Water Supply of Bloomington
The source of the water supply of Bloomington Ill., is wells in the valley of Sugar Creek, which lies to the north of the town. The strata penetrated for these wells till the water is reached, are as follows: Surface gravel, 33 feet; blue clay, water-bearing gravel, front 60 to 80 feet. Borings have shown a belt of gravel about 2,000 feet in width, leading down to the creek valley from the immediate neighborhood of the water works. The wells lie at some distance front Bloomington, and normal sewage which is discharged into the creek considerably below them. The wells are thn in number, and two of them have been sunk about 400 feet apart from each other, and about 5n teet from the creek on the north side of the stream. The location of the third is about a quarter of a mile above the other two. The wells and their equipment are of the following type: Concrete shafts, 12 feet in diameter were sunk to a depth of 12 teet in the case of the two wells adjoining each other and 52 in that of the one more distant. At the bottom each was sealed with concrete floors and made waterproof throughout. I*’our lb-inch tubular wells extend through the water-bearing strata to a depth of 30 feet below the bottom of the shaft. Each ot these is placed on the corners of a square 4 feet apart and is equipped with a 10-inch No. 20 Cook well-strainer, 24 feet long, all four being piped to the suction of a single centrifugal shaft set on the floor of the shaft. This pump is driven through a vertical steel shaft by a 50-horsepower VVestinghouse motor set on the floor of a small house built over the well and on a level with the surface of the ground. This pump has a flinch suction and a 10-inch discharge, with a capacity of 1,100 gallons per minute. Water at the bottom of tile shafts when the pumps are idle is at times under a head of 40 feet. At one time, however, during the past summer a suctionlift of about 12 feet was exerted by the centrifugal pumps. During the greater part of the time that these wells have been in use, the capacity of one well has been sufficient to supply the entire city, and there has never been any danger of a water shortage.
The 10-inch force mains from the three wells lead across the creek and over the top of the wt II of an open storage reservoir, the top of which is at an elevation of about 18 feet above the land on which are the two nearer wells. In this way is made a total lift of about CO leet for the pumps. I lte walls of the reservoir rise about 3 feet above the surrounding ground and the reservoir itself is surrounded at a distance of about 6 feet in circumference by a woven wire fence. The reservoir is of concrete. Its diameter is 300 feet; depth at the walls 12 feet, at the center, 25; storage capacity nearly 10,000,000 gallons enough to supply the city for four days at the average rate of consumption. The reservoir has no dividing wall when by the cleaning process might he facilitated. In consequence, it has not been cleaned once during the 7 years it has been built. The moss, etc., which has grown in the reservoir have caused the water to be at least unpleasant in smell and has, also, been sucked into the pumps and forced through the mains, thereby causing stoppages of the service-pipes. The average done stic pumping pressure at the plant is about 05 pounds; iti the business districts the pressure is from 50 to 70 pounds. For fireservice purposes the pressure can be raised to 125 pounds. Each of the litre wells and their equipment cost approximately $10,000, and the entire cost of the 1910 and 1011 improvements—practically amounting to replacing the entire equipment by the system was about $150,000. The whole of the present system represents an investment of probably $500,000 and the revenues from the sale of water during the past fiscal year was $15.18.1 50 an average of 4.8 cents per each 1,000 gallons pumped. All the water is metered; the rates arc as follows: Twenty-five cents per 1,000 gallons, when not more than 100,000 gallons are used per quarter; for all over 100,000 gallons a charge of 15 cents per 1,000 gallons is made. In eases, where not over 50 cents worth of water is used in three consecutive months a minimum charge of 50 cents is made. The quality of the water is too hard and it has an excess of iron, which could easily be removed by the proper equipment. The water, however, is perfectly free from anything approaching to pollution. The same cannot he said of the private wells, of which there are many in use in Bloomington. These are mostly from 20 to 50 feet deep and are chiefly of the open dug type. In 1009 samples taken from them proved that the majority was contaminated, and it was recommended that their use should be abandoned and the citizens compelled to use the public supply. The recommendation, however, has not been followed, nor apparently has even a mild epidemic of typhoid tev;r in 1011 sufficed to make the people wise to the fact that to allow a further use of polluted water may yet be productive of a deadly outbreak of some water-borne disease.