabb (1986) mentioned that high

turbidity is generally recognized as an acute stress

that fish can tolerate for short periods of time and

that they may migrate away from it. As discussed

earlier in this report, there has not been substantive documentation of large or persistent increases

in turbidity during ship passage on the Great Lakes

connecting channels. Liston and McNabb (1986)

also cited documentation where several species

of fish were exposed to very high levels of suspended solids (as high as 20,000 ppm) and turbidity (up to 500 NTU) without abnormal behavior or apparent harm.

These levels are far in excess of those observed

by Poe et al. (1980), Sletten (1986) or Hodek et al.

(1986) for ship passages on the St. Marys, St. Clair

and Detroit Rivers. Liston and McNabb (1986)

found ambient turbidity levels at their sites on

the St. Marys River to range from 1.3 to 45.5 NTU

during the summer and 0.5 to 2.3 NTU in the

winter. For ship passages monitored during the

open-water season, no reading exceeded 11.8 NTU.

The measurements of Hodek et al. (1986) on the

St. Marys River showed typical ambient turbidity levels of 5–30 JTU, with a maximum reading

of 380. During vessel passages their measurements

typically ranged from 6 to 30 JTU, with a maximum of 53. On the Detroit and St. Clair Rivers,

Sletten (1986) reviewed the Environmental Protection Agency STORET database and estimated

that mean turbidities varied from 7.3 JTU in the

summer to 8.7 in the winter. Sletten also monitored turbidity during 42 ship passages and found

maximum levels ranging from 2.3 to 73 JTU. The

maximum turbidity measured during his “winter” field periods (April and December 1984) was

7 JTU. Liston and McNabb (1986) concluded that

suspended solids levels in the St. Marys River

would cause no direct harm to the fishery unless

catastrophic increases in sediment load occur.

Haas et al. (1985) studied the movement and

harvest of adult fish in the SCDRS during 1983

and 1984. The objective of the study was to describe the existing adult fish community and to

consider any potential impacts from operation of

the locks on the St. Marys River to 31 January ±2

weeks. Since navigation throughout the winter

was already occurring on the SCDRS, they presumed that the existing fish population was persisting without any severe stress from prior levels of shipping and limited their speculations to

the potential effects of increased winter vessel

traffic.

A total of 57,579 fish of 57 species and three

hybrids were identified during the study. The predominant species included rock bass, yellow perch,

walleye and white perch. They also made spawning condition determinations on 23 species. Yellow perch comprised 66% of the fish observed in

spawning condition, followed by rock bass (14%)

and white bass (8%). There was no apparent correlation with the species composition of fish eggs

and larvae determined by Muth et al. (1986), in

which alewife, smelt and logperch comprised the

bulk of the eggs collected, while larvae were dominated by alewife, gizzard shad, white perch and

emerald shiner.

A fish tagging and creel survey effort showed

that the combined shore and boat angling effort

in the U.S. waters of the SCDRS averaged 810,000

hours on the St. Clair River, 1,409,000 hours on

the Detroit River and 1,953,000 hours on Lake St.

Clair. The average annual harvest was 164,000 fish

from the St. Clair River, 1,421,000 from the Detroit River and 1,198,000 from Lake St. Clair. A

total of 29,168 fish of 43 species were tagged during the study to gather information on movements,

exploitation and abundance. Angler tag returns

during the period from December through March

constituted only 10% of the total 1,081 returns by

sport and commercial fishermen. Ice angling was

determined to account for only 12% of angling

hours and 17% of the total catch.

Haas et al. (1985) considered potential impacts

of winter navigation on both the fish community

and the winter angling fishery. They felt that fish

spawning and food availability might be influenced by physical disruption of critical habitats

by ice gouging and that additional vessel passages could alter patterns of ice formation that

might interfere with ice fishing activities. Although

considered less likely, they also mentioned the

possibility of interference with fish migration. The

significance of each of these effects was considered to decrease with distance from the navigation channel.

While they provided no documentation or

speculation as to the significance of their proposed

impact mechanisms, their observations on fish be33
havior are relevant. They noted that their data

on winter fish distribution in the SCDRS suggest

that fish generally move to overwintering areas

in the fall and that wintertime movement rates

are low. From their fish tagging and net catch data

they further concluded that fish concentrations

are substantially reduced in the vicinity of the

channels and that fish that remain near the navigation channel seek out the adjacent marshes and

channels as overwintering sites. They also noted

that the angler effort and harvest on the SCDRS

were quite low in winter with the exception of

the yellow perch fishery. That fishery was concentrated in Anchor Bay, an apparent wintering

area, which is well away from the navigation

channel. Further, much of the St. Clair and Detroit Rivers remain ice free, limiting ice fishing

opportunities.

To evaluate the validity of their postulated impact mechanisms, they proposed that a two-year

study take place if the season were extended to

evaluate possible impacts on fish and furbearers.

They suggested that such a study should be concentrated on the St. Clair River, where they felt

that winter shipping would have the most influence on fish and the sport fishery. Data from that

effort could be compared with the information

from their present report, which would serve as

a baseline. Since their combined catch of nine

selected species varied approximately 28% from

1983 to 1984, however, they noted that extended

season operations would have to cause even

greater changes in the fish population to be detectable. Further, since winter trap net catches

yielded only about 8% of those during summer

high-catch periods, it would be difficult to make

judgments about winter fish behavior.

Hudson et al. (1986) captured 1771 fish of 36

species in 1983 and 1038 fish of 26 species in 1984

in the Detroit and St. Clair Rivers during the openwater season. The catches were dominated by yellow perch, rock bass, hornyhead chub, spottail

shiners, striped shiners, rainbow smelt and white

suckers. These species made up 86% of the total

catch. They conjectured that the fish communities observed in their study did not exhibit obvious ill effects from existing levels of winter navigation. However, winter vessel traffic and other

physical changes have occurred for many years,

and there was no true baseline from which to judge

prior effects.

As discussed in the section on benthos, however, a major ice jam on the St. Clair River in 1984

afforded an opportunity to compare conditions

before (1983) with those after the ice jam. This

jam represents perhaps a worst-case scenario for

ice effects. Fish catches were usually lower in 1984

in both rivers, but Hudson et al. did not consider

the difference to be statistically significant. They

felt that the lower catches may have been due to

the effect of lower water temperatures on the development of plant beds, general activity level

and seasonal migrations.

Muth et al. (1986) conducted a study on the

SCDRS to provide baseline information on the

abundance and distribution of fish eggs and larvae and to assess potential impacts on fish reproduction that might occur from extending the

lock operation season on the St. Marys River.

Analyses of the distribution and abundance of

the eggs of 19 species and the larvae of 29 species

suggested that abundance varied significantly

between the St. Clair and Detroit Rivers and between the 1983 and 1984 data collection seasons.

The number of eggs collected from the Detroit

River (22,000) was more than 2.5 times greater

than from the St. Clair (8,974). Rainbow smelt eggs

dominated the St. Clair River samples, while those

of gizzard shad and white bass dominated samples

from the Detroit River.

Egg abundance was less in 1983 than in 1984

for both rivers. Fish larvae were also less abundant in 1983, but the difference was greater for

the St. Clair River. Alewives were the most abundant larvae in both rivers during both years. The

larvae of rainbow smelt, various darters and

logperch were also abundant in the St. Clair River,

while gizzard shad and emerald shiners were

abundant in the Detroit River. The distribution

of larvae varied significantly between rivers, sites,

months and study years.

Muth et al. (1986) noted that both water temperature and ice conditions can affect the abundance of eggs and larvae. They attributed low egg

and larvae abundance in 1983 to low water temperatures and a slow rate of warming. Although

the 1984 ice jam on the St. Clair River probably

delayed fish spawning throughout the system,

they felt that rapid warming in May and June may

have resulted in greater egg and larvae production than in 1983. While the water temperatures

at their sites on the St. Clair River were comparable in May of each year, June temperatures were

typically 3–5°F lower in 1983 than in 1984 and

July and August temperatures were typically 1–

2°F lower. Water temperature differences between

the two years were not as consistent on the Detroit River, but June and August temperatures were

34
typically 3–6°F cooler in 1983. The Detroit River

is typically about 5°F warmer than the St. Clair

River during May through July, when many species spawn.

Interestingly the mean monthly water temperatures collected at the water intakes for the cities

of Port Huron and Detroit cited by Hudson et al.

(1986) as a possible cause of the lower abundance

of macrophytes, benthos and fish in 1984 directly

conflicts with the trends used by Muth et al. (1986)

to explain lower egg and larvae abundance in 1983.

Mean monthly water temperatures near Port Huron on the St. Clair River were higher for 1983

than for 1984 during April, May, July and September and were equal during June and August.

On the Detroit River near Belle Isle, 1983 temperatures were higher from May through October, with the exception of June, when the 1984

temperature was 2°F higher.

Because only three species of fish identified

during their study spawn during fall or winter

(and none were abundant in their samples), Muth

et al. (1986) felt that it was highly unlikely that

extended season navigation would destroy significant numbers of fish eggs or recently hatched

larvae. They did, however, speculate on the potential for adverse impact due to habitat alteration. They suggested that increased shipping

could result in increased ice accumulations and

movement that could scour spawning sites and

reduce available habitat. Such scouring, however,

has not been documented. They also felt that extended season navigation could alter water temperatures by facilitating or delaying ice breakup

or jamming. If water temperatures were altered,

the impact could be either positive or negative.

Although a major jam occurred during their period of study, and significant shipping and

icebreaking activities took place during its threeweek duration, they did not attempt to directly

address its impact on egg and larvae populations.

