Recent Information of the Plant and Repairs of Forty-Inch Steel Main.
The Cambridge waterworks system dates back to 1837, when the Cambridge Aqueduct company was chartered. In 1855, the Cambridge Waterworks company was organised and took the plant over, and in 1875 the works were purchased by the city. The source of supply was Fresh pond, in Cambridge, and Stony brook, in Waltham. An additional supply was obtained by laying a conduit of wood, 4,061 feet long, to Spy and Little ponds and Wellington brook at a cost of $80,000—an extension which was soon given up, as the water was pronounced unwholesome. In 1877 the Stony brook system was completed, the basin there being connected with Fresh pond by seven miles of pipe. The size of the reservoir that was increased in 1888, has already been described in these pages (FIRE AND WATER, March 20, 1896, pp. 90, 91, and December 4. 1897, PP 434, 435, 444, 445 )• By subsequent additions, such as the Payson Park and the Hobb’s brook reservoirs, the reservoir capacity has been increased to 2,270,000,000 gallons. The water is gathered at the Stony brook basin, whose capacity is 350,000.000 gallons. The original thirty-inch pipe line from Stony brook to Fresh pond, laid in 1884. was replaced by one of thirty-six inches for about a mile; thence for seven miles by one of thirty inches. This in course of time has proved insufficient for the needs of the rapidly growing city. The united waters of Fresh pond and Stony brook were pumped from a low elevation to the reservoir and standpipe. a small portion being delivered by highservice pumps, so as to give a pressure of about sixty pounds, the larger portion being pumped to th reservoir and giving about thirty-five pounds pressure. To increase the supply pressure and pumping capacity, enlarged storage was called for, and by a fresh act of the legislature last year, the water board now has authority to borrow $500,000 to lay a new pipe line from Hobb’s brook in Weston to the Fresh pond reservoir in Cambridge. At present the Hobb’s brook water flows by Open brook to Hobb’s brook reservoir, thence by pipe to Fresh pond. When the line is fully completed, a sixty-three-inch concrete conduit will be laid to Fresh pond, following the Fitchburg tracks, and, when the independent line is completed, the combined maximum capacity of the two conduits will be 30,000.000, instead of 7,000,000 gallons daily. In 1892 the land for a new basin at Fresh pond was acquired by the council. It is divided into two parts, the upper basin being about one-third the capacity of the lower, whose average depth is fifteen feet. There is an artificial lake, in length about two miles and a half; in breadth about one mile at the broadest part. Its cost was about $700,000. Its capacity is 40,000,000 gallons; height above the city base 177. To make the necessary connections about five miles of riveted pipe were laid. The extension of the works in 1896 included the increase of storage capacity. The Stony brook watershed area was already twenty-two acres, and nearly 1,000 acres were taken on Hobb’s brook, a branch of Hobb’s brook, and two dams—the Lincoln, where the valley is narrow and is crossed by Lincoln street —and the main dam—the Winter street, in Waltham. Each is mainly built of earth, with concrete walls and a highway on the top. The Waltham dam is thirty-five feet wide on the top; its slope is one and one-half to two feet on the water side, and two to one on the loam side; core wall, seven feet thick, carried to the bedwork sixteen to eighteen feet below the surface. At the bed of the brook the i,ooo-foot dam has a large overflow wasteway, or overflow conduit, about seven feet in diameter, in a chamber at the end of which are dashboards regulating the height of the water, while a relief wasteway in the crest of the dam provides an outlet for freshet water. The supply in the basin controled by the dam is 165 feet above the level of the water in Fresh pond. The construction of the Lincoln dam, which is 600 feet in length and twenty-seven feet wide on top, is much the same as that of the Waltham. The basin, when filled is about 650 acres in extent and two and a half miles in length; its capacity is about 2,000,000 gallons, affording about 1,500,000 gallons available for use. From this storage basin the water flows along the natural bed of the brook to the lower basin at Stony brook, thence by an iron pipe conduit to Fresh pond. This was laid, with the intention of eventually paralleling it with the larger pipe from the Stony brook reservoir to Fresh pond. Payson Park reservoir has been built in the park of the same name, and is connected with the pumping station and the centre of the distributing system by riveted steel forty-inch pipes. It is concrete-lined, 750 feet long, 500 feet wide and twenty feet deep, and is in two compartments separated by a masonry wall. Its capacity is 40,000,000 gallons. The core is fieldstone laid solid in cement and resting on the sheet