Not just storm barriers. Nature-based experiences in Venice at a glance
Creators: name: Lipari, Giordano
name: Cecconi, Giovanni
Publisher: name: Zenodo
Year: 2016

description: The slideshow in this deposit supported the joint talk of Watermotion | Waterbeweging and The Venice Resilience Lab for the audience in the congress The Sand Engine: Five Years of Building with Nature organized on 14-15 Sept 2016 in The Hague by Rijkswaterstaat, Ecoshape and the Province of South Holland, in the framework of the NatureCoast research project.

This guest talk offered an informed bird's eye view of 30 years of nature-based studies and interventions in the Lagoon of Venice, a UNESCO World Heritage site. The measures relate to the wetland restoration for the safeguard of the lagoon in the aftermath of the storm tide of 1966. A 10-minute long bird's eye view offered an impression of the context, experiences and methods in the natural and managed development of dunes, tidal flats and salt marshes in the Venetian Lagoon. The talk underlined the consideration held for the local network of abiotic, biotic, societal and cultural aspects, so much valued by the Building-with-Nature philosophy. Especially intriguing and challenging is to identify the scales and frequencies of sandy interventions that sustain stabilizing nature-based solutions in diverse wetland conditions worldwide. Underscoring commonalities and complementarities with the Sand Engine experience aimed to invite scholarly exchange. 

Historical and geographical context 

Nearly fifty years ago before the conference, on 4 Nov 1966, a storm tide rose the water levels in Venice to an all-time record of 1.94 m. The vulnerability of the Venetian Lagoon had been amplified by enduring relative lowering and flattening of the sea bed, in turn exacerbated by groundwater extraction and capital dredging works. These interventions triggered and fuelled a fast-paced self-reinforcing transformation of the lagoon into a bay-like environment, with huge bearings on the Venetian ecosystem and society.

The shared aim thereafter has been to halt and reverse degradation, and reinstate the natural resilience of a shallow-water environment against natural extremes. The well-known MOSE storm-surge barrier system, devised for the three lagoon inlets, has only been a subset of a grand plan of studies, experiments and works to support informed decision-making in the lagoon as a whole. With funding of the Italian Government since 1984 worth about € 13 billion, the 550 km² of the Venetian Lagoon and 2100 km² of its catchment have been studied with an integrated approach. Notably, the 1600-year old symbiotic relationship between Venice and its lagoon made them jointly a UNESCO World Heritage Site since 1987.

Relevance

In spite of a rich technical and scientific output, also backed by international collaborations, not all of the systemic research on the Lagoon of Venice has received proportionate attention beyond the national context. This talk opened the view on some highlights from the Venetian experience repository in which the consonance with the Building-with-Nature philosophy stands out.

In particular, degraded lagoons call for solutions adequate to sheltered, low-energy, mud-rich environments. Specifically, the wetland restoration works in the Venetian Lagoon have included rebuilding 106 salt marshes and 18 tidal flats by relocating 20M m³ of sediments from maintenance dredging over almost 30 years. There, the role of sand has proven essential in providing texture to geo-engineering interventions as well as substrate for biostructuring habitats and for successful ecological successions. Hence, leaning on the engine metaphor, we hope to highlight the importance of the ‘sand fuel’ for reinstating self-sustaining habitats, supporting biodiversity, harnessing ecosystem services and providing useful mechanical functions in the largely muddy Venetian Lagoon.

Acknowledgement

This talk and presentation took place with the permission of the information owner, the Ministero delle Infrastrutture e dei Trasporti – Provveditorato Interregionale delle OO.PP. del Veneto, Trentino Alto Adige, Friuli Venezia Giulia (The Italian Ministry of Infrastructures and Transports – The Public Works Department of the Triveneto Area).