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Higgins Beach, Scarborough
Background geology and characteristics
Annual and seasonal beach profile changes
For HI1, beach profile data were available for 1999, and 2001 through 2007. Overall, the beach monitored at HI1 is relatively stable and has undergone little change from 1999-2007, with the majority of the variability concentrated in the first 30 m (Figure 13). These variations are less than 0.5 m. The offshore portions of all profiles - from about 100 m offshore and greater - vary very little, less than 0.25 m. The 2001 and 2002 annualized mean profiles appear to hold the largest volume of sediment, while the 2007 profile (which accounts for the months of December-April) appears to hold the least amount of sediment. This is likely due to the seasonal bias (winter data only) for the 2007 collection period. HI1 shows typical seasonal variability for beach profiles in Maine (Figure 14). The summer profile has substantially more sand on the beach profile than the winter profile, with the winter profile being flatter and more sediment-starved. Profile envelopes show that HI1 can undergo changes on the order of about 0.5 m in summer, and almost a full meter in winter. Standard deviation values indicate that vertical berm fluctuations are mostly within the first 20 m of the profile and are values of about 30 cm or less (Figure 15a).
Aside from mean profiles from 1999 and 2001, which appear to have started at a different location than the remaining years, HI2 shows very little annualized change, especially in the nearshore (Figure 16). Farther offshore (120 m and greater), there is slightly more variability in the mean profiles. This may indicate that HI2 is also relatively stable, with the majority of changes occurring at the lower portion of the profile. HI2 also shows a distinct seasonal variability, with the mean summer profile showing a much more well defined berm (between 40-120 m from the pin) than the winter mean profile (Figure 17). For the summer mean, much of the profile variability is concentrated in the first 40 m of the profile. The winter mean profile shows more stability in the nearshore, with greater variability from the mean starting around 100 m offshore. This makes sense since sandbar variability should be greater in the winter than in the summer, since sediment is typically removed from the upper portion of the beach profile in the winter and stored in offshore bars. The calculated standard deviation values for summer and winter profiles show marked berm development in the summer, which varies about 40 cm vertically and is concentrated near the 20 m mark (Figure 15b).
HI3 shows dramatic variability on an annualized basis (Figure 18). This variability is a result of the influence of the beach spit's end and proximity of the profile location to the ebb-tidal delta of the Spurwink River. This area of Higgins Beach is called a "sediment sink"; that is, this area typically receives sediment moving along Higgins Beach and becomes trapped in the ebb delta. Annual variability is marked; from a low in 2001, to highs in 2007, variability is on the order of 1 m or more, especially past the 50 m mark. Based on this data, it appears that this area of Higgins Beach is generally accreting. Seasonal variability at HI3 is not comparable with the other profiles (Figure 19). Profile envelopes show variability on the order of a meter or more for both seasons, and the summer and winter profiles do not show typical characteristics of the other profiles along Higgins Beach. The standard deviations show summer berm development much farther offshore, near the 40 m mark with vertical variations on the order of nearly 60 cm. Variations offshore in the summer profile reach nearly 80 cm vertically, while the winter profile is closer to 60 cm (Figure 15c).
The variations in the profiles along Higgins Beach may relate to the three different beach types found at each of the profile locations. HI1 is located at the base of a large rip-rap seawall; this wall is "active" at high stages of the tide - that is, tidal water and wave activity is in contact with the seawall. This is reflected in less berm development and general low variability of the mean profiles, especially as compared with HI2. HI2, though it starts at a seawall, is located at a portion of the beach that has more sediment, undergoes more seasonal changes, and is not active during high tide phases. HI3 is heavily influenced by the spit end of Higgins Beach, which terminates at the Spurwink River ebb-tidal delta; this area undergoes large changes due to sediment movement and availability at the spit and ebb-tidal delta.
Last updated on January 3, 2008
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