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Show PART II PRESENT STATUS ready-mix concrete manufacturers in the stone, clay and glass industry. Livestock, governmental, and commercial water requirements made up a significant part of total requirements. Commercial and governmental water withdrawal requirements accounted for 11 and 9 percent of total withdrawals, respectively. Livestock requirements accounted for 31 per- cent of total withdrawals and 59 percent of total depletions. Evapora- tion from stock watering ponds accounted for 8,200 acre-feet or 79 percent of total livestock depletions in the San Juan-Colorado Subregion. Water Supply Requirements - Quality Physical, chemical, and biological qualities of water for municipal and industrial water uses must be controlled to prevent undesirable esthetic, physiological and economic effects. Quality requirements for all of these uses are generally satisfied by water of quality meeting the recommended limits of the Public Health Service Drinking Water Standards of 1962 (39). Water of higher quality is required for many manufacturing water uses. Water of lower quality may be satisfactory for many manufac- turing water uses, livestock water use, and lawn irrigation. Domestic Water Use Domestic water uses require a safe, clear, potable, and esthetically pleasing water supply which meets the recommended limits of the Public Health Service Drinking Water Standards of 1962. These standards for physical, chemical and biological characteristics reflect our national attitudes toward domestic water quality criteria. Physical qualities include the turbidity, color, taste, odor, and temperature of water which must be limited to be acceptable to domestic water use. Turbidity is caused by the presence of suspended and colloidal matter which affects the clearnesss of water and the penetrability of light. Turbidity should be limited to less than 5 turbidity units. Color is caused by substances and materials of natural mineral or vegetable origin and by inorganic or organic soluble wastes (32). Color makes drinking water less acceptable and may cause dullness in clothes, and may stain food, fixtures and utensils. Color should be limited to less than 15 color units. Undesirable tastes and odors can be caused by decaying orgainic matter, waste products and the presence of living organisms. Objection- able tastes and odors should be virtually absent from domestic water supplies, and odors should be limited to a threshold odor number of 3. Temperature increases may be caused by natural climatic phenomena or by discharged waste waters. Water becomes less palatable and less useful 17 |