Birds

The potential effects of winter navigation on

waterfowl and raptorial birds were studied by

Robinson and Jensen (1980) in the vicinity of the

St. Marys River as part of the FY79 Environmental Effects Working Group program. The objectives were to describe the species and numbers

of waterfowl and raptors in the area, to define

areas used by resident and migrating populations

along with the frequency of visits and their activities while observed, and to analyze the effects

of winter-navigation-related activities on bird

behavior. Waterfowl and raptors were observed

on 60 days between January and April 1979. About

1000 ducks were present in January, declining

slightly in February due to emigration, and increasing again in late March. The most frequently

observed raptors were a pair of adult bald eagles.

Bird mortality appeared to be very low during

the winter of 1978-79 (no dead birds were found)

despite unusually harsh weather.

Critical areas occupied by wintering duck

populations were identified as the St. Marys Rapids, the Edison Soo hydroplant outfall and openwater stretches along the Canadian shore near

Sault Ste. Marie. Open water in the shipping lanes

was scarcely used by ducks, perhaps due to a lack

of food there. For eagles, two perch areas along

the northeast shore of Sugar Island were found

to be important. The direct impact of the 425 vessel passages that occurred during the study period was considered minor, with flushing of birds

being the only observed effect. In virtually all incidents where ducks were flushed by ships, the

number of ducks did not return to their pre-passage levels. During the colder months, however,

both ducks and eagles tended to avoid the shipping lanes and incidents of flushing were rare.

By April, with more open water and more ships,

the number of incidents increased dramatically.

The metabolic significance of flushing, because

of energy expenditures, remains unknown. However, most flushing takes place in April (during

the regular shipping season) when food resources

are being uncovered and are becoming available.

The influence of ship-induced turbidity and

ice scouring of vegetation on duck foods, and the

possibility of spills of oil or toxic materials, were

cited as potential effects but were not assessed,

and no data were presented. The potential for

scouring of vegetation by ice has been considered by Liston and McNabb (1986) and discussed

in the section of this report on aquatic plants.

Hudson et al. (1986) also described the 1984 ice

jam on the St. Clair River and its impact on aquatic

plants. The potential for oil or toxic material spills

is addressed in a separate part of this report.

Although the critical open-water areas cited

in the report have not been sampled, studies by

Hodek et al. (1986), Sletten (1986), Gleason et al.

(n.d.) do not support large or persistent increases

in turbidity during vessel passages. This would

appear to be particularly true for sites isolated

from the navigation channel, such as the St. Marys

Rapids and pools along the Canadian shoreline.

Further, the lack of an ice cover in these areas is

35
most often due to the presence of swift, turbulent ambient water velocities. There are some areas along the Sault Ste. Marie, Ontario, shoreline,

however, where thermal discharges may contribute. Ship-induced water velocities would have

to significantly exceed these ambient velocities

before turbidity could be noticeably increased.

The open water at the Edison Soo site is not only

highly turbulent, but the large inflow of water

from the power canal would serve to dilute or

flush any ship-induced turbidity.

Summary

Although numerous potential mechanisms for

environmental damage due to extended season

navigation have been proposed, the results of studies on the Great Lakes connecting channels thus

far provide no substantive documentation of actual damage. If these damage mechanisms are

indeed valid, the lack of documentation may be

because the effects are not sufficient to cause lasting changes or because of the complexity of biological response and its interpretation given a short

period of record. Most of the documentation relevant to winter navigation on the Great Lakes

occurred on the St. Marys River in 1979 or later.

This allowed only one season, 1979, with nearly

year-round navigation, and the “baseline” data

collection efforts in subsequent years followed

several seasons of year-round navigation under

the demonstration program.

Increases in turbidity or suspended solids were

cited as potential causes of damage for benthos,

aquatic plants, fish and birds, but no significant

damage was documented. Further, the data do

not suggest large or persistent changes in these

parameters, and ambient variations were found

to equal or exceed vessel passage values. There

was some evidence that benthic drift rates might

be higher for navigation in ice, but the magnitude and significance of this increase could not

be determined. Two studies showed that macrobenthos densities were not significantly affected

by navigation in ice. Similarly the possibility of

damage to emergent vegetation by the movement

of ice frozen about rootstocks was discussed but

not observed. The ice movements could be due

to either vessel-induced water level fluctuations

or ice breakup in the spring.

For fish the major effects were considered to

be increases in suspended solids and damage to

aquatic vegetation. Direct damage to fish by ships

was largely discounted since the vast majority

of fish were found to be outside the navigation Figure 15. Location of test sites on the St. Marys River.

channel. Those fish found in the channel were

generally winter-active and could presumably

avoid impacts during vessel passage. The major

effect of winter navigation on waterfowl appeared

to be flushing during vessel passage, but this occurred mainly in April in the St. Marys River, after the traditional shipping season had resumed.

Its physiological significance is unclear. Other

concerns were centered on changes in open-water areas, but it does not appear that the critical

areas described would be significantly affected

by vessel passage.

VIBRATIONS CAUSED

BY SHIP TRAFFIC

One of the problems identified during the eightyear demonstration program was vibrations on

shore caused by ship traffic in ice. Wuebben (1977)

36
Analysis of the data enabled the magnitude

of the vibrations to be identified. With a frequency

analysis of the data, a dominant frequency associated with propeller noise was obtained for each

ship. The vibration magnitudes were plotted on

a standard vibration damage chart; a typical plot

is shown in Figure 17. This figure indicates the

vibration levels caused by the Roger Blough as it

passed the Gordon site on 22 January 1979. Each

ship had its own distinctive dominant frequency

produced by the number of propeller blades and

shaft rpm. For the Roger Blough this frequency

was 8 Hz. In Figure 17 x is perpendicular to and

y parallel to the ship channel; z is vertical.

During the one-year study the maximum vibration levels were about an order of magnitude

lower than those required to cause damage to

buildings. Vibration levels during 1979 may have

been lower than those experienced during other

winter seasons since there were no ice jams in

the river and a deep snow cover prevented the

ground from freezing. This unfrozen ground acted

to alleviate the vibration levels. In fact, a deep

snow cover (natural or artificial) or other means

of keeping the ground unfrozen could be a strategy for reducing vibration levels. Two other results from the data analysis to note are:

reported complaints by residents with

homes on the St. Marys River south of Sault

Ste. Marie, Michigan. The problem area is

shown in Figure 15. These vibrations were

reportedly most severe when an icebreaker

was ramming an ice accumulation, with a

thick ice cover on the river and frozen soil

between the shore and the affected structure. An ice boom was installed at Little

Rapids Cut in 1975 to control brash ice accumulation, reduce the resultant flow retardation and facilitate ferry operations to

Sugar Island (Perham 1978b). The boom-induced changes in ice accumulation have

also apparently mitigated the vibration

problem to some degree. Although it was

originally part of the Winter Navigation

Demonstration Program, the boom has

since become a regular feature of Corps operations on the river and is redeployed each

year.

An extensive study of the onshore vibrations was made in the winter of 1978-

79 by Haynes and Määttänen (1981). They

instrumented two sites, the Gordon and

Doran sites, shown in Figure 15. The instrumentation at each site consisted of accelerometers on a house, geophones in the soil

between the house and shore, accelerometers on

the ice between the shore and the ship channel,

and a hydrophone below the ice near the accelerometers. A layout of the instrumentation is shown

in Figure 16. Data from all of the instruments were

recorded for 70 ship passages at the Gordon site

and 30 at the Doran site.

Figure 16. Vibration instrumentation layout.

Figure 17. Magnitude of vibrations for the Roger Blough passing the Gordon site.

37
transfer or melting will occur, so it is the thermal

reserve in the water represented by above-freezing temperatures that allows the bubblers to work.

Other methods of inducing a current, such as a

submerged motor-driven propeller or the natural flow currents, will have the same effect. Bubblers are generally chosen because they are convenient to install and operate, particularly if a

long narrow zone of ice suppression is desired,

since all that is required is to space orifices along

a diffuser line. Limitations to the use of bubblers

include limited thermal reserves in the water, limitations on the zone of influence due to the rather

narrow zone of melting (rarely more than tens of

feet), and their slow but persistent rate of action.

They are particularly effective in local suppression of ice as at slips or docks or in providing a

relief zone in an otherwise intact ice cover to allow easier vessel maneuvering in the adjacent ice

cover.

Environmental effects

There have been two sites at which environmental effects of heat-transfer bubbler systems

have been intensely studied under the Great Lakes

Winter Navigation Program: at the Duluth–Superior Harbor area and in the St. Marys River.

There were many environmental concerns addressed in these studies, but they may be summarized under three main subjects: effects on fish

movement and population, effects on sediment

resuspension, and changes in water quality.

A number of studies assessed the possible effects on fish movement and populations. Behmer

and Gleason (1975) recorded fish movements at

the edge of the shipping channel of the St. Marys

River and Whitefish Bay. Dahlberg et al. (1980)

also prepared two annotated bibliographies, attached to their report, on ecological effects of air

bubblers and on winter fish and macrobenthos

communities. Both reports should be consulted

for details but the general findings were that the

proposed bubbler systems would not have

an adverse effect on the aquatic biota in

winter. Bubbler systems similar to those proposed for navigation aids have been considered as a means of preventing fish from

entering intakes and generally found to be

ineffective. The less intense bubbler systems

used for ice suppression are similarly ineffective; fish movement appears to be unimpeded by the bubble streams and associated currents, which are widely spaced

relative to their diameters.

• The vibration levels caused by a ship passage with an ice cover were about four times

those without an ice cover; and

• The vibration levels with a solid ice cover

and with a broken ice cover are about the

same.

