SPECIAL PUBLICATION NO. 43
1981; U. S. Department of Commerce, Deguchi, 1980;Watanabe and others, 1980; 1987a, 1987b). Quick and Har, 1985; Kinose and others, 1988; Larson and Kraus, 1988; and
It is worthwhile to note that Berrigan Seymour and Castel, 1988). In this paper, and Johnson (1985) compared wave power the "summer" or lull season wave steepness computations to shoreline position for seven is expressed as QL = HL/(g TL 2), and the years of data at four localities along Ocean "winter" or storm season steepness as O)s = Beach, San Francisco, California. Deep Hs/(g Ts2). It became apparent that water wave data were measured at sites incorporation of the wave steepness ratio ranging from 3.9 to 26.7 kilometers offshore induced numerical consistency in (Berrigan, 1985). While some refraction quantitative prediction. Whether the ratio is effects may have occurred due to the San evaluated as Q$L/(s or Ps/L becomes Francisco entrance bar, there appears to be important. The form of the ratio for various a correlation between an increase in wave arrangements of relating expressions for power and decrease in beach width, assessment purposes is given in Table 2.
Hence, if (Q$L/S) < 1.0 then wave height
Results during the storm season must be more important; if (j/Cs) > 1.0 then wave
There is, from Figure 1, an indication steepness plays a stronger role. In fact, it that astronomical tides play a role in would be expected that QL/Q(S results in seasonal variability. The mean range of tide, better correlation, since beaches are eroded hmrt, and seasonal wave height difference, by steeper waves, with lower steepness AH = Hs HL, might be expressed as a sum, waves resulting in accretion. i.e., hm, + AH, or as a product, i.e., he,
(AH). Since energy according to classical In addition, beach sediment wave theory is proportional to the height characteristics have been touted to play a squared, the product, i.e., hi, (AH), might significant role. The general view is that, be more appropriate. On the other hand, the holding force elements constant, a beach sum has merit because laboratory data, if composed of coarser sediment is more stable available, could be used (i.e., since tides are than a beach composed of finer material almost never modelled in laboratory studies, (e.g., Krumbein and James, 1965; James, a product would be meaningless because the 1974, 1975; Hobson, 1977), i.e., a beach result would always be zero). In either comprised of coarser sediment should exhibit event, many combinations of parameters less seasonal variability than a beach were investigated (Balsillie, 1987b; see also composed of finer sediment (note that this Table 2 for some of the equations), and it explanation is not so straightforward, and was found that the sum was not nearly as will be addressed in greater detail in the successful as the product; either scatter was following section). Since a number of excessive as indicated by a low correlation investigators have published general coefficient, r, and/or the fitted regression line quantifying relationships which in addition to did not pass through the origin of the plot. wave height and steepness, incorporate sand size (e.g., Dean, 1973; Hattori and
Many researchers have emphasized Kawamata, 1980; Sawaragi and Deguchi, the importance of wave steepness in 1980; Watanabe and others, 1980),it would influencing the shore-normal direction of be prudent to consider granulometry in this sand transport (e.g., Johnson, 1949; Ippen study. and Eagleson, 1955; Saville, 1957; Dean,
1973; Sunamura and Horikawa, 1974; Again, it is to be noted that many Hattori and Kawamata, 1980; Sawaragi and forms of possible relating parameters were
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