WATER SUPPLY OF ROCKFORD
The following information concerning the water supply of Rockford, Ill., is contained in a report, issued by the Fire Prevention Committee of the National Board of Fire Underwriters, on conditions in that city, the report superseding that of 1909: The works are owned by and operated by the municipality and water is supplied to practically all the built up territory within the city limits. The original construction of the works was commenced in 1875. Ross P. Beckstrom has been superintendent since January, 1913, and Oscar E. Bulkeley is assistant superintendent and engineer. As to fire service the report says the main pumping station receives all box alarms upon a gong through a single fire alarm circuit and all other alarms by telephone. Pressures at the station, normally maintained at 65 to 70 pounds, arc raised to 80 or 90 pounds, depending upon the location and size of the fire. The supply is from driven wells. The main supply from wells adjacent to the pumping station is delivered by low-lift pumps to storage reservoirs from which the distribution system is supplied in one service by direct pumping. Supplemental supply from wells remote from the main station is pumped from one well to the storage reservoirs and from another directly into the system. The total capacity of the ten wells now equipped for service is estimated to be about 7,000,000 gallons per day. The equipment of Potsdam Well No. 8 during 1915 is expected to add 2,000,000 gallons to this total. The eight wells adjacent to the main station, called tfu Mead system, have a capacity of about 4,000,000 gallons per day. Potsdam Well No. 3, located on Peach street, west of Main street, has a caacity of 1,000,000 gallons per day, which can e pumped through a 12and 16-inch cast iron pipe line to the storage resdrvoirs or to the suction lines of the service pumps. This well has not been operated for the past two years. Potsdam Well No. 7, located on Eleventh street, south of Seventeenth avenue, has a capacity of 2,000,000 gallons per day, which can be pumped directly into the distribution system. Potsdam Well No. 8, located at Camp avenue and Auburn street, has an estimated capacity of 2,000,000 gallons per day and will be equipped during this year to pump directly into the distribution system. A rectangular reservoir, adjacent to the Main station, about 144 by 52 feet, built partly in excavation of concrete with walls faced with brick above the surface of the ground, was permanently repaired in 1913 and covered with roof of reinforced concrete, supported by I-beams upon cast iron columns; it is about 18 feet deep with overflow at elevation 115.75 and has a storage capacity of 1,000,000 gallons. A circular concrete reservoir 90 feet in diameter, partly in excavation with walls above the ground faced with brick, was built in 1912, adjacent to the main station; it is about 16 feet deep with overflow at elevation 115.75 and has a storage capacity of 775,000 gallons. The combined capacity of the two storage reservoirs is 1,775,000 gallons, of which not more than 1,500,000 can safely be considered available for emergency supply.
The main pumping station is located on Park avenue on the westerly bank of Rock River with elevation of floor 108, or 8 feet above recorded high wat_____. Built in 1875; has been since enlarged and rearranged. Equipment:—The low lift pumps, with a combined capacity of 15,000,000 gallons per day, each has independent gated suction connection with the header in the shaft, and discharges through a common header into a 16-inch loop so gated that the discharge may pass to cither reservoir or both, or directly to the suctions of the high-lift pumps; steam is supplied through a branch to each pump from a single main connecting with the duplicate header above the boilers. The high-lift pumps, with a combined capacity of 19,000,000 gallons per day, can each take suction from the reservoirs or directly from the discharge main from the low-lift pumps, and each can discharge into either or both the 20and 16-inch mains outside the station. Each pump has a single steam supply from a duplicate header above the boilers. In practice the 10,000,000 gallon pump is operated continuously under small suction head from the reservoirs, the 3,000,000and 6,000,000-gallon units are turned over frequently and the latter operated monthly. Four boilers, equipped with stokers and traveling link grates, are arranged in two batteries. Two boilers are ordinarily fired. The auxiliary pumping station is located at Well No. 7.
