(a) The powers, authority and rights conferred by this chapter are in addition and supplemental to any other general, special or local law conferring powers to counties, industrial development corporations or port authorities, and the limitations imposed by this chapter do not affect the powers conferred to any county, industrial development corporation or port authority created by any other general, special or local law.

(b) This chapter is remedial in nature, and shall be liberally construed to effect its purposes of:

(1) Promoting navigation on the Tennessee River;

(2) Facilitating the movement and transfer of goods and merchandise to, from and through the counties of Decatur, Hardin, Perry and Wayne;

(3) Encouraging utilization of the natural and recreational resources therein; and

(4) Promoting the growth and development of commerce and industry in such counties.

(c) Nothing in this chapter shall:

(1) Grant any power or control to the board of commissioners over any land or facilities now under the control of any existing port authority created by general or special act;

(2) Prohibit or preclude any existing port authority from exercising control over any land or facilities now under its control or that may come under its control prior to the time the board adopts by resolution a plan for development of such land or facilities;

(3) Prohibit any county from transferring by any means any interest in any land to any port authority in existence in such county on May 1, 1980; or

(4) Prohibit any county from exercising any power granted by any general or special act with regard to any port authority in existence in such county on May 1, 1980.