9530394 Lwiza In this project, the PIs will study the dynamics of transverse flow in a coastal plain estuary, specifically the James River estuary in Virginia. Two parallel transects with high spatial resolution measurements will be occupied, using an Acoustic Doppler Current Profiler, and CTD casts during two tidal cycles on spring and neap tides. In addition, high temporal resolution measurements will be made with three current meter moorings at each one of the two transects and two bottom pressure recorders at either side of the estuary between the two transects. Three different dynamical regimes in the year will be addressed, namely, high river discharge (May), low river discharge (August), and the weakest vertical stratification (October). A number of objectives relating to the transverse circulation will be addressed, culminating in an evaluation of the dominant terms in the transverse momentum balance, both from the observations and from a numerical model.