ENGINEERING AND

ENVIRONMENTAL EFFECTS

OF HEAT-TRANSFER

BUBBLER SYSTEMS

Air bubblers are systems used to induce melting or retard the freezing of ice covers. Their use

in locally reducing the ice cover thickness in navigation channels was investigated under the Winter

Navigation Demonstration Program. The principle

of operation is to release air at some depth below

the ice cover; the rising bubbles create an upward

current of water that impinges against and flows

along the underside of the ice cover. If the water

is above freezing, this flow of water results in heat

transfer to the ice cover and causes melting. Both

point-source bubblers (one orifice releasing air)

or line-source bubblers (orifices spaced along a

line) are used.

Figure 18 is a schematic of a bubbler system.

A compressor at point A delivers air into a supply line B. The air flows through the diffuser line

C and is discharged through very small orifices

distributed along the length of the diffuser. The

rising bubbler streams (region D) entrain water,

creating a rising plume of water that impinges

against the ice cover (region E), and this plume

spreads and flows beneath the ice cover (region

F), where it transfers heat to the underside, then

gradually dissipates (region G).

The cause of the melting is the “wiping” of

the warm water against the ice, and the only purpose of the air bubbling is to induce this current.

If the water is at the freezing point of 0°C, no heat

Figure 18. Schematic of a bubbler system.

38
Two extensive studies were made to evaluate

the effects of bubbler systems in the Duluth–Superior Harbor (Sydor et al. 1974, Swain et al. 1975).

Neither study directly addressed fish movement

and populations in detail, but since no apparent

adverse changes were observed in the many water quality variables studied, it is reasonable to

conclude that there would be no adverse effects

on fish due to changes in the surrounding environment.

In January–April 1976 heated water from a

power plant was released from a diffuser pipe in

the vicinity of the Saginaw Bay shipping channel

for the purpose of locally reducing the ice cover

thickness. The water was released over short durations, and the excess water temperature was

1°C or less. The warmer water collected near the

bottom and had little effect on the ice cover. (However, if a bubbler had been used to deliver the

water to the ice cover, the suppression could have

been significant.) Over the period 1972–1976

baseline and operational data were collected to

evaluate the effects of the heated water release

on the local benthic communities and fish (Argyle 1974, Hatcher 1977). No differences in populations of a wide variety of fauna were found that

could be attributed to the heated water except

one. Statistical tests and comparisons suggested

the possibility that the under-ice release of warm

water resulted in increased densities of immature

oligochaetes (tubificids). The study did provide

a good picture of the distribution and diversity

of species present in the Saginaw Bay channel area.

The question of possible sediment resuspension

in the vicinity of bubbler systems was considered

by Swain et al. (1975), who found that any possible resuspension would be extremely small when

compared to other factors that cause resuspension

in the harbor, such as storm effects, natural runoff effects, vessel traffic effects, and industrial and

municipal inflows. Sydor et al. (1974) measured

currents in the vicinity of an operating bubbler

system and described them as gentle near the bottom. A study by National Biocentric, Inc. (1973)

similarly found that operation of a bubbler did

not appear to be effective in resuspending organic

material, sediments or nonsoluble nutrients.

Water quality during the operation of bubbler

systems in the Duluth Superior Harbor was considered in detail by National Biocentric, Inc. (1973),

Sydor et al. (1974) and Swain et al. (1975), including

monitoring of temperature, dissolved oxygen and

an extensive list of chemicals. In the very near

vicinity of the bubbler, the temperatures become

very uniform over the depth due to the mixing

by the bubbler-induced flows and are contracted

with the slight stratification that exists in undisturbed portions of the harbor. Swain et al. (1975)

observed an increase in dissolved oxygen after

the bubbler was turned on but a nearly similar

increase 150 ft away. Whether the increase is due

to bubbler operation or other effects is unclear,

but there were no deleterious effects due to the

bubbler operation. The National Biocentric, Inc.

(1973) study found slightly higher oxygen contents at lower depths in the region of the bubbler

but noted that the small increase could not be

expected to much enhance fish populations. The

Swain et al. (1975) study concluded that there was

no increase in levels of major water quality variables due to bubbler operation but did find a tendency to damp large, naturally occurring oscillations of the variables measured. In summary, no

adverse effects on water quality were found, while

some slight evidence of beneficial effects were

found. In most studies other effects greatly dominated the small influence of the bubbler operation. These include effects of vessel traffic and

natural events such as runoff, which cause more

marked changes.

ICE CONTROL STRUCTURES

This summary of ice control structures and related studies under the Great Lakes Winter Navigation Program is presented to the extent possible in chronological order. The use of ice booms

as an ice control tool for winter navigation did

not appear to be recognized at first. What was

recognized was that navigable openings were

needed in certain ice booms that the hydroelectric power companies set across the St. Lawrence

River in early winter to ensure dependable electric power generation in winter. One scheme was

to leave part of the boom open but connected,

and then pull it closed after the last ship passed

through using an electric winch mounted on a

cell structure (USACE 1969). Before long it was

seen that criteria required for the design of ice

booms to retain ice on the St. Lawrence Seaway,

St. Marys River and others were not available. In

particular, information on the magnitude of ice

forces was lacking. The task of making these determinations fell to the Ice Engineering Work

Group.

39
St. Lawrence River

The first effort in the study of ice booms for

the winter navigation program began 30 September 1971 with a meeting in Massena, New York,

attended by representatives of the St. Lawrence

Seaway Development Corporation, the Power Authority of the State of New York, Ontario Hydro

of Canada and the Cold Regions Research and

Engineering Laboratory. The meeting resulted in

approval to use a crane boom weighing cell (100

kips capacity) at the shore anchor of the South

Galop (Island) ice boom. A new design called a

tension link was conceived and developed in

1972 and used in the Main Galop ice boom (Perham

1974). The tension link could be used in-line in

ice boom structures without needing a supplemental safety loop. It was electrically operated,

submersible, sensitive and fairly light. Eventually the tension link design, including signal

cable, recorder, etc., was adapted for use in 1974

by Hydro Quebec in their forebay boom on the

Beauharnois Power and Ship Canal 25 miles west

of Montreal, Canada, by Arctec, Inc. for use in

the Copeland Cut test boom (Uzuner 1975) and

as an integral part of the St. Marys River ice boom

since 1975 (Perham 1977). This study program

has provided a wealth of information about ice,

ship and boom interactions, about how booms

are designed, built, installed and removed, about

how they work, and about their contribution to

ice cover formation.

Lake Erie

The Lake Erie ice boom was patterned after

the Galop Island booms. The floating boom was

a series of 22-in.-wide × 14-in.-thick × 30-ft-long

Douglas fir timbers. Its primary functions are to

hold back lake ice from the Niagara River and

reinforce the easterly downstream ice edge to help

it resist breakup from wind and wave action (Bryce

and Berry 1967). The effects of this ice boom on

the local climate have been a recurring theme of

study (Acres, Ltd. 1972, Rumer et al. 1983), but

its main purpose of improving the use of water

for generating electric power in winter has been

very beneficial to the area (Perham 1976).

St. Marys River

A perspective of the St. Marys River portion

of the Great Lakes navigation route and a summary of the ice problems that developed there is

illustrated by a quote taken from one of the annual reports:

The St. Marys River has always been considered one of the key links in the Great

Lakes–St. Lawrence Seaway transportation

system. Both the United States and Canadian

governments, as well as commercial concerns,

have made considerable investments to ensure safe and economic transportation of

goods and materials through the St. Marys

River, especially in the Sault Ste. Marie area.

Besides its involvement in building four of

the five navigation locks, which bridge the

20-plus ft of fall at the St. Marys Rapids, and

in erecting powerhouses and a compensating works in the same area, the United States

government has constructed the Little Rapids Cut, which is a 600-ft-wide channel between Sugar Island and the mainland of

Michigan. Prior to the winter of 1975-76, experience had shown that winter ship traffic

produced some restriction of normal travel

and commerce between Sugar Island and the

mainland. These restrictions were caused by

broken, floating ice entering Little Rapids Cut

from the harbor at Sault Ste. Marie (Soo),

Michigan and Ontario, causing ice build-up

in the Cut. Periodically this would hinder

normal ferry operations.

In addition to the influx of ice floes and brash

ice, substantial quantities of frazil slush were often generated in Little Rapids Cut, and (on occasion) snow storms would aggravate the situation.

Acres American, Inc. of Buffalo, New York,

conducted physical hydraulic model studies and

analytical studies of the area. The purpose of the

study was to select and evaluate possible remedial measures in alleviating the problems that arose

from too much ice collecting in the Little Rapids

Cut section of the St. Marys River. Cowley et al.

(1977) provide an excellent summary of the work

done in the study.

Acres built a scale model of the Soo Harbor

and Little Rapids Cut Area and developed a capability of simulating the harbor ice breakup

phenomena that were responsible for the movement of ice floes and the subsequent formation

of ice jams in the Cut (Acres American, Inc. 1975).

The 1:120-scale Froude model of the 4.5-mile reach

from Soo Locks to below Frechette Point limited

studies to macroscale effects and provided primarily qualitative rather than quantitative results.

