MS4 (Municipal Separate Storm Sewer System)

The United States Congress directed the Environmental Protection Agency (EPA) to issue further regulations to identify and regulate additional stormwater discharges that were considered to be contributing to national water quality impairments. On December 8, 1999, the EPA issued regulations that expanded the existing National Pollutant Discharge Elimination System (NPDES) Storm Water Program to include discharges from small MS4s in "urbanized areas" serving populations of less than 100,000 and stormwater discharges from construction activities that disturb more than one acre of land. These regulations are referred to as the NPDES Phase II Storm Water Program. The urbanized area portion of Lake County met these criteria and was consequently designated as an MS4 entity.

NPDES Phase II Program

In the State of Indiana, the Indiana Department of Environmental Management (IDEM) is responsible for the development and oversight of the NPDES Phase II Program. IDEM initiated adoption of the Phase II Rules which was codified as 327 IAC 15-13 (Rule 13). Rule 13 became effective on August 6, 2003 and requires designated MS4 entities to apply for permit coverage by submitting a Notice of Intent (NOI) and developing Storm Water Quality Management Plans (SWQMPs) through a phased submittal process.

Stormwater Quality Management Plan

IDEM's initial phased submittal requirements included the implementation of a Crown Point Stormwater Quality Management Plan which was initially approved on March 1, 2005. Crown Point has updated the plan multiple times in the intervening years and the City is currently in Year 3 of a 5-Year IDEM NPDES Phase II Stormwater Permit.