Table 4. Survey results on data collection methodology in use by USACE Divisions. Survey
results on data collection methodology.
Method
Number
of data
of positive
collection
responses
MRD
NAD
NCD
NED
NPD
ORD
SPD
√
√
√
√
√
√
√
Corps personnel
76
√
√
√
√
√
√
√
Observe from shore or structure
72
√
√
√
√
√
√
Observe from motor vehicle
43
√
√
√
√
√
√
Other agency (such as USGS)
27
√
√
√
√
Observe from ice surface
26
√
√
√
√
√
√
DCP (data collection platform)
26
√
√
√
√
√
√
Observe from aircraft
13
√
√
Other
13
√
√
√
√
√
Volunteer observers
9
√
√
√
√
Observe from boat
4
√
√
√
Satellite imagery
3
choices dealt with the types of personnel making
although more time may be involved.
the observations.
Observations from the ice surface are less com-
The survey results for this question, shown in
monly made and have the same disadvantage of
Table 4, indicate that most ice observations are
being at a single observation point, but do allow
made by USACE personnel from the shore or from
for close examination of the ice. Ice observations
a structure such as a bridge, levee, lock, or dam.
made manually can be manpower-intensive and
Reliance upon, or cooperative agreements with
thus costly. Walking and carrying heavy equip-
national, state and local agencies is quite common
ment onto an ice cover is not without risk, how-
in the water control arena, but apparently not so
ever, and the instability of an ice cover or jam of-
for ice-related measurements according to these
ten prohibits observations from its surface. In ad-
survey results. The use of volunteers for ice-related
dition, few personnel are trained in ice surface
observations does not appear to be common yet.
observations and rescue techniques.
A recent ice observation program involving vol-
Observations from a boat or aircraft do allow
unteers as well as cooperation with the Omaha
the observer to cover the entire river reach in de-
District, USGS, NWS, and state agencies has been
tail, if that is desired. Observations from aircraft
quite successful in Nebraska (White and Kay 1996).
may not allow for close examination of the ice sur-
The ice observations can be input and viewed in
face, and differences in the ice surface may be in-
almost real time on a World Wide Web site (ad-
distinguishable without some form of ground
dress http://cavent.nrc.state.ne.us/cgi-win/
truth. The use of aircraft can also be rather costly
icejam.exe). Plans are underway for a similar ef-
if used on a frequent basis, but does allow for wide
fort in Pennsylvania following widespread ice jam
areal coverage in a short period of time. Observa-
flooding and damage in 1996.
tions from a boat may allow for close examination
It is not surprising that most ice observations
of the ice, but examination of a wide or shallow
are made from shore or from a structure, consid-
river may be difficult, and some ice conditions that
ering the relative levels of effort, safety, and ex-
are of most interest to observe, such as heavy frazil
pense in making such observations. Viewing ice
runs, thick ice covers, or breakup jams, may make
and river conditions from the shore or a structure
light boat operation impossible. The survey shows
such as a bridge, lock, or dam is easy and safe, but
that most observations from boats were provided
these observations allow only a single view of the
by towboat or other towing industry personnel.
river at a particular location at a particular time.
The survey showed that two types of remote
Even if an individual makes several observations
observational methods are being used, although
throughout the day or from several locations, the
to a smaller degree than direct observation meth-
observations may not be representative of the to-
ods. The use of DCPs was reported by about only
tal river reach in question. Observations from a
one-fourth of the respondents, which is smaller
motor vehicle are similarly limited in scope, but
than might be expected given the extent of gen-
do allow an observer to cover more territory,
eral use of DCPs by USACE Districts in the water
7
Previous Page
