SOURCES OF WATER
The staff engineer is responsible for locating and developing water sources. The
senior medical advisor, in cooperation with the engineer, gives advice and makes
recommendations on the selection of water sources. In the selection of a water source,
many factors are considered--the tactical situation, the quantity of water needed, the
quality of the source, the accessibility of the source, and the type of purification
equipment available. The possible sources of water are a public water supply system
(the preferred source), surface water, ground water, rain collected from roofs or other
catchment surfaces, ice or snow, and distilled seawater. Water taken from any of these
sources, except a public water supply system approved by the AMEDD, must be
properly treated before use, as all of them are presumed to be contaminated.
a. Surface Water. Surface water sources include lakes, rivers, streams, and
ponds. These sources are ordinarily more contaminated than ground sources, but they
are frequently selected because of their greater quantity and accessibility. Virtually all
surface waters are contaminated to some extent with fecal materials; therefore, all such
water is considered unfit for human consumption until it is adequately treated.
b. Ground Water. Ground water--that obtained from wells and springs---is
usually less contaminated than surface water. It is therefore a more desirable source.
However, the limited supply provided by a well or spring may render it impractical as a
source of water for large units. Because of the time and labor involved in digging or
drilling wells, combat units normally select this source only when existing wells or
springs are available. Although well or spring water may be aesthetically pleasing in
appearance and odor, it must be presumed to be contaminated and therefore must be
treated before use.
c. Other Water Sources. Rain, melted snow or ice, or sea water may be used
in special instances where neither surface nor ground water is available. Water
obtained from any of these sources must be treated before use. Sea water cannot be
used for human consumption until the salt has been removed by distillation.
Section II. PRINCIPLES OF WATER PURIFICATION
Purification is the process of removing or destroying enough of the impurities
present in water to make the water safe and pleasant to drink. The amount and type of
treatment required depends on the quality of the raw water, the quantity of purified
water needed, and the degree of purification required. A series of treatment processes
is generally employed. A good quality water ordinarily results after treatment of raw
water with the following arrangement of processes--coagulation, sedimentation,
filtration, and disinfection. Under certain conditions, additional treatment processes are
required to remove undesirable dissolved impurities.