ERDC/CHL CHETN- IX-7
December 2001
Wave Conditions: Environmental data were collected at 1 Hz for 20 min every 3 hr using a
PUV pressure gage located in the entrance channel and a National Oceanic and Atmospheric
Administration (NOAA) buoy located approximately 363 km (196 navigation mile (NM)) from
the site. The pressure gage was positioned approximately 0.9 m (3 ft) off the bottom and 1.5 m
(5 ft) from the south channel wall near Sta 2200. Figure 4 is a time series of wave heights
measured for both the pressure and NOAA buoy. Offshore wave heights varied from 1.2 to
2.7 m (4 to 9 ft), while inshore values were between 0.3 to 0.6 m (1 to 2 ft). In general, pressure
gage data collection was continuous and good quality with missing data only from 28 to 31 May.
Large offshore wave heights at the buoy do not necessarily correspond to larger wave heights in
the channel because of directional characteristics of the waves and nearshore processes such as
bathymetry, diffraction, reflection, and wave breaking that may strongly affect wave energy
inside the channel. Directional wave data were measured in the channel with the PUV gage, but
preliminary analysis indicated that the directional analysis was not reliable due to the wave
transformation inside the entrance channel. Visual observations during ship transits, however,
indicated that waves were primarily from the south with some spreading.
3.0
NOAA 51003 Buoy
Channel PUV Gage
2.5
2.0
1.5
1.0
0.5
0.0
1
6
11
16
21
26
31
May 1999
Figure 4. Measured significant wave heights by the NOAA offshore buoy and the
entrance channel PUV gage
PHYSICAL MODEL STUDY
Model Setup: An undistorted, three-dimensional model of Barbers Point Harbor (Figure 5)
was constructed in 1990 at a model to prototype scale Lr = 1:75 (Briggs et al. 1994). The near-
shore area extends to the 30.5-m (100-ft) mllw contour and includes approximately 1,067 m
(3,500 ft) on either side of the entrance channel. Total area of the model is over 1,022 m2
5
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