Consumption is measured by pump plunger displacement with 3 per cent. allowance for slip. The average daily consumption in 1914 was 2,643,000 gallons. The population supplied by census estimate was 52,337 and the gallons per capita was 50.5. The number of services is 9,914 and of meters, 9,058. A recording gage at the pumping station, elevation about 112, shows pressure ordinarily maintained at 65 to 70 pounds. Distribution is in one service supplied by direct pumping. From the main pumping station there extend for two blocks westerly a 20-inch and a 16-inch main which supply two 12-inch mains extending southerly in parallel streets through the principal mercantile district; one continues southerly through an important manufacturing district, and reducing to 10-inch crosses the river and extends through a manufacturing district on the east side. Easterly from the main pumping station a 16-inch and a 12-inch main cross the Rock River and the former increasing to 20 inches parallels the East mercantile district on the north and east and reducing successively to 16-inch and 12-inch, extends southerly through the Seventh street mercantile district and connects with the 10-inch main which crosses the river from the West side. There are a few, mainly short lengths, of 10and 12-inch secondary feeders, one of the latter extending a short distance westerly from the auxiliary pumping station at Well No. 7. Minor distributors, mainly 6-inch with more 4inch than 8-inch, make up a gridiron generally complete in closely built up sections and with long unsupported lengths in the outlying districts; 9.7 per cent. of the total mileage is in 6and 4-inch dead-ends. Mains are cast iron and nearly all are tar-coated. Many of the original mains are still in service; 27 per cent, of the mains have been laid in the past 6 years and 56 per cent. in the past sixteen. Practically no 4-inch pipe is being installed at present. There are 1,356 gate valves.
On January 1, 1915, there were 709 post hydrants in service of various makes, among which the Holly, Corey and Mathews predominate; all open to the right. About 400 have one 4-inch and two 2 1/2-inch outlets, and most of the remainder have two 2 1/2-inch outlets; one has one and a few have three 2 1/2-inch outlets. About 300 have 4-inch connection to main and 4-inch foot valve, the remainder have 6-inch branch and 5or 6-inch foot valve. About 40 per cent. have gated branch. Present practice is to install Corey hydrants with 6-inch barrel, 5-inch foot valve and 6-inch gated branch. All hydrants are provided with automatic drip valve and are set in pockets of loose stone to insure quick drainage. A few are connected with the sewers. The average linear spacing of hydrants in the principal mercantile district is 200 feet, and the area served by each hydrant is 59,400 square feet. In a representative residential district the average spacing was found to be 1,000 feet and the area served is 330,000 square feet.
Since the National Board report of 1909 about 28.5 miles of pipe have been added to the distribution system, 13 per cent. of which is 10 inches or larger in diameter; these mains have materially improved the supply in the mercantile districts. The per capita consumption has decreased nearly 40 per cent., due to metering. Although the available constant supply from the wells near the pumping station has diminished, a well in the southeastern part of the city has increased the available supply 2,000,000 gallons per day and another well of equal capacity in the northwestern part of the city will be equipped during the present year; this will make the available constant supply 9,000,000 gallons per day as against 5,000,000 gallons in 1909. The emergency connection with Rock River has been removed. Storage capacity at the station has been increased 775,000 gallons by an additional reservoir. Additional hydrants have been installed in the mercantile districts and many of the small hydrants have been replaced by hydrants of good size and type; gate valve spacing has been improved. The fire flow tests show a marked improvement as compared with the previous report.
Among the recommendations made are that steps be taken to increase the supply sufficiently to maintain fire flow for 10 hours at time of maximum consumption, either by developing a new source, or by sinking additional wells and providing additional storage and that additional pumping capacity be provided to enable full fire flow being obtained with two pumps out of service. That the water department extend as rapidly as possible the large mains in accordance with its plans, and such additional mains as may be necessary to furnish fire protection supply as follows: a. In residential districts, 1,500 to 3,000 gallons, the former to be considered sufficient only in outlying sections not closely built up. b. In mercantile and manufacturing districts, 4,000 to 6,000 gallons per minute, c. In the important mercantile districts, 7,000 gallons per minute. The above quantities to be in excess of domestic consumption and to be available in high value districts about any large building or group of buildings and in residential districts about any block through hose lines none exceeding 600 feet in length.