TEE TYPE OF THE PANAMA CANAL 439 



careful study of all existing data, on the assumption that the water 

 surface of the lake will have an area of 110 square miles, he gives the 

 following figures: 



The water available is estimated at not less than 1,225 cubic feet 

 per second natural flow at Gatun during the three months of lowest 

 river stage, and to this amount there are to be added an additional 

 volume of 1,577 cubic feet per second, resulting from a four feet allow- 

 able fluctuation of the lake surface. There are then 2,802 cubic feet 

 per second available, of which the difference between 2,802 and 1,437, 

 or 1,365 cubic feet per second, will be available for lockages. This 

 amount of water, according to General Abbot, will be adequate for 26 

 daily transits. Should there be need for more stored water, the same 

 can be secured by the construction of a dam at Alhajuela, where suffi- 

 cient water can be impounded to increase the number of lockages by 

 40, though only 27 have been assumed by the minority. 



It is absolutely certain that there can be no deficiency of water for any 

 conceivable traffic demands. 



Since the foregoing estimates were made it has been found that the 

 Gatun Lake will have a surface area of about 164 square miles, instead 

 of 110, as assumed. The lock dimensions have also been increased, as 

 explained, and more water will be required for each transit through 

 the canal. The estimates relating to the available water supply as above 

 quoted therefore need revision. 



And thus, in the light of the infomiation then available, the type 

 of the canal was fixed in 1906 by action of the Congress of the United 

 States in substantial conformity with the recommendation of the minor- 

 ity of the board of engineers, and for three years the work of construc- 

 tion has been actively pushed. 



The progress that has been made is clearly set forth in the records 

 of work done. Measured by cubic yards of excavation it has been 

 highly satisfactory. The graphical presentation herewith is from a 

 recent summary published by the Engineering News. It appears from 

 the figures compiled for that summary that the total excavation since 

 the canal became the property of the United States at the close of the 

 year 1908, amounted to 59,980,000 cubic yards, of which 53,161,000 

 cubic yards had been taken out of the canal prism, and 6,819,000 cubic 

 yards were excavated from the locks and spillway sites and from other 

 points outside of the canal proper. Of the total work, that done by 

 steam shovels (work in the dry) amounted to 37,155,000 cubic yards, 

 and dredges had excavated 22,825,000 cubic yards. 



It has been estimated by the canal commission that the total exca- 

 vation to complete the canal on the lines of the accepted project (not 

 including the work by the French canal companies) is 142,000,000 

 cubic yards. According to these figures there were about 89,000,000 

 cubic yards yet to be removed from the canal prism on January 1, 1909. 



