POLLUTION OF WATER SUPPLY SOURCES.

POLLUTION OF WATER SUPPLY SOURCES.

CITY and town councils and private water companies are gradually awaking to the fact that, if wholesome water is to be supplied to the citizens and if, as in a recent case in Wisconsin, those who supply the water are not to be mulcted in heavy damages in the case of disease or death resulting from drinking impure water, the supply, at least, if not the source must be kept pure. To keep the source uncontaminated, is not always easy, and, as a rule, is accompanied with serious expense. Sometimes it is even impossible to secure the land,which must be kept vacant so as to secure the necessary freedom from the possibilities of pollution. In such a case filtration must of necessity be resorted to. In many cases the source of supply is close to a city or town in a fairly populated territory, or, if a new source is proposed, it may lie at a great distance off and present considerable engineering difficulties t before it can be made available for use. In any case, land nearly everywhere is becoming more and more valuable,since the increase in population is rapidly calling into use more lands for agricultural purposes and more extensive cultivation of the soil and the application of chemical fertilizers—all of which tend towards developing a greater vegetable growth. Consequently more decaying vegetable matter, along with much waste fertilizing material in the form of chemical salts, is carried direct into streams by every passing rainstorm—and more frequently and abundantly as the forests are cleared away. It will, therefore, be found that, except in a few cases where the whole, or a large portion of the watershed is owned by the municipality or company, the water supply must be filtered before delivery to the consumer. Otherwise disease and death, as is the case in some parts of Philadelphia at present, must ensue. In the borough of Manhattan the authorities have for some time been guarding against the evils of a polluted source and have gradually been acquiring the title to p of land about 300 feet wide on each side of all streams tributary to the Croton supply, and fencing the same. Similar steps in a smaller way are being taken for the prevention of the pollution of one portion of the Brooklyn supply. Other municipalities are doing the same thing, and in designing new works or improvements to old ones within recent years have been influenced in the arrangement of their supply system by these considerations. It must not be forgotten, however, that large streams and bodies of water may remain unaffected to any appreciable extent for all time, on account of the great dilution of infecting matter or by a natural process of purification operating in open waters. There are many exceptions to this; notably the southern end of lake Michigan in front of the city of Chicago and the Hudson river at Albany. But these waters are polluted with sewage. All pollution from manufacturing refuse and foul water drainage can, of course, be legislated against,easily detected, and abated with results beneficial to all; but to check the progress of farming operations would be a serious blow to the country’s wrelfare. Wherefore, when the purchase of the surroundings of the watershed is an impossibility, there remains only one course open for the supply of pure water—and that is, filtration. This is always possible under any circumstances; it should be looked upon as the cheapest, handiest, and most fitting method, when, as in Philadelphia, there is a superabundance of water at the very doors of a city, which can be purified and delivered to the people at an expense much less than to buy out land at a great distance from the locality to be supplied, and to build expensive works for pumping, storing, and conducting the water to the place required.

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