Section 2. Prohibition inapplicable to lands and properties no longer useful; disposition authorized

The prohibition of sale, abandonment or other disposition contained in section one of this article shall not apply to barge canal lands, barge canal terminals or barge canal terminal lands which have or may become no longer necessary or useful for canal or terminal purposes; nor to any canal lands and appertaining structures constituting the canal system prior to the barge canal improvement which have or may become no longer necessary or useful in conjunction with the now existing barge canal. The legislature may by appropriate legislation authorize the sale, exchange, abandonment or other disposition of any barge canal lands, barge canal terminals, barge canal terminal lands or other canal lands and appertaining structures which have or may become no longer necessary or useful as a part of the barge canal system, as an aid to navigation thereon, or for barge canal terminal purposes.