Indiana has 12 municipal separate storm sewer systems (MS4s) in the Lake Erie basin, all of which have approved Storm Water Quality Management Plans (SWQMPs), as required by Indiana's general MS4 permit.
SWQMPs include three parts:
- Part A: Initial Application, which lists the entities covered in the plan, identifies a program implementation schedule, and provides the budget allocation for the MS4 area’s storm water program for each facility;
- Part B: Baseline Characterization, which provides a summary of the baseline water quality (or a plan to establish the baseline) for each receiving water and an evaluation of land use and where improvements/best management practices (BMPs) are needed; and
- Part C: Program Implementation Plan, which is a working document that outlines priorities, goals, and implementation strategies, including implementation milestones.