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<br />'~ <br />~ <br />y, <br /> <br />.<1 <br />< <br />~ <br /> <br />MUNICIPAL AND INDUSTRIAL WATER REQUIREMENTS <br />AN'D PROBLEMS <br /> <br />F <br />.(~ <br /> <br />by <br />LEON W. JACKSON <br /> <br />1_1 <br /> <br />Engineer, Headman, Ferguson and Carollo, <br />Consulting Engineers, Phoenix, Arizona <br /> <br />'., <br /> <br />INTRODUCTION <br /> <br />;0: <br /> <br />Among the many needs of a modern municipality, <br />one of the most vital is an adequate, safe, and de~ <br />pendable supply of domestic water. <br />The purpose of this paper is to present information <br />which will lead to a better understanding of the water <br />requirements and problems of municipalities and their <br />relationship to those of the agficultural field. It is <br />only through mutual understanding of all problems <br />involved that we can correctly solve the many probM <br />lems so closely inter-related. <br />The scope of this paper is limited to the existing <br />trends and normal pattern of growth and expansion of <br />cities in arid regions where the Sources of raw water <br />for domestic purposes are adequate, though not un- <br />limited, for normal domestic and industrial activities. <br />It is recognized that deficiencies in sources of water <br />supply can and would seriously alter and over-ride <br />the trends, factors, and influences which are later <br />presented in this paper as being characteristic of <br />specific cities. <br /> <br />~ <br /> <br />> <br /> <br />WATER REQUIREMENTS PER CAPITA <br /> <br />The average per capita water requirement is a fac~ <br />tor obtained by dividing the total quantity of water <br />required by the total number of people served with <br />domestic water. This factor reflects many things <br />about the life and habits of the people in a given <br />city. It is the weighted average of many influences <br />expressed as one factor to be used in the study of <br />the past, present, and probable future requirements <br />of municipal water. <br />Temperature, rainfall, and humidity of an area rank <br />. high in the order of importance in influencing the per <br />capita water requirements. The mode of living, as <br />reflected in the types and number of units of water <br />using equipment, such as sanitary facilities, air con~ <br />ditioning equipment, washing machines, and cleaning <br />equipment has its influence. The quantity of flower~, <br />shrubs, and lawns and the number and types of in~ <br />dustries, institutions, or establishments such as <br />hospitals and parks, also influence the average per <br />capita water requirement. <br /> <br />The water fate structure has a very direct influ- <br />ence upon the per capita use, and consequently it <br />can be and often is used to artificially control the <br />demand for water. This method, as well as the en~ <br /> <br />forcement of laws and regulations on use of water, is <br />sometimes used to curtail the use of water when the <br />supply is insufficient to meet the demand or to pre~ <br />vent excessive or wasteful use of water. <br />The general trend dudng the past twenty years,' as <br />shown in Plate No.1, is toward an increased per <br />capita use of water. This is a result of progressive <br />changes in the influences previously referred to in <br />this paper. Most of these normal changes have been <br />such as to result in increased use of water. <br />The average annual rate of increase in per capita <br />use for cities in arid regions is about 4 gallons per <br />capita per day per year. <br />In some cases this trend toward increased use per <br />capita levels off naturally as people get sufficient <br />water for their needs. In other cases where an ab- <br />normal or undue quantity of water is being used or <br />where the supply is limited, due to limited sowce <br />or limited facilities, the practice in many cities is <br />toward some artificial control on the quantity of water <br />used. It is not likely m feasible that the present <br />upward trend in per capita use will continue for long <br />at the existing rate of rise. <br />By reference to Plate No.1 it can be seen that <br />the average per capita requirements of water for nine <br />different cities in Texas, New Mexico, Arizona, and <br />Utah, all in relatively arid areas, range from 100 <br />gallons per capita per day for Santa Fe, New Mexico, <br />to 260 gallons per capita per day for Yuma, Arizona. <br />EI Paso, Texas, requires 144 gallons per capita per <br />day, and Albuquerque, New Mexico, requires 152 <br />gallons per capita per day. The extremely high per <br />capita quantity for :Vuma, Arizona, is influenced <br />largely by the high temperatures and by very low <br />water rates. The Salt Lake City high rate of 235 <br />gallons per capita per day reflects the relatively low <br />water rates, as well as the water-using habits re... <br />suiting fwm a long histmy of a plentiful supply of <br />good, easily available water. <br />Santa Fe, New Mexico, has a relatively low rate <br />of per capita usage of 100 gallons per ,capita per day <br />and, among other influences,arethe higher elevation, <br />lower temperature, less irrigation and air condi- <br />tioning requited, higher water rates and only a .small <br />amount of light industry. <br />El Paso, Texas, and Albuquerque, New Mexico, <br />are similar in character and have similar per capita <br />rates of about 150 gallons per capita per day, which <br /> <br />OCj~:;:;O <br /> <br />17 <br />