The original summit at Culebra Cut was 333 feet above the sea; it was lowered by the French to 157 feet and the lowest point at the summit is now 143 feet above sea level.
The lake section of the Central Division extends from Gamboa to Gatun. The Chagres River here crosses the line of the canal 23 times, forming a series of peninsulas. A portion of the channel 2,700 feet long, 500 feet wide at the bottom and 50 feet deep, was completed May 25, 1909 and the waters of the Chagres turned in. A total of 1,784,459 cubic yards were taken out, of which 1,350,308 were removed in 1908–’09. From the remainder of this division 2,625,283 cubic yards were excavated in 1908–’09.
To secure the necessary width and depth between Pedro Miguel and Miraflores on the Pacific Division 1,279,600 cubic yards of material, of which 63,600 are rock, must be excavated. The material still to be taken out between Miraflores and deep water is 13,000,900 cubic yards of loam and 1,725,000 cubic yards of rock. It has been decided to remove all rock between the locks and for 2 miles below the Miraflores locks, in the dry. This will leave 3,600,000 cubic yards of loam and 123,000 of rock to be removed by dredging and blasting.
The dredging fleet in Panama Bay for 1908–’09 consisted of one sea-going suction dredge, one 20 inch suction and pipe-line dredge, one 5 yard dipper dredge, and four French ladder dredges. They removed 8,475,931 cubic yards of material during the year. The channel is completed for about 5 miles from deep water in the Pacific.
The entire present steam-shovel equipment on the Isthmus consists of forty-eight 95-ton, forty-two 70-ton, ten 45-ton, and one 38-ton steam-shovels, or a total of one hundred and one steam-shovels.
Dry excavation for the first quarter of the fiscal year 1908–’09, (July 1 to October 1), cost 63 cents per cubic yard for direct charges and 12 cents per cubic yard for general administration, making a total of 75 cents. Dredging cost 9 cents per cubic yard for direct charges and 2 cents per cubic yard for general administration. The average cost per cubic yard for excavation was 40 cents for direct charges and 8 cents for general administration, making a total of 48 cents.
VIII. CONSTRUCTION OF THE LOCKS
Locks
As before stated there are to be 6 locks on the Panama Canal, 3 at Gatun, 1 at Pedro Miguel and 2 at Miraflores. All of these locks are arranged in duplicate, i.e., at any group of locks a vessel may ascend at one side of the middle wall, while another is descending at the other side. It is the intention that Pacific bound vessels use one side and Atlantic bound the other.