Salt marsh restoration to safeguard the Venice Lagoon

DEME is a world leader in the highly specialised fields of dredging, land reclamation, marine infrastructure, offshore energy and environmental remediation. The group is committed to developing and adopting nature-based solutions, critical for creating resilient and climate proof infrastructures, and is investing in innovation and research to support this.

“Venice is an iconic world heritage site and is also a fragile ecosystem, perfect for testing DEME’s latest Nature-Inclusive Design solutions, a part of our journey toward increasing natural capital and improving biodiversity.” said Marc Huygens, Environmental Manager, DEME Group.

An important part of salt marsh restoration is devising ways to support and accelerate the process of re-naturalising artificial infills so that these areas become ecologically functional within the Lagoon system, providing the same benefits as naturally occurring salt marshes.

In the central Lagoon, SIDRA and We are here Venice (WahV) are now collaborating to introduce simple, specific interventions on a recent infill made with dredged sediments from Port Authority channel maintenance, overseen by the Provveditorato.

As a result, the new infill is being connected to adjacent salt marsh and to the adjacent lagoon via openings in the fencing that allow the tide to flow freely in and out the salt marsh, bringing sediment and seeds with, thereby improving the inundation frequency and vegetation growth.

Federico Pasqualetto, who has overseen the execution of the infill since the beginning in 2020, was the health and safety coordinator.

The total area of recreated salt marsh in the lagoon is 1310 ha (according to the proposed update of the 2021 Morphological Plan for the Venice Lagoon) of which a significant percentage has been eroded and needs to be restored. In addition, there is potential to introduce hundreds of hectares of new salt marsh that will benefit Venice by hosting natural capital and providing other benefits and protection for the historic city.

Luca Sittoni: "Marine infrastructures should be developed in harmony and integrated with the natural ecosystem, to achieve a much larger aggregate value and superior climate resiliency. It is a privilege to start from Venice through the fruitful complementary collaboration with We are here Venice! This pilot represents an important milestone to show the added value of nature-based solutions in practice".

Nautilus’ role in the project

Nautilus srl, specialists in industrial diving and maritime works, are providing the technical expertise or these interventions. The company has been active in the Venice lagoon for over 20 years.

Nautilus srl, specialist in maritime and underwater works, is providing the technical skills for these interventions. The company owes a great deal to the lagoon area where it was born and where it has been working for over 25 years. It is precisely the gratitude towards this landscape and the work within a fragile territory such as the Venice Lagoon and its coasts, which has led Nautilus, over the years, to adopt, improve and export respectful working methods even outside the lagoon of the environment.

With the spirit of continuing to actively promote environmental protection, Nautilus has accepted the challenge of supporting VITAL and has demonstrated proactivity in collaborating with SIDRA and WahV by providing its in-depth knowledge of the Venice Lagoon, their expertise and the equipment provided.

These interventions were executed in June 2023.

WahV and SIDRA are now following the evolution through an innovative monitoring programme developed with help from Prof Pietro Teatini of Padua University (Hydrology and Hydraulic Engineering), among other, as regards changes in marsh morphology, vegetation colonisation and carbon storage in the sediments.