Table 2. Ice parameters currently monitored, by Divisions (as of 1995).
Ice parameters currently monitored, by Divisions
Ice parameter
MRD
NAD
NCD
NED
NPD
ORD
SPD
√
√
√
√
√
√
√
√
√
√
√
√
√
√
Water stage
√
√
√
√
√
√
√
Air temperature
√
√
√
√
√
√
Water temperature
√
√
√
√
√
√
Ice thickness
√
√
√
√
√
√
Condition of ice
√
√
√
√
Date of ice out
√
√
√
√
√
Ice areal coverage
√
√
√
√
√
√
Ice movement
√
√
√
√
Date of ice in
√
√
√
√
Ice concentration
√
√
√
√
√
Freezeup stage
Note: Southwestern Division does not currently monitor ice conditions.
is somewhat diminished. The only other two pa-
and progression, and knowledge of freezeup stage
rameters that were assigned some degree of im-
is increasing in importance as a predictor of later
portance by the respondents are ice thickness and
ice cover breakup.
the condition of the ice.
Clearly, the parameters deemed by survey re-
The responses shown in Table 3 indicate that
spondents to be the most important parameters
most respondents desire the development of in-
to monitor are discharge and water stage (Table 3
struments to measure ice thickness and ice move-
and Fig. 4). Instrumentation for measuring these
ment. Instrumentation for detecting ice movement
parameters both in the field and remotely has been
(described later) has been developed and field
widely available, so it is not surprising that they
tested and could be readily adapted by Districts
are also the two most frequently monitored pa-
for field use. Experimental remote ice thickness
rameters. Air and water temperature are the next
most commonly monitored parameters, but their
measuring devices have also been laboratory or
rated importance relative to discharge and stage
field tested. Stage, discharge, and air and water
Table 3. Ice conditions currently monitored and desired to be monitored
ranked in order of relative importance.
Number of positive responses
Parameter
a) Currently use
b) Desire to use*
c) Relative importance†
Discharge
78
(1)
79
(1)
3.86
(1)
Water stage
77
(2)
78
(2)
3.82
(2)
Air temperature
75
(3)
75
(3)
2.99
(3)
Water temperature
66
(4)
69
(4)
2.89
(4)
Ice thickness
43
(5)**
54
(5)
2.42
(5)
Condition of ice
39
(6)
46
(6)
2.21
(6)
Date of ice out
35
(7)
41
(7)
2.01
(7)
Ice areal coverage
32
(9)
37
(9)
1.99
(8)
Ice movement
26
(10)
36
(10)
1.96
(9)
Date of ice in
35
(7)
41
(7)
1.95
(10)
Ice concentration
18
(11)
26
(11)
1.79
(11)
Freezeup stage
12
(12)
21
(12)
1.68
(12)
* The number of responses includes those who only marked the "currently use."
† Items left blank by respondents who otherwise completed the question were assigned a value of 1.
** Number in parenthesis indicates relative rank of surveyed parameter in each column.
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