IV. Retreating Shorelines
233
The following steps are suggested in the establishment and management of
artificial beaches : establishment of various conditions affecting the beach under
consideration and choice of the size and methods for the project, assessment of
the environmental conditions, detailed facilities design, implementation and,
after completion, beach administration (table 3).
The survey program related to a beach nourishment scheme involves bathymetric
soundings, beach evolution (eventually by remote sensing) and monthly
terrestrial measurements (beach profiling). At least once a year sampling should
be carried out on the beach, the nearshore and the seabed. Winds, littoral drift
and tides affect sediment transport and effects must be measured. The survey
requires hence the gathering of tides, waves, currents and winds data (table 4).
For instance sediment transport study along the Zeebrugge to Zwin area of the
Belgian East Coast, showed that tidal currents - irrespective of sedimentation
effects - eroded some 250,000 m 3 (327,500 cu. yd) a year initially. With a new
outer harbor at Zeebrugge jutting out 3.5 km (2.17 mi) into the sea, this removal
reached 300,000 m 3 (393,000 cu.yd) a year, and if one groin were added beach
regression would be double and 500,000 m 3 (655,500 cu.yd) a year lost. It should
not be overlooked that with the shoreline pushed back 100 m (985 ft) the wider
beach offers a large dry sand area for recreational use but also to eolian erosion !
Kerckaert et al. (op. cir.) have calculated that the wind removes 80,000 m3/year
(131,000 cu.yd/yr). An attempt to plug up this loss has been made by planting
osier hedges and setting up wooden wind screens. Still another 420,000 m3/year
(550,000 cu.yd) is ascribed to wave action, bringing the yearly loss to 800,000 m 3
(1,310,000 cu.yd).
These mathematical predictions, however, proved to be grossly exaggerated but
in the early 90s, another 1,000,000 m 3 (1,310,000 cu.yd) of sand were added to
the easternmost beach area.
On the Strait of Georgia (Vancouver, Canada), in Monte Carlo (Monaco), at
Hook (a.k.a. Hoek) van Holland (The Netherlands) and on Bora Bora, artificial
beaches have been built. In Monaco dolomite chips were used instead of sand
(fig. 7). In Vancouve r large cobbles were used to stem sand cliff erosion, and
such nourishment has apparently the desired effect. The use of calcium carbonate
sands has been under study for some time ~s~.
233
The following steps are suggested in the establishment and management of
artificial beaches : establishment of various conditions affecting the beach under
consideration and choice of the size and methods for the project, assessment of
the environmental conditions, detailed facilities design, implementation and,
after completion, beach administration (table 3).
The survey program related to a beach nourishment scheme involves bathymetric
soundings, beach evolution (eventually by remote sensing) and monthly
terrestrial measurements (beach profiling). At least once a year sampling should
be carried out on the beach, the nearshore and the seabed. Winds, littoral drift
and tides affect sediment transport and effects must be measured. The survey
requires hence the gathering of tides, waves, currents and winds data (table 4).
For instance sediment transport study along the Zeebrugge to Zwin area of the
Belgian East Coast, showed that tidal currents - irrespective of sedimentation
effects - eroded some 250,000 m 3 (327,500 cu. yd) a year initially. With a new
outer harbor at Zeebrugge jutting out 3.5 km (2.17 mi) into the sea, this removal
reached 300,000 m 3 (393,000 cu.yd) a year, and if one groin were added beach
regression would be double and 500,000 m 3 (655,500 cu.yd) a year lost. It should
not be overlooked that with the shoreline pushed back 100 m (985 ft) the wider
beach offers a large dry sand area for recreational use but also to eolian erosion !
Kerckaert et al. (op. cir.) have calculated that the wind removes 80,000 m3/year
(131,000 cu.yd/yr). An attempt to plug up this loss has been made by planting
osier hedges and setting up wooden wind screens. Still another 420,000 m3/year
(550,000 cu.yd) is ascribed to wave action, bringing the yearly loss to 800,000 m 3
(1,310,000 cu.yd).
These mathematical predictions, however, proved to be grossly exaggerated but
in the early 90s, another 1,000,000 m 3 (1,310,000 cu.yd) of sand were added to
the easternmost beach area.
On the Strait of Georgia (Vancouver, Canada), in Monte Carlo (Monaco), at
Hook (a.k.a. Hoek) van Holland (The Netherlands) and on Bora Bora, artificial
beaches have been built. In Monaco dolomite chips were used instead of sand
(fig. 7). In Vancouve r large cobbles were used to stem sand cliff erosion, and
such nourishment has apparently the desired effect. The use of calcium carbonate
sands has been under study for some time ~s~.