Any person, firm or corporation organized for the purpose of improving the navigation upon a navigable river in the State of Alabama, and of developing in connection therewith a water power thereof by a dam and lock, or a system of dams and locks, and electrically transmitting and distributing such power for the use of the public, which shall have acquired the necessary lands upon both sides of said river to the extent of at least one more than half of the necessary abutment sites for the said dam or system of dams, and lock or system of locks and shall have been organized or incorporated for the specific and particular purpose of improving the navigation of and developing water power in connection with a particular and specified river, and has prepared plans for the construction of a dam or system of dams and a lock or system of locks appertaining thereto, and filed a copy of said plans in the office of the Secretary of State of Alabama, together with a certified copy of its articles of incorporation (if a corporation), which provide both for the improvement of navigation of such river, and for the developing of the full water power of the same over the stretch of river thus to be improved, shall have authority to construct a dam or system of dams, with a lock or system of locks appertaining thereto in such river, for the improvement of navigation of said river by one or more slack water pools, due to the construction of said dam or dams and the development of water power in connection therewith, and to that end and in consideration of the benefits to the public by reason of the improvement of navigation of such river and the development of water power thereof, as herein provided, is granted an easement for power purposes to and in the waters and bed of the river in which dam or system of dams, and lock or system of locks are to be constructed, for the full area covered by the slack water pool or pools which will be created by the construction of the said dam or system of dams, to the extent necessary for developing the full power of said river over that length of same upon which navigation is to be improved as provided herein, and for providing suitable and convenient sites for the said dam or system of dams, locks, power houses and other features appurtenant thereto and necessary for navigation and power purposes, or for either of them, and to the extent made necessary by the impounding, diversion and conversion of the said waters as the same may be caused by the construction of the said dam or system of dams, or by any other change from the normal state of the said river, due to said construction, and necessary for the purpose of deriving the energy therefrom.