CE-QUAL-W2 is a two-dimensional water quality and hydrodynamic code supported by the U.S. Army Engineer Research and Development Center (Cole and Buchak 1995). The model has been widely applied to stratified surface water systems such as lakes, reservoirs, and estuaries and computes water levels, horizontal and vertical velocities, temperature, and 21 other water quality parameters (such as dissolved oxygen, nutrients, organic matter, algae, pH, the carbonate cycle, bacteria, and dissolved and suspended solids). A typical model grid is shown in Figure 1 where the vertical axis is aligned with gravity.

This technical note documents the development of CE-QUAL-W2, Version 3, which incorporates sloping riverine sections. Version 3 has the capability of modeling entire river basins with rivers and interconnected lakes, reservoirs, and/or estuaries. Four example applications illustrate the use of Version 3.