THE PANAMA CANAL 



161 



the supplies are shipped to the various 

 subdivisions of the canal-work for which 

 they were purchased, or they are placed 

 in storehouses along the line for issue 

 when required. 



It was only after these various yet 

 necessary adjuncts had been provided 

 and the forces for their operation were 

 organized that the principal work in 

 hand — the building of the canal — could 

 be pushed forward with any hope of 

 success, and too much praise cannot be 

 given to those who conceived and estab- 

 lished them in a working condition. 



The Department of Construction and 

 Engineering is divided into three con- 

 struction divisions. The Atlantic Divis- 

 ion embraces the engineering construc- 

 . tion from deep water in the Caribbean 

 Sea to include the Gatun locks and dam ; 

 the Central Division extends from Gatun 

 to Pedro Miguel, and the Pacific Divis- 

 ion from Pedro Miguel to deep water in 

 the Pacific Ocean. 



KEEPING THE FLOODS OUT OE CULEBRA CUT 



As already noted, the Americans con- 

 tinued the work in progress by the 

 French in the cut through the continental 

 divide, commonly known as the Culebra 

 Cut, utilizing the French machinery until 

 it could be replaced by more modern 

 appliances. This is the most formidable 

 part of the enterprise on account of the 

 magnitude of the cutting, and also be- 

 cause of the difficulties attending it, due 

 to the excessive rainfall and to the vary- 

 ing character of the materials encoun- 

 tered. 



The efficient and economical working 

 of the plant requires that provisions be 

 made for the disposition of the large 

 quantities of water that result from the 

 rains. Whatever water is not carried off 

 by the streams enters the cut, either 

 through direct fall over the excavated 

 area or by seepage into it. Proper drain- 

 age of the cut is therefore an ever-exist- 

 ing problem, and two distinct phases are 

 presented, viz : 



1. To keep out the water of the sur- 

 rounding country. 



2. To rid the excavated area of the 

 water that collects in it. 



A system of diversion channels accom- 

 plishes the first, and gravity drains and 

 pumps solve the second. The canal line 

 follows the Obispo River, which drains 

 the area from the divide to the Chagres 

 River. It has four principal tributaries, 

 two from the east, the Masambi and the 

 Sardinilla, and two from the west, the 

 Mandinga and the Comacho. These are 

 cared for by two diversion channels. 



On the east side of the cut the Obispo 

 diversion has been constructed almost 

 parallel to the canal and carried through 

 a depression in the hills so as to dis- 

 charge into the Chagres about one mile 

 above the point at which the canal line 

 crosses the river. 



To the west of the cut the Comacho 

 diversion carries the waters from Cule- 

 bra to the Chagres River through the 

 old channel of the Obispo River. Through 

 a hill between Haut Obispo and Bas 

 Obispo, which sharply deflects the river, 

 the French had built a tunnel for divert- 

 ing the flood waters, and this forms a 

 part of the new diversion. 



The canal follows the Rio Grande on 

 the southern slope of the divide, and its 

 waters are cared for by a diversion chan- 

 nel constructed by the French. They 

 also constructed a dam across the valley, 

 impounding the waters, and the resulting 

 reservoir supplies the settlements from 

 Culebra to and including Panama. Dur- 

 ing the wet season the diversion channel 

 carries the overflow from the reservoir. 



HOW THE SHOVELS WORK 



The French so planned the excavation 

 that after the removal of the peak of 

 the divide and lesser summits they could 

 work a number of excavators simultane- 

 ously at several points, so that a succes- 

 sion of benches resulted, lying one above 

 the other, each with the natural surface 

 as the point of beginning. By working 

 in the direction of the length of the cut, 

 the face of the bank gives the longest 

 cutting possible, reduces the number of 

 times the excavator must be hauled back, 

 and secures a satisfactory drainage ar- 

 rangement, since the cutting is carried 

 up grade on either side of the summit. 



The Americans have followed this 



