Water-power; an outline of the development and application of the energy of flowing water . tion of the retaining-wall. Fig 31 is a section of the dam built by the State of Massa-chusetts, on the Deerfield River, about the year 1864, to furnishpower, in the form of compressed air, required in the construc-tion of the Hoosac It is more properly designated asa log dam than as a tree dam, being made of round logs,notched at their intersection and flatted to receive the drainage-area tributary to this dam is 234 square miles ofmountainous country. The dam rests partly on rock
Water-power; an outline of the development and application of the energy of flowing water . tion of the retaining-wall. Fig 31 is a section of the dam built by the State of Massa-chusetts, on the Deerfield River, about the year 1864, to furnishpower, in the form of compressed air, required in the construc-tion of the Hoosac It is more properly designated asa log dam than as a tree dam, being made of round logs,notched at their intersection and flatted to receive the drainage-area tributary to this dam is 234 square miles ofmountainous country. The dam rests partly on rock and partlyon gravel, underlaid by rock. At one end it abuts against aprecipitous rock, at the other against an abutment of masonry,resting on gravel and faced with planking which is fastened totimbers built into the masonry. The spillway is 250 feet long,being rather more than i foot for each square mile of drainage- * Report of the Canal Commissioners of the .State of New York for Tenth Census Report U. S., vol. xvi. Region Tributary to LongIsland Sound, p. 109. TREE DAMS. 65 I. ?66 coa^stHuctiOiV of dams. ground, whereas the Olean dam just described has but i footto 5 square miles, and the^Schoharie Creek dam i to 2^. On this stream the ice sometimes gorges and forms tem-porary Such a gorge, obhterating the fall at this dam,is a serious danger to be provided for, the buoyancy of such amass of timber tending to lift and derange the dam. Thisdanger is understood to be met by a loading of stone, thespaces represented as vacant being filled with stone. Log Dams and Lumbermans Dams.—The main overflowshown at Fig. 32 is a typical log dam, consisting of a cobworkof logs, supporting a deck of inclined planking or timber, oneend of which projects over the logwork and the other rests onthe ground and is covered b\- a bank of gravel. Such damsare often built remote from any source of supplies, with suchmeans as can be transported over very rough roads, in sipallboats, o
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Keywords: ., bookcentury1900, bookdecade1910, booksubjecthydraulicengineering
