Table 16. Ice-jam mitigation methods.
Table 17. Ice-jam mitigation strategies.
Technique
Jam type
Type of mitigation
1. Protect surrounding areas from flood damages
Dikes, levees, and floodwalls
a. Structural
Floodproofing
Dikes, levees, floodwalls
F,B
P
Floodplain land use management
Dams and weirs
F,B
P
Flow diversion
Ice booms
F,B
P,A
Sandbagging
Retention structures
F,B
P
Levee closing
Channel modifications
F,B
P
Evacuation
Floodproofing
F,B
P,A
2. Reduce ice supply
Ice storage zones
B
P,A
Thermal control
b. Nonstructural
Revised operational procedures
Forecasting
F,B
A,P
Ice booms
Monitoring and detection
F,B
E,A,P
Dams and weirs
Thermal control
F,B
E,A,P
Ice storage zones
Land management
F,B
P
Ice retention
Ice cutting
B
A
3. Increase river ice and water conveyance
Operational procedures
F,B
E,A,P
Channel modifications
Dusting
F,B
E,A
Revised operational procedures
Ice breaking
F,B
E,A
4. Control ice breakup sequence
Mechanical removal
F,B
E,A
Detection and prediction
Blasting
F,B
E,A
Ice booms
c. Traditional techniques
Ice retention
Floodproofing
P
Dusting
Sandbagging
A,E
Ice cutting
Evacuation
A,E
Icebreaking
Levee closing
A,E
Revised operational procedures
F = Freeze-up jam
5. Displace ice jam initiation location
B = Breakup jam
Dams and weirs
P = Permanent measure
Ice piers, boulders and cribs
A = Advance measure
Ice booms
E = Emergency measure
Channel modifications
Dusting
Ice cutting
Icebreaking
Breakup ice-jam control focuses on affecting
6. Remove ice
the timing of the ice-cover breakup (thereby re-
Thermal control
ducing the severity of the resulting jam to the
Ice breaking
point where little or no flooding occurs) or con-
Mechanical removal
trolling the location of the ice jam by forcing the
Blasting
jam to occur in an area where flooding damages
will be inconsequential, or at least acceptable.
Table 16 summarizes the currently available
jam mitigation techniques. In the following sec-
Ice booms are the most widely used type of
tions, these methods are described in some detail.
ice-control structure. They are relatively inexpen-
Traditional flood-fighting methods, namely flood-
sive and can be placed seasonally, thus decreas-
proofing, sandbagging, levee closing or evacua-
ing environmental impacts. Booms are most com-
tion, are obviously applicable to ice-jam floods.
monly used to stabilize or retain an ice cover in
Table 17 lists common ice-jam mitigation strate-
areas where surface water velocities are 2.5 ft/s
gies and corresponding techniques.
or less and relatively steady. Ice-control booms
are also used to promote ice-cover formation dur-
Permanent measures
ing freeze-up as an ice-jam mitigation effort. They
Dikes, levees and floodwalls physically sepa-
can be placed to direct ice pieces away from an
rate the river from property to be protected. These
intake or navigation channel.
are used to protect against open-water floods as
Breakup ice-jam frequency and flood levels can
well as ice-jam floods. However, designs adequate
be reduced by storing ice upstream from damage-
for open-water protection may not be adequate for
prone areas. Ice-storage zones reduce the volume
the stages and physical damage caused by ice jams.
and/or rate of ice moving to a downstream jam
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