824 THE KEPUBLIC OF PANAMA. 



tion is about 43,00(1,000 cubic ^^ards. It is the greatest single feature 

 of the entire canal construction. 



The summit of Bohio Lake level ends ata point called Pedro Miguel, 

 about li miles southeasterly of the Culebra Cut and 38 miles from 

 Colon, where is located a flight of two locks arranged in twin plan like 

 the others, each one of the pair having a lift varying from 27 to 31 

 feet, according to the varying height of water in Lake Bohio. By 

 means of these two locks the water surface in the canal is brought 

 down to an elevation about 28 feet above sea level. The last lock on 

 the line is at a point called Miraflores, a little less than a mile and a 

 half from the Pedro Miguel locks. From Miraflores to the end of the 

 canal, at a point called La Boca on the Bay of Panama, is less than 5 

 miles, and this portion of the canal constitutes what may be called the 

 Pacific section or level. 



The water of this Pacific section of the canal rises and falls coinci- 

 dental ly with the tides in the Bay of Panama, and as the range of tide 

 in that bay is about 20 feet, the oNIiraflores lock is largely a tidal lock. 

 Its mininnun lift, therefore, at high tide, is 18 feet, while the maxi- 

 nuun lift at low tide is 38 feet. It is obvious from these tidal condi- 

 tions that if the canal were constructed as a sea-level canal a tidal lock 

 would be needed at or near its Pacific end. That part of the canal 

 line between ^Miraflores and the Bav of Panama is located closely along 

 the course of the Rio (xrande, which is mainly a tidal river, its two 

 principal tributaries above ^Mirafloi-es being Rio Pedro Miguel and 

 Rio Caimitillo, ])oth being small and insignificant streams. 



The length of the canal between the shore lines is about 44 miles, 

 although the length between the 6-fathom curves on the two sides of 

 the Isthnms, as has alread}' been stated, is 41) miles. 13 of which lie in 

 the artificial Lake Bohio. The creation of Lake Bohio would necessi- 

 tate the relocation and rebuilding of the railroad between Bohio and 

 Oliispo. throwing it back upon higher ground. 



. No canal with locks can be operated without provision for the water 

 used in taking boats through the locks, for evaporation, for seepage, 

 and for other purposes incident to the maintenance and operation of 

 the canal. At each lockage on the Panama Canal a lock full of water, 

 representing a volume nearly 750 feet long, 84 feet wide, and 45 feet 

 deep, would be used in the Bohio locks and about two-thirds as much 

 in the Pedro Miguel locks. This requires a large supply of water, 

 which the Isthmian Commission computed for all purposes to be 1,070 

 cubic feet per second for an annual traflic of 10,000,000 tons passing 

 through the canal. This water supply is afforded b}' the Chagres 

 River, and without it or its equivalent the canal would not be possible. 



In view of the complete s^^stem of self-control of the Chagres floods 

 by the Gigante Spillway, the Chagres River, instead of being an insur- 

 mountable obstacle to the construction and maintenance of the canal, 



