information should be stated as follows, for purposes of
this manual only not available (nval) ; not indicated (NI);
included whenever practicable. (To avoid repetition,
not pertinent (NP). If information is available and
graphic material which is pertinent to more than one
pertinent to the basic subject, but cannot logically be
major subject is included with the first subject to which it
included under any of the prescribed subject items, it
pertains and is referenced, but not repeated, in
should be given in a footnote.
subsequent major subjects.)
SECTION IV
MAJOR SUBJECT COMPILATION
follow this sequence precisely. The major subject
of
compilations of paragraphs 13 through 24 are presented
of
in columnar form. The requirement is stated in the first
data. The numerical arrangement of items is given
in
column and the data is given in the second column.
logical sequence, but the compiler is not required
to
13. Watersheds. San Antonio Creek Watershed.
Item No.
Requirement
Complication
1
Name of stream draining watershed.
San Antonio Creek.
2
Country or countries, state or province and so on,
U. S., Calif.
in which the major item is located.
3
Main river basin in which the subject is located.
Santa Ana River (fig. 1).
4
Name of reference point or the point of lowest eleva-
San Antonio Dam.
tion on the main stream draining the watershed.
5
Distance and direction from a city or some other
San Antonio Dam is about 30 mi east of Los
definite geographic reference point.
Angeles, and about 22 mi west of San
Bernardino.
6
Distance from reference (item 4) to river mouth.
About 19 mi.
7
Coordinates of any local grid-coordinate system.
NI.
8
Drainage area of watershed above reference point.
26.7 sq mi.
9
Length and width of watershed.
About 10 mi by 3 mi.
10
Length of streams in watershed.
a. main stream.
a. about 10 mi.
b. main tributaries.
b. 3 tributaries about 4 mi long each.
c. lined or improved channels.
c. No improved channels.
11
Indicate whether elevations are based on mean sea
Feet above mean sea level, 1927 datum.
level or on some other reference.
12
Elevations in watershed.
a. Highest point.
a. 10,800 ft,
b. Lowest point.
b. 2150 ft.
c. Mean (do not give average for a and b above,
c. about 5,500 ft.
but mean elevation for the entire watershed).
13
Period of record of runoff for watershed. (Give dates
1931-1945.
for beginning and end of period.)
14
Runoff from watershed.
a. Maximum storm of record and date, if known.
a. 10,800 acre-feet, Mar. 1938.
b. Average annual total, if known.
b. NI.
c. Minimum annual total and year, if known.
c. NI.
15
Number and size of natural lakes in watershed. (Give
None.
surface area and storage volume of each lake. if
known).
16
Number and size of manmade reservoirs in water-
None.
shed. (Give surface area and storage volume of
each reservoir, if known.)
17
Give the following subarea values:
100% mountainous, 50% timber.
a. Cultivated.
d. Swampy.
b. Hilly.
e. Timbered.
c. Mountainous.
f. Urban.
AGO 3898A
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