Ice was simulated by using plastic pellets 0.1

in. on a side, with the same density as ice, to form

a layer on the water. The layer was sprayed with

a chemical compound to cause interpellet adhe40
sion and provide a strength comparable to that

in the prototype. The ice cover would be broken

by radio-controlled scale models of a 20-ft-beam

by 700-ft-long or 105-ft-beam by 1000-ft-long prototype, each having a 27-ft draft and a prototype

speed of 3–5 mph. The ship speeds monitored

during 125 vessel passages in ice averaged 9.7

ft/s (2.9 m/s) for upbound ships and 12 ft/s (3.7

m/s) for downbound ships (Perham 1978b). This

is significantly above the 4.4- to 7.3-ft/s prototype speeds employed in the model study by Acres

(1975) and may have influenced their results. In

his final, general report on the performance of

the St. Marys River ice boom, Perham (1984) included information on forces that can be exerted

on the boom by vessel passage.

Open-water tests and ice-cover tests were run

to calibrate the hydraulic performance of the

model, followed by icebreaking tests to measure

ice losses without structures. It was found that

the fracturing, movements and accumulations of

the model ice cover simulated the effects seen in

the prototype very well.

The remedial measures evaluated in the model

were lines of cells; lines of pile dolphins of various lengths, spacings and locations; booms of

different lengths at different locations; and riprap

jetties. Navigation gap lengths through these structures were also varied. An initial series of tests

produced a most promising structural arrangement, which was then further evaluated to determine the proper location relative to the head

of Little Rapids Cut, the navigation gap width

and the gap position relative to the navigation

course centerline. Certain remedial measures such

as ice harvesting (removal of excess ice), ice suppression (air bubblers) and ferry crossing relocation were analyzed and found to be impractical

(Acres American, Inc. 1975).

A baseline ice production test with a river flow

of 75,000 cfs and no structural controls produced

an average of 82,000 cubic yards of ice per ship

passage through Soo Harbor at prototype scale,

and ice pack thicknesses in the cut were estimated

to be from 3–5 ft. Wide variations in ship-induced

ice releases were observed.

Tests of possible ice control structures included

the application of wind forces to move ice into

and through lines of dolphins, and as a result

dolphin spacing had to be reduced for better restraint. It was subsequently concluded that booms

were a better solution than dolphins. Based on

these tests it was concluded that configuration F

Figure 19. Location of the St. Marys River ice

control structures. (From Perham 1984.)

(shown in Figure 19) had the best combination of

location and structural element sizes, and it permitted ice losses averaging only 16,100 cubic yards

per ship passage, or an 80% reduction. The need

for the two rock islands shown upstream of the

ice booms in Figure 19 to provide additional stability to the ice cover was recognized later, after

the prototype structure had been installed for its

second winter of use (Perham 1978a).

The St. Marys River ice boom was designed in

the summer of 1975 based on the best available

information at that time. The forces on the ice boom

would come mainly from the drag of water and

wind on the Soo Harbor ice cover and from the

action of ships passing through the ice cover. Since

the latter effect was practically unknown, the boom

was instrumented so that forces could be continuously monitored. A test program conducted the

previous winter at Copeland Cut on the St.

Lawrence River provided little guidance on ship

forces except that the forces can be attenuated

almost completely by a solid ice cover bonded to

shore (Uzuner 1975).

The ice control structures, shown in Figure 20,

are composed of 3 shore anchors, 13 river bottom anchors, 17 anchor cables and 7 boom cables.

The boom cables are 250 ft long (76.2 m), and the

length-to-chord ratio is approximately 1.3:1. Each

timber is 1 ft × 2 ft × 20 ft long (0.30 × 0.61 × 6.10

m long). A novel feature used at the upstream

41
end of the east boom was a 60-ft-long floating

horizontal column used to transfer forces so as

to avoid putting an anchor line in the navigation

openings.

The study of the performance of the St. Marys

River ice boom lasted for four years, ending with

the Winter Navigation Demonstration Program

at the close of the winter 1978-79 season. During

the early years a problem developed due to the

stability of the ice sheet above the west boom. It

was observed that this ice sheet could break

free from the shoreline as a single sheet as

much as 1.5 miles in length and would exert forces sufficient to damage some of the

boom components. An additional anchor line

(3′ in Fig. 20) was added following the first

season to remedy the situation.

In January of 1977, however, two minor

cables (3 and 3′ in Fig. 20) as well as the

main shore anchor broke. Following the

incident, cables 3 and 3′ were strengthened,

and a 300-ton barge and six crane weights

totaling 95 tons were positioned in shallow

water upstream to help anchor the ice sheet.

In addition, a small ship has been used to

keep the ice sheet from freezing solidly to

the ice boom timbers. The highest recorded

boom forces occurred during the first two

seasons, indicating that the performance was

indeed improved by the anchor line modifications and the addition of the barge and

crane weight ice anchors. While large ice

sheets could still break free between the

vessel track and anchors, the resultant forces

were not sufficient to damage the boom. The

temporary ice anchors were replaced with

rock islands in 1981.

The peak loads that developed in some

of the boom structures during the winter of

1976 are shown in Table 2. The anchor cables

are identified as being in the west or east

boom by the corresponding letter suffix on

the cable number and are shown in Figure

20. The expected load is the design load and

was calculated for each of the components (Perham

1977). The ice and ship effects on the booms during the winter of 1976-77 were also published by

Perham (1978b). A noteworthy finding was that

there was little difference in peak force levels on

the boom between upbound and downbound

ships, the force level being about 25,000 lbs.

Ice passage through the boom was also monitored. Ice release during periods that were busy

Table 2. Peak loads on the St. Marys River ice boom, 1976.

Tension link

Anchor Expected load Force recorder charts design capacity

cable (lbf) (kN) (lbf) (kN) (lbf) (kN)

ClW 65,000 289 77,000 343 180,000 801

C2W 97,000 431 94,000 418 180,000 801

C3W 13,000 58 53,000 236 60,000 267

ClE 43,000 191 160,000 712 120,000 534

C4E 5,000 67 4,100 18 60,000 267

C5E 8,200 36 1,500 7 60,000 267

Figure 20. Details of the St. Marys River ice boom.

42
with ship transits varied from 5,200 to 10,000 cubic

yards per ship passage and averaged 7,230 cubic

yards. The maximum was approximately 40,000

cubic yards per passage. In the model study the

average was 16,100 cubic yards. In terms of the

dimensionless parameter Ar/b2 (area of ice released per gap width squared), the average ice

release values are 2.9, 4.3, 2.2 and 3.0 for the four

winters studied (Perham 1985).

Reference measurements

The following information is a summary of data

obtained by the Detroit District to monitor the

ice boom performance and its effect on levels and

flows. The primary survey of ice conditions and

water levels for the Navigation Season Extension

Demonstration program was conducted by the

U.S. Army Engineer District, Detroit, and consisted

of:

• Field observations using three time-lapse

movie cameras;

• Aerial photography of the entire St. Marys

River but with somewhat greater emphasis on Soo Harbor;

• Monitoring of water levels in Soo Harbor

and Little Rapids Cut;

• Discharge measurements taken in the two

channels around Sugar Island to determine

the effect of the ice boom on flow distribution; and

• Ice thickness measurements throughout the

winter above and below the boom.

From this information one can tell when the

ice cover began, its area and extent during the

winter, and some information about the ice edge

location in Little Rapids Cut. Some conclusions

reached during 1978 are:

• The ice boom helps maintain a fairly stable

ice cover on Soo Harbor, similar to before

winter navigation began, by retaining the

ice that might otherwise move down into

Little Rapids Cut.

• Ice in Little Rapids Cut is a major factor in

retarding flow between Soo Harbor and Frechette Point, but the quantity of ice and

degree of retardation do not directly correlate.

• The rock-filled scow and crane weights

proved effective in anchoring the Soo Harbor ice field to shore.

• Ice jamming in and below Little Rapids Cut

is believed to be due to large open-water

areas in the Cut, frazil ice and heavy snowfall (USACE 1978).

In 1979 the same measurements were made as

during 1978 except that a substantial effort was

applied to measuring the flow distribution around

Sugar Island. The winter measurements were taken

from 27 February to 3 March 1979, and the data

revealed that 67% of the flow went through Little

Rapids Cut and 33% of the flow went through

the North (Lake George) Channel. Summer flow

measurements were taken from 13 June to 16 June

1979, and the data showed that 71% went down

Little Rapids Cut and 29% went down the North

Channel. The flow distribution measurements

during the winter periods indicate that the variance of 5% is within the obtainable accuracy range

for this type of measurement, and therefore no

significant change (effect of the ice boom on river

flows) is evident (USACE 1980).

Although the Winter Navigation program

ended after the 1978-79 winter season, it was decided to continue installing the ice boom as part

of the Soo Area Office, Detroit District regular

winter operation. The boom system has been of

value in stabilizing the ice cover in Soo Harbor,

reducing the extent of ice accumulation in Little

Rapids Cut and reducing the amount of ice in

the Sugar Island ferry crossing. These benefits

occur whether there is winter navigation or not,

as the harbor ice usually breaks up due to wind

and weather several times a year.

By lessening the possibility of ice jams in the

Cut, the boom has decreased the chances of flooding in Soo Harbor along with possible power losses

at the hydropower plants. By reducing the adverse effects of natural ice conditions on the Sugar

Island ferry, it has contributed to more reliable

transportation between Sugar Island and the

mainland.

Port Huron

During 1979 a study was initiated to provide

the necessary criteria for the detailed design of

an ice control structure at Port Huron (Fig. 21),

with the major criteria being structural configuration and forces. The main problem was that ice

leaves Lake Huron via the St. Clair River, which

is typically ice free, and passes through to Lake

St. Clair, which is usually ice covered. The moving ice accumulates in this stagnant reach just north

of Lake St. Clair and often forms deep jams. Two

physical models were employed: one to evaluate

hydraulic conditions, the other to evaluate the

effects of wind.

