Environmental Engineering Reference
In-Depth Information
Chapter 6
Planning Considerations
Abstract
A number of key considerations that need to be taken into account
when planning beach renourishment are introduced. Environmental impacts, both
positive and negative are discussed, along with the costs of beach renourishment.
Predictions of global warming and a world-wide sea level rise are considered and
the implications for beach renourishment projects discussed.
6.1 Environmental Impacts of Beach Renourishment
Beach renourishment is generally beneficial, and widely regarded as a better alter-
native to the construction of hard structures (Adriaanse and Coosen
1991
; Hamm
et al.
2002
; Finkl
2002
), but it can produce adverse impacts on the environment
(Speybroeck et al.
2006
). When works are undertaken the activity is often inten-
sive (Fig.
6.1
).
Beach renourishment requires the extraction of suitable fill from a source area,
its transportation to the shore and its deposition on a beach. Each of these pro-
cedures may have negative environmental impacts, both during construction and
once the construction activity has ceased. Impacts can include sediment distur-
bance leading to increased turbidity in nearshore waters and waters close to the
sediment source, the displacement or burial of plant and animal communities, and
associated changes in oxygen, temperature, salinity, light penetration, and the cir-
culation of nutrients and chemicals in the sea and on the sea floor. Marine plant
and animal communities may be reduced or destroyed, and their revival may be
very slow, depending on the degree of disruption and the availability and vigor of
recolonising biota (Pullen and Naqui
1983
).
Negative effects of beach nourishment dominate in the short to medium term,
the size of the impact being determined by (1) activities during the construction
phase, (2) the quality and the quantity of the nourishment sand, (3) the timing,
place and size of project, and (4) the nourishment technique applied (Speybroeck
