Environmental Engineering Reference
In-Depth Information
Fig. 6.1
Beach renourishment on the Lincolnshire coast, United Kingdom. Between 2010 and
2015 15,000 m
3
of sediment per day was pumped ashore and placed on the beach using hydraulic
pipes. Sediment was then spread across the beach using excavators and bulldozers. © Dredging
International
et al.
2006
). Some of these effects can be reduced by planning the timing of dredg-
ing, transportation and delivery of sediment to renourish beaches. This depends
partly on favorable weather conditions, and should also avoid breeding seasons
so that the impact on biota is less severe. The preferred time for renourishment
depends on the nature, location and the species inhabiting the site.
The assessment of potential environmental impacts is undertaken for large
renourishment projects, but the statutory requirement changes from country to
country and is usually determined by the construction time frame or project size
(placement quantity). For example, in Spain an Environmental Impact Assessment
is a legal requirement for projects involving a placement of more than 500,000 m
3
,
while in the United Kingdom environmental assessments are undertaken to a
level of detail proportionate to the project size. In some instances an assessment
of the potential environmental impacts is completely lacking. For example, ren-
ourishment of the beach at Balneario Camboriu in 2002 was not preceded by any
specific environmental assessment, yet 50,000 m
3
of material was hydraulically
dredged and placed along 800 m of beach. The renourishment caused a number of
impacts including significant changes to the beach and bay sedimentology, death
of macrofauna due to the dredging operations and suffocation from placement, and
suffocation of filter feeders such as bivalves (Pezzuto et al.
2006
).
A comprehensive assessment of environmental impacts would consider a num-
ber of environmental parameters, including ecology, water and sediment quality,
