Subject to the provisions of Section 1 of "An Act to define the powers of members of police forces established and maintained by park districts", approved April 29, 1931, as now or hereafter amended, whenever any park district is located along any such navigable body of water as set forth in Section 11-2, the right is hereby given to the corporate authorities thereof to take charge of, control and police such body of water and the land thereunder for a distance of three hundred feet along any park, boulevard or pleasure drive constructed by it and bordering thereon.
70 ILCS 1205/11-4