TITLE:
Short-Term Assessment of Retreating vs. Advancing Microtidal Beaches Based on the Backshore/Foreshore Length Ratio: Examples from the Basilicata Coasts (Southern Italy)
AUTHORS:
Sergio G. Longhitano
KEYWORDS:
Beach Profile, Subaerial Beach, Backshore, Foreshore, Equilibrium Profile
JOURNAL NAME:
Open Journal of Marine Science,
Vol.5 No.1,
January
26,
2015
ABSTRACT: A straightforward
conceptual method is proposed to quantitatively assess the seasonal-scale
tendency of retreatment or advancement on microtidal beaches by using the
backshore/foreshore length ratio. This method is based on measuring the
cross-shore profile of a beach when it passes through the “transitional state”
that separates the high-from the low-energy season, period during which the
morphological characteristics of the beach tend to its equilibrium profile. In
order to obtain real measurements of backshore (B) and foreshore (F),
the definition of the limits bounding these two important components in
subaerial beaches is reviewed and discussed. The approach based on the
measurement of theB/Flength ratio assumes that foreshore
and backshore have equivalent lengths in beaches that approximate to their
state of morphodynamic equilibrium (B/F~
1). A backshore length exceeding the foreshore length is indicative of a state
of beach recession, with aB/Flength ratio > 1. When the
foreshore length is greater than the backshore length, the shoreline is
advancing or, alternatively, it is developing in a state of morphological
confinement,i.e.due to the presence of a sea cliff,
with aB/FB/Flength ratio.