A major task of Office of Coast Survey’s Coast Survey Development Laboratory (CSDL) is the implementation, vetting, and transition to operational status of circulation models for critical regions of the U.S. Coastal waterways. These models have multi-purposes, including being the methodology to establish nowcast/forecast systems of water levels and the three-dimensional structure of currents, temperature, and salinity in a region of interest; an important component in the framework to establish continuous bathymetric/topographic surfaces; and provide transport mechanisms to understand the fate of natural and anthropogenic organisms and chemicals in the water column. As the needs and uses for these models increases, development and operational demands also increase. How does CDDL/MMAP objectively evaluate existing and emerging modeling technologies to select appropriate community models to support requirements for models to address navigational, inundation, and ecological issues? The selection process must be based on quantitative measures of accuracy, adaptability, portability and sustained supportability. Approach Establish a series of Modeling Evaluation Environments (MEE) that consist of sufficient data and information to CONFIGURE, i.e., shoreline, bathymetry; EXECUTE, i.e., model initialization, and specification of synoptic environmental conditions at lateral open-ocean boundaries, river discharges, and at the air-sea interface, and DETERMINE MODEL UNCERTAINTIES, i.e., observations of water levels, currents, and C/T/D. Each MEE is representative of a class of dynamic regimes, e.g., shallow, well-mixed coastal estuaries, tidal marshes, deep fiords. The initial MEE underdevelopment is for Delaware River and Bay. Six community models are being evaluated, which include both 2-D and 3-D models that are defined on either structured (orthogonal grids) or unstructured (highly variable triangular elements). Establishment of a Model Evaluation Environment for Delaware River and Bay    Locations of Delaware Bay CTD (conductivity-temperature-depth) surveys used for model evaluation.    Locations of Delaware Bay current velocity surveys used for model evaluation.