This report presents results from physical and numerical model tests on the effects of the proposed I-664 James River Bridge-Tunnel complex on (a) sedimentation in the federally maintained channels (Newport News, Norfolk Harbor, and Elizabeth River); (b) general sedimentation in the lower James River; (c) changes in overall flushing characteristics; and (d) changes in current velocities and flushing near the Craney Island disposal site. The navigation channel sedimentation was evaluated using the TABS-2 finite element numerical models RMA-2V for hydrodynamics and STUDH for sedimentation with an existing numerical mesh of the Elizabeth River and lower James River areas. For the general sedimentation investigation, a new numerical mesh was created and the same numerical models, RMA-2V and STUDH, were used. Data for the flushing and currents evaluation were provided by the Virginia Institute of Marine Science. Results from the physical model tests indicate circulation changes will be localized with minimal effects on the general circulation of the lower James River. Results from the numerical sedimentation modeling indicate that sedimentation will be generally unchanged or reduced except on either side of the north island where increases can be expected. The areas experiencing unchanged or slightly reduced sedimentation rates include the oyster grounds, the Elizabeth River and Norfolk Harbor Channels, and the Newport News Channel. (fr).