for input to the STWAVE model. The two-dimensional spectra were rotated 10-deg west
of north to correspond with the grid orientation. Tide elevation data from Water Level
Station 1 were used to modify depth for each 3hr time period to account for water level
(and depth) fluctuations of the tide.
Model validation with the field data shows good correlation. A preliminary comparison
of wave height at seven wave gauge locations (Stations 0 through 6 in Fig. 1) to the model
results at these locations is given in Fig. 8. Wave attenuation from Station 0, to Station 2,
to Station 3, to Station 6 is clearly evident. The maximum wave height at Stations 0
through 2 is over 4 m. Wave heights at Stations 4 and 5 (in the inlet throat) do not exceed
2.8 m during this same time period. Wave height at Station 3 does not exceed 1.2 m and at
Station 6 (most bayward) does not exceed 0.4 m. All stations show some evidence of tidal
influence, with the most predominant influence at the interior stations (Stations 3 and 6).
The difference between measured and calculated wave height shows that model results are
typically within 0.5 m of the measurements.
Impacts of Currents and Water Level on Wave Transformation
Climatological conditions were determined from the CDIP buoy data (August 1993
through November 1999). The wave climate was divided into 6 height, 5 period, and 6
significant angle bands to drive the STWAVE model, for a total of 180 STWAVE
simulations (Table 1). Wave conditions were first run at mean tide level (MTL) with no
current. These base condition results were monitored at all inlet data-collection locations
(Fig. 1). The majority (45.1%) of the waves are in the1-2 m range and result in waves at the
entrance to Grays Harbor of approximately 0.5 to 2 m. Wave heights in the 2-3 m range at
the CDIP buoy have a 24.7% occurrence, producing waves of 0.5-3 m at Grays Harbor
entrance. The largest waves (>6.5 m) have a probability of occurrence of less than 1%, but
result in wave heights of 1-8 m in the inlet entrance. Wave heights at Tripod Station 3
(bayward side of the inlet entrance) have an 80% probability of being less than 1 m.
Table 1. Wave Conditions from Grays Harbor Wave Climate (1993-1999)
Significant Wave
Peak Period,
Wave Direction,
Compass
Height, m
sec
Deg from North
Direction
0.5
6
202.5
SSW
1.5
8
225.0
SW
2.5
12
247.5
WSW
3.5
16
270.0
W
5.0
20
292.5
WNW
6.5
315.0
NW
Cialone & Kraus
7
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