This part is supplemental to and in addition to the drain code of 1956, Act No. 40 of the Public Acts of 1956, being sections 280.1 to 280.630 of the Michigan Compiled Laws. This part does not amend or repeal any law of the state relating to the public service commission, the department, and the department of public health relating to waters and water structures, or any act or parts of acts not inconsistent with this part.