The hydraulic model study used Froude scaling with an undistorted geometric scale of 1:85

43
rafted ice field. Interestingly there appeared to

be little difference in the forces exerted on the ice

control structure during upbound and downbound passages. The conclusion that loads applied to the ice boom are independent of vessel

direction was also made for the St. Marys River

ice boom (Perham 1978b). The dynamic loading

of the ice control structure during vessel passage

was expected to average three to five times greater

than the static load.

The effects of wind stress on the ice cover were

examined in a follow-on study of a Port Huron

ice control structure (Sodhi et al. 1982). Here water

flowing beneath the model ice was used to simulate wind blowing over an ice cover. The ice was

restrained by two configurations of barriers, which

were instrumented for forces. One was a large

funnel arrangement simulating the Lake Huron

shoreline near Port Huron, and the other was a

much smaller inverted funnel simulating an ice

control structure.

Tests of ice releases resulting from ship transits were conducted for both upbound and

downbound passages and for different ice control structure orientations. Sodhi et al. (1982) concluded that the ice cover could arch across the

navigation gap at values of a/b ranging from 0.11

to 0.15, or 44 to 60 ft at the proposed gap width

of 400 ft. Further, the mean value of ice area released per vessel passage, Ar/b2, would be less

than 3 (or 480,000 ft2). Mean ice forces on the ice

control structure due to wind loading by a 40-mph

wind were estimated to be 380 lb/ft, with maximum forces of up to 1000 lb/ft of structure length.

The model tests for an ice control structure at

Port Huron were conducted near the end of the

Winter Navigation Demonstration Program. It was

never constructed nor even designed in detail. If

it were to be built at some future date, the design

loads on the structure could be determined by

superposition of the hydraulic and wind stress

forces estimated in the studies by Calkins et al.

(1982) and Sodhi et al. (1982).

ICE CONTROL AT LOCKS

A significant effort in the Winter Navigation

Demonstration Program was to determine methods to minimize ice problems in and around navigation locks. There are two sources for the ice that

causes the problems: ice that simply freezes in

place and brash ice arriving at the lock from upstream. This section will review a number of concovering approximately a 1-mile length of prototype (Calkins et al. 1982). A wire-line-towed model

ship of prototype dimensions 105 ft beam, 1000

ft long and 27 ft draft was used to represent vessel passages. Plastic ice floes of both random and

square shapes, as well as natural ice, were used

in separate tests.

The results of the testing program showed that

ice passage through the gap was greater for square

floes than for random-shaped floes of comparable

size and that for random-shaped floes the dominant variables affecting vessel-induced ice passage were the floe size/gap opening ratio, a/b,

and the direction of vessel passage. The average

ice discharge per vessel (in terms of ice area per

the square of the gap width, Ar/b2) varied from

0.1 to 1.0 depending on the floe size, with downbound transits causing greater ice releases than

upbound ones. The minimum a/b ratio for reestablishing a stable arch across the gap was approximately 0.075 (or 30 ft for the proposed 400-

ft gap).

The surface condition of the ice floes above

the ice control structure was also very important,

as a non-rafted ice field allowed a two- to fivefold greater ice release per vessel transit than a

Figure 21. Location of the Port Huron ice control structure. (After USACE 1979a.)

Point Edward

Port Huron

Lake

Chipican

N

Lake Huron

CANADA

UNITED STATES

44
cepts that were demonstrated at the Soo Locks

during the Demonstration Program. Additional

information on ice control at locks can be found

in Hanamoto (1977) and USACE (1982).

Minimizing ice adhesion

to lock walls

Ice can form on lock walls either by direct freezing of water or by the adhesion of broken ice that

is crushed and smeared against a wall by ships.

The most significant accumulations of ice occur

in a several-foot-thick collar extending down from

the water surface at the upper pool elevation. A

number of techniques were investigated to try to

either minimize the formation of such ice deposits or reduce the strength of ice adhesion to the

lock walls.

Modification of operating procedures

Since the surface of a lock wall must be cooled

below 32°F before significant ice can form on or

adhere to a lock wall, it is unlikely that a submerged portion of a wall will undergo the necessary cooling. Thus, there is a strong incentive to

hold the lock at the highest feasible water level

during the long intervals between ship passages,

preventing ice accumulation on the lower portions of the wall.

Built-in wall heaters

Ice adhesion can be prevented by maintaining the wall temperature above 32°F, or ice collars can be shed by raising the wall temperature

above freezing periodically. Possible arrangements

include embedded electrical heating cables, conductive surface materials and internal piping or

ducts for warm fluids. No special merits have been

found for a hot fluid system compared to an electrical system for heating lock walls.

Pavement heating systems designed to melt

snow and ice usually use a power density of 30

W/ft2. By using 11 lines of heating cable running

horizontally at 5-in. centers, with a burial depth

of 3 in., full heating coverage for a 5-ft depth of

bonded ice collar is achieved. At a power density

of 30 W/ft2, the cable has to dissipate 15 W/ft. If

the system is amortized over 20 years, the average

annual cost for amortization plus direct operating

cost is approximately $25,000 at 3 cents/kW-hr.

Conductive panels have also been considered,

but they would find their best application where

the conductive material can be recessed so as to

maintain a flush face on the lock wall. Conductive panels attached directly to an existing lock

wall would slightly decrease the effective width

of the lock and be subject to damage by impact

from ship hulls and shear forces transmitted

through any attached ice. With ice tightly packed

between a ship hull and the lock wall, lock operation could impose a vertical shearing force on

the order of 100 lbf per foot of wall length in critical sections.

Surface coatings

There is a long history of study on adhesion

reduction coatings for a variety of applications,

but chemical coatings that shed ice reliably and

repeatedly have not yet emerged for commercial

use. The only chemical treatment that has been

used successfully on a large scale is repeated application of chemicals that depress the freezing

point of water. As far as horizontal concrete surfaces are concerned, the classic treatment for ice

removal is application of sodium chloride or calcium chloride.

An ice collar control method using a chemical

coating to reduce the adhesive force between the

coated surface and the ice that forms on it was

tested at the Soo Locks during the Demonstration Program (Frankenstein et al. 1976). The basic material is a long-chain copolymer compound

of polycarbonates and polysiloxanes. The material is produced on order by the General Electric

Co. in Pittsfield, Massachusetts, with a trade name

of LR 5630 (new designation GR 5530). The compound comes in coarse powder form.

A solution of the compound, silicone oil and

toluene leaves a thin coat of the copolymer and

silicone on the surface of the lock wall. The surface to be coated must be clean and dry. For concrete and metal surfaces, steam cleaning is sufficient. A detergent was added to the steam cleaner

water supply in one case where the walls were

heavily coated with oil and algae. Once the surface is clean and dry, the solution can be sprayed

on using an airless spray gun. A single pass will

deposit a coat 1–2 mils thick. Three coats are recommended for a coating thickness of about 5 mils.

Tests were also conducted to examine the merits

of an undercoating for the copolymer on concrete

surfaces that are worn and rough. An epoxy-type

coating was employed, acting as a filler over the

rough concrete, and it resulted in a surface to which

the copolymer adhered better. While sprayed-on

coatings of copolymer can reduce the strength of

adhesive bonds, it appears that a subsidiary mechanical system is need to actually dislodge the

ice that accumulates. Periodic renewal of the coat45
Floating ice control

Ice problems at navigation locks are primarily

caused by brash ice floating downstream or being pushed ahead of downbound traffic. The floating ice pieces can hinder gate opening and closing, adhere to lock walls reducing the effective

lock width, and add significant additional loads

to lock gates because of the weight of attached

ice. Large quantities of ice pushed ahead of a

downbound ship often require an additional lock

cycle to clear ice before the vessel can enter.

Attempts have been made to control this ice

by installing pipe manifolds that would allow hydraulic flushing while the lower lock gates were

open (Oswalt 1976). However, this still required

additional, time-consuming operations and extra cycling of the lock gates and water levels. If

ice could be prevented from entering the lock in

the first place, most of these problems would not

occur. A high-flow, high-velocity air screen shown

in Figure 22 was installed across the upper entry

of the Poe Lock at Sault Ste. Marie, Michigan

Figure 22. Schematic of an air screen.

ing is also required due to abrasion by ship hulls

and ice.

Mechanical ice removal

At many lock installations, ice is removed mechanically. A frequently used expedient method

involves scraping the ice off the wall with a backhoe. The wall is scraped vertically by drawing

the bucket teeth up the face of the concrete. With

a light machine, this may require multiple passes

to scrape down to the concrete, and frequent repositioning of the machine is necessary. With a

heavier, track-mounted machine, a single pass is

usually sufficient. It is also easier to move the

machine along the wall since there are no spuds

to be set. However, with forceful operation, damage to the wall seems inevitable, and serious

spalling of the concrete can occur on grooved or

paneled walls.

Inflatable deicers, such as those used on the

leading edge of aircraft wings, were tried at the

Soo Locks to remove the collar from the lock wall

(Itagaki et al. 1975). The device proved effective

but is not used, primarily because of its vulnerability to ship-induced damage and its thickness,

which reduces the available lock width.

A 150-hp high-pressure water jet capable of

continuous duty at 10,000 lbf/in.2 was tested and

found to be capable of cutting through a 3-ft-deep

ice collar at a traverse speed of about 3.5 ft/min,

which would require about five hours to clear a

single 1000-ft wall. This approach was dropped

due to its high operating costs (Calkins et al. 1976).

Steam has frequently been used when it was available at the desired locations, but it too is time

consuming.

46
(USACE 1982). The screen created sufficient horizontal water velocity in the upstream direction

to keep the downbound ice from being pushed

ahead by a ship. This system has also been used

more recently to keep debris out of the lock approach during open water periods.

