Sec. 7. A county establishing a department of public works shall have the following powers to be administered by the board of public works subject to any limitations thereon: (a) To acquire a water supply system within 1 or more areas in the county and to improve, enlarge, extend, operate, and maintain the system. (b) To acquire a sewage disposal system within 1 or more areas in the county and to improve, enlarge, extend, operate, and maintain the system. (c) To acquire a refuse system within 1 or more areas in the county and to improve, enlarge, extend, operate, and maintain the system. (d) To make lake improvements within 1 or more areas in the county and to improve, enlarge, extend, operate, and maintain the improvements. (e) To acquire an erosion control system within 1 or more areas in the county and to improve, enlarge, extend, operate, and maintain the improvements.