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Surface Water Quality Modeling Tools

Surface water quality modeling tools help water quality professionals address water quality problems and support the development of Total Maximum Daily Load (TMDL) plans, assess permit conditions for National Pollutant Discharge Elimination System (NPDES) facilities, evaluate policy and water quality effects of potential actions, and conduct other water quality analyses.


The Ask WATERS application offers a query tool for collecting various data from the WATERS database. There are two kinds of queries available, simple and expert, which answer frequently asked questions about WATERS data.

HAWQS (Hydrologic and Water Quality System)

HAWQS is a water quantity and quality modeling system that evaluates the impacts of management alternatives, pollution control scenarios and climate change scenarios

How's My Waterway

The user-friendly How's My Waterway application shows conditions of local streams, lakes and other waters anywhere in the U.S. 

NHDPlus (National Hydrography Dataset Plus)

The NHDPlus framework provides comprehensive data about surface water and water quality.


The WATERS (Watershed Assessment, Tracking & Environmental Results System) framework unites water quality information from various unconnected database systems.

WATERS GeoViewer

WATERS GeoViewer is a web mapping application which allows users to view data and execute web services provided by the US EPA Office of Water’s Watershed Assessment, Tracking & Environmental Results System (WATERS).

Water Quality Analysis Simulation Program (WASP)

WASP is a dynamic compartment-modeling program for aquatic systems, including both the water column and the underlying benthos.

Water Quality Framework

The Water Quality Framework streamlines water quality assessment and reporting by integrating existing systems.