That the sanitary district of Chicago shall have the right and power to appoint and support a police force, the members of which may have and exercise police powers over and within its right of way and for a distance of one and one-half miles on each side of its main drainage channel, such police powers as are conferred upon and exercised by the police of organized cities and villages; but such police force, when acting within the limits of such city or village, shall act in aid of the regular police force of such city or village, and shall then be subject to the direction of its chief of police, city or village marshals or other head thereof.