412 DOCUMENTARY HISTORY OF THE FLORIDA CANAL

 Side slopes for the excavation have been established at 1 vertical to one-half
 horizontal in rock and 1 vertical to 8 horizontal In soft material in the land
 cuts and existing open waterways, except for certain sections in the latter,
 where a slope of 1 to 4 has been adopted. Berms are to be 100 feet wide.
 The canal is designed to accommodate approximately 94 percent of the sea-
 going vessels ordinarily engaged in commerce between Gulf ports and those of
 the Atlantic Ocean and connecting waters lying north of the 80* parallel north.
 It will be essatially a hig-speed canal, and to this end the route has been
 laid out along lines free of sharp bends. The channel is to be of such width
 and depth that it is expected a ship can proceed with a minimum speed of 7
 knots, with permissible speeds up to 10% knots in sections where local traffic
 will permit and where the cut will be through material sufficiently stable to
 enable the banks to withstand the wash. It is estimated that the average
 transit time thus will be about 25 hours. The channel will be provided with
 necessary aids to navigation, which will permit its use for 24 hours per day.
 It will be wide enough, even in its narrowest sections, to allow two ships to
 pass each other while making reasonable speed.
 The nature of Ocala limestone through which some 27 miles of the canal's
 interior section will be cut has an important bearing on the engineering prob-
 lems involved. This rock hardens upon exposure to the atmosphere, and where
 it is exposed in the banks of existing waterways there has been little erosion
 from current or wave action. Appropriate works will be provided where uncon-
 solldated materials are encountered at the water line. The absence of tilted
 beds, bedding planes, Joints, and clay seams from the Ocala limestone precludes
 the likelihood of serious slides with the side slopes outlined above.
 The St. Johns River is practically free from high water stages, and its flood
 discharge into the canal is expected to be negligible. Although flood discharges
 from the Oklawaha and Withlacooehee Rivers are normally small, retention
 reservoirs are planned for both streams and for two or three smaller spring-fed
 streams along the canal's course.
 Tidal fluctuations in both the t. Johns and the Gulf entrance are relatively
 mall, and it is anticipated that resulting tidal currents in the canal will be
 negligible.

 KoNINNIBG WORKS
 Construction of the canal will entail the excavation of approximately 571,-
 00,000 cubic yards of material, of which about 170,000,000 will be rock and
 the remainder wet and dry earth. The maximum cut will be 141 feet, in the
 high country south of Ocala, of which about 58 feet will be in earth and the
 rest in rock of varying kinds
 Five railroad bridges and from five to seven highway bridges will have to be
 constructed or rebuilt All will have a horizontal clearance of from 800 to 540
 feet, depending on their type and location. The plans provide that, with one
 exception (a mixed high-level bridge on the Dixie Highway at Santoe, about 6
 miles south of Ocala), all bridges will be of the vertical lift type, with a vertical
 clearance of 18 feet in the open position. The Santos structure will have the
 same clearance. It is possible that further study will show that fixed high-level
 bridges will be more economical at some of the locations where lift spans are
 now contemplated.
 Three turning basins, of sufcient size to enable the largest vessel transiting
 the canal to make a safe turn, are planned for the interior section between
 Palatka and the Gull. Loading facilities in these basins may be erected by
 private or local interests.
 Preliminary surveys by the special board of Army engineers had indicated
 that a sea-level canal traversing the Ocala limestone along part of the route
 might, by lowering the water table adjacent to the canal, damage underground
water supplies. The board of review, with more data available, reported that
any such damage would be negligible. In order to determine conclusively the
results to be anticipated a special board of engineers and geologist, appointed
by the district engineer, is engaged in an intensive study of the subject An
Interim report of this board, submitted to the district engineer on December 18,
1985, pointed out that the draw-down of the water table, naturally to be ex.
pected along that part of the canal traversing Ocala limeetone, will be essen-
tially dissipated about 15 miles from the canal; that the artesian reservoir will