REPORT OF BOARD OF CONSULTING ENGINEERS, -PANAMA CANAL.


t95


 ESTIMATED COST FOR PROJECT RECOMMENDED.

 An abstract of the estimated cost of the canal with sunnit level at elevation 85, using the unit prices adopted by the Board, is as follows, full details being presented in Appendix T:

 I Miles. cost.
 Breakwaters in Limon Bay ..................... ........ ........ ...... 0,300,000
 channel in Limon Bay-...................... .......................... 4.55 1,245,000
 Limon Bay to Gatun locks .............................................. 2.60 3, 921., 000
 Gatun locks, including excavation and back filling...................... .59 15.691, 000
 Approach walls to Gatun locks-.......................................... ....500,000
 Gatun dam and spillway-..- - --.- .-............................................... 7, 788,000
 Gatun to Obispo.......... ..................................... 23.51 5, 005, 000
 Obispo to Pedro Miguel ................................................... 8.13 43, 337,000
 Pedro Miguel locks, including excavation and back filling........ .23 6,988,000 Approach walls to Pedro Miguel locks............................. ...... ... -.... 300,0011
 Pedro Miguel to Sosa locks............................................... 5.47 420, 000
 Sosalocks, including excavation and back filling ........................ 41 13,092,000
 Approach walls to Sosa locks ....... ...........----------------- .................... 450,000
 Sosa locks to deep water in Panama Bay............................ 4.23 1, 939,000
 La Boca darn................................................ .......... 1,675,000
 Ancon-Sosa and Ancon-Corozal dams..............................1,645,000
 Diversion channels between Obispo and Pedro Miguel............................. 850,000
 Diversion channel and regulating works at Ancon.............................. 275,000
 Diversion of Panama Railroad.................................... .......... 3,700,000
 Movable dams at ends of summit level..............................2,000,000
 Land damages ....................................................... ... .......... 300,000
 49.72 116,421,000
 Administration, engineering, and contingencies, but not including interest during construction, sanitation, or expenses of Zone government........... 23,284,200
 Total estimated cost.......... .......................... .......... 139,705,200

 Neither the foregoing estimate nor that for the sea-level canal contains an allowance for the fortification of the route.
 The total amount of excavation from the canal prism is 95,955,000 cubic yards, of which 53,765,000 cubic yards are from the Culebra cut. The cross sections of the canal used in coinputing excavation are shown on Plate X.
 An allowance of 20 per cent for administration, engineering, and contingencies is provided, as in the Board's estimate for the sea-level canal. In the estimates of the Isthmian Canal Commission of 1899-1901 the same allowance was made, but this allowance was to cover somewhat different items. The allowance in the present estimates does not cover sanitation and Zone government, which were included in the allowance in the former estimate, but does include another item which may prove to be a large one, viz, revetments of the sides of the canal in the Culebra cut.
 In the project of the Commission of 1899-1901 the concrete retaining wall was to extend the entire length of the narrow section through the Culebra cut, which, in the plans of that Commission, was 7.91 miles, and was estimated to cost, exclusive of the 20 per cent allowance, $9,619,304. It is now believed that for a large part of the distance through the Culebra cut the rock sides will be sound enough to stand vertical and remain smooth if properly formed 4by channeling machines, and where this is the case a revetment will not be required, while for the remaining distance some form of revetment will be necessary; it is also believed that the extent and best form of revetment can only be determined by a study of the materials actually seen in place as the excavation proceeds, and that items of this character are appropriately considered as contingencies. It should be pointed out that the cost of revetment on the sea-level canal woul(l be greater than for the summit-level canal by the reason of the greater length of narrow section ii the former. In the plan for a summit-level canal the length of the narrow section is reduced to 4.70 miles by widening to 300 feet at each end, while in the sea-level cana-l there would be 19.47 miles of channel 200 feet wide excavated partly or wholly in stock.