Gravity Water Supply.
George W. Rafter of Rochester contributes a recent paper on the gravity system of water supply. It is accompanied by process illustrations of Hemlock and Canadice lakes and two views of the Mount Hope reservoir, showing the fountain in operation. In the course of his contribution Mr. Rafter says:
“In classifying water supplies with reference to safety and certainty one may easily place gravity supplies first. When such a supply is derived from a deep mountain lake, of sufficient elevation to permit of delivery from too to 200 feet above the municipality, ideal conditions arc attained, and nature may be said to have exhausted her resources in this direction in providing for the comfort and convenience of civilized man. Gravity water supplies in all ages have demanded the highest skill of the engineer, whether in the design and construction of great masonry aqueducts or in devising methods ol distributing water to the different parts of cities. First and foremost, a gravity supply is operated not only without machinery, but without any expenditure for power. The universal force of gravitation carries the water to the fortunate municipality, and when there anti confined in pipes its stored energy may be utilized directly for fire streams, the driving of motors and elevators, the flushing of sewers, and for the many other uses ol a public water supply. In the United States and Canada there are nearly 700 towns with gravity supplies. There are no statistics tor proving the proposition with exactness, hut it may be stated in a general way, assuming that the works have been rationally designed, that in these 700 towns the certainty of operation of the water supply, under all circumstances, is somewhat better guaranteed than in the 1400 towns in which pumping is by reason of the conditions an integral part of the water systems.
“ The utility of gravity supplies may be illustrated further by referring to the opportunity which they afford for the formation of public parks at the large storage reservoirs frequently required, or about the sources of supply when they are either large ponds or moderate sized lakes. This quality has been utilized in the Cochituate gravity supply at Boston, where considerable areas around Lake Cochituate are owned by the municipality and arranged with reference to permanent use for park purposes. At Chestnut Hill reservoir, in the outskirts of Boston, the Chpstnut Hill reservoir park also affords a fine illustration of the utility of large storage reservoirs as the [mint of interest about which to group an extensive development of suburban park. Such development, however, while contributing to the attractiveness of the locality, should be made with reference to maintaining the purity of the water supply under all conditions. To this eml human habitations and the usual wastes resulting therefrom should be kept scrupulously at some distance from the water’s edge, or when located near thereto, only allowed under such regulations as will certainly maintain the purity of the stored waters. This is the theoretical conclusion, but it need hardly be said that theoretical condition is often exceedingly difficult to attain.”