- - SPECIAL PUBLICATION NO. 43
equation (2) results in a mean 60 grain size of 0.318 mm which, VS. 78-S hmrt (a )L/ s using the Wentworth vs 40 r o.o047 classification scheme, is a medium-sized sand (Wentworth, t 20-* 1922).
I I, I J
0 oI (2 0.3 04 0.5 0.6 07 DISCUSSION hmrt (AM) */0S (/2)
Figure 6. Illustration of mathematical fit for equation (1). A favorable result from
many of the prediction equations 60- r r r tested during the course of this vs o0.0o25 hmrt (AN) /LS V D
investigation is that most showed s = o.9a72 a trend between Vs and the relating parameters (e.g., column 1 of ) 2 Table 2). Ostensibly, such consistency should not be 0 5oo 1,00ooo so00 2000 surprising since the major factors art(,) is (m)
0
known to cause seasonal Figure 7. Illustration of mathematical fit for equation (2). variability were considered, and
the remainder of the work
involved rearranging the variables to reduce become available to further test and/or scatter. Further, the goal to delineate enhance the prediction relationships. seasonality was a simplified approach Nevertheless, the results presented here are (compared to relating the entire time series statistically valid; one should not be timid in of monthly values which becomes applying resulting computational values increasingly complex), pending future refinement in prediction methodology. One purpose of this paper is Equations (1) and (2) engender some to act as a plea for more data. Following are heterogeneity that needs discussion. Both discussions of a few concerns related to AH and OL,/s are seasonal parameters. seasonal shoreline variation predictions. Granulometry as it appears in equation (2) is a property element application, although a The Single Extreme Event and seasonal response element application is the Combed Stom Season possible and is discussed in a later section. The quantity, hmrt, however, is not a The sandy littoral zone is comprised, seasonal measure. It is, rather, an average from offshore-to-onshore, of the nearshore, approximate hourly measure where one tide the beach, and the coast. Each of these (diurnal) or two tides (semi-diurnal) occur in three subzones is created and maintained by one tidal day of 24 5/6 hours. Hence, hmrt sets of force elements normally different is also a property element that is a signature from each other within the long-term value for each site, noting that it can vary temporal framework. When a storm or significantly depending upon the locale, hurricane impacts the littoral zone, the Seasonal mean sea level change for which following scenarios are possible: 1) the there are no site-specific data for Table 1 extreme event produces a combined total localities, is discussed in a following section. storm tide which rises above the beach-coast interface elevation to affect all three The results of this work might be best subzones, 2) the combined total storm tide viewed as a first appraisal until more data does not rise above the beach-coast
9