Automated Validation System for the Offshore Operations Committee Mud and Produced Water Discharge Model Describes the development of an aut omated validation system for the Offshore Operators Committee Mud and Produced Water Discharge Model (the “OOC Model”), a computer progra m that predicts the initial fate of drilling fluids, drill cutti ngs, and produced water discharged into the marine environment. The system automates the process of validating OOC Model predictive capabilities by comparing model predictions with the results of laboratory and field studies of plume behavior. The system was developed to automate the laborious process of confirming that model code enhancements do not degrad e the predictive abilitie s of the OOC Model. The automated validation syst em approach described here also serves as a template for routine documentation of discharge model performance that could be applied to other models used by industry, consultants, or regulatory agencies. Two of relevant studies found in a literature search were incorporated into the suite of autom ated test cases for the OOC Model. Summaries of the data sets used for OOC Model validation were prepared in such a way that they could be used conveniently outside of the automated system to validate of an y relevant discharge model. November 2002 | CD - ROM Only Publ 4664 Mixing Zone Modeling and Dilution Analysis for Water - Quality - Based NPDES Permit Limits This report is designed to • provide an overview of the U.S. Environmental Protection Agency’s (EPA) policies and technical guidance on the role of mixing zones in the National Pollutant Discharge Elimination System (NPDES) permitting process; • present state mixing zone regu lations, policies, and guidance; • introduce important concepts relate d to the hydrodynamics of effluent dilution in receiving waters and the design of outfall diffusers; • review available mixing zone models; • identify EPA sources for the models; • discuss