TIDAL CIRCULATION PROTOTYPE DATA COLLECTION EFFORT 

 PART I: BACKGROUND 



1. The Ports of Los Angeles and Long Beach (LA/LB), California, are 

 conducting planning studies for harbor development in coordination with the US 

 Army Engineer District, Los Angeles. The US Army Corps of Engineers (CE) is 

 charged with the responsibility for providing deeper navigation channels and 

 determining the effects of harbor expansion on the environment. To upgrade 

 the CE's capability to determine these effects based on state-of-the-art mod- 

 eling technology, the US Army Engineer Waterways Experiment Station (WES) is 

 executing the Los Angeles/Long Beach Harbors Model Enhancement Program. 



2. This program is separated into two major studies. The first will 

 address long-period wave energy in the harbors and its effect on moored ves- 

 sels. The second will provide improved tidal circulation modeling with a more 

 efficient numerical model system that will couple hydraulics and water quality 

 variables (CE 1987). The prototype data for model calibration and verifica- 

 tion have been collected by the Prototype Measurement and Analysis Branch of 

 the Coastal Engineering Research Center (CERC) , WES. This report describes 

 the methodology and results of that data collection effort. 



3. Los Angeles and Long Beach Harbors are adjacent ports situated 

 behind a rubble-mound breakwater in San Pedro Bay, California (Figure 1). In 

 the initial WES study of the harbors, a fixed-bed three-dimensional (3-D) phy- 

 sical model (McAnally 1975) and a depth- averaged- flow, two-dimensional numeri- 

 cal model (Raney 1976) were developed. Advancements in the state of the art 

 of prototype measurement and hydraulic simulation provided the means to 

 enhance the models. The upgraded numerical model of this program provides 

 simulation of the time series of the resultant 3-D water currents and water 

 surface elevations in the harbors given the physical boundaries and the water 

 surface elevations in the open ocean outside the harbor breakwater. 



4. Boundary conditions are established by obtaining the positions of 

 the shoreline, including structures, and the bathymetry of the area modeled. 

 Water surface elevations measured using tide gages placed outside the harbor 

 provide the input forcing function that drives the system. Measurements of 

 tidal elevation and water currents at selected positions inside the harbor are 

 compared with predicted values to calibrate and verify the model. 



