WATER SUPPLY OF DETROIT.
DURING the past year since July 1, 1891 the water rates in Detroit, Mich., have been reduced one-half—and this, in spite of the fact that prior to that reduction they were already lower than those of any other city in the United States probably in the world. The outlay for permanent improvements during the year, including pipe extension, was$95,000. The indebtedness of the board of water commissioners is now $1,033,000, with annual interest of $64,320. During 1807 $100,000 worth of bonds has been matured and canceled. The total expenditure for the year was $424,230.31; the receipts were $433,892. :8. After careful analysis by the board of health the »atcr has been pronounced free from any unwholesome contamination. Electrolysis however, is threatening the water mains. Attention has been called to the capacity of pipes for the requirements of the fire department. Previous to 189!, the minimum size of pipe was four inches, which then amounted to about forty-six per cent, of the entire system. Since 1891, four-inch pipe has been replaced by pipe of larger size, and in other localities reinforced by parallel or cross lines. The minimum size now laid is six inches, and the percentage of four-inch pipe has been reduced from for y-sixto thirty. Although the board has believed that the supply of water was adequate for any emergency, the engineer has been instructed to confer with the fire department and report if any enlaigement of supply is required. By a resolution of the water board all water rates charged against the city for public purposes are to be placed in the general budget,collected as other citytaxes, and paid over to the board. Extensions to the pipe system were made last year only on petitions for the supply of new’ territories. These amounted to ali tie over ten and one-half miles,of which nearly three miles were Lid outside city limits—of these there are now nearly seventeen and one-half miles, ail paid for by those who petitioned for such extensions. ‘1 he net increase to the pipe system during 1897 was a little over nine and onehalf miles, thirty percent, of which was four-inch and lesser sizes. For the future six-inch is to be the minimum size. Parallel lines of larger mains have also been laid in the central and bu>iness portions of the city, so as to provide better fire protection. In other localities the system has been reinforced by larger cross lines, upon which to a considerable extent the hydrants are located. No complaints have been made for some years as to a short supply in the suppression of fires, and. with the possible exception of a few localities, the protection from fires is comparatively well provided for. Connected with the mains—there are now in the city 3.002 hydrants and 549 reservoirs. The number of gate valves in the system is now 6.314. Meterage of water is popular in Detroit, as is proved by the fact that there are now in service in the city 5,393 meters with fifteen indicators attached to hydraulic elevators. In 1897 809 meters were placed. Of those in service 5,146 are of the Thomson type; fifty-nine, Hersey; fifty-one Worthington; twelve Union rotary, one Buffalo; one Venturi, and the balance, various. Owing to the reduction in water rates, many metered premises are now being transferred to the the assessment rolls, as these rates on the ordinary house, with bath, closet, etc., are less than the minimum rate for meters ($9 per annum. The meters however, will not be removed, but will remain on the premises (doing sentinel duty as it were) and warning the tenants that they will have to be called upon to pay for any excess over the estimated quantity. The inspection for leaks during the year has been very diligent and exact. On June 30, 1807, the yearly competitive trials were made by Mr. George Barrus.of Boston,between a Murphy, mechanical stoker and a Hawley down-draft furnace. These embraced a series of smoke observations and evaporative trials on two of the water tube boilers at the pumping station. Mr. Barrus reports that, when using Pocahontas coal, the Murphy furnace
was practically smokeless. When using Ilocking slack and Bellinore pea coal, the quantity of smoke pioduced by the Murphy furnace was insignificant. When using Jackson nut and slack coal, there were periods when the Murphy furnace was smokeless; but at other times it emitted a large quantity of smoke. When Pocahontas coal was used, the Hawley furnace frequently emitted a varying amount of light smoke. This occurred after the fires were disturbed or fresh coal was added, and 1 sted from fifteen seconds to three minutes. When the other three coals were ustd, the quantity of smoke produced by the Hawley furnace was greater than with the Pocahontas coal. For a part of the time when Jackson nut and slack coal was used, the Hawley furnace produced no more smoke than the Murphy stoker; but for the entire run the quantity was greater. The Hawley furnace was more efficient in fuel economy than the Murphy stoker when the furl was Pocahontas coal. The difference in favor of the Hawley furnace with this coal was 5.S per cent, if credit is given for the coal which fell through the grates of the Murphy furnace, and fourteen per cent . if the comparison is based on the total coal fired. The first, applied to the cost of coal fora year’s run of the pumping station (taken at an evaporation of 125.000.000 pounds of water) represents an annual difference of $850. and the second, an annual difference of $2,325 in favor of the Hawley furnace. With the three remaining coals, the Murphy stoker operated with greater fuel economy than the Hawley furnace, the difference varying from 5.6 per cent, to 10.5 percent, corresponding to a yearly saving of $850 and $1,787 respectively. In point of cost, none of these coals, whether burned in the Murphy or in the Hawley furnace, gave so good results as the Pocahontas coal on the test of the Hawley furnace.
The pumpage for the year was 12,928,326 gallens—daily average, 35.421,428; cost of full consumed. $17,355.58 The cost of fuel per million gallons pumped was $1.34 and per million gallons pumped 100 feet high $1.24. The total expense of pumping water was $38,123.99, making the cost per million gallons $2 94—a decrease from the year before of $1.08. The full expense for 1897 was twelve and three-quarters less than it was in 18S4, with fifty-two per cent, more water pumped. The total expense at the pumping station was $15,295.07 less than in 1796.