CE-QUAL-W2 is a two-dimensional (longitudinal/vertical) hydrodynamic and water quality model that has been under development for over 25 years and has been successfully applied to over 400 systems throughout the U.S. and the world. It is the reservoir model of choice for TVA, USGS, USBR, USEPA, and USACE. Version 3 can now model entire waterbasins including sloping rivers, reservoirs, and estuaries.
Relevant hydrodynamic/transport capabilities include dynamic adjustment of the timestep to help ensure numerical stability, variable vertical/longitudinal grid spacing, wetting/drying, multiple point/nonpoint sources, and a higher-order numerical transport scheme (QUICKEST/ ULTIMATE) that reduces numerical diffusion and eliminates physically unrealistic over / undershoots.
Relevant water quality capabilities include any number of generic consitutuents that could include a conservative tracer, and/or water age, and/or coliform bacteria groups. These generic constituents are defined by a settling velocity, and/or a 0-order decay rate, and/or a 1st order decay rate, and/or an Arhennius temperature rate multiplier. The model can also simulate any number of phytoplankton groups, any number of CBOD groups, any number of inorganic suspended solids groups, phosphate, ammonium, nitrate/nitrite, dissolved silica, particulate biogenic silica, dissolved iron, dissolved oxygen, total inorganic carbon, and alkalinity. The model also has the capability to internally compute and output derived variables such as pH, TOC, DOC, POC, DOP, TOP, etc. for comparison to measured observed data.
Typical year long simulations to a single river, reservoir, lake, or estuary take less than 10 minutes on a 1Ghz pentium machine although, with V3.1, applications to a waterbasin may take several hours of CPU time. The model has been used routinely for decade long simulations. Over 50 master's students and over 20 Ph.D. students have used the model for their research and over 50 professors in various universities in the U.S. and throughout the world are using the model in their research. The model is currently being used extensively for FERC relicensing projects and TMDL's.
The model will continue to be developed in the future including adding sediment transport, sediment diagenesis, macrophytes, periphyton, zooplankton, and contaminants.
User's Guide Available?
Approved by EPA for regulatory uses.
Documentation can be downloaded.
Provides: (1) an abstract or abstract equivalent in the introduction, (2) schematic/diagram showing model structure and interaction of model components, (3) equations, equation solution methodologies, and related simplifying assumptions, (4) example input/output files, (5) input and output variable documentation including definitions, units, temporal/spatial dimensions, temporal/spatial resolution options, and (if applicable such as with FORTRAN) format, (6) guidance on selecting and/or estimating values and/or distributions for input variables (including guidance on calibration and selecting default values and/or distributions), (7) guidance on the analysis and interpretation of output, and (8) description of sensitivity analysis, uncertainty analysis, and testing (validation) methodologies and results.