No improvements shall be acquired or constructed, by the port district, unless such improvements shall, when completed, be the property of such port district, the county in which such port district is located, any city within such port district, the state of Washington or the United States of America, and the funds of such port district may be expended in the acquirement or construction of any harbor improvement embraced in such general plan adopted as in this chapter provided in conjunction with the county in which such port district is located, any city in such port district, the state of Washington or the United States of America, or all or any of them.