Space and time are important to allow incipient dunes on the backshore to
survive erosion by wave uprush during small storms and to increase in size to
create foredune ridges large enough to survive storms of annual or greater
frequency/magnitude. If space and time are not available, these constraints can be
partially overcome by aiding natural processes using sand fences or vegetation
planting, or by using earth-moving equipment. These human actions can be used to
build and rebuild dunes in a sand-deficient environment, but inevitably, beach
nourishment is required to maintain a healthy, well-vegetated dune on an eroding
shore (Mendelssohn et al. 1991).
2.2 Dune-Building Practices in Urban Areas
We use the generic word ‘‘urban’’ to refer to both moderately and intensively
developed shores (suburbs and cities). We do not distinguish between these types
of shores because the largest lengths of developed dunes in some countries
(e.g., the USA) occur outside cities. In many cases, it is not the intensity of
development that is the issue, but the proximity of houses, protection structures
and support infrastructure to the backshore, and the frequency of beach raking. The
methods used to build dunes in developed areas are similar to those used in coastal
parks and preserves. The differences affecting the way dunes look and evolve in
developed areas are due to restricted beach widths or changes in grain size
characteristics if beach fill is used. There is no fundamental difference in the ways
dunes should be restored in developed areas except for the need to control some of
the natural dynamism where human infrastructure is close to the water and to
control subsequent degradational human activities.
2.2.1 Accommodating Natural Aeolian Processes
The biological and geomorphological processes forming new or incipient natural
foredunes on undeveloped beaches are reviewed in Hesp (1989, 1991) and
Kuriyama et al. (2005). On these beaches, wind-blown sand will accumulate at the
seaward-most vegetation and wrack lines that form on the backshore. These duneforming features are missing on raked beaches. On many human-altered shores
that are eroding, the presence of infrastructure close to the water restricts
backshore width, requiring artificial nourishment to provide the wider sediment
source for aeolian transport and greater protection for newly formed dunes from
wave erosion. As a result of growth by slow natural accretion, the resulting dune
will have the internal stratification, topographic variability, surface cover, and root
mass of a natural dune. The wide cross-shore gradient of physical processes will
allow for a suite of distinctive habitats, from pioneer species on the seaward side to
woody shrubs and trees on the landward side. A large-scale beach nourishment
2 Foredune Restoration
19
survive erosion by wave uprush during small storms and to increase in size to
create foredune ridges large enough to survive storms of annual or greater
frequency/magnitude. If space and time are not available, these constraints can be
partially overcome by aiding natural processes using sand fences or vegetation
planting, or by using earth-moving equipment. These human actions can be used to
build and rebuild dunes in a sand-deficient environment, but inevitably, beach
nourishment is required to maintain a healthy, well-vegetated dune on an eroding
shore (Mendelssohn et al. 1991).
2.2 Dune-Building Practices in Urban Areas
We use the generic word ‘‘urban’’ to refer to both moderately and intensively
developed shores (suburbs and cities). We do not distinguish between these types
of shores because the largest lengths of developed dunes in some countries
(e.g., the USA) occur outside cities. In many cases, it is not the intensity of
development that is the issue, but the proximity of houses, protection structures
and support infrastructure to the backshore, and the frequency of beach raking. The
methods used to build dunes in developed areas are similar to those used in coastal
parks and preserves. The differences affecting the way dunes look and evolve in
developed areas are due to restricted beach widths or changes in grain size
characteristics if beach fill is used. There is no fundamental difference in the ways
dunes should be restored in developed areas except for the need to control some of
the natural dynamism where human infrastructure is close to the water and to
control subsequent degradational human activities.
2.2.1 Accommodating Natural Aeolian Processes
The biological and geomorphological processes forming new or incipient natural
foredunes on undeveloped beaches are reviewed in Hesp (1989, 1991) and
Kuriyama et al. (2005). On these beaches, wind-blown sand will accumulate at the
seaward-most vegetation and wrack lines that form on the backshore. These duneforming features are missing on raked beaches. On many human-altered shores
that are eroding, the presence of infrastructure close to the water restricts
backshore width, requiring artificial nourishment to provide the wider sediment
source for aeolian transport and greater protection for newly formed dunes from
wave erosion. As a result of growth by slow natural accretion, the resulting dune
will have the internal stratification, topographic variability, surface cover, and root
mass of a natural dune. The wide cross-shore gradient of physical processes will
allow for a suite of distinctive habitats, from pioneer species on the seaward side to
woody shrubs and trees on the landward side. A large-scale beach nourishment
2 Foredune Restoration
19