high water (MHHW) is 5.2 feet above MLLW. Because of the low probability 

 that an extreme wind tide, a high astronomical tide, and extreme storm 

 waves would occur simultaneously, the selection of a Stillwater level some- 

 what less than the maximum recorded tide appeared reasonable. Accordingly, 

 the MHHW stage of +5.2 feet was selected as representative of conditions 

 normally expected to occur during a severe storm, and this Stillwater level 

 was used for all tests conducted in the model. Since Monterey Harbor is 

 subject to the action of intermediate-, long-, and short-period waves, it 

 was necessary to incorporate these wave types into the testing program. 

 Little is known about the basic causes of surging in Monterey Bay. Wave- 

 refraction diagrams that were drawn for incident waves from south-southwest 

 clockwise to west-northwest indicated that regardless of the deepwater di- 

 rection all long-period waves reach Monterey Harbor from practically the 

 same direction. An analytical study of the intermediate- and long-period 

 oscillations was conducted in the Monterey Bay area for the possibility of 

 related response in Monterey Harbor. Based on these results, the proto- 

 type wave periods selected for the intermediate- and long-period phases 

 of the model study were T = 35, 38, 41, 44, 47, 51, 55, 60, 66, 72, 80, 

 88, 97, 100.2, 114, 124, 132, 138, 144, 158, 172, 185, 205, 225, 234, 

 257, 280, 305, 330, and 360 seconds. The short-period waves (Table 4-9) 

 were selected from National Marine Consultants (1960) and a refraction 

 diagram study. In evaluating the various design plans tested, corres- 

 ponding model data (i.e., test results using similar input test conditions 

 with different plans installed) were compared to determine the relative 

 effectiveness of each individual plan. The long-period wave phase of 

 the study included the comparison of: (a) Both maximum and average wave 

 heights recorded in the individual harbor basins; (b) current velocities 

 in the harbor basins and entrances; (c) modes of oscillation in the bay 

 area; (d) frequency- response data for the various basins; and (e) time- 

 exposure photos of float movement in critical areas. Visual observations 

 during model testing and test notes aided in the analysis. In the short- 

 period wave phase of the study, the relative merits of the various plans 

 tested were evaluated by (a) comparison of wave heights at selected loca- 

 tions in the harbor, and (b) extension of the wave height data into tables 

 showing the estimated duration of waves of various magnitudes that can be 

 predicted at the selected locations. Visual observations, photos of wave 

 crest patterns, and test notes were also used in the short-period wave 

 test analysis. In the wave height data analysis, the average height of 

 the highest one-third of the waves recorded at each gage location was 

 selected for the computations. The direction and magnitude of surface 

 currents in the model were measured by taking time-exposure photos of 

 surface floats from camera positions directly above the model harbor 

 area. From these photos, the progress of the floats over one wave cycle 

 was measured relative to a horizontal grid system painted on the model 

 floor, and the corresponding velocities were computed. Wave heights at 

 selected locations in the model were recorded on chart paper by an elec- 

 trically operated oscillograph. The input to the oscillograph was the 

 output of electrical wave height gages that measured the changes in the 

 water surface elevation with respect to time. The electrical output of 

 each wave height gage was directly proportional to the submergence of the 

 gage in the water. 



270 



