Chapter 92 – NPDES Permits Watershed Permits Issue: Some pollutants persist and accumulate in the watershed, resulting in a threat to water quality standards only after a threshold loading or concentration is reached at some point in the watershed. Biological monitoring detects problem Existing process poorly positioned to address watershed-wide water quality concerns effectively and at minimum cost

New methods and tools have enabled the Department to better determine when watershed- wide concerns apply, and to assign appropriate limits to address the problem. The ability to issue watershed-based NPDES permits for point source discharges will provide the implementation process to complement these watershed-wide assessments. Chapter 92 – NPDES Permits Watershed Permits

Challenge: Minimize costs. Watershed permits avoid need for broad-brush, excessively conservative approaches. Customized wasteload allocation is the standard. Watershed permits provide the framework for pollutant credit trading. This flexibility is required to control costs and provide incentive for highest, cost-effective degree of treatment (because excess credits can be sold). Chapter 92 – NPDES Permits Watershed Permits