Numerical Water Quality Model Study for the Los Angeles Harbor Pier 400 Project

摘要

The Port of Los Angeles plans to construct an additional port facility referredto as Pier 400. The Pier 400 harbor facility may affect water quality by changing the tidal circulation and flushing patterns. Numerical water quality model simulations were used to compare flushing and dissolved oxygen (DO) resources at existing conditions and two stages of plan implementation. The flushing simulations computed the transport and dilution of a conservative tracer inserted into various regions of the harbor. The flushing studies provided a qualitative comparison between plans where a decrease in flushing rate prolongs the period of time that oxygen-demanding substances exert their influence on the DO concentration. The water quality simulations included the variables temperature, phytoplankton, phosphate, nitrate, biochemical oxygen demand, and DO, and were conducted for the period August 1-31, 1987, where a complete set of field data were available to establish initial and boundary conditions and to calibrate the model under existing conditions. Two flushing studies were conducted: injection of tracer into all regions interior to the Federal breakwaters, and injection. of tracer only in the region east of the Stage 1 access causeway. The first flushing study revealed that the two stages of plan implementation inhibited flushing in the LA Outer Harbor, Fish Harbor, Seaplane Lagoon, and Main Channel. The second flushing study showed that the access corridor prevented advection to areas west of the causeway; the dilution rate decreased by an order of three. -BKA.