A compressor with an output of 1150 cfm at

110 psi was available at the Soo Locks for use in

the air screen trials. The optimum air flow conditions were obtained using a 2-in.-diameter manifold and supply line system, with 0.40-in.-diameter nozzles spaced 10 ft apart. The manifold line

was 2-in. galvanized pipe with 2- × 2- × 1-in. tee

joints for each 10 ft of pipe. A 1-in. stainless steel

plug was mounted at each tee, and each plug had

a 0.4-in. hole drilled in it that acted as the nozzle.

The air screen was installed at the upper approach to the Poe Lock on the downstream, vertical face of an emergency stop-log gate sill. The

sill is located about 200 ft above the lock gates.

The riser line was installed in a stop-log recess in

the wall. The width of the lock at this point is 110

ft, and the height from the top of the sill to the

top of the lock wall is 39 ft.

The air screen has demonstrated that it can hold

back ice pushed ahead of downbound traffic. With

ships in the 70-ft-beam class, the ice was held back

until the bow entered the air stream. The screen

was not as effective with 105-ft-beam ships. Once

the bows of these wider ships pass the nose pier

about 130 ft upstream of the screen, the approach

is just a little over 110 ft wide, so most of the ice

remaining ahead of the ship is pushed into the

lock. This problem might be remedied by relocating the air screen upstream of the nose pier

area and providing an area for ice to be pushed

out of the vessel track.

Summary

One of the major obstacles to be overcome in

extending the navigation season on the St. Marys

River was to develop methods to mitigate ice problems in and around the Soo Locks. The two major ice problems encountered were ice accumulations on lock walls, which reduced the usable

width of the lock, and large quantities of brash

ice entering the lock from upstream, which could

hinder the operation of the miter gates and interfere with ships entering the locks.

During the program a variety of concepts were

examined, including changing lock-operating procedures, minimizing ice adhesion, removing the

mechanically and controlling floating ice. A chemical, ice-release coating was developed that significantly reduces the problem of ice accumulation on lock walls. The air screen system demonstrated during the program largely solves the floating ice problem by diverting ice from the lock

and its approach. This not only limits the quantity of ice that can hinder gate operation and block

the entry of ships into the lock, but it also reduces

the supply of ice that can be crushed and smeared

onto the lock wall.

LITERATURE CITED

Acres American, Inc. (1975) Ice model study of

the Little Rapids Cut area of the St. Marys River,

Michigan. Draft contract report to the Detroit District, U.S. Army Corps of Engineers, Contract No.

DACW35-75-C-0014.

Acres, Ltd. (1972) Study of Lake Erie ice boom.

Prepared by Water Supply Canada by H.G. Acres,

Limited.

Alger, G.R. (1977a) A study of ice related sediment transport and shoreline erosion, St. Marys

River–Sault Ste. Marie, Michigan, Vol. 1: Main

Report. Contract Report to the USA Cold Regions

Research and Engineering Laboratory, Contract

No. DACA89-76-C-0013.

Alger, G.R. (1977b) A study of ice related sediment transport and shoreline erosion, St. Marys

River–Sault Ste. Marie, Michigan, Vol. 2: Appendices. Contract Report to the USA Cold Regions

Research and Engineering Laboratory, Contract

No. DACA89-76-C-0013.

Alger, G.R. (1978) A study of ice related sediment

transport and shoreline erosion, St. Marys River,

St. Clair River, Detroit River, Michigan, Vol. 3.

Contract Report to the USA Cold Regions Research and Engineering Laboratory, Contract No.

DACA 89-76-C-0013.

Alger, G.R. (1979a) A study of ice related sediment transport and shoreline erosion; St. Marys

River, St. Clair River, Detroit River, Michigan, Vol.

4, with Appendix. Contract Report to the USA

Cold Regions Research and Engineering Laboratory, Contract No. DACA89-76-C-0013.

Alger, G.R. (1979b) Ship-induced waves: Ice and

physical measurements on the St. Marys River.

Report to the Great Lakes Basin Commission in

support of the Winter Navigation Board-Environmental Evaluation Work Group.

Alger, G.R. (1980) A study of ice related sediment

transport and shoreline erosion, St. Marys River–

Sault Ste. Marie, Michigan, Vol. 5. Contract Report to the USA Cold Regions Research and En47
gineering Laboratory, Contract No. DACA89-80-

M-795.

Alger, G.R. (1981) Field study of the effect of ice

on sediment transport and shoreline erosion, St.

Marys River, Michigan, Vol. 6. Contract Report

to the USA Cold Regions Research and Engineering Laboratory, Contract No. DACA89-81-M-0649.

Alger, R.G. and R.J. Hodek (1986) Development

of a predictive model to assess the effects of extended season navigation on Great Lakes connecting waters; Users’ manual: Prediction of vessel

impacts in a confined waterway. Supplemental

volume to the main contract report (Hodek et al.

1986) submitted to the USA Cold Regions Research

and Engineering Laboratory by Michigan Technological University, Contract No. DACA89-85-

K-0001.

Argyle, R.L. (1974) Evaluation of environmental

baseline data—Saginaw waste heat demonstration. Interim Report for the period November 1972

through October 1973, Fish and Wildlife Service,

Great Lakes Fisheries Laboratory.

Ashton, G.D. (1974a) Evaluation of ice management problems associated with operation of a mechanical ice cutter on the Mississippi River. USA

Cold Regions Research and Engineering Laboratory, Special Report 214.

Ashton, G.D. (1974b) Air bubbler systems to

suppress ice. Report to the Detroit District, U.S.

Army Corps of Engineers by the USA Cold Regions Research and Engineering Laboratory,

Contract No. NCE-IA-73-108, USA Cold Regions

Research and Engineering Laboratory, Special

Report 210.

Ashton, G.D. (1975) Experimental evaluation of

bubbler induced heat transfer coefficients. Proceedings of the Third International Symposium on Ice

Problems sponsored by the International Association

for Hydraulic Research, Hanover, New Hampshire,

August, pp. 133–141.

Ashton, G.D. (1978) Numerical simulation of air

bubbler systems. Canadian Journal of Civil Engineering, 5(2): 231–238.

Ashton, G.D. (1979) Point source bubbler systems

to suppress ice. Cold Regions Science and Technology, 1(2): 93–100.

Ashton, G.D. (Ed.) (1986) River and Lake Ice Engineering. Littleton, Colorado: Water Resources Publications.

Baca, B.J., T.E. Lankford and E.R. Gundlach (1986)

Environmental impacts of oil and hazardous material spills with emphasis on winter conditions

in the Upper Great Lakes Region. Prepared for

the Detroit District, U.S. Army Corps of Engineers

by Coastal Science and Engineering, Inc.

Behmer, D.J. and G.R. Gleason (1975) Winter fish

movement at a proposed bubbler site; St. Marys

River system. Contract Report to the U.S. Fish

and Wildlife Service by Lake Superior State College, Contract No. 14-16-0003-30.

Berlamont, J. and A. Van der Beken (1973) Solutions for lateral outflow in perforated conduits.

Journal of the Hydraulics Division, American Society of Civil Engineers, 99(HY9): 1531–1549.

Bryce, J.B. and G.T. Berry (1967) Lake Erie–

Niagara River ice boom. Proceedings of the 1967

Congress of Canadian Engineers, Montreal, EIC-68-

CIV, May, p. 28–35.

Calkins, D.J., D.S. Deck and D.S. Sodhi (1982)

Hydraulic model study of Port Huron ice control

structure. USA Cold Regions Research and Engineering Laboratory, CRREL Report 82-34.

Calkins, D.J., M. Mellor and H. Ueda (1976)

Lockwall de-icing with high velocity water jets

at Soo Locks, Michigan. USA Cold Regions Research and Engineering Laboratory, Technical Note

(unpublished).

Camp, T.R. and S.D. Graber (1968) Dispersion

conduits. Journal of the Sanitary Division, American Society of Civil Engineers, 94(SAl): 31–39.

Carey, K.L. (1980) Estimating costs of ice damage to private shoreline structures on the Great

Lakes connecting channels. Prepared for the Detroit District, U.S. Army Corps of Engineers by

the USA Cold Regions Research and Engineering Laboratory, Contract No. NCE-IA-76-195,

Special Report 80-22.

Carter, D., Y. Ouellet and P. Pay (1981) Fracture

of a solid ice cover by wind-induced or ship-generated waves. In Proceedings, 6th International Conference on Port and Ocean Engineering under Arctic

Conditions (POAC ‘81), 27–31 July, Quebec, Canada.

Université Laval, p. 843–856.

Cowley, J.E., J.W. Hayden and W.W. Willis (1977)

A model study of St. Marys River ice navigation.

Canadian Journal of Civil Engineering, 4(3): 380–391.

Dahlberg, M.D., J.W. Duncan and J.M. Burke

(1980) Winter fish population in probable locations of air bubblers in the St. Marys River–Lake

Superior area. Contract Report by NUS Corporation to the U.S. Fish and Wildlife Service in cooperation with the Detroit District, U.S. Army Corps

of Engineers, FWS Contract NO. 14-16-0009-79-087.

Dalton, Dalton, Little and Newport, Inc. (1975)

Report on shoreline erosion and structural damage along the St. Marys River, Michigan. Contract

48
Report to the Detroit District, U.S. Army Corps

of Engineers, Contract No. DACW35-74-C-0128.

