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The National Geographic Magazine 



the Isthmus except a mass of plans and 

 papers in the office of the canal company 

 at Paris. The Commission in its report, 

 under date of November 16,1901, recom- 

 mended, in case of selection of the Pan- 

 ama route, payment of $40,000,000 to 

 the new Panama Canal Company for all 

 its property, rights, and concessions con- 

 nected with the unfinished canal. That 

 offer, as made by the United States Gov- 

 ernment, has since been accepted by the 

 French company. 



The Isthmian Canal Commission 

 adopted the French line for its estimates, 

 but made some material changes in the 

 plans for the work. The canal as 

 planned by the Commission is a lock 

 canal, its typical or standard section for 

 firm earth having a bottom width of 

 150 feet, a minimum depth of water of 

 35 feet, and a top width of 269 feet. 

 This section is suitably modified for 

 harbor sections, for sections in soft 

 ground, for sections in rock and in lakes 

 and wherever required by unusual con- 

 ditions. These adopted sections would 

 afford ample waterway for the greatest 

 ships afloat at the present time, as re- 

 quired by the law creating the Commis- 

 sion. 



The locks for this canal are great ma- 

 sonry constructions, having a usable 

 length of 740 feet with a clear width of 

 84 feet, more than large enough to ac- 

 commodate any vessel now afloat or 

 planned to be built. 



Beginning at the 6-fathom curve in 

 the harbor of Colon, the canal is planned 

 to be excavated for a distance of 7 miles 

 through the low, marshy grounds in that 

 vicinity to Gatun, where the line meets 

 the Chagres River. From that point to 

 Bohio, about 17 miles from Colon, a 

 little east of south from the point of 

 starting, the canal would be excavated 

 generally along the marshy lowlands 

 through which the Chagres River flows 

 in that vicinity, cutting the course of 

 that river four or five times. This 17- 

 mile section of the canal is a sea-level 



section, but at Bohio is found a compar- 

 atively narrow place in the valley of the 

 Chagres River with rock outcroppings 

 on one side and at which a dam may be 

 built. At this point it was the purpose 

 of the French company also to build a 

 dam, but the Isthmian Canal Commission 

 provisionally located its dam at a site 

 nearly half a mile downstream from that 

 of the French dam, and proposes to build 

 it materially higher. 



THE GREAT DAM AT BOHIO 



This dam would retain behind it the 

 waters of the Chagres River at an eleva- 

 tion varying from 85 feet to 90 or 92 

 feet above mean sea level, thus form- 

 ing what has been called Lake Bohio. 

 It would back up the water of the 

 Chagres River for a distance of about 20 

 miles, through about 14 of which the 

 course of the canal would be laid. Lake 

 Bohio would constitute the summit level 

 of the canal, and would be reached by 

 two great masonry locks built together, 

 i. e. , in series near one end of the dam at 

 Bohio, the lift of each one of these two 

 locks being 45 feet as a maximum. 

 These locks would be built as twin 

 structures, so that if an accident should 

 happen to one side the other side would 

 still be available for use, and thus save 

 the operation of the canal from being 

 broken. A great ledge of rock affords 

 an excellent site for the construction of 

 these locks. 



The building of this great dam at 

 Bohio, with its top nearly 100 feet above 

 the water in the river in its normal con- 

 dition, is one of the great works of the 

 entire canal construction. As the safety 

 and operation of the canal would depend 

 entirely upon the stability of this dam, 

 the Commission recommended a plan of 

 construction by which a masonry core 

 wall 30 feet thick at the bottom and 8 

 feet at the top would be built up from 

 the rock beneath the bed of the river to 

 the top of the dam, thus efficiently pre- 

 venting all leakage of water through the 



