The Pat Harrison Waterway Commission is hereby authorized and empowered to do any and all things necessary and desirable in making a survey or surveys of the Pascagoula, Leaf, and Chickasawhay Rivers, the Tallahala Creek, and their tributaries in co-operation with the federal government and other agencies of the State of Mississippi; to promote the establishment of barge canals linking the cities of Meridian, Hattiesburg, Laurel, and other cities and communities along the Pascagoula, Leaf, and Chickasawhay Rivers, the Tallahala Creek, and their tributaries with the Gulf of Mexico. Each county represented on said commission, or two or more such counties acting in concert, pursuant to a plan to be approved by said commission, are authorized to improve all or any part of such waterways within said county or counties for navigation or flood control purposes.