312 National Geographic Magazine. 



this a 40-foot flood and we have a water surface one hundred and 

 ten feet above the bed of the canal. 



In order to keep this immense vohime of water from the canal 

 it was proposed to build a large dam at Gamboa, and to convey 

 the water by an entirely different and artificial route to the 

 Atlantic. It is impossible to show on the map the whole drain- 

 age area of the Chagres, but a rough calculation shows it to be 

 about 500 square miles. This seems a small total drainage area, 

 but when it is considered that the annual rainfall is about 12 peet,^ 

 that this rainfall is confined to about one half the year, and that 

 in six consecutive hours there has been a precipitation of over six 

 inches of rain, some idea of the amount of water that finds its 

 way through the Chagres river during the wet season may be 

 formed. 



As I said before it was proposed to protect the canal from the 

 waters of the upper Chagres by an immense dam at Gamboa, and 

 for the purpose of controlling the water tributary to the lower 

 Chagres two additional canals or channels were to be constructed 

 on either side of the main canal. Thus, as the river is veiy tor- 

 tuous and the axis of the canal crossed it twenty-five or thirty 

 times, many deviations of the former became necessary. In some 

 places the canal was to occupy the bed of the river and in others 

 it cut across bends leaving the river for its original natural 

 purpose of drainage. The difficulty in retaining the floods in 

 these constructed channels would of course be immense, especially 

 in some of the cases where the water rushing along its natural 

 channel is suddenly turned at right angles into an artificial 

 one. Thus it is clear that aside from the enormous expense 

 incident to the removal of the immense amount of earth and 

 rock necessary to complete the canal, that granting all this ac- 

 complished, it would be practically impossible to maintain a sea- 

 level canal by reason of the difficulty in controlling the Chagres 

 and preventing the canal fi'om filling up. 



The canal company finally came to the conclusion that the sea- 

 level scheme was impracticable and it was abandoned, and plans 

 were prepared for a lock system. As seen on the profile there 

 were ten locks proposed, five on each side of the summit level. 

 The summit level was to be 150 feet above sea level and conse- 

 quently each lock would have a lift of thirty feet. The profile 

 was constructed especially to show the amount remaining to be 

 executed to complete the lock system, and a mere inspection will. 