of concrete at the natural surface, and is all cement-plastered. The gatevalve is circular. The force-mains and the supply pipes are of riveted steel, the plates being about seven feet long and five-sixteenths of an inch thick, rolled, circular riveted and caulked like a boiler, four plates to the section, put together in inside and outside courses, each dipped in a protective coating of linseed oil and asphalt, and baked in an oven till hard. The sections were hand riveted together in the trench, as many as 644 feet (twenty-three sections) being so treated at a time. When there were curves the plates were sheared to a mitre and then riveted up, the smallest radius used being 100 feet. At two points on the line, over a railway and over a roadway, the pipe, which was there three-eighths of an inch thick, was carried over quite deep cuts and made selfsupporting between the abutments, the span being seventy-five feet clear in one instance and ninetyfour in the other. In the latter, the pipe was reinforced by two heavy angle irons, which were extended about two-thirds of the length of the span, and were riveted on the top and bottom, expansion-joints being placed at one end of each exposed pipe. The pipe was then tested by waterpressure in sections to a pressure of ioo pounds per square inch, and all leaks were stopped. The joints made in the field and all defects in coating were coated twice over with asphalt paint. The top of the pipes was placed at an average depth of four feet below the surface. Very strong and very heavy thirty-six-inch valves were used. The stuffing-box expansion-joints used were made of cast iron and in two sections. One, having a spigot end, had a brass bushing attached on the inside. The other had a long deep hub, into which the spigot end of the first fitted. The fifteen lead joints between the two were changed, and airvalves were placed at the summits and blow-offs at the low points. The force-mains are controled in the gatehouse and will deliver the water at the extreme corners of the basins. The water will be taken out by the supply main through a perforated drum-strainer at the end of a movable section of pipe jointed at one end to a fixed end of the pipe coming out of the gatehouse. A float and tackle raises or lowers the other end of the movable section, to which the strainer is attached. The elevation of the water in the reservoir is 162 feet above that in Fresh pond, and by its means the whole city is supplied at a uniform pressure and with only one service. A new highduty Groshon pump of 2,000,000-gallon capacity was also added. All the water pumped runs down hill, and it is then pumped up to the reservoir, back at practically the height it starts from. Electrolysis, due to the stray current from the Boston Elevated Railway company has caused rapid deterioration in the mains, and not least in the forty-inch riveted steel pipe. In many instances the pipe, as will be seen by the accompanying illustration, was completely perforated. The repairs consisted in filling the holes with plugs, secured by straps. Some method of relief must be devised to save the iron and steel pipes from destruction. Meterage is greatly in vogue in Cambridge, no less than over 2,600 having been installed. So highly is the system valued that the watertakers ask for the meters to be installed. Only those whose supplies have been metered without their consent are dissatisfied because they are obliged to pay for the water they use, while others in the city whose supplies are not meastired can use or waste all the water they like. The extension of the meter system will put an end to all such complaints. The meters in service at the end of 1904 were as follows: Mersey, 1,192; Trident, 741; Worthington, 337; Lambert, 132; Union, rotary, sixty-six; Keystone, fifty-five; Crown, forty-three; Nash, sixteen; Thomson, nine; Ball & Fitts, two; Empire, two—total, 2,596, besides forty-eight in public buildings from which the department receives no income. The estimated total population of Cambridge is 97.826, all of whom are water takers; total pumpage for the year, 2,831,342,145 gallons; purchased from Metropolitan system, 379,640,000 gallons—total consumption, 3,210.982,145 gallons; passed through meters, 1,143.795.390 gallons—-making a percentage of consumption metered 35.6 per cent.; average daily consumption, 8,773,175 gallons; to each customer and inhabitant, 89.08 gallons; to each of the 14,803 taps, 593 gallons; total cost of supplying water per 1.000,000 gallons pumped, figured on total maintenance operating expenses, $21.39; on total maintenance plus interest on bonds, $65.95. The total mileage of cast iron pipes, forty inch to two-inch, now in use, is 125.62; hydrants, public, 1,018; pressure, forty-live pounds to fifty-five pounds; services (galvanised cast iron), 115.16 miles in use; average length, forty-three feet; percentage metered, seventeen per cent. The superintendent of the system is Edwin C. Brooks.