No expenditure for acquisition or improvement of property in an industrial development district shall be made by a port district until a comprehensive plan for such industrial development shall have been adopted by the port commission in the same manner, and upon the same notice as provided in this act for the adoption of a comprehensive plan of harbor improvement and port development; provided that, moneys may be expended prior to the adoption of such plan for studies, preliminary engineering, and the planning of such industrial development district, either separately, or in connection with other studies and engineering of the district, and either by the district alone or in connection with other federal or state agencies or instrumentalities.
Recognizing that it will be necessary that port districts engage in long-range planning, and that it will normally be necessary to alter such plan from time to time, such plan need only be in general terms.