Here is the download package (source code and other utilities) for the FVCOM-ICMv4.0 model, which was originally developed at University of Massachusetts with support from U.S. Army Corps of Engineers USACE. Pacific Northwest National Laboratory (PNNL) completed subsequent developments and improvements as part of an effort to establish a robust unstructured biogeochemical model for Puget Sound, Georgia Basin, and the Strait of Juan de Fuca (Salish Sea) for U.S. EPA and Washington State Department of Ecology (Ecology). The unstructured biogeochemical model FVCOM-ICM has been through numerous phases of testing, and model performance has been well documented via peer-reviewed journal publications and several study reports. Initial testing and Phase 1 and 2 with model applications to the Puget Sound domain were completed in 2012. The most recent updated version, 4.0 includes explicit calculations for kinetics of zooplankton and submerged aquatic vegetations. The model is going through continuous developments and improvements. Thus, users should use the recommended procedures together with their own best judgments in model applications.