(1) Completely reliable.
7. Units of Measure.
a.
Compilation of
hydrologic intelligence from original sources in foreign
(2) Usually reliable.
countries will usually require the use of units of measure
(3) Fairly reliable.
different from those employed in the United States. It is
(4) Not usually reliable.
recommended that data be compiled in whatever units it
(5) Unreliable.
may appear. The hydrologist can then make whatever
(6) Reliability cannot be judged.
conversions are necessary.
c. The person using the data will also make an
b. It is essential that all numerical data be given in
evaluation of its accuracy. This evaluation will be
specific units of measure to be of use.
entered in the compilation using the following standard
c. Elevations should be given in relation to a
intelligence terms to express the degree of accuracy.
specific datum, such as feet above mean sea level or
(1) Confirmed by other sources.
meters above the Adriatic Sea (m u A).
(2) Probably true.
(3) Possibly true.
(4) Doubtful.
are more expressive and more readily understood than
a mass of text. Compilers should therefore include any
(5) Improbable.
pertinent graphic material which may be available.
(6) Truth cannot be judged.
Reference should be made to such graphic material
under the appropriate subject item. The material should
be so labeled as to permit refiling even if separated
from the parent compilation.
SECTION III
COMPILATION OF DATA
requirements, and should be included in the compilation
9. General. a. The compilation of hydrologic
when needed.
intelligence may be conducted under varying conditions.
On the one hand, the compilation may itself be the
11. Specified Subjects. a. Items of information on
subject of a study; on the other, it may be the byproduct
the following major subjects, of vital concern to the
of other intelligence endeavors. The objectives of the
military hydrologist, are shown in section IV with
compiler will dictate the method of presentation to be
example compilations:
used. If, for example, the compiler is systematically
(1) Watersheds.
gathering data on the dams and reservoirs in a given
(2) River and canal channels.
area, he may well find mimeographed cards with spaces
(3) Stream or river gages.
ruled for specific entries very useful.
(4) Precipitation gages.
b. This section explains the method used in this
(5) Bridges.
bulletin to present examples of compilations for the
(6) Fords and ferries.
major subjects covered in section IV, and describes the
concepts involved therein.
(7) Dams and reservoirs.
(8) Hydroelectric plants.
10. Required Items. The required items listed for
(9) Flood protection structures.
the major subject compilations in paragraph 13 through
(10) Navigation locks.
(11) Irrigation projects.
needed by the hydrologist. If these data cannot be
(12) Drainage projects.
obtained, they must be estimated from other sources of
b. In many instances it will not be possible or
information. For instance, if the depth, width, and
necessary to give information for every subject item
velocity of a stream at a ferry crossing are not known,
listed. In such a case the reason for not giving the
the draft of the ferryboat and its course across the
stream can be used to obtain an estimate of the stream
conditions. Such data may be considered secondary
AGO 3898A
3
