Figure 6. Ice jam at the intakes of the NYPA Niagara Falls Power Project on the Upper Niagara River. (Photo
courtesy of P.A.S.N.Y.)
estimate ice concentrations and identify areas of
bined analyses of historical ice events with the use
of physical and numerical hydraulic models (Shen
moving or stopped ice. The radar is especially
valuable at night when other means of observing
and Su 1997) to assess operational and structural
ice near the intakes are not possible. Finally, video
alternatives to mitigate ice jams. The numerical
cameras, mounted on the roof the Marine Mid-
modeling results indicated that, under certain lake
land Center in Buffalo, continuously monitor ice
ice run scenarios, ice stoppages and jams in the
conditions in the vicinity of the Lake ErieNiagara
vicinity of the NYPA intakes might be prevented
River ice boom (Crissman and Lalumiere 1997).
or at least delayed by altering the schedules for
Much of this information is disseminated via com-
diversion flows. The studies found that for long-
puter networks to operators at the NYPA and OH
duration (more than 24 hours), high-volume lake
power plants.
ice runs, ice jams are likely regardless of the hy-
dropower diversion flows.
As part of their ice mitigation program, NYPA
Midwinter flow control and
and OH have developed an extensive ice moni-
winter navigation
Most of the winter navigation in the northern
toring and ice management program that continu-
U.S. takes place on rivers with stage-regulated
ously informs project operators of ice conditions
navigation dams, such as the Illinois, Ohio, and
and provides advance warning of lake ice runs.
upper Mississippi Rivers. During periods of
Water levels and flows are monitored and dis-
heavy ice, winter flows on the Illinois and upper
played graphically for the operators. Low-light-
Mississippi are typically low, and relatively
level television cameras are used to monitor ice
steady. At these projects, operators must clear
conditions near the intakes. In addition, a marine
brash ice from the upstream approach to the locks
radar system continuously maps the ice surface
and move the ice through gates past the dam.
in the vicinity of the NYPA intakes and is used to
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