Fertilizer runoff and Lake Michigan discharges.

Amends the water pollution control law effective July 1, 2024, to: (1) eliminate an exception to the prohibition against causing water pollution that applies to fertilizer runoff from a field in a storm event or irrigation return flow if the fertilizer was applied to the land in compliance with rules of the state chemist; (2) eliminate a provision requiring the commissioner of the department of environmental management (commissioner) to allow for a mixing zone in a permit that involves a discharge into Lake Michigan if the permit applicant can demonstrate that the mixing zone will not cause harm to human health or aquatic life; and (3) eliminate a provision under which the commissioner, in issuing a permit authorizing a discharge into a mixing zone in Lake Michigan, is required to allow for mixing initiated by the use of submerged, high rate diffuser outfall structures (or their equivalent) that provide turbulent initial mixing and minimize organism exposure times. Makes conforming changes.