The second phase of the Life Lagoon Refresh project coordinated byISPRA. The process of inversion of the marinization of the Northern lagoon of Venice. The introduction of fresh water from the Sile to the Lagoon, which started on May 20, 2020, marks the beginning of the second phase of the Life Lagoon Refresh project which aims to promote re-colonization of about 20 hectares of reeds and the repopulation of the area by numerous fish and bird species. Started in 2017, the Life project, coordinated by ISPRA, has a five-year duration and involves, in addition to the Institute, the Environment Directorate of the Veneto Region, the Interregional Superintendency for Public Works of the Triveneto, the Ca 'Foscari University of Venice (DAIS) and IPROS Ingegneria Ambientale Srl.
The construction sites, which began in October 2009, have suffered various slowdowns due to various unforeseen events, such as the exceptional climatic weather event of November 2019 and the health pandemic of 2020. Both the hydraulic works and the first part of the work have finally been completed. morphological and is now active the introduction of fresh water from the Sile to the Lagoon. The hydraulic work, carried out by the Veneto Region with the IPROS Works Management, is located in correspondence with the embankment that separates the cut of the Sile from the Lagoon in the locality of Trezze di Portegrandi, about 30 m downstream of the existing spillway that overflows the flow rates of the river in the Lagoon.
The work just carried out allows the passage of fresh water from the Sile to the Lagoon through two 800 mm pipes in diameter and two channels that connect them respectively to the Sile and the Lagoon. Fresh water flows by gravity into the intake structure, depending on the difference in water level between the river and the lagoon, with variations in flow rate that depend on the tidal fluctuations. The first adjustment of the gates allows an average flow rate of 300 l / s. To slow down the dispersion of fresh water, biodegradable structures have been placed on the bottom of the lagoon that make up the morphological work of the project.
This action, on the part of the Superintendency, is carried out in two successive phases. The first excerpt has already been completed, providing for the insertion of several rows of wooden poles inside which big bags in coconut fiber have been housed, in an area of about 30 hectares, in the lagoon area in front of the intake work on the embankment of the Cutting of the Sile. Environmental compatibility is guaranteed through the use of morphological elements in biodegradable material, positioned in order to retain the fresh water introduced and to constitute a substrate on which the reeds can grow. The mixing of fresh and salt water will take place slowly and gradually.
The next steps include the planting of reeds and aquatic seagrasses, thanks also to the help of hunters and fishermen, regular visitors to the area, previously trained during a course held by the Ca 'Foscari University of Venice and ISPRA. Furthermore, the progressive increase of the fresh water flow up to average maximum values of 1000 l / s and the construction of the second front of biodegradable big bags that delimit the flow of fresh water. There will be monitoring activities to verify the effectiveness of the work and the effects on the animal and plant communities of the project area. The concrete actions of the Life Lagoon Refresh have in fact the objective of recreating the saline gradient, now lost following the diversion of rivers, and the increase in biodiversity of fish, birds, moving bottom animals and plants. The official inauguration is for now postponed pending fewer restrictions on the social distancing of the period.