A considerable effort is put forth by regulatory agencies (Maine Department of Marine Resources, U.S. Army Corps of Engineers, Maine Department of Environmental Protection, National Marine Fisheries Service, U.S. Fish and Wildlife Service, etc.)  To monitor hydrodynamic, water quality, and benthic conditions and to evaluate environmental impacts of net-pen aquaculture operations. The efficiency of this work may be significantly enhanced through the use of mathematical models that give more complete information regarding the physical conditions in the domain. An efficient mathematical modeling package called Auqaculture Waste Transport Simulator (AWATS) provides first-order estimates of the physical dispersion of finfish aquaculture wastes for regulatory purposes. The modeling strategy entails the utilization of a vertically averaged, two-dimensional few model to produce flow-field information; this information is input to a particle tracking waste transport model to simulate the resulting transport of wastes. Since earlier studies have shown that the transport modeling results are sensitive to the threshold shear stress at which settled fish-pen wastes are resuspended, field work was conducted to improve the parameterization of erodibility in the transport model. Application of AWATS to several aquaculture sites in coastal Maine (selected by the Maine Department of Environmental Protection) shows that it is a convenient tool in the regulatory process.