resulting solely from the wave - induced , cross -shore component of sediment 

 transport. Recently, Birkemeier (1985a), Sallenger, Holman, and Birkemeier 

 (1985), and Howd and Birkemeier (1987) have reported results from repetitive 

 concurrent field measurements of the beach profile, waves, and water level. 

 However, horizontal spacing between measurements along the profile was 

 typically tens of meters , and the time interval between surveys was on the 

 order of a half day to a week, during which wave conditions and water level 

 varied substantially. Hands (1976) quantified several geometric properties of 

 a longshore bar system in Lake Michigan but could not make direct correlations 

 with the waves and water level due to a lack of measurements. Wright, Short, 

 and Green (1985) made daily observations over 6-1/2 years of Narrabeen Beach, 

 Australia, and related gross change in nearshore morphology to a single 

 parameter, the dimensionless fall speed, discussed further below. 



163. Several descriptive models of beach profile change have been 

 developed based on field observations and measurements, but these are primari- 

 ly statistical or conceptual and are not capable of quantitative prediction 

 (e.g., Evans 1940; King and Williams 1949; Shepard 1950; Bascom 1951; Sonu 

 1969; Davis and Fox 1972; Davidson-Arnott 1975; Aubrey, Inman, and Nordstrom 

 1977; Owens 1977; Short 1979; Sasaki 1983; Takeda 1984; Wright and Short 1984; 

 Wright, Short, and Green 1985; Wright et al . 1986; Sunamura in press). 



Prototype -scale laboratory approach 



164. The third approach available for quantitative investigation of 

 beach profile change is use of large wave tanks (LWT) . Such facilities enable 

 controlled reproduction of near-prototype conditions of beach slope, wave 

 height and period, turbulence induced by wave breaking, and resultant sediment 

 transport and beach change. The problem of scaling is eliminated, and the 

 required high resolution measurement of the profile can also be attained. 

 Disadvantages associated with wave tanks include contamination by reflection 

 from the beach and wave generator and formation of wave harmonics (Buhr Hansen 

 and Svendsen 1975). Experience suggests that these factors are negligibly 

 small under reasonable experiment design. 



165. Experiments using LWTs have been performed with monochromatic 

 waves (Saville 1957; Caldwell 1959; Kajima et al . 1983a, b; Dette and Uliczka 

 1987a; Kraus and Larson 1988a) and irregular waves with random heights and 



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