c. Contaminated Water. Contaminated water is water that is unfit for human
consumption due to the presence of pathogenic organisms or excessive levels of
chemicals, organic matter, or radioactivity. Contaminated water may be palatable, but it
is not potable.
d. Polluted Water. Polluted water is water that contains substances that make
it objectionable because of appearance, taste, or odor. Polluted water is usually
contaminated and may be detected easily.
e. Brackish Water. Brackish water is highly mineralized water that contains
dissolved solids in excess of 1,000 parts per million (ppm). Brackish water is found in
many regions throughout the world. Most frequently, it is found in arid or semiarid
climates as ground water and as ground or surface water along seacoasts and in
swampy, marshy areas where water is impounded for long periods of time.
a. Quantity. The quantity of water required for troops varies with the season of
the year, the geographical area, and the tactical situation. In garrison, per capita
consumption may be as high as 150 to 200 gallons per day. This figure, of course,
includes such activities as vehicle washing, laundering clothes, watering lawns, and
other uses. In the field, water usage must be restricted to essential activities--drinking,
cooking, and personal hygiene. A guide for planning to meet the water requirements in
a temperate zone is five gallons per man per day for drinking and cooking. When
showering facilities are made available, the amount required will be at least 15 gallons
per man per day. In extremely hot climates, large quantities of potable water are
required to replace body fluid losses. Table 5-1 is a guide to average drinking water
requirements for various activities and climatic conditions. These levels will increase
when troops are performing heavy labor in temperatures of 90F or greater with high
humidity or in temperatures of 110F or greater with low humidity. Troops should be
encouraged to drink more water and to drink it more frequently than is necessary to
quench sensations of thirst. The myth that men can be taught to adjust to decreased
water intake has been disprove many times.
b. Quality. In addition to the criteria for potability (para 5-3a), there are certain
characteristics that affect the quality of water. These characteristics are acquired as the
water passes over and through the earth, picking up various impurities from the soil
(table 5-2). The following are the most common characteristics of water:
(1) Turbidity. Turbidity is a muddy or unclear condition of water that is
caused by suspended material. Water running over soil picks up small bits of dirt and
carries them in suspension. This suspended material varies from sand, silt, and clay to
organic material including decaying vegetation and animal wastes. The size of the
particles carried depends on the velocity of flow. When the flow of water stops, all but
the finest particles settle out. Ground water (para 1-5) is clearer than surface water
because of the natural filtration process it undergoes in percolating through the soil.