Pilot project to protect low-lying areas using dykes as a soft-structure technique
The northern part of the Nile Delta coast is classified as a lowland area that faces flooding during high-intensity storms and increased flood risk from climate change. There is urgent need for innovative solutions to protect the area from the negative impacts seawater flooding during winter storms. This pilot project, then, may be considered as a first step towards developing a climate change adaptation strategy for the coastal area.
Based on extensive studies and systems used by the local farmers many years ago, dykes seemed to be the most appropriate soft solution for the area. Three dyke structures were designed and implemented, each 250 metres in length. The structures were observed during storm season to help decide which was most appropriate for covering the 60-kilometre lowland stretch along the shore between Rosetta and Burullus.
The first design includes a core of Geotubes filled with in-site sediments and covered with clay layer of dredged material from El Burullus Lake. The clay layer is covered with in-site sediments, and then with layer of a dolomite stones to ensure fixation to the top layer.
The second design is essentially a fence of reeds that acts as a sand trap for naturally forming dunes.
The third design depends on the use dredged material from El Burullus Lake as a core, which is covered with a layer of in-site sediments. Local plants are then cultivated to fix the dyke’s surface layer
Pictures of the 2 designs:
- Winter storms run from December through the end of February. Even so, the structures built so far have been effective in stopping flooding of the sea into the area during recent storms, but without coming directly into contact with sea waves. Two months remain for the full evaluation results to come out, but the preliminary results are very promising and show that the area is currently being developed into a flood control area.
- As the dyke structures allow the collection of dew water, plants have started to grow on them naturally. This is a good indicator that the area is an incubator environment for habitats in general. In addition, the dykes are successfully trapping the wind-driven sand.
- The key success factor for the project is in demonstrating that soft-structure techniques, as a means of coastal protection, have certain advantages over traditional hard structures in certain conditions.
- The project also shows that dredged material should be recognised as an ecological resource material, not solely as waste material. Dredged material should be used, whenever possible, to maximise potential benefits.
- Sand moved by wind within the coastal area is enough to create a low-cost barrier structure against flooding, and is also useful for repairing storm damage to the structure.
- Water collection allows the dyke to grow vegetation suitable for small-scale agricultural activities.
- Non-traditional solutions are being brainstormed to help solve different problems, and experts are now holding scientific discussions to help reaching the best conclusions to reach the best solutions
- Sand accumulation factor on dyke
- Plant growth factor
- Fresh water level inside the dyke
- Deterioration level during storms
The system is suitable for lowland areas with abundant windblown sand, naturally occurring coastal vegetation, and low- to medium-intensity storm events.
- EGP 3,882,094.35 (1 EGP was equal to 0.1 EUR during the implementation period)