(2) Analyzing river crossing sites for
3. Hydrology. a. In broad terms, hydrology is the
conditions of velocity, depth, and width.
science that deals with the characteristics of water in its
various states, and its relation to human activity.
(3) Preparing studies, for Army commanders
Hydrology concerns itself with the occurrence of water in
in areas of operation, on hydrologic and hydraulic
the earth's atmosphere, on the earth's surface, and in
factors which affect the operations, such as: occurrence
the soil and rock near the earth's surface. Hydraulics,
and frequency of floods; normals and extremes of
closely related to hydrology, is that branch of
stream flow; channel characteristics at low, medium,
engineering concerned with the flow of fluids, especially
and high stages; ice conditions; and operation and
the flow of water in natural and manmade drainage and
effects of hydraulic structures.
transportation systems.
(4) Making technical investigations of the
b. Military hydrology includes all aspects of
feasibility of artificial floods created by breaching of
hydrology and hydraulics relating to any aspect of
dams, regulation of hydraulic structures to produce
runoff, stream flow, and ground water that may have an
streamflow variations, and construction of stillwater
important effect on military planning and operations.
c. Some of the duties of the military hydrologist
(5) Analyzing sites for military installations,
include:
from the point of view of flood incidence.
(1) Providing predictions of flood stages,
(6) Furnishing technical advice on hydraulic
discharges, velocities, depths, and durations, with
features of logistic operations such as surface water
corresponding data for low and medium stages.
supply, power, and navigation.
SECTION II
PRINCIPLES OF COMPILATION
b. Information may be dated by placing the date in
4. General. Hydrologic intelligence, to be of use to
parentheses following each item or by grouping item
military commanders, must be systematically compiled
numbers at the end of the report as being valid for
and filed. No specific filing system is presented in this
particular dates. This may be accomplished by stating
bulletin, but the compiler should follow some orderly
which items were taken from specific reports or
method of compilation and maintain standards of
documents, whose dates in turn are given. The most
uniformity.
This section discusses methods for
convenient but clear method should be used.
achieving easily usable compilations.
6. Sources. a. Information, to be of use, must be
5. Dating. a. The collector of any type of
valid. The compiler should state the source of the
intelligence is faced with the problem of logically dating
information, so that the person using the data can better
information. In some cases the material may be
determine its reliability and accuracy.
Personal
compiled immediately after personal observation, and
observations, estimates by local residents, or hearsay
the date of preparation of the report will be valid for the
information should be labeled as such. Published
information. However, the information may also be
sources from which data is extracted should be listed,
gathered from several sources of various dates. In
with the name of the author or preparing agency and the
these cases the compiler should, as clearly as possible,
date of publication.
indicate the date of each item of information. A third
possibility arises when information is collected over a
b. The person using the data evaluates the
long period of time.
Many items of hydrologic
reliability of a source and enters this in the compilation
information, such as stream discharge data,
using the following standard intelligence terms to
precipitation data, and maximum stages, change and
express the degree of reliability.
must be constantly brought 2 up to date. In this case
the date of making each entry should be shown.
AGO 3898A
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