Environmental Engineering Reference
In-Depth Information
difficult to justify. In the 1970s beach erosion at Miami led to demands for public
help, but by then 95 % of the beach had passed into private ownership. The United
States Army Corps of Engineers decided to make unimpeded public access a con-
dition of beach renourishment at public expense.
It has been found that renourishment of beaches on the east coast of the United
States has been of benefit to property owners because it provides more effective
protection from storm damage and gives them an improved recreational resource
(Olsen
1982
). On Tybee Island, Georgia, Landry and Hindsley (
2011
) showed that
increased width of beaches and dunes augments property values within 300 m of
the coastline. Prices of land and housing have risen, as do incomes from rent and
tourist expenditure, behind beaches widened by renourishment in South Carolina
(Pompe and Rinehart
1994
) and North Carolina (Gopalakrishnan et al.
2011
). On
the Atlantic coast generally beach renourishment can increase real estate values by
up to 21 % (Black et al. 1988), and prompt further development or rehabilitation
of existing development (Stronge
1990
; Bodge
1991
).
Nevertheless, many coastal engineers remain cautious about the economic via-
bility of beach renourishment projects. In the words of the British engineer, Barrett
(
1989
): 'I have no doubt that there is a consensus amongst coastal engineers that
the ideal form of coastal defence in purely engineering terms is a massive beach.
Whether this can be achieved in future economic terms and in proper long-term
use of available resources are quite another matter'.
6.3 Response of Renourished Beaches to Climate Change
and a Rising Sea Level
Predictions of global warming and a world-wide sea level rise should now be
taken into account in long-term planning for coastal management, including beach
renourishment (Bird
1993
). In the past century global average sea level has risen
10-20 cm, as measured by tide gauges located around the world (Church et al.
2001
), as has the rate of rise (Mitchum et al.
2010
). The latest (fifth) Assessment
Report of the Intergovernmental Panel on Climate Change (IPCC
2013
) estimates
that sea level will continue to rise to the end of the 21st century and beyond, with
estimates varying depending on scenarios for global emissions, because of thermal
expansion of the oceans, melting of glaciers and ice sheets and changes in terres-
trial water storage (Walsh et al.
2004
).
Projected sea level rise has significant spatial variation. In Britain rates of sea
level rise are influenced by relative land level changes: in Scotland sea level rise
is somewhat reduced by the isostatic rebound (rising) of land since the last gla-
cial period, while in the south of England relative sea level rise is expected to be
greater because of land subsidence.
The effects of climate change may also include regional changes to storm fre-
quency and intensity (IPCC
2013
), which will impact on beaches. Small changes
in wave direction may modify longshore drift and beach orientation.
