If the board of supervisors determines that it is beneficial to the county, and an equal or greater sum of money has been made available from private sources, it may appropriate and expend money from the general fund of the county for making surveys, maps, plans, and plats and for obtaining data and information preliminary to the development, improvement, or construction of a deep water canal, waterway, or water facilities for transportation purposes through, across, or along the county and any adjoining county.