The Pat Harrison Waterway Commission may hereafter be organized in this state under the provisions of this article, in the manner hereafter provided for. This water management district shall be an agency of the state and a body politic and corporate, and may be composed and is composed of the following counties, to-wit: Clarke, Covington, Forrest, George, Greene, Jackson, Jasper, Jones, Lamar, Lauderdale, Newton, Perry, Smith, Stone, and Wayne.