THE CLEVELAND WATER TUNNEL.
Description of the Submarine Aqueduct From Lake Erie.
The new tunnel from lake Erie, which is to supply Cleveland, Ohio, with water, has been completed, and, as soon as the new pumping station has been finished, the city will be furnished with water from a steel-crib located three and one-halt miles from the nearest shore point and about five miles obliquely from the new Kirtland street pumping station. Between that station and the intake the tunnel has been constructed—a distance of 26,000 feet. The intake itself has been established at a depth of about fifty feet of water, at a point where there seems to be no danger of contamination from the city sewers. The aqueduct itself consists of a circular tunnel brick lined. Its diameter is nine feet; its walls, thirteen inches thick, penetrate through strata of hard clay, with pockets of sand and gravel, and occasionally seams of quicksand, running horizontally. The tunnel lies as nearly as possible parallel with the lake bottom, and at an average depth of from fifty to sixty feet below it. Its lining is thirteen inches thick, of concentric rings of brick laid in mortar composed of one part of hydraulic cement to two of clean lake sand. All the spaces outside this lining are built up in solid masonry.
The father of the tunnel project was Superintendent M. W. Kingsley, of the waterworks department. The commission which decided upon its construction was composed of Rudolph Hering, George H. Ben zenherg, and Desmond Fitzgerald—all expert engineers with City Engineer M. E. Rawson and Supt. Kingsley as ex-officio members. This commission planned the tunnel in connection with the intercepting sewer system, while Supt. Kingsley, assisted by C. F. Schultz, first assistant engineer of the department, completed the plans for tunnel and crib. Before the actual work on the tunnel began two temporary wooden cribs were built for protection, besides the steel intake crib. In this way the work was carried on from the shore outwards, from this steel crib inwards, and front each of the temporary protective cribs. From each crib, also, and from the point on the shore where the new Kirtland street pumping station is to be located were sunk four circular shafts. The shore crib, which was built first, has a diameter of ten feet and a depth of 112. After the building of this shaft a small section of the tunnel was excavated, the compressed air method being adopted. An air-lock was then set in the tunnel about seventy feet from the centre of the shaft This lock was large enough to admit a twocar train This air-lock was a riveted steel, eylin drieal chamber, seventeen feet in length by five and one half in diameter, and was built into the tunnel in a setting of heavy brick work, reinforced by heavy, transverse, horizontal timbers against the outer end, passing through the tunnel wall. The lock was fitted with the usual doors, valves, and bull’s eves, and contained a connecting section of eighteen-inch track, to match that laid in the tunnel invert for the transportation of materials and spoil. In order to prevent the unnecessary waste of a considerahle volume of compressed air every time that pipe lengths or rails were passed through, a convenient provision was made by establishing an auxilary lock, consisting of a six-inch pipe a little longer than the main lock, and built alongside about three feet above the invert. At the shore end of this pipe it was capped with a diaphragm in which was a hole about five inches square, with a simple flap valve consisting of a piece of board with a leather seat and hinged in on the upper side on the inside of the diaphragm. At each end of the nipo. iust out side of the masonry, there was a small petcock. and at the lake or outer end, a convenient board was kept at hand to cover the end of the pipe. When it was put in place, and the air was exhausted by means of the petcock at the shore end, the opening in the diaphragm could be unclosed and several lengths of pipe or rails could be inserted. Then air-pressure was admitted by the other petcock. and the flap valve seated itself with the pressure, and allowed the materials to be removed into the tunnel. This device was operated by signals, consisting of a code of raps, by two men. one at each end of the main lock. The air-pressure was admitted to the main Jock by a valve, and was taken directly from the general supply in the heading, which was admitted through a four-inch pipe. The air supply pipe stopped on the pressure side of the air-lock, but the air for filling the lock was drawn from the working heading through a three-inch pipe leading from the heading of the air-lock. The continual opening and closing of the lock thus drew out each time about 400 cubic feet of foul air. gas. etc., from the heading and compelled a constant flow forward of fresh, cool air to the workmen at the heading From the screen well aqueducts were also built to the pump well of the station. The tunnel was driven for a full-sized heading, which was excavated chiefly with miners’ picks. Ordinarily but little timber was required, and it was set by the excavators, when necessary. When pockets of gas were found, as was frequently the case, explosions ensued, and large masses of rock were displaced, rendering it necessary to provide shields for the protection of the men, who trimmed the sides of the excavation and smoothed them so as to correspond with the outside of the brick lining. The bricklayers then first laid the inverts to an ordinary template, and afterwards built the arch from The centres, which were set about three feet apart on the horizontal bench planks, the latter being carried by inclined side pieces a little below the springing line. The centres were covered with two by four-inch lagging in lengths of from six to eighteen feet, as required, and were generally wedged out from a quarter to seven-eighths of an inch, in order to allow for the flattening of the