Sustainable coastal communities: the use of crenulate bay theory at different scales of coastal management

Abstract

Crenulate bay theory is well developed and natural examples of this type of bay are evident along many coasts. Case studies are presented here in which this theory has been applied and adapted at different scales to address the needs of management and coastal communities. In many places, these needs are not currently met because coastal protection is constraining landward shoreline movement, leading to erosion and consequential loss of property, infrastructure, public access and amenity value.Abereiddy, in west Wales has a small locally important beach backed by a seawall. With no intervention, seawall collapse will lead to realignment and a more natural beach form, but a reduction in car parking area. Crenulate bay theory was applied to understand what shoreline shape would result if the seawall was lost. Coyote Point, in San Francisco Bay, California is a popular recreation area. Coastal defence structures are failing, leading to erosion of the coastal path and beach loss. In order to develop an innovative sustainable solution to the erosion problem, whilst maintaining recreational functions and good public access, crenulate bay setback options were examined.These local examples can be set within the wider context of integrated coastal zone management. Axiomatic principles, such as crenulate bay theory, assist in interpreting existing broader-scale erosion monitoring in the context of geomorphological control. Examples are provided demonstrating regional benefits of the approach by taking a landscape-scale view of coastal evolution.

Shoreline variability and coastal vulnerability: Mossel Bay, South Africa

“…In naturally functioning systems, undisturbed by anthropogenic interference and where direct human pressure is low to non-existent, phases of accretion and erosion and associated shoreline change pose no immediate risk as the coastal system is naturally dynamic. However, when infrastructure is placed within the beach or immediately landward, the interaction of a naturally dynamic system with human occupation and uses can have far-reaching consequences (Thom, 2020), including: loss of property, infrastructure, public access and amenity value (Brew et al, 2011). Hence, understanding the dynamics of the coastal zone and the impact on coastal erosion, as well as the implications for coastal hazards and associated risks to human occupation is a long-lived concern for coastal managers (Philips and Jones, 2006).…”