. Electrical world. work in the West, especially along the Mississippi River,where it has been necessary to resist the eroding tendency of theFather of Waters. In this construction the cofferdam is made up ofsmall saplings or brush made into fascines, as they are called, placedwith tops up stream, and in alternate layers with hea\-y stones. Overthe completed mass of brush and stone an outside layer of earth isplaced. The cofferdam built in this way near Bulls Bridge resistedseveral floods on the Housatonic when the water went over the top ofthe dam for days together. The only apparent effect o
. Electrical world. work in the West, especially along the Mississippi River,where it has been necessary to resist the eroding tendency of theFather of Waters. In this construction the cofferdam is made up ofsmall saplings or brush made into fascines, as they are called, placedwith tops up stream, and in alternate layers with hea\-y stones. Overthe completed mass of brush and stone an outside layer of earth isplaced. The cofferdam built in this way near Bulls Bridge resistedseveral floods on the Housatonic when the water went over the top ofthe dam for days together. The only apparent effect of this flow ofwater was to wash a few inches of earth from the top of the brush andstone. The rock section of the canal just mentioned begins about 30 the east end of the main dam, and is separated from it by ahigh ledge, as may be seen from one of the photographs. This firstrock section of the canal is about 600 ft. long from the river to thepoint where the entrance gates and waste gates are located. At its. fig. 2.— of bull s bridge andboardmans bridge water pow ers. river end the stone floor of the canal is 17 ft. below the crest ofthe main dam, and 15 ft. below the crest of the weir dam at thehead of the run-around, so that water will flow through this part ofthe canal with a depth of 15 ft. In cross section this portion ofthe canal is 25 ft. wide and has a depth of not less than 17 ft. withvertical sides, though the depth is much greater than this in someparts of the cut. The cross section of water flowing through thisrock cut will be 375 sq. ft. when the fiowage line is up to the top ofthe small dam at the run-around. At about 600 ft. from its river end the canal widens out into anentrance chamber, and here the flush, waste and entrance gates arelocated. The waste gates, of which there are two, are located at thedown-stream end of a spillway on the side of the canal to theriver. This spillway is about 150 ft. long and its elevation is thesame as that
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectelectri, bookyear1883