arch under pressure. The arch was laid by from two to four bricklayers working on each side until only a narrow space about twenty inches wide was left at the crown. This space was keyed in by one bricklayer working backwards front the finished ring and laying the final bricks on a short centre piece made of a plank about twenty inches long and a foot wide, properly curved on top and supported on each end by rebates in the upper edges of the last two picas of lagging. Some of the bricklayers worked under an average pressure of twenty-three pounds. A perfect alignment was secured by plumb bobs suspended front permanent iron hooks driven into the brick roof, end levels were preserved by metal plugs driven about too feet apart into the roof of the tunnel lining. The work was checked off every too feet. To transfer the alignment from the surface of the tunnel, a diamond drill hole was bored in it about . sixty-five feet from the centre of the shore shaft, and cased with six-inch pipe driven down through the roof of the tunnel. A plmnb hob was suspended through it exactly in the axis of the tunnel, as determined by the surface line, and another in the same way in the shore shaft, when, the transit being set up in the air-lock, a perfect line of ample length was obtained. A small duplex puntp was placed in the tunnel for drainage purposes. Its cylinders were hushed to reduce their area, and the steam cylinders were connected with the air supply pipe, while the pump was operated by compressed air. It was seldom used, however, as very little water was encountered. Each of the temporary wooden cribs is pentagonal in plan, with sides fifty-four feet long and having a concentric pentagonal well, with parallel sides nineteen feet long. The shaft at each temporary crib consists of one steel plate cylinder and eight cast-iron cylinders each nine feet long. The brick lining from bottom of sumo to the cylinders is twelve and one-half inches thick. The intake or permanent crib, the lake connection of the tunnel, is built of steel, and of the same form and dimensions as the temporary cribs. Its shaft consists of a cylindrical steel structure too feet in diameter, and seventy and one-half feet high, with a concentric inside cylinder fifty feet in diameter, both made of steel plates three-eighths of an inch thick, thoroughly riveted and calked, and connected hv twenty-four radial vertical plate diaphragms, which divide the annular space into twenty-four watertight compartments Floor beams across the top of the inner well support a square steel dwelling and lighthouse structure thirty-one feet in height. The house affords storage and a residence for the lighthouse keeper. The inside well will communicate with the open lake by means of twelve radial inlet tunnels through the annular space, with orifices in both cylindrical surfaces to admit the water at levels of fourteen and twenty-six feet below the surface. After the completion of the tunnel the temporary cribs will be removed altogether, and their protecting rip-rap leveled to a depth of at least thirty-five feet below the surface. The tunnel will be arched over continuously at the bottoms of the shafts of these cribs, and their suntphs will he filled to the line of the invert. Then the lower, part of each shaft will be rammed full of puddled clay to a depth of twenty feet, after which it will he filled up to the level of the lake bottom with either clay or earth, well packed.
The tunnel and Kirtland street pumping station, when completed, will have cost between $1,500,000 and $2,000,000. Among the equipment at the station are two Holly triple-expansion engines of 25,000,000 gallons capacity each.
The following are the contracts up to date: Wood en protection crih No. 1. $62,566.15: wooden protection crib No. 2. $44,454.98; steel inlet protection crib. $160,786.IQ; tunnel and shafts (actual amount paid), $440,083.07: Kirtland street station grounds, purchase price. $35,279.34; rip-rap stone along sea wall, $13,318.78; pile and timber jetty. $29,115.20; for building Kirtland street station foundations, aqueduct, pump well screen well, etc., $171,111.96; for building superstructure Kirtland street engine house, $69,454; for building superstructure for boil er and coal storage house, $119,969: for building brick chimney, Kirtland street station, $13,905: traveling crane for the engine house, $4,672; two 25,000,000-gallon pumping engines, $249,400. In addition to the above the boilers for the Kirtland station will have to be bought; a spur of track will have to be built from the Lake Shore railway to the engine house; and the floor system and heating system of the engine house, the electric lighting plant, etc., will be large items of expense.
On the completion of the new tunnel, the West Side tunnel, which now supplies the whole city through the Division street pumping station, will bo extended from the present intake to the new steel crib, or possibly to a submerged inlet near that crib. Both stations will then draw a pure water supply about three and orte-half or four miles from shore. When the Kirtland street station is completed to the full capacity of the new tunnel, it will have a pumping capacity ot 20,000,000 gallons daily. The Division street station now has two 20,000,000-gallon triple-expansion pumps, one to.ooo.ooo-gallon pump, and one 20,000,000 high-duty, Worthington pump, four low-duty pumps in the old building of the station. to be used in case of emergency, and may be dismantled entirely. When the pumps at the Kirtjand street station arc put into service, some time in 1903. the city will have a daily capacity of 50,000,000 gallons at that station, and 70,000,000 gallons daily capacity of high-dutv engines at the Division street station. In addition, if it is needed, there will be the four low-duty pumps of 55,000,000 daily capacity. There will he room in the Kirtland street pumping station for two additional 25,000,000-gallon engines
