Annual Report of the Water Department of Detroit
The annual report of the general superintendent of the water department of Detroit, Mich., Theodore A. Leisen, includes reports of the engineering construction and operating departments for the year ending June 30, 1917.
Population by the United States Census of 1910, 465,786. Date of construction, 1827. By whom owned, the Board of Water Commissioners of the City of Detroit. Source of supply, Detroit River, near Lake St. Clair. Mode of supply, pumping.
Pumpage and Distribution.
All of the statements of water pumpage or consumption are based on the records of the venturi meters, representing approximately 3 per cent, less than the quantity determined by plunger displacement, which covers all losses due to pump slippage and all water used in and about the pumping stations which does not pass through the venturi meters. The total pumpage for the current fiscal year amounted to 52,040,254,250 gallons, of which 38,275,113,750 gallons was distributed through the low service system, and 13,765,140,500 gallons through the high service. The total pumpage for the year shows an increase of 11 1/2 per cent, over the records of the previous year, as compared with an estimated increase of 10¼ per cent, in the population supplied. The average daily consumption for the entire system was 142,576,039 gallons, equivalent to a per capita consumption of 165 gallons per diem, based on an estimated population of 861,427 inhabitants for the City of Detroit and the environs supplied. The rapidly increasing number of meters being installed should have an appreciable effect in the next few years in reducing the per capita consumption. The number of metered services was increased from 46,991 in 1916 to 65,542 in 1917, a net increase of 18,551, and the total quatity furnished through metered services was 29,509,010,557 gallons, or 56.7 per cent, of the total consumption, and produced 66.3 per cent, of the revenue derived from the sale of water. The quantity of water utilized by the manufacturing plants, railroads, hotels and other business enterprises, which may be classified as industrial consumption, is estimated approximately at 18,000,000,000 gallons, or about 35 per cent, of the total consumption. The remaining quantity amounting to 34,000,000,000 gallons which may be designated as domestic consumption, includes all water used by residences, and for flushing and sprinkling streets, fire protection and incidental leakage and other unaccounted for quantities. This domestic consumption was equivalent to a daily per capita consumption of slightly over 100 gallons. Reports from the fire department for the year indicate a total consumption of 30,664,000 gallons for fire protection service, amounting to one seventeenth of one per cent, of the total quantity pumped.
The work on the construction of new extensions of water mains was materially hampered during the latter half pf 1916 by shortage of labor, and throughout the Spring of 1917 by excessive rains. In an effort to overcome the difficulties due to lack of labor, the use of machinery was restored to as far as possible. Four mechanical trench excavators were purchased, one steam and three gasoline operated, and also four gasoline operated back-fillers, and one portable air-compressor for caulking. The use of these machines throughout the current year resulted in the laying of a larger quantity of pipe with a considerably smaller force than would have been possible by the use of hand labor only, and despite the unfavorable weather conditions which prevailed for the first half of 1917, the total length of water mains laid was the greatest of any year in the history of the Water Board. The total quantity of pipe actually laid during the year was 369,959 feet or 70.0 miles, of which 9.5 were main feeders, 12 inches in diameter or larger. Of the total mileage given, 153.2 miles is 12 inches in diameter and larger, and the 54.2 miles is 42 inches and 48 inches diameter. The total amount expended in the construction of water mains for the current year was $637,872.63, the unit costs of the several sizes being shown in the table below:
The general increase in the unit cost of pipe laid as shown in the tabic is due to the higher cost of material; to shortage of labor resulting in gangs too small for good economic results; to higher wages paid, and to unfavorable weather conditions, all of these being contributory factors in raising the cost, which was offset in part only during a portion of the year by the utilization of trenching machines, and by the adoption of the method of laying longer extensions, regardless of whether any houses have been built or started on the line of proposed extensions.
Quality of Water.
The character of both the river and the treated water has been remarkably good during current year, the bacterial counts and the positive tests of B. Goli both having been considerably below the records of previous years. The only treatment given to the water was by means of chlorination, the quantity of Squid chlorin used averaging about two pounds per million gallons of water treated; equivalent to one quarter of one part of chlorin per million parts of water. The river water averaged 27 bacteria per c. c. on agar at 37 degrees, and confirmed evidence of B. Coli in 63 out of 589 samples of 1 c. c. and 866 out of 2,945 samples of 10 c. c. The treated water showed an average of seven bacteria per c. c. on agar at 37 degrees, and confirmed evidence of B. Coli in only 16 out of 2,945 samples of 10 c. c. and no positive indication in any of 589 tests of 1 c. c. samples. The cost of the chlorination treatment was approximately 40 cents per million gallons.
The average mean pressures maintained throughout the city were practically the same as for the preceding year, and resulted in very satisfactory service, and a more uniform pressure was kept up as indicated by the fact that the average of the extreme low pressures was greater than for the previous year, although the consumption was considerably greater. This result was due to the constantly increasing number of mains of large sizes.
Services and Meters.
During the years 11,863 new services were installed, and 180 old services were removed, making a net gain of 11,683, which makes a total of 143,713 service connections of all sizes in the system.
All new services were metered and 6,868 old services were equipped with meters, the total net gain in metered services being 18,551, making a total of 65,542 meters in services at the end of the fiscal year. The following table gives
Cost Per Foot of Water Mains.
the cost of installing, cost of testing and the types and sizes of meters in service:
Cost of Installing Meters, Year Ending June 30th, 1917.
Cost of Meter Testing, Year Ending June 30th, 1917.
Kind of Meters in Service, Year Ending June 30th, 1917.
Pumping Station and Grounds.
The general work of improvement to the grounds around the pumping station was carried on throughout the year, and some progress made in filling in some of the canals at the westerly end of the grounds. On account of war conditions it was deemed advisable to guard the stations and the grounds have been fenced in and visitors excluded from the immediate vicinity of the station. The work on the eight feet diameter tunnel to connect the new station was completed to within about twenty feet of the connecting end when work was suspended, owing to the inability to obtain the 72 inch gates for the connection to the water gallery; as soon as these gates are received and set, the remaining portion of the tunnel will be completed. Contracts were let on December 26, 1916, to the Worthington Pump and Machinery Co. (Snow-Holly Works) for two 37,000,000 gallon vertical triple expansion pumping engines at a cost of $418,250 for the two engines. These pumps will have a maximum capacity of 40,000,000 gallons each, and will be set
in the new pumping station. The foundations for these pumping engines have been completed and the work on the construction of the engines is progressing satisfactorily at the Snow-Holly Works at Buffalo. An ice fender around the intake crib, as recommended in last year’s report, was constructed during the past season, and apparently it accomplished the desired results, as no inconvenience was experienced last winter from ice clogging the ports.
New and Proposed Work.
The work on the proposed extension of 48-inch mains from the pumping station to the northwesterly section of the city, as recommended in the last annual report, has progressed to the extent of contracting for all of the necessary pipe, part of which has been received and distributed, but actual work of construction has been confined to the extension of the 36-inch main and to a portion of the 42-inch line. The recommendations submitted last year regarding additional coal storage facilities; on improvements to the Settling Basin, still hold good, but it was found impossible to commence this work during the present year. In connection with the proposed coal storage facilities, the superintendent recommends the installation of a new unloading derrick, and improvements to the coal conveying devices.