DOCUMENTARY HISTORY OF THE FLORIDA CANAL 345

the services of expert geologists and water engineers. A special board of re-
view, formed pursuant to instructions from the President, also had the services
of a competent water engineer. The preliminary data gathered by the Depart-
ment indicated that there was some possibility of adverse effects on the under-
ground-water supply. The more detailed information which is now available
clearly indicates that the adverse effects are largely local and not of a serious
nature. When the project was placed under way as a part of the relief pro-
gram, I had the district engineer at Ocala, Fla., assemble a board of selected
experts to consider the data gathered by the two boards, the State geological
department and the Geological Survey, and to undertake additional and ex-
haustive field investigations. These experts have recently submitted their
interim report, which definitely concludes that the effects of the sea-level canal
on the underground-water supply will not be serious but local in nature and
capable of control with reasonable expenditures for remedial works. The
authentic information available permits the conclusion that the sea-level canal
will not contaminate the underground-water supply of adjacent areas.
 4. You refer to paragraph 4 of the resolution which proposes an inquiry into
"the nature and extent of the available traffic to warrant the ultimate expendi-
ture of between $140,00,000 and $200,00,000"0, and asked if a sufficient in-
vestigation and examination has been made and data compiled to enable a
decision as to the amount of cost of the project which available traffic will
justify. The special board of engineers had available data compiled by the
Department of Commerce. In addition, they made a detailed study to deter-
mine the economic benefits to transportation which would result from the con-
struction of the canal While this information and data have not been re-
viewed in detail by the Board of Engineers for Rivers and Harbors, it is most
complete and adequate for a full determination of the estimated value of the
benefits to navigation which will result from its construction.
 5. You refer to my appearance before the subcommittee of the Committee
on Commerce on January 17, in which certain questions were asked with
respect to the replies received from shipping concerns to a questionnaire sent
out by the special board of this Department in connection with their investi-
gation, and asked if these letters were used to establish the economic justi-
fication of the project, and further as to the usual factors which are studied
in determining economic justification. This Department has not stated that
the replies to these questionnaires represented the economic justification for
the canal project, nor are such letters generally used for the establishment
of economic justification. The special board of Army engineers made an
extensive economic survey and was aided in the preparation of its report by
an independent survey undertaken by the Department of Commerce, at the
request of the Chief of Engineers.
 The determinations of the special board to shipping concerns, so that it
might be informed as to their opinions with respect to the effect of the project
on the individual interests of the companies concerned. In determining the
economic justification of a proposed river and harbor improvement, the investi-
gating officers ascertain the definite savings in time and distance which will be
made available to navigation without increased hazards as a result of the
improvement in question. These savings in time and distance converted into
monetary savings and such other incidental benefits as clearly accrue to water-
borne commerce and the general public interest, such as a reduction in the
hazards of navigation, form the basis for the determination of the economic
justification of a project. The views of navigation and commercial interests
as to the effect which the proposed improvement may have on their operations
are an aid to the board in weighing the public value of the savings and bene-
fits as determined by the board.
 I trust that the information contained herein answers the specific questions
propounded in your letter. I shall be pleased to furnish any information desired
on request.
 Very truly yours,
 E M. MARKHAM,
 Major General, Chief of Engineers.
 "Attention is invited to a recapitulation of the record as regards the findings
 of the several examining agencies with regard to cost and economic justification.
 In the first place, it should be borne in mind that the engineers of the Public
 Works Administration and the special board of survey of the Corps of Engineers
 developed their cost estimates from plans and specifications for a lock canal