Davis, T.E. and R.W. Irwin (1982) Potential impacts of winter navigation upon migratory birds

on the Upper Great Lakes. Prepared for the Detroit District, U.S. Army Corps of Engineers by

the Office of Biological Services, U.S. Fish and

Wildlife Service, issued as OBS Report 82/51.

Frankenstein, G.E., J.L. Wuebben, H.H.G.

Jellinek and R. Yokota (1976) Ice removal from

the walls of navigation locks. Proceedings of the

American Society of Civil Engineers Conference Rivers 76, Fort Collins, Colorado, June, p. 1487–1496.

Garfield, D.E., B. Hanamoto and M. Mellor (1976)

Development of large ice saws. USA Cold Regions

Research and Engineering Laboratory, CRREL

Report 76-47.

Gates, E.T. and J.B. Herbich (1977) The squat phenomenon and related effects of channel geometry.

Hydraulics in the Coastal Zone, 25th Annual Hydraulics Division Specialty Conference, American Society

of Civil Engineers, College Station, Texas.

Gatto, L.W. (1978) Data base for environmental

conditions along the U.S. shoreline of the St. Marys,

St. Clair, Detroit, and St. Lawrence Rivers. USA

Cold Regions Research and Engineering Laboratory, Internal Report No. 553.

Gatto, L.W. (1980a) Shoreline conditions and bank

recession along the U.S. shoreline of the St. Marys,

St. Clair, Detroit and St. Lawrence Rivers. USA

Cold Regions Research and Engineering Laboratory, CRREL Report 82-11.

Gatto, L.W. (1980b) Shoreline conditions and

shoreline recession along the U.S. shoreline of the

St. Marys, St. Clair, Detroit, and St. Lawrence

Rivers. Prepared for the Detroit District, U.S. Army

Corps of Engineers by the USA Cold Regions

Research and Engineering Laboratory, Internal

Report No. 533.

Gatto, L.W. (1982) Bank conditions and recession

along the U.S. shorelines of the St. Marys, St. Clair,

Detroit and St. Lawrence Rivers: Ancillary data.

Prepared for the Detroit District, U.S. Army Corps

of Engineers by the USA Cold Regions Research

and Engineering Laboratory, Internal Report No.

747.

Gleason, G.R., D.J. Behmer and R. Hook (n.d.)

Evaluation of lake whitefish and herring spawning grounds as they may be affected by excessive

sedimentation induced by vessel entrapment due

to the ice environment within the St. Marys River

system. Report to the Detroit District, U.S. Army

Corps of Engineers by Lake Superior State College in support of the Winter Navigation Board—

Environmental Evaluation Work Group, Contract

No. DACW-35-79-M-0561.

Gleason, G.R., D.J. Behmer and K.L. Vincent

(1979) Evaluation of benthic dislocation due to

pressure waves initiated by vessel passage in the

St. Marys River. Report to the Great Lakes Basin

Commission by Lake Superior State College in

support of the Winter Navigation Board—Environmental Evaluation Work Group.

Haas, R.C., W.C. Bryant, K.D. Smith and A.D.

Nuhfer (1985) Movement and harvest of fish in

Lake St. Clair, St. Clair River, and Detroit River.

Michigan Department of Natural Resources, Fisheries Division, Contract Report to the Detroit District, U.S. Army Corps of Engineers.

Hanamoto, B. (1977) Lockwall deicing studies.

USA Cold Regions Research and Engineering

Laboratory, Special Report 77-22.

Hatcher, C.O. (1977) Evaluation of environmental impact data—Saginaw waste heat demonstration program, April 1973 through September 1976.

Fish and Wildlife Service, Great Lakes Fisheries

Laboratory.

Haynes, F.D. and M. Määttänen (1981) Vibrations

caused by ship traffic on an ice-covered waterway. USA Cold Regions Research and Engineering Laboratory, CRREL Report 81-5.

Hiltunen, J.K. (1979) Investigation of macrobenthos in the St. Marys River during an experiment to extend navigation through winter, 1974-

75. (Revised from version of 1978), U.S. Fish and

Wildlife Service Report to the Detroit District, U.S.

Army Corps of Engineers.

Hochstein, A.B. and C.E. Adams (1985a) An assessment of the effects of tow movements on the

Kanawha River. Contract report to the Huntington District, U.S. Army Corps of Engineers.

Hochstein, A.B. and C.E. Adams (1985b) A numerical model of the effects of propeller wash from

commercial navigation in an extended navigation

season on erosion, sedimentation, and water quality in the Great Lakes connecting channels and

harbors. Contract report to the Detroit District,

U.S. Army Corps of Engineers.

Hochstein, A.B. and C.E. Adams (1986) A numerical model of the effects of propeller wash and

ship-induced waves from commercial navigation

in an extended navigation season on erosion, sedimentation, and water quality in the Great Lakes

connecting channels and harbors. Contract report

to the Detroit District, U.S. Army Corps of Engineers.

49
Hodek, R.J., M.D. Annable, G.R. Alger and H.S.

Santeford (1986) Development of a predictive

model to assess the effects of extended season navigation on Great Lakes connecting waters. Contract Report to the USA Cold Regions Research

and Engineering Laboratory by Michigan Technological University, Contract No. DACA89-85-

K-0001.

Hudson, P.L., B.M. Davis, S.J. Nichols and C.M.

Tomcko (1986) Environmental studies of macrozoobenthos, aquatic macrophytes, and juvenile

fishes in the St. Clair–Detroit River system, 1983–

1984. U.S. Fish and Wildlife Service, Great Lakes

Fisheries Laboratory, Contract Report to the Detroit District, U.S. Army Corps of Engineers.

Itagaki, K., M. Frank and S.F. Ackley (1975) Laboratory experiments on lock wall deicing using

pneumatic devices. USA Cold Regions Research

and Engineering Laboratory, Technical Note (unpublished).

Jude, D.J., M. Winnel, M.S. Evans, F.J. Tesar and

R. Futyma (1986) Drift of zooplankton, benthos,

and larval fish and distribution of macrophytes

and larval fish during winter and summer, 1985.

Contract report to the Detroit District, U.S. Army

Corps of Engineers by the University of Michigan, Contract No. DACW35-85-C-0005.

Liston, C.R. and C.D. McNabb (1986) Limnological and fisheries studies of the St. Marys River,

Michigan, in relation to proposed extension of

the navigation season, 1982 and 1983. Contract

Report to the U.S. Fish and Wildlife Service by

Michigan State University, Contract No. 14-16-

0009-790-13

Muth, K.M., D.R. Wolfert and M.T. Bur (1986)

Environmental study of fish spawning and nursery areas in the St. Clair-Detroit River system. U.S.

Fish and Wildlife Service, Sandusky Biological

Station, Contract Report to the Detroit District,

U.S. Army Corps of Engineers.

National Biocentric, Inc. (1973) Environmental

review report for demonstration bubbler system

in the Superior entry, Duluth–Superior Harbor.

Prepared for the St. Paul District, U.S. Army Corps

of Engineers, Contract No. DACW37-73-C-0058.

Nicholson, S.A. and K.W. Dixon (1979) Review

and evaluation of existing contingency plans and

response capabilities for spills of oil and hazardous substances in the Great Lakes system. Contract report to the Detroit District, U.S. Army Corps

of Engineers by the St. Lawrence–Eastern Ontario

Commission, Contract No. DACW35-79-R-0042.

Normandeau Associates (1979) Ship generated

drawdown and surge study, St. Lawrence River

near Ogdensburg, New York. Prepared for the St.

Lawrence Seaway Development Corporation,

Washington, D.C.

Ofuya, A.O. (1970) Shore erosion-ship and wind

waves, St. Clair, Detroit, and St. Lawrence Rivers. Department of Public Works of Canada, Marine Directorate, Design and Construction Branch,

Report No. 21.

Oswalt, N.R. (1976) Ice flushing from St. Lawrence

Seaway locks. Prepared for the St. Lawrence Seaway Development Corporation by the USA Engineer Waterways Experiment Station, Technical

Report H-76-9.

Palm, D.J. (1977a) Evaluation of shore structures

and shore erodibility, St. Lawrence River, New

York State. Prepared by the St. Lawrence–Eastern Ontario Commission for the St. Lawrence

Seaway Development Corporation, U.S. Department of Transportation.

Palm, D.J. (1977b) Evaluation of shore structures

and shore erodibility, St. Lawrence River, New

York State, Appendix B. Prepared by the St.

Lawrence–Eastern Ontario Commission for the

St. Lawrence Seaway Development Corporation,

U.S. Department of Transportation.

Palm, D.J. and T.M. Cutter (1978) Evaluation of

shore structures and shore erodibility, St. Lawrence

River, New York State, Phase II. Prepared by the

St. Lawrence–Eastern Ontario Commission for the

St. Lawrence Seaway Development Corporation,

U.S. Department of Transportation.

Perham, R.E. (1974) Forces generated in ice boom

structures. USA Cold Regions Research and Engineering Laboratory, Special Report 200.

Perham, R.E. (1976) Some economic benefits of

ice booms. Proceedings, 2nd International Symposium on Cold Regions Engineering, Fairbanks, Alaska,

12–14 August, University of Alaska–Fairbanks. Cold

Regions Engineers Professional Association, p.

570–591.

Perham, R.E. (1977) St. Marys River ice booms:

Design force estimate and field measurements.

USA Cold Regions Research and Engineering

Laboratory, CRREL Report 77-4.

Perham, R.E. (1978a) Performance of the St. Marys

River ice booms 1976–77. USA Cold Regions Research and Engineering Laboratory, CRREL Report 78-24.

Perham, R.E. (1978b) Ice and ship effects on the

St. Marys River ice boom. Canadian Journal of Civil

Engineering, 5: 222–230.

