Table 6. Flow-control objectives; breakup period.
Control
Promote
Prevent
Control ice
timing of
ice passage
structural
River; Structure
jam location
breakup
at structures
damage
Aroostook River; Tinker Dam
Secondary
Secondary
Connecticut River; Wilder Dam
Possible
Possible
Ohio River; Markland Dam
Primary
Primary
Illinois River; Dresden Island Lock and Dam
Primary
Primary
Susquehanna River; Safe Harbor Dam
Primary
Primary
Clark Fork River; Thompson Dam
Primary
Primary
Clark Fork River; Milltown Dam
Primary
Primary
examining the effect of flow regulation on ice pro-
periods. Although there is some potential to con-
cesses at other sites.
trol flow to affect the location and timing of
breakup, the primary operational goals at most
Flow-control guidance for
river projects are to pass ice as it arrives and avoid
passing ice at dams
damage to the structure. Ice jam location can be
Passing ice at Corps navigation structures on
controlled to some extent by regulating pool lev-
major U.S. rivers is one of the greatest winter
els prior to breakup, and, in some cases, dam gates
operations challenges faced by the Corps. A great
can be operated during the event to either pass
deal of operational experience exists, but much of
or retain the breakup ice, depending on the ice-
this information is site-specific and not well docu-
control objective. As far as the timing of ice
mented. A summary and analysis of operational
releases, project operations may, to a limited
ice passage methods at Corps structures would be
extent, either delay or precipitate breakup. Table
a worthwhile effort. CRREL researchers have
6 lists flow-control objectives during the breakup
investigated ice passage at specific sites with
period at the projects described in this report.
physical model studies using real ice. The two-
There is little analytical guidance in these
dimensional model developed by Shen et al.
areas, and operators rely mainly on experience.
(1998) to simulate ice jamming at the mouth of the
Ferrick and Mulherin's (1989) model for pre-
Missouri River has potential for assessing ice pas-
dicting breakup (or non-breakup) is a poten-
sage operations at navigation structures. In addi-
tially valuable tool for forecasting the effect of
tion, a discrete element model under developed
a flow release on the downstream ice cover. A
at CRREL by Hopkins et al. (1998) could be
refinement of this breakup model or incorpora-
adapted to simulate flowicestructure interac-
tion of ice-breakup routines in existing one- and
tions in three dimensions.
two-dimensional ice transport models would be
a worthwhile research direction in the field of
Operational guidance for dam releases
flow control to manage river ice.
under conditions of low flow and ice
Adjusting winter release schedules from stor-
LITERATURE CITED
age reservoirs to compensate for downstream ice
jam formation and flow deficits is an important
Ashton, G.D. (Ed.) (1986) River and Lake Ice Engi-
operational issue at some Corps structures. With
neering. Littleton, Colorado: Water Resource Pub-
the exception of the study by Wuebben et al. (1992,
lications.
1995), little guidance is available for predicting the
Beltaos, S. (1984) A conceptual model of river ice
likelihood of ice-related flow deficits and adjust-
breakup. Canadian Journal of Civil Engineering, 11:
ing release schedules accordingly. Further work
516529.
in this area would be valuable.
Beltaos, S. (1995) River Ice Jams. Highlands Ranch,
Colorado: Water Resources Publications.
Breakup period
Breland, A. (1995) Ice study on the Yukon River
During breakup, the opportunities for manag-
at Whitehorse. In Proceedings of the Eighth Work-
ing ice through flow regulation are more limited
shop on the Hydraulics of Ice Covered Rivers, Com-
than during the ice-formation and midwinter
mittee on River Ice Processes and the Environment,
23
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