Steam Shovel Buried Under Fall of Rock
The Great Gaillard Cut
At this point the canal is cut through what is practically a mountain range. The material excavated consisted largely of rock and formed one of the hugest engineering problems in the world’s history. The cut is nine miles long, 300 feet wide, 272 feet greatest depth and required the excavation of 100,000,000 cubic yards of material.
Gatun Lake, impounded by Gatun Dam, has an area of 164 square miles when its surface is at the normal elevation of eighty-five feet above sea level, and is the largest artificially-formed lake in the world. The area of the water-shed tributary to the lake is 1,320 square miles. During the rainy season, from April to the latter part of December, the run-off from this basin exceeds considerably the consumption of water, and the surplus is discharged through the spillway of Gatun Dam. Toward the end of the rainy season the surface of the lake is raised to about eighty-seven feet above sea level, in order to afford a surplus or reserve supply to keep the channel full to operating depth during the dry season, in part of which the consumption and evaporation are in excess of the supply. It is calculated that when this level has been attained at the beginning of the dry season the reserve is sufficient to assure a surface elevation of at least seventy-nine feet at the end of the dry season in spite of the consumption at the hydroelectric station, and allowing forty-one passages of vessels through the locks each day with the use of the full length of the chambers, or fifty-eight lockages a day when the shorter sections of the chambers are used and cross filling is employed, which would usually be the case. This is a greater number of lockages than can be made in one day.
Steam Shovel Loading Rock