ENVIRONMENTAL RECOVERY PLANS
ENVIRONMENTAL REHABILITATION OF THE COASTAL WETLAND OF MOLENTARGIUS
AND PROTECTION OF POETTO LITTORAL – CAGLIARI, SARDINIA

Client:  Ramsar  Molentargius  Consortium  for  the Ministry of the Environment

Services: Feasibilty study, basic and preliminary design. environmental impact assessment study; final design of the coastal protection works

Period:  1991-1994

Construction cost:  € 61,974,828

The project:
The wetland of Molentargius is considered a very peculiar and fragile ecosystem and therefore is included in the Ramsar list of areas to be protected and conserved. This Project launched by the Italian Government to rehabilitate this area includes: hydraulic rearrangement, phyto-purification plant, redevelopment of the area as a nature reserve, protection of the littoral, surface waters depuration, ecological dredging of the top layer of polluted sediments, coastal protection works.

Within this Project, TECHNITAL has been entrusted with the definition of the general plan of the intervention, the environmental impact assessment study, the detailed design of coastal works.

The Poetto littoral is a long strip of beach of some 7 kilometres located close to Cagliari. The closeness to the city, its inclusion in a highly appreciated and unusual environmental context, which also includes Molentargius salt-pans and pools, and the quality of the sand, quartz-bearing and pale coloured, are the principal elements which give the Poetto great appeal, from both the tourism and landscape/naturalistic points of view. Since the end of the war, however, successive human interventions carried out without due respect for the delicate morphology of this narrow beach have created problems of widespread erosion and environmental decay.

As part of a broader programme for the environmental rehabilitation of the hydrographic basin behind the littoral, TECHNITAL was commissioned in 1992 to carry out the specialist studies and the designs of the interventions needed to restore conditions of morphological stability and environmental balance throughout the Poetto. The studies involved the use of mathematical and physical models. Models were used to study the propagation of wave motion, reproduce the current field and calculate sediment transport and coastline evolution. On the basis of the acquired information a balance of the sediments along the littoral was formulated, both reconstructing the recent past and predicting the future trend, for several reference frames corresponding to various intervention proposals. The study with the physical model served to define and check the new interventions.

The interventions foreseen on the coastal strip in the Preliminary Design included:

•      rebuilding  of  the coastal dune and moving the  littoral  road inland;
•      artifical beach nourishment with sand taken from the sea;
•      moving a water inlet currently located on the shore-line out to sea;
•      removal of some of the illegal buildings present along the littoral and overlooking the shore-line;
•     transplanting Posidonia Oceanica to restore, in part, the meadows which were once very extensive and which are now greatly        reduced due to anthropic action.

At the end of the assessment and approval stage of the Preliminary Design, the Final Design was developed for the 1st section, consisting of the rebuilding of the first part of the dune belt and a pilot operation for transplanting Posidonia Oceanica.
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