Perham, R.E. (1984) The effectiveness and influ50
ences of the navigation ice boom on the St. Marys

River. USA Cold Regions Research and Engineering Laboratory, CRREL Report 84-4.

Perham, R.E. (1985) Determining the effectiveness of a navigable ice boom. USA Cold Regions

Research and Engineering Laboratory, Special Report 85-17.

Poe, T.P. and T.A. Edsall (1982) Effects of vesselinduced waves on the composition and amount

of drift in an ice environment in the St. Marys

River. Fish and Wildlife Service, Great Lakes Fisheries Laboratory Administrative Report No. 82-6.

Poe, T.P., T.A. Edsall and J.K. Hiltunen (1980)

Effects of ship-induced waves in an ice environment on the St. Marys River ecosystem. U.S. Fish

and Wildlife Service, Great Lakes Fisheries Laboratory, Administrative Report 80-6.

Robinson, W.L. and R.W. Jensen (1980) Effects

of winter navigation on waterfowl and raptorial

birds in the St. Marys River area. Report to the

Great Lakes Basin Commission by Northern Michigan University in support of the Winter Navigation Board-Environmental Evaluation Work

Group.

Rumer, R.R., W.F. Bialis, F.H. Quinn, R.A. Assel

and D.W. Gaskill (1983) Niagara River ice boom,

effect on environment. Journal of Technical Topics

in Civil Engineering, American Society of Civil Engineers, 109(2): 104–116.

Schulze, R.H. and M. Horne (1982) Probability

of hazardous substance spills on the St. Clair/

Detroit River system. Contract Report to the Detroit District, U.S. Army Corps of Engineers by

Arctec, Inc., Contract No. DACW35-82-C-0049.

Schulze, R.H., G. Wohl and L. Wallendorf (1982)

Probability of hazardous substance spills on the

St. Marys River. Contract report to the Detroit

District, U.S. Army Corps of Engineers by Arctec,

Inc., Contract No. DACW35-81-C-0076.

Shen, H.T., P.D. Yapa and M.E. Petroski (1986)

Simulation of oil slick transport in Great Lakes

connecting channels, Four volumes: 1) Theory and

model formulation, 2) User’s manual for the river

oil spill simulation model, 3) User’s manual for

the lake-river oil spill simulation model, and 4)

User’s manual for the microcomputer-based interactive program). Contract Report to the USA

Cold Region Research and Engineering Laboratory by Clarkson University, Clarkson Report No.

86-1, Contract No. DACA33-85-C-0001.

Sletten, R.S. (1986) Investigation of potential water

quality effects on the Detroit-St. Clair River system from operation of the Sault Locks to 31 January + 2 weeks. Contract Report to Detroit District, U.S. Army Corps of Engineers by the USA

Cold Regions Research and Engineering Laboratory (Draft).

Sodhi, D.S., D.J. Calkins, and D.S. Deck (1982)

Model study of Port Huron ice control structure:

wind stress simulation. USA Cold Regions Research and Engineering Laboratory, CRREL Report 82-9.

Sorenson, R.M. (1973) Water waves produced by

ships. Journal of the Waterways, Harbors and Coastal

Engineering Division, American Society of Civil Engineers, 99(WW2): 245–256.

Stortz, K.R. and M. Sydor (1980) Transports in

the Duluth–Superior Harbor. Journal of Great Lakes

Research, International Association for Great Lakes

Research, 6(3): 223–231.

Swain, W.R., R.M. Wilson, R.P. Neri and G.S.

Porter (1975) Evaluation of the effects of a harbor bubbler system for winter navigation on the

water quality of Howards Bay in the Duluth–

Superior Harbor—Winter 1974-75. Prepared for

the St. Paul District, U.S. Army Corps of Engineers by the University of Minnesota-Duluth,

Contract No. DACW37-75-C-0124.

Sydor, M., B.O. Krogstad and T.O. Odlaug (1974)

Evaluation of bubbler system for winter navigation, Howards Bay, Superior, Wisconsin, winter 1973–

74. Prepared for the St. Paul District, U.S. Army

Corps of Engineers by the University of Minnesota-Duluth, Contract No. DACW37-74-C-0060.

USACE (1969) Survey report on Great Lakes and

St. Lawrence Seaway navigation season extension:

Main report and final environmental impact statement. Prepared by the U.S. Army Corps of Engineers, Detroit District.

USACE (1974) Report on effects of winter navigation on erosion of shoreline and structure damage along the St. Marys River, Michigan. Prepared

by the Detroit District, U.S. Army Corps of Engineers, Draft Report.

USACE (1978) Model study of the Little Rapids

cut area of the St. Marys River, Michigan. Prepared by the U.S. Army Corps of Engineers, Detroit District.

USACE (1979a) Final survey study for Great Lakes

and St. Lawrence Seaway navigation season extension: Main report and final environmental

impact statement. Prepared by the U.S. Army

Corps of Engineers, Detroit District.

USACE (1980) St. Marys River–Little Rapids cut

ice boom and its effects on levels and flows in

the Soo Harbor, winter of 1979-80. Prepared by

51
the U.S. Army Corps of Engineers, Detroit District.

USACE (1982) Ice Engineering. U.S. Army Corps

of Engineers, Office of the Chief of Engineers, Engineer Manual EM 1110-2-1612.

USACE (1988) Draft environmental impact statement: Supplement II to the final environmental impact statement—operations, maintenance,

and minor improvements of the federal facilities at Sault Ste. Marie, Michigan (July 1977),

operation of the lock facilities to 31 January + 2

weeks. Detroit District, U.S. Army Corps of

Engineers.

USACE-SLSA (1972) Report on vessel speed and

wave study, Detroit and St. Clair Rivers. U.S. Army

Corps of Engineers, Detroit District and Operations Branch, St. Lawrence Seaway Authority.

USACERC (1984) Shore Protection Manual. U.S.

Army Corps of Engineers, Coastal Engineering

Research Center.

USCG (1973) Oil pollution problems associated

with the extended navigation season.U.S. Coast

Guard, p. 133–156.

Uzuner, M.S. (1975) Copeland cut ice boom design criteria and data analysis, winter 1974-75.

Report to the St. Lawrence Seaway Development

Corporation, Vol. 1 of 2.

WNB (1979) Demonstration program final report.

Prepared by the Great Lakes and St. Lawrence

Seaway Winter Navigation Board.

Wuebben, J.L. (1977) Ship induced vibration program, St. Marys River. USA Cold Regions Research

and Engineering Laboratory, Technical Note (unpublished).

Wuebben, J.L. (1978) Vessel passage during winter

ice conditions: Observations of 25 January 1978.

Letter report to the Detroit District, U.S. Army

Corps of Engineers, from the USA Cold Regions

Research and Engineering Laboratory (unpublished).

Wuebben, J.L. (1981a) St. Marys River: Shoreline

erosion and shore structure damage, 1980 closed

navigation season. Contract report to the Detroit

District, U.S. Army Corps of Engineers by the USA

Cold Regions Research and Engineering Laboratory, Contract No. NCE-IA-80-035.

Wuebben, J.L. (1981b) Evaluation of the effect of

vessel size on shoreline and shore structure damage. Prepared for the Detroit District, U.S. Army

Corps of Engineers by the USA Cold Regions Research and Engineering Laboratory.

Wuebben, J.L. (1981c) St. Marys River: Shoreline

erosion and shore structure damage, 1980–81

closed navigation season. Contract report to the

Detroit District, U.S. Army Corps of Engineers

by the USA Cold Regions Research and Engineering Laboratory, Contract No. NCE-IS-81-0027-ER.

Wuebben, J.L. (1983a) Effect of vessel size on shoreline and shore structure damage along the Great

Lakes connecting channels. USA Cold Regions

Research and Engineering Laboratory, Special

Report 83-11.

Wuebben, J.L. (1983b) Shoreline erosion and shore

structure damage on the St. Marys River, 1980

closed navigation season. USA Cold Regions Research and Engineering Laboratory, Special Report 83-15.

Wuebben, J.L., G.R. Alger and R.J. Hodek (1978a)

Ice and navigation related sedimentation. Proceedings of the Fourth International Symposium on Ice

Problems sponsored by the International Association

for Hydraulic Research, Luleå, Sweden, August, p.

393–403.

Wuebben, J.L., L.W. Gatto and S.L. DenHartog

(1978b) Assessment of shoreline areas potentially

impacted during winter navigation. Contract report to Detroit District, U.S. Army Corps of Engineers, USA Cold Regions Research and Engineering Laboratory, Internal Report No. 590.

Wuebben, J.L., W.M. Brown and L.J. Zabilansky

(1984) Analysis of the physical effects of commercial vessel passage through the Great Lakes connecting channels. Contract to the Detroit District,

U.S. Army Corps of Engineers by the USA Cold

Regions Research and Engineering Laboratory,

Internal Report 884.

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Winter Navigation on the Great Lakes: A Review of Environmental Studies

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Great Lakes Navigation Winter navigation

UNCLASSIFIED UNCLASSIFIED UNCLASSIFIED UL

In 1970, Congress authorized a three-part Great Lakes–St. Lawrence Seaway Navigation Season Extension Program. It authorized a winter navigation demonstration program, a detailed survey study of season extension

feasibility and a study of insurance rates for shippers. This report provides a review of numerous environmental

and engineering studies conducted as part of the demonstration and feasibility portions of the program, as well

as many environmental studies conducted after the completion of the original program. Topics include sediment transport, shoreline erosion, shore structure damage, oil and hazardous substance spills, biological effects,

ship-induced vibrations and ice control systems.