bridge, dam, lock, or levee. Visual observations
Table 7. Survey results on types of computer
using still and video cameras are the most com-
storage formats used.
mon type of data collection method. Some instru-
ments or methods to collect data from the ice sur-
Positive
Computer file
responses
face (e.g., ice thickness kit) are used by a number
format
(%)
of Districts, but require intensive human effort. The
use of DCPs is fairly common, but they are typi-
DSS database
24
cally used to measure stage, discharge, and a few
Commercial database
12
meteorological conditions.
GIS
8
Spreadsheet
8
The three types of USACE projects most often
Word processor
28
impacted by ice are flood control structures, navi-
Other
20
gation traffic, and locks. Freezeup problems alone
predominate over breakup problems alone for all
operations and structures included in the survey
Jam Database can be updated annually.
except flood control structures. The number of
Among those using a computer to store ice data,
projects impacted by both freezeup and breakup
word processing programs and HECDSS, the time
is equal to the number affected by freezeup alone.
series data storage system developed by the Hy-
Currently, ice data are predominantly stored in
drologic Engineering Center (HEC 1990), are the
paper form. The information being stored digitally
most common storage formats (Table 7). As noted
on computer is being stored in several different
previously, the need for a centralized data storage
formats. The survey results indicate much poten-
system is important, so Districts should strive for
tial for automating the storage and retrieval of ice
software uniformity as much as possible to avoid
data, but the willingness of observers to convert
data translation problems. It is envisioned that
to computer storage was not gauged.
future storage requirements will require a fairly
The survey results are useful in identifying gen-
robust database system and that GIS querying of
eral trends in collection of ice-related data by the
that data will be performed as computer systems
USACE, and provides some guidance for future
evolve.
instrumentation development. More quantitative
analysis and interpretation is limited by missing
data and some conflicting responses. Overall, how-
Summary of survey results
A survey designed to identify existing and de-
ever, the survey results do indicate there is poten-
sired ice data collection instrumentation, methods,
tial for increased use of existing instrumentation
data storage, and type of ice impacts was sent to
and that some new types of instrumentation are
24 Corps of Engineers Districts (in eight Divisions)
desired.
and the New England Division. Ninety-nine sur-
vey responses were received from eight Divisions.
The number of surveys returned from each Dis-
INSTRUMENTATION EVALUATION
trict corresponds fairly well to the number of
USACE projects in ice-affected areas, except that
Capabilities of existing instrumentation and
the low response rate from a few Districts with a
observation methods
number of navigation projects may skew the sur-
All USACE Districts maintain some level of in-
vey results away from navigation-related ice moni-
strumentation to observe various hydraulic and
toring and impacts.
hydrologic parameters, but the quantity and types
Based on survey responses, the parameters
of ice observations vary greatly between Districts.
rated highest for importance are stage and dis-
This may be a reflection of the severity of ice prob-
charge, followed by air and water temperature, ice
lems experienced or of knowledge of the impor-
thickness and condition of ice. As pointed out pre-
tance of ice data collection. The end use of the
viously, however, the relative importance of col-
measurement data appears to affect how "high-"
lecting other parameters, particularly ice concen-
or "low-tech" the measurement devices are. For
tration and freezeup stage, may increase as the
example, stage may be visually inspected and re-
knowledge of ice processes increases.
corded once a day in a log book by personnel at
The vast majority of ice observations are cur-
one project location, while another individual may
rently being made by USACE personnel observ-
be interested in continuously monitoring the rise
ing from the shore or a nearby structure such as a
and fall of stage at multiple locations during
11
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