WATER SUPPLY.
How Oakland is Supplied from Extensive Reservoirs.
The Contra Costa Water Company, which supplies our city, is well worthy an extended description.Oakland was but a village when in 1868 Mr. Chabot first introduced water into its streets by a pipe line laid from the bed of Temescal creek, some three miles away, but its promise of growth was such that it seemed to warrant the construction of a reservoir of moderate dimensions for impounding water, and in the spring of the same year the Temescal dam was begun at a point 4.72 miles northeast of the city. A point was selected some 500 feet above the present site of the dam, but after building heavy masonry arches of cut stone for a waste-way, and excavating for a puddle-wall, the bottom proved defective, and the work was abandoned after expending some $15,000. The present site was then selected, and the dam built to a height of 105 feet above the creek bed, or 427 feet above Oakland base, with a top width of 18 feet, and slopes of about 2 1⁄2 to 1 on both sides, which have since been increased from year to year by sluicing in material from the hillsides, by means of ditches that run full for a few days after heavy storms.
The area of the high water surface of the reservoir is 184 acres, its maximum capacity is estimated at 188,274,000 gallons, and the water shed tributary to it at 1,500 acres, or 2.34 square miles. Numerous accidents have been described as occurring during the construction, and subsequently which have entailed expense, one of which was a landslide that overturned the heavy brick tower in the lake, in which the regulating gates were placed.
About the same time that the Temescal reservoir was under construction the small distributing reservoir near McClure's Military Academy, on Hawthorne street, was built. Its elevation is 100 feet above Oakland base, and it is supplied from the Temescal reservoir.
The water from the Temescal reservoir is now used for the supply of Piedmont, Temescal and other high suburbs of the city; a portion of it is supplied to the Highland Park reservoir, which was built in 1879 at an elevation of 203 feet above city base. The latter reservoir is chiefly supplied, however, from the Sausal creek, a small stream passing through Fruitvale [illegible] and it is supplemented [illegible] Summer and fall, when other sources run short, by water pumped some 6,000 feet from large artesian wells, bored near tide level in 1871.
As the city increased in population and the demand for water began to tax the capacity of the works then in existence, Mr. Chabot in 1870 sought a larger source of supply, where a reservoir might be constructed, whose capacity would be practically unlimited, as the small water shed of the Temescal reservoir warranted no further increase in the dimensions of the dam, and extension of supply in that direction was impracticable. From surveys made in 1870 for this company of the water shed on the San Leandro creek, it was ascertained that its area was fifty square miles, the fall of the stream, comparatively light, allowing large areas to be flooded by a dam of practicable height, and that all conditions were favorable to such a construction as Mr. Chabot had in view, including material suitable for the embankment in quantities, at a narrow point between two high hills, at a convenient distance from the city
All these advantages decided the selection, and the company at once set about the purchase of the necessary land to cover the site of the reservoir, and as much of the watershed as was necessary to protect the waters from pollution.
By Mr. Chabot's wise forethought in inaugurating the works for this supply. an impending water famine in Oakland was averted, and an unlimited supply secured for the future.
The construction of the San Leandro dam was begun in the summer of 1874, at a point one and one-half miles above the village of San Leandro, and nine and one-half miles southeasterly from Oakland, where the creek bed had an elevation of 115 feet above Oakland base, and the width between the hills at a height of 115 feet above was but 400 feet. The work was continuously prosecuted until in the fall of 1875 the dam had reached a height of 215 feet above the base; the mains were laid and water turned into the city. The dam has since been carried 17 feet higher, and its crest is now 232 feet above city base.
The elevation of the water surface at the time surveys were made was 222.7 feet above city base, at which height the reservoir contained 4,323,446,500 gallons, above the mouth of the outlet tunnel. The building of the dam was attended by many expensive accidents, to which all constructions of that magnitude are liable, necessitating many changes of plans and the expenditure of labor and money which are not now apparent from a casual inspection.
As planned, the dam will be carried 75 feet higher, when its capacity will be about fifteen thousand million gallons, or about five years' supply at the rate of the greatest daily consumption thus far recorded.
It has been the uniform custom of this company to overlook the excessive amounts of water used by consumers for irrigating our public parks; also our gardens, lawns, plants, etc., which ornament all our residences, and gives our city at all seasons of the year the most beautiful appearance.
To keep pace with the probable future growth of the city, Mr. Chabot has looked forward to a still further increase of the supply, and has secured for the company a tract of land in the Pleasanton valley, covering a valuable water right. Considerable work has already been done in digging a canal to drain the lagoon formed by the large springs on the tract, and the surveys have demonstrated that a canal line to lead from this source to the San Leandro lake is quite feasible.
The cost of the works is estimated at about $3,500,000. The total length of pipe laid is 157 miles, and the average cost per mile, all sizes, $10,201 70. The total length of pipe in use is 152.2 miles, The company have secured for the use of the city an abundance of fine and wholesome water for many years to come.
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