X REPORT OF BOARD OF CONSULTING ENGINEERS, PANAMA CANAL.

 SEA-LEVEL PLAN.

 The plan recommended by the majority of the board is a canal at the sea level, following essentially the line heretofore adopted by Congress, except near the terminals, the depth to be 40 feet, and the width at bottom to be 150 feet where the side slopes are gentle, and 200 feet where the side slopes are nearly vertical, as in rock. The least area of cross section is 8,276 square feet. At the Panama end is a tide lock, having a usable length 1,000 feet, width 100 feet, and depth over the miter sills 40 feet. In Panama Bay the channel is to be 35 feet deep at extreme low water of spring tides, which will give the fll 40 feet provided elsewhere in the canal, except upon rare occasions.
 To control the Chagres River, a dam of masonry, or of earth and masonry, is proposed at Gamboa, jnst off the line of the canal, built to a height 180 feet above the sea, forming a reservoir called Gamboa Lake, of which the maximum flow line is to be at elevation 170, into which the flood waters are to be received, but no design therefor is submitted.
 This dam is to be fitted with controlling sluices by which a maximum discharge of 15,000 cubic feet per second is to be admitted to the canal prison, all in excess of that amount being temporarily stored until the subsidence of the flood. Of the tributaries entering the Chagres below Gamnboa, the most important are diverted entirely from the canal and conducted by separate channels to the sea. There will still remain a number of tributaries and other streams to be taken into the canal. Their volume is assumed by the Board to be such that, added to the 15,000 cubic feet to be admitted through the sluices, they will create currents of which the highest mean velocity is computed by the majority to be 2.6 miles per hour. Ordinarily the velocity will not exceed 1 mile per hour.
 Extensive harbor improvements are proposed at Colon.
 The cost of the canal under this plan is estimated by the majority at $247,000,000. From the nature of the case this estimate can not be made with great preision. The quantity of each class of work to be done can, as a rule, be accurately measured, but the unit price for~ each class must be largely a matter of judgment. It is the opinion of this Commission that the unit prices adopted by the Board are, upon the whole, judicious, except in the ase of rock excavation under water, which seems to us low, but is accepted'here for purposes of comparisson; and that otherwise the estimates are as near an approximation to the truth as can now be reached, in all except two items. These items are the excavation in Culebra Cut below elevation +10, given on page 51 as $20,242,877.50; and the completion of river diversions, regulation of rivers floxing-, into the canal, etc., given on page 58 as $3,500,000.
 The first item covers 16,194,302 cubic yards of excavation, of which 11,439,612 cubic yards is below and the remainder above the level of the sea. The majority of the Board has adopted a uniform unit price of $1.25 per cubic yard for the whole. This price seems fair for the portion above the level of the sea. For the portion below, it seems to the Commission that the price of rock excavation under water, $2.50 per cubic yard, should be applied here as it is in the adjacent sections of the canal by the Board. If that be done, the cost of this item will be increased $14,299,515, and adding the usual 20 per cent for contingencies, the estimate will be increased $17,159,418.
 The estimate, $3,500,000, of the cost of completing the river diversions, formation of dams across tributary streams, regulation of rivers which flow into the canal, etc., is believed to be too low. To show the magnitude of this feature of a sea-level canal, a table is presented giving the names of the more important streams which enter the site of the canal, the distance of the point of junction from the Caribbean end of the canal, the height above sea level of their junction with the Chagres', Obispo, or Rio Grande rivers, and the volume of discharge at igyh stage as far as observed or estimated. It must be remembered that while gaugings


of the Chagres at several points have been systematically carried through thfe river year COv Tering both low waters and floods, nothing of this sort has been done on the other streams, where gaugings have only been made desultorily, at such times and for such periods as were convenient. The discharges given in the table are in many instances obtained by distributing