ESTIMATES OF THE TRANSPORT THROUGH THE EAST RIVER, NEW-YORK

The hydrodynamic characteristics of the East River, New York, which co nnects Long Island Sound to New York Harbor, have been investigated vi a a high-resolution, topographically conformal and orthogonal curvilin ear grid together with high-quality acoustic Doppler current profiler measurements. The objective is to determine the volume flux of water t hrough this important water body. The model was calibrated and validat ed through comparisons with measured salinities, water levels, current velocities, and data-based estimates of volume flux. Detailed statist ical analyses demonstrated that both the tidal and meteorological band s spanning inverse frequencies between 3 hours and 5 days were well si mulated by the model. The climatological band (inverse frequencies gre ater than 5 days) did not exhibit uniformly good agreement because of the paucity of salinity and temperature measurements available for use as model forcing functions. Results from an 18-month (1988 to 1989) s imulation indicate that the net long-term flux of water is directed ou t of Long Island Sound and toward New York Harbor. The total rate was found to be about 310 m(3) s(-1). At the eastern end of the East River near its confluence with Long Island Sound, the net flow was distinct ly two-layered with flows of about 260 m(3) s(-1) directed toward the sound in the surface layer and flows of approximately 570 m(3) s(-1) i n the bottom layer directed toward New York Harbor. There appeared to s be a 100 m(3) s(-1) monthly variation about the mean transport at th e eastern end. However, s on shorter timescales the transport reversed direction for days at a time.