Estuaries are subject