Summary
In the XV century there were about 500 saltpans in the Aveiro lagoon. About 50 years ago, the saltpans producing salt were near 270 and nowadays only 8 are exploited. The artisan salt activity is in decadence, conducting to the existence of many abandoned fields. The degradation process and abandonment of the saltpans is accelerated by the intense currents during high tides that penetrate inside the lagoon, destroying the protection walls of the saltpans (motas) and digging the bottom of the channels. The motas are small rudimentary dikes, built by the farmers, with low top crest levels and constituted by the consolidation of mud with stones and organic material. The absence of the traditional craft maintenance of the motas also contributes to it progressive degradation. These motas guaranteed the defence of the lagoon against the progress of the salt water and controlled, with the support of floodgates, the hydrodynamics of the lagoon. Currently, motas do not protect in an effective way the land, due to the deficient conservation state, the permeability and the reduced crest levels. This situation allows the water to skip the walls, affecting the definition of the cross sections of lagoon channels and generating large reservoirs supplied in high tide situation. As described, the impact of saltpan wall destruction is important on the hydrodynamic and morphologic behaviour of the lagoon, with consequences on the local populations. Some land owners already tried to stop this tendency, by applying different materials to reduce the degradation process. The results of these interventions are apparently unsatisfactory, as a result of the occurrence of large settlements and the negative impacts on an environment with unique characteristics that should be protected.
Objectives
Team
Coordinator: Carlos Coelho (Universidade de Aveiro)
Aveiro University: Margarida Pinho Lopes, João Miguel Dias, Paulo Silva
Laboratório Nacional de EngenhariaCivil:André Fortunato, Luís Portela,