Reserves

3972

Reservoirs

confining Ihe aboriginal population to nar-
rower limits. At first the reservations were
formed chiefly as a result of the cession of
land to the government, the Indian tribe re-
taining a specified part of such land for its
own use, such cessions being governed by
treaty. In 1871 this practice was terminated,
and transactions with the Indians were
brought under the immediate control of Con-
gress. The Indian Reservations are admin-
istered by the Bureau of Indian Affairs. They
are subject to the jurisdiction of the United
States, but as far as possible the regulation of
their own domestic affairs is left to the In-
dians. The U. S. Government endeavors to
protect them from unscrupulous whites and
from their own ignorance as well; educational
work is stressed; and a constant endeavor is
made to make of the Indian wards good and
useful citizens. There are Indian reservations
in Arizona, California, Colorado, Florida,
Idaho, Iowa, Kansas, Nevada, New Mexico,
New York, North Carolina, North Dakota,
Oklahoma, Oregon, South Dakota, Texas,
Utah, Washington, Wisconsin and Wyoming.

Reserves, in military usage, forces and
materials held for future use. In actual battle,
the reserves are troops not in action but kept
back and held ready to act at a critical mo-
ment in order to insure victory or turn aside
defeat. Reserve supplies of materials, such as
ammunition, provisions, and other necessi-
ties, are always established near the scene of
action to be available without delay when
needed. The term reserves is also applied to
those men w*ho have received some military
training and can be called upon in time of
national emergency, but who ordinarily fol-
low the pursuits of civil life. Their organiza-
tion varies in different countries. The United
States Army Reserve Corps numbers H3r
177 officers and 2,998 enlisted men; the Naval
Reserve 12,578 officers and 40,012 men; the
Marine Corps Reserve 14,945 officers, most
of whom were called up in 1940-41.

Reservoirs are receptacles for the storage
of supplies held in reserve. The term is gen-
erally limited to structures for storing fluids,
particularly water, but, broadly 'speaking, it
includes any container of stored materials or
energy. The object of the reservoir may be
to equalize supplies which vary in production
or consumption, or to maintain a uniform
level, head, or pressure. Kitchen, or cooking
stoves, or ranges, for use in houses without
running water or plumbing fixtures were often
provided with reservoirs (water backs) for
maintaining a supply of hot water. Generally

speaking, however, a reservoir is a relatively
large structure, built wholly or partly in the
earth, for the storage of water for domestic
and industrial uses, fire protection, irrigation,
water power, navigation, or flood protection.

Water Reservoirs in General.—These faii
into three main classes: (i) receiving or im-
pounding, which are generally located at the
source of supply, and are designed to make
good the deficiencies in yield in times of
drought; (2) distributing or supply, located
near the point or area of water consumption,
to meet interruptions in the supply due to
breaks in the conduits, or to meet fluctua-
tions in the consumption or use of water
from hour to hour or day to day; (3) equal-
izing, to maintain a uniform flow of water,
or to give a constant level or head, either for
pumps to work against or to afford a fairly
uniform pressure, as in a water-works dis-
tributing system. Either distributing or
equalizing reservoirs may afford considerable
storage against the falling off in the yield of
the source of supply. Impounding reservoirs
are located on perennial or on intermittent
streams, and are filled by gravity. Other
reservoirs may be located wherever conditions
are favorable, and may be filled either by the
natural flow of streams, by gravity conduits,
or by pumping through force mains.

There are many important reservoirs with
*a capacity of 50 billion gallons and more in
the United States, as, for example, those
which form a part of the water supply sys-
tem of New York City (see CATS KILL AQUE-
DUCT). See DAMS, AQUEDUCTS, IRRIGATION.
Large reservoirs include the one formed by the
Assuan, across the River Nile, which supplies
water for irrigation in Egypt and the Gatun
reservoir, connected with the Panama Canal,
which is reported as having a capacity of
1,370 billion gallons.

Reservoirs, Use in Flood Prevention.
The floods in New England and Pennsylvania
in 1936 served to focus attention on the
necessity for prevention. Among the methods
used were the dredging of river beds and the
erection of dams and reservoirs to hold the
surplus water. Work then done was insuffi-
cient to prevent, although it did check, the
disastrous floods in the Mississippi Valley in
1937. With the completion of the system of
reservoirs in the near future it is hoped that
the danger from floods will be entirely
eliminated.

Most of the dams in the system are for the
purpose of irrigation and power as well as
flood control. The Tygart Dam in West