On November 12, 2019, an exceptional meteorological event caused considerable damage to the entire coastal area of Veneto. Municipalities and local associations are once again asking for defensive structural interventions and works to mitigate storm damage. They are no longer thinking only about rigid structures at sea, and sand replenishments, which have already shown all their limitations.
Now they are asking to introduce a new element of effective and eco-sustainable protection: the dunes.
The European and global scientific community has demonstrated years ago, the extraordinary importance of dunes as an element of natural mitigation of the coastal risk, whether it is erosion or, as in this case, flooding. Beaches and dunes are very dynamic environments, with a high resilience. They are the result of the slow sand accumulation processes made by the wind and the plants, the real dune engineers. The plants slow down the wind and trap the sand thanks to their stems and roots, triggering the physical process of dune constitution. It is precisely this dynamic balance between sand, wind and plants that makes the dunes “the sacrificial elements” of the coastal systems: in the event of heavy storms, they are partially eroded, but in this way they dampen the force of the sea, protecting the inland, and give the sand back to the beach.
The first two years of experimentation, in different points of the Veneto coast, allowed the Life Redune team, and all the stakeholders who follow the project closely, to verify and confirm those aspects that condition the correct functioning of the dunes.
The first aspect is time. The time needed for the plants to grow and effectively exercise their function as dune builders and consolidators. If we analyze the historical data of the sea storms, we can observe a temporal cyclicity of the most important events, but the cycles are shortening. We have little time, we must start immediately!
The second is proper planning. Not only of how and where to build new dunes or reinforce existing ones, but also of their maintenance over time.
The accesses to the sea must be planned. After the last storm, it is under everybody’s eyes, how, in the presence of dune breaks, the water, finding no obstacles, has penetrated even for hundreds of meters. Where the dunes are interrupted, they lose the strength to protect the beach and the inland. When we look at our shorelines from the sky, we see a tangle of paths that people create walking on the dunes toward the sea instead of using the equipped accesses, sometimes for an unfortunate sense of adventure, sometimes just for laziness. But prolonged trampling weakens the plants. And without the plants, the dunes become simple accumulations of sand destined to be swept away by the wind and the waves.
Beach cleaning operations must be planned. Plants, algae and beached wood are not waste. In addition to being an economic burden, the total mechanical removal of the biological material removes a vital element from the beach and the dunes. The removal of plants, algae and trunks causes a real physical and biological damage to the beach and the dunes, subtracting a reserve of nutrients for the plants and exposing the coastline to a greater risk of erosion and desertification.
The third aspect, perhaps the most important, is the need to start a path that leads to the integration of environmental sustainability and the value of natural ecosystems, into the local territorial planning and development processes.
The best time to intervene is from autumn to spring, and the REDUNE team has never stopped using all its skills and strength for both the design and the execution of interventions, in order to have new dunes ready for next summer. At the same time, the team continues the training and communication activities with the local bodies responsible for the design and management of the coastlines.