The Water Quality Analysis Simulation Program (WASP) can be used to model the fate and transport of water quality constituents in tidal estuaries. WASP is a three-dimensional, uncoupled, water quality model developed by the USEPA. The model has been used in five different states as well as in the District of Columbia to aid in the development of USEPA-approved TMDLs for tidal estuaries.
Since WASP is an uncoupled water quality model, an external hydrodynamic model is required in order to simulate river hydrodynamics. In the past, a number of different hydrodynamic models have been coupled with WASP. Suggested hydrodynamic models for use with WASP include Link-Node Tidal Hydrodynamic Model (DYNHYD), River Hydrodynamics Model (RIVMOD-H), and Environmental Fluid Dynamics Code (EFDC).
In addition, WASP contains a specific subroutine for modeling fecal coliform bacteria. WASP is a time-variable model that is capable of modeling more than one tidal cycle. The model generates a solution using a finite difference scheme and is capable of automatic time stepping in order to ensure model stability.