DOCUMENTARY HISTORY OF THE FLORIDA CANAL


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 The only possible disadvantage of a sea-level canal would be the possibility
of overdralnage of an area contiguous to the canal with resulting damage
to water supply due to lowering of the ground-water table.
 Any possible damage to agriculture beyond the limits of the right-of-way
to be secured for the canal would be negligible, due to the fact that the water
table is now from 80 to 70 feet below the ground along the route of the canal
and for miles on either side of it. The damage to water supply would be
small and would consist of only lowering levels in nearby wells. The possi-
bility of salting the water supply at a high level would be eliminated.
 Estimates of board of review for sea-level canal--All in all, damages result-
Ing from a sea-level canal, if any, should not reach a very large figure. The
board of review, therefore, feels constrained to recommend a sea-level canal in
preference to a lock canal on account of lesser engineering difficulties and lesser
cost. It is estimated that a sea-level canal 35 feet deep with suitable allow-
ances for overdepth and bottom widths as selected by the special board of Army
engineers, can be built in 6 years for $175,543,000.'
 A 80-foot sea-level canal is estimated to cost $146,100,000.' In the estimates
of cost are included figures for the purchase of right-of-way amounting to
$2,411,000 for the lock canal and $5,000,000 for the sea-level canal On Federal
projects of this nature it is customary for local interests to furnish such a
right-of-way tree of cost to the United States, and the board of review is of the
opinion that if the construction of the canal is authorized that a condition
precedent to beginning work should be that local interests should furnish assur-
ances satisfactory to the Secretary of War that suitable rights-of-way, flowage
rights, and disposal areas for dredging will be furnished free of cost to the
United States when and if required.
 It is felt that under present conditions alterations to bridges are charges
 which properly may be borne by the United States. Any other arrangement
 would indefinitely postpone the commencement of the work.
 Deducting the estimated costs for rights-of-way and disposal areas, the esti-
 mated costs of construction for the 85-foot sea-level canal becomes $172,000,000
 and for the 30-foot sea-level canal becomes $142,700,000, both exclusive of
 interest
 Justifiable espenditres.-This board was not instructed to estimate the bene-
 fits accruing from the construction and operation of this canal However, if
 it be assumed that the economic study made by the special board of Army
 engineers for a lock canal is sound and considering the lower maintenance and
 operating costs of a sea-level canal, the cost of a canal which would be justified
 at 4-percent interest would be:
 Sea-level canal:
 80-foot depth------ $100, 000, 000
 5-foot depth----..- ..- 17 177, 0000000
 Lock canal:
 30-foot depth--- .... .... 141,000,000
 35-foot depth --_th--___ .-. 157,0,000000
 The board gave the following summary comparison of the cost
 estimates of the special board of survey of the Army engineers and
 the Engineering Division of the Public Works Administration for a
 lock canal and the estimate of the board of review for a sea-level
 canal.
 For details see table 5 herewith.
 For details see table 6 herewith.