NATURE'S TRANSFORMATION AT PANAMA 



Remarkable Changes in Faunal and Physical Conditions in 



the Gatun Lake Region 



By George Shiras, 3rd 



Illustrations b\ the Author and H. E. Anthony 



THE world-wide interest in the 

 Panama Canal, from an engineer- 

 ing standpoint and the great eco- 

 nomic changes destined to follow the use 

 of this new channel of trade and inter- 

 course, has been evidenced by thousands 

 of visitors and the many articles bearing 

 upon the various aspects of this wonder- 

 ful work. 



One of the essential features in the 

 plan of construction has been somewhat 

 subordinated when viewing the project 

 as a whole, namely, Gatun Lake ; for be- 

 yond regarding it as a convenient part of 

 the passageway across the Isthmus, few 

 realize that it is the basis of the whole 

 scheme. Xot only is it the largest fresh- 

 water lake ever created by man- — a navi- 

 gable viaduct almost bridging the two 

 oceans and reached by terminal elevators 

 in the form of locks — but, in addition, a 

 vast reservoir for the adjoining water- 

 sheds, assuring throughout the year a 

 sufficient water supply for the operation 

 of the locks, for electric power, for the 

 establishment of inland fisheries, and for 

 potable and other domestic uses, besides 

 allowing greater freedom in the move- 

 ment and speed of vessels and the open- 

 ing up of the many lateral valleys to local 



A BOUNTIFUL WATER SUPPLY 



The great saving of time and money in 

 thus utilizing a part of the surface of this 

 reservoir, instead of excavating a narrow 

 and deep canal all the way across the 

 intervening land, was inconsequent, how- 

 ever, compared with the original pur- 

 pose — a continuously abundant supply of 

 water for operating the canal locks — thus 

 insuring the regular daily movement of 

 vessels throughout the year. Without the 

 converging watersheds of 1,400 square 



miles, without a large natural basin for 

 impounding these waters, and so located 

 that a water-tight and stable dam could 

 be built across the Atlantic end, only a 

 sea-level canal could have been consid- 

 ered — a much more costly and probably 

 an impracticable scheme. 



However narrow the Isthmus, nature 

 has aided as much more in a combination 

 of low rolling hills, with wide valleys 

 only a little above sea-level, an almost 

 continuous rainfall, while the compact 

 but easily excavated soil made the canal 

 construction rapid, its banks water-tight, 

 and the subsequent use of much of the 

 excavated material a great economy in 

 the building of the great earth dams. 



The original plans, under which the 

 initiatory work of the French syndicate 

 was begun, called for a much smaller 

 lake, ignoring the advice of its most bril- 

 liant engineer, M. de Lipiany, by not in- 

 cluding the waters of two large rivers — 

 the Gatun and the Trinidad. Judging 

 from the amount of water required at 

 the locks and for various other purposes, 

 the de Lessep plans seem fundamentally 

 defective. 



BIRTH AXD GROWTH OF THF LAKE 



When the information came from Pan- 

 ama that the great basin for holding the 

 waters of the proposed Gatun Lake was 

 finally completed by the long embankment 

 at the north end, thus closing the only 

 gap in the rim of hills left open by na- 

 ture, and that month by month the gath- 

 ering waters of tributary streams were 

 slowly covering the lowlands, creeping up 

 the .wild tangled valleys, drowning the 

 mighty forests -and the rank tropical jun- 

 gles, flooding out native villages and de- 

 stroying scattered plantations, marooning 

 wild creatures like the monkey, ocelot, 



i59 



