(a)      Whenever any county among the geographical subdivisions of this State, as that term is defined in § 4 of Article XI-A of the Constitution of the State, shall have adopted for itself a charter or form of government under the provisions of said Article XI-A of the Constitution, it shall be entitled to exercise the following express powers, said powers being, as to the counties of Maryland adopting such charter or form of government, granted as a substitute for and in extension of the powers codified in Article 25 of the Code, title "County Commissioners", it being the intent of the General Assembly of Maryland that said Article 25 shall continue to be operative in any and all such counties of Maryland as do not adopt for themselves a charter or form of government under the provisions of said Article XI-A of the Constitution, but that the powers herein granted shall be operative in any and all such counties of Maryland as do adopt such charter or form of government.

      (b)      Notwithstanding the provisions of this section, the subtitle "Draining Lands" of Article 25 of the Code applies to a county that adopts a charter form of government under the provisions of Article XI-A of the Constitution.