Surface water quality models are critically important tools for managing our nation's surface waters. Quantitative models help local communities and environmental managers better understand how surface waters change in response to pollution and how to protect them.

Water quality specialists use models for many purposes:

• Assessing water quality conditions and causes of impairment
• Predicting how surface waters will respond to changes in their watersheds and the environment (e.g., future growth, climate change)
• Developing Total Maximum Daily Loads (TMDLs) and National Pollutant Discharge Elimination Systems (NPDES) permits
• Forecasting quantitative benefits of new surface water protection policies

EPA's Water Modeling Workgroup (WMW) works to facilitate the use of surface water quality models through collaboration, information-sharing, and training on models and modeling resources.

Resources:

• Assessment of Surface Water Model Maintenance and Support Status
• Surface Water Quality Modeling Training