Engineering Wonders of the World
Volume I

140 ENGINEERING WONDERS OF THE WORLD. Qätun Lake Cu/ehra Division 4 Cc <0 0 £ .'s co A/or ma/ Wafer Leve/-/- 85 ßot/om of Cana/ ±4-0 Mf>An Ocean /?7/an he Ocean-Lf-rp <- 7/SM/ies ->* 3/ 72 Mi/es Sca/e 0/ M/ies I» * ■° * £ Kfo/er Z ere/ 4 4-3 I Bottom of Cana/+io* H/ffh Wafer/.eve/e/0' Mea/rOceanLe^e/-Q Loh Wafer L eve/-so ßo/To/n 0/ Oana/—4s' Pac if/c Ocea n Lew/ 1234367 83 fO. ft. !21314 13.16 f7 18.f920,2f,2Z,23242S.26 2728 2930 3/ 32 33 343*36 J/JS5P 40 4^4243 444*464748 49 LONGITUDINAL SECTION OF THE PANAMA CANAL, SHOWING RELATIVE POSITIONS OF THE LOCKS AND GATUN LAKE. Dam will be the, greatest structure of its kind in the world. On each side of a 300-foot channel Gatun Dam. intersecting it, through, which the Chagres at present flows, but which is later to be converted into a per- manent spillway, will rise great earth embank- ments, of the cross section illustrated on page 142. Their tops will be 30 feet above the water-level in Gatun Lake and 80 feet wide ; and the thickness at lake-level 374 feet, and at sea-level 2,625 feet (half a mile). The diver- sion works in connection with the dam will be capable of discharging 140,000 cubic feet of water per second when the level of the lake is not more than one foot above the normal. No engineering project of modern times has been the subject of more serious criticism than has the Gatun Dam. On the Board of Con- sulting Engineers to which, in 1905, President Roosevelt submitted the important question whether the Canal should be completed with locks or at sea-level were men of world-wide fame in connection with canal construction. Not one of them can be justly accused of timidity. Yet all the European representa- tives, and three of their American colleagues, argued that a ship canal of the dimensions demanded by the United States must be of the sea-level type, otherwise it would be quite unsafe for the passage of great ocean-going vessels. They added that the existence of a costly waterway designed to serve the com- merce of the world for all time should not depend upon great reservoirs held up by earth embankments resting literally upon mud foundations, or even those of sand and gravel. Absolute safety was essential. These counsels were certainly justi- fied in part by the crudity with which the lock - canal champions stated their case, especially as regards the foun- dations and design of the mon- ster Gatun Dam. It is quite possible that, but for the foregoing criticism, many neces- sary precautions might have been neglected. Towards the close of 1908 some American newspapers published several lurid reports of a great disaster at Gatun, as proof of the in- stability of the dam and the need for abandoning the high- False Scares. level project. One “ scare ” headline summed up the position as follows : “ Chagres River plunging through 60-foot gap in Isthmian Wall. Engineers face Problem.” The thrilling narra- tive appended lost, however, some of its point when the reader remembered that the dam was not yet built, and consequently could hardly contain a gap. What had happened was this : Much of the rock; excavated from the site of the Gatun locks had been dumped along the south side of the dam site to protect the dam from floods during construction, and to help to support the slope on the lake side after completion. As a result of heavy rains the soil underlying this rock pile was softened, and allowed the rock dump to settle—very advantageously. To reassure the public as to actual condi- tions, President Roosevelt invited Mr. Taft to accompany to the Isthmus a special board of engineers appointed to examine the work in progress and the plans for the various structural accessories to the Canal. The result was a report, transmitted to Congress on February 17 of the present year, in which