Baltimore Waterworks Extension
GENERAL NEWS ARTICLES
Baltimore is spending $5,000,000 on the enlargement of its water supply. The work on the development of the various parts of the new Gunpowder River supply system is advancing rapidly, and is now assuming tangible form. Contracts running into hundreds of thousands of dollars each are being carried out, while others are yet to be awarded.
The accompanying illustrations show the excavations and partial construction of the Loch Raven dam, seven miles from the reservoir at Lake Montebello, located in the northern suburbs of Baltimore and the work at the filtration plant near the lake. Two bridges, 600 feet and 1,000 feet in length, respectively, are required to give highway passage over the great water area that will be formed by the construction of the dam. The new Loch Raven dam is one-half mile up the river from the present dam of the Baltimore water works. One of the illustrations includes the cross-section of the new dam as now being constructed, that is, to the 192-foot level above the tide or 52 feet above the roadbed of river. The dam is built of concrete without reinforcement, on the gravity principle, and is bedded on rock bottom. The concrete cut-off extends about 20 feet down from the base into rock to prevent water from working under the base. The construction includes draimvays for any water that might percolate into the dam, and an inspection gallery passing through the dam lengthwise. The gallery is about three feet wide and eight feet high, and receives the water seepage from the small drains through porous concrete drains. The main drains front this gallery run into the river, so that it is full, except when the water between the new dam and the present dam below is run off sufficiently to permit inspection of the interior of the gallery passage.
The principal dimensions of the dam as now being built, that is, up to the 192-foot level, are: Length. 500 feet; height to crest, 52 feet, including the four-foot dashboard on top, width of base. 114 feet. This width of base is due to the fact that it has been designed for a possible construction in years to come of a dam to the 300-foot level, or 160 feet high. It is expected that it will not be long before a dam to the 237-foot level, or 97 feet high, will he built. But the present construction is for a dam to be built within the authorized appropriation, that is. to the 192-foot level
The filtration plant under construction at Lake Montebello will receive the water from the Loch Raven basin through the seven-mile conduit already in use. The plant will consist of 32 mechanical filter tanks, each of 4,900,000 gallons daily capacity, built of reinforced concrete; a mixing basin covered with concrete-groined arches and baffled with wooden partitions, with capacity of 3,000,000 gallons; two uncovered coagulating basins, with concrete walls; a filtered water reservoir of 15,000,000 gallons capacity, and a dam to form a wash water basin where water used in flushing out the filters will be properly cared for to prevent muddy waters from flowing into Herring Run. This dam will be an earth gravity dam with concrete waterproof facing on upstream side and a concrete toe wall. The three filter-water basins will occupy the entire area beneath the filters, and will have a combined capacity of 2,500,000 gallons. They are being built entirely of concrete, and will be covered with a groined-arch roof, which will form the support for the filters. There will be two wash-water tanks, each of 125,000 gallons capacity, made of reinforced concrete, and brick buildings will be constructed covering them.
As the water comes from the Loch Raven conduit it will be pumped up to the mixing basin, passing through a Venturi registering meter and eight-foot conduit, then through the filtering and purifying process’ on to the reservoirs, from which it will pass to the city mains. The Loch Raven works, when completed, will consist of the present dam and basin, the new dam and gatehouse and the greatly enlarged water area covering about 620 acres. In the construction of the new dam 50,000 cubic yards of concrete will be used, and the cost of the dam and equipment will amount to about $450,000.
The bridge 3 1/2 miles above the dam will have one 90-foot concrete pier and concrete abutments. It will consist of two 300-foot spans, with steel superstructure, and cost about $75,000. The contract for the substructure has been awarded to the Singer-Pentz Company, Baltimore, and the steel superstructure to the Roanoke Bridge Co., Roanoke, Va., amounting to about $50,000. Security cement, made by the Security Cement & Lime Co., Hagerstown, Md., will be used in the construction of the substructure. In carrying out this work the mayor, water board and water department, under Water Engineer Ezra B. Whitman, have co-operated, with the view of having each integral part under responsible and efficient engineers, and a complete organization has been established. The Loch Raven works are under the supervision of Division Engineer Emory Sudler and Assistant Engineer P. A. Beatty. The filtration works are under the charge of Division Engineer James W. Armstrong. The various contracts that have been awarded have been divided into definite and distinct undertakings, and each given its official number. The filtration plant contract is for the 15,000,000gallon concrete filtration reservoirs, amounting to about $175,000. Contracts for the special castiron pipes were awarded to the Glamorgan Pipe & Foundry Co., Lynchburg, Va., at about $45,-900; to the Columbia Iron Works, Chattanooga, Tenn., for valves to the value of about $30,000, and to the Coffin Valve Co., Boston, Mass., for the sluice gates to the value of about $16,000.
We are indebted to the Manufacturers’ Record for loan of the photographs from which the illustrations were made and abstract of the foregoing text.