Existing residential areas are protected against flooding by mean of two special multipurpose embankments:
- The dune ridges along seaside are remodeled into wind nourished beaches and a new elevated bike path is created (2);
- A floating waterfront is set along the newly created canal whose green sea walls allow a direct relation with water (3).
The new Columbia Point urban development is designed according to the concept of a total resilient eco-city in which a comprehensive watersheet activation plan plays a central role.
Such strategy means to:
- Maximize green and pervious surfaces;
- Use stormwater wetlands and phytoremediation for tertiary wastewater treatment (9);
- Create a direct relationship between the water shore and housing areas;
- Re-use all the sediment from the excavations for the new swales and constructed wetlands;
- Reorganize and integrate water drainage systems and urban facilities underneath the newly raised areas.
The proposed set of interventions can be replicated into different coastal sites of Boston and it can be integrated into a wider strategy involving the whole harbor bay. This approach focuses on an extensive environmental reconstruction of the most anthropized shores through:
- Living shorelines – including self-adaptive systems such as dune ridges – to reduce storm surge (1);
- Oyster reefs and berms to reduce wave intensity and erosion (5-6-7);
- Salt marshes and intertidal zones to restore the natural environment and improve biodiversity (8);
- Seagrass meadows to protect the seabed from erosion (4);
- Bioremediation wetlands using Halophytes to improve water quality (9).
Such measures fully comply with the worst case scenario of sea level rise presented in the call.
Nevertheless, according to up-to-date European approaches, higher levels of resilience and adaptability could be obtained associating, in a larger bay scale, the proposed measures to a system of mobile storm surge barriers (10-11) enabling the territory to face future possible more critical sea level rise scenarios and extraordinary events (hurricanes, tsunamis..).
This integrated system will guarantee the required resilience and a high operational flexibility:
- Management of river flows and open-sea storm tides through an optimized combined use of Charles and Mystic river barriers and storm barriers at sea;
- Water quality management by better control of inflow and outflow through the rivers and the bay inlets;
- Protection from extreme events of the self adaptive capacity (e.g. salt marshes and oyster reefs) of the bay environment;
- Better control of the emergencies and worst case scenarios in a more flexible way, adapting to different combinations of storm factors,
- Better and safer management of the harbor activity (12).
Thetis S.p.A. – Castello 2737/f – 30122 – Venezia – Italia
Giovanni Zarotti, Hydraulic Engineer / team leader
Luca Dall’Acqua, Coastal & Environmental Engineer
Sarah Colonna, Architect / urban planner
Francesco Lanza, Architect
Giovanni Cecconi, Director of building with nature active knowledge center