In all cases where preliminary examinations and surveys are authorized a preliminary examination of the river, harbor, or other proposed improvement mentioned shall first be made and a report as to the advisability of its improvement shall be submitted unless a survey or estimate is expressly directed. If upon such preliminary examination the proposed improvement is not deemed advisable, no further action shall be taken thereon without the further direction of Congress; but in case the report shall be favorable to such proposed improvement, or that a survey and estimate should be made to determine the advisability of improvement, the Secretary of the Army is authorized, in his discretion, to cause surveys to be made, and the cost and advisability to be reported to Congress. And such reports containing plans and estimates shall also contain a statement as to the rate at which the work should be prosecuted: , That every report submitted to Congress, in addition to full information regarding the present and prospective commercial importance of the project covered by the report and the benefit to commerce likely to result from any proposed plan of improvement, shall also contain such data as it may be practicable to secure in regard to the following subjects:
((a)) The existence and establishment of both private and public terminal and transfer facilities contiguous to the navigable water proposed to be improved, and, if water terminals have been constructed, the general location, description, and use made of the same, with an opinion as to their adequacy and efficiency, whether private or public. If no public terminals have been constructed, or if they are inadequate in number, there shall be included in the report an opinion in general terms as to the necessity, number, and appropriate location of the same, and also the necessary relations of such proposed terminals to the development of commerce.
((b)) The development and utilization of water power for industrial and commercial purposes.
((c)) Such other subjects as may be properly connected with such project: , That in the investigation and study of these questions consideration shall be given only to their bearing upon the improvement of navigation, to the possibility and desirability of their being coordinated in a logical and proper manner with improvements for navigation to lessen the cost of such improvements and to compensate the Government for expenditures made in the interest of navigation, and to their relation to the development and regulation of commerce: , That the investigation and study of these questions may, upon review by the Board of Engineers for Rivers and Harbors when called for as provided by law, be extended to any work of improvement under way and to any locality the examination and survey of which has heretofore been, or may hereafter be, authorized by Congress.