Table 2. Modeling results for Salmon River ice booms.
Test 1
Test 2
Section 1 Section 2 Section 3 Section 1
Section 2
Section 3
Test 3
Average depth
(ft)
6.1
6.9
6.2
8.2
8.2
7.4
11.9
(m)
1.9
2.1
1.9
2.5
2.5
2.3
3.6
Velocity
(ft/s)
1.1
1.3
1.6
2.3
3.9
3.7
2.5
(m/s)
0.3
0.4
0.5
0.7
1.2
1.1
0.7
Froude number
0.08
0.08
0.11
0.14
0.24
0.24
0.12
Discharge
(cfs)
2.3
2.3
2.3
4.1
4.1
4.1
1.0
(cms)
0.07
0.07
0.07
0.12
0.12
0.12
0.03
Capture efficiency
Single-sag boom
high
high
high
negligible negligible
negligible
negligible
Shear boom
high
high
high
high
A similar experiment on the arch shape de-
cess of the Salmon ice boom in a river where the
sign was conducted in a model study by Burgi
Froude criterion was considered unacceptable.
(1971), with an ice boom named an "upstream V."
This suggests that the criterion has exceptions and
Burgi noted that it provided a more stable ice cov-
warrants further study. The shear boom config-
er than the sag boom configuration tested. The
uration should be considered for any future ICS
"upstream V" ice boom formed a 45 angle to the
installation.
shoreline. Burgi concluded that the ice stability
Plastic beads are very sensitive to minor
was a result of the wedging of the floating ice be-
changes in water velocity and are difficult to cap-
tween the boom and the riverbanks.
ture, making them ideal for laboratory experi-
Following the lab experiments the Salmon ice
ments studying model ice boom geometries. Lab-
boom right-bank anchor was moved 266 ft up-
oratory experiments have shown conclusively that
stream from its previous location (Fig. 7). This new
a change in orientation and shape of an ice boom
geometry and orientation directed more ice to the
can dramatically improve the plastic ice stability
lower-velocity zone on the left bank, increasing
and capture efficiency.
water levels and ice collection. The resulting ice
The design of low-cost ice control structures
cover progressed more than five miles upstream
is an ongoing research effort at CRREL. Total con-
and reduced the total volume of ice available to
struction cost savings of
||content||
million or more may
cause a downstream ice jam. A detailed analysis
result when compared to the .2-million conven-
of historical winter temperature records estab-
tional Oil Creek structure completed in 1988.
lished a method to predict when an ice jam would
reach the town of Salmon (Zufelt and Bilello 1992).
LITERATURE CITED
They concluded that the reduction in ice volume
could be attributed to the collection of frazil at the
Burgi, P.H. (1971) Ice control structure on the North
ice boom upstream of Salmon.
Platte River, A hydraulic model study. Engineer-
An evaluation of the performance of the Salm-
ing and Research Center, Bureau of Reclamation,
on River ice boom concluded that the change in
REC-ERC-71-46.
the shape of the ice boom resulted in an ice cover
Calkins, D.J., D.S. Deck and D.S. Sodhi (1982)
formation upstream of the boom, preventing ice
Hydraulic model study of Port Huron ice control
jam flooding at Salmon in the winter of 1990-91
structure. USA Cold Regions Research and Engi-
(White and Zufelt 1993).
neering Laboratory, CRREL Report 82-34.
Deck, D.S. (1984) Frazil ice control on Oil Creek,
Pennsylvania. USA Corps of Engineers, report to
CONCLUSIONS
the Pittsburgh District.
Full-scale tests in Salmon, Idaho, varied the
Deck, D.S. and G. Gooch (1981) Ice jam problems
ice boom geometry dramatically, improving the
at Oil City, Pennsylvania. USA Cold Regions
ice stability, capture efficiency and ice cover pro-
Research and Engineering Laboratory, Special
gression. Model and full-scale tests demonstrate
Report 81-9.
the importance and sensitivity of the ice boom
Deck, D.S. and G. Gooch (1984) Performance of the
geometry. Use of this boom shape led to the suc-
Allegheny River ice control structure (1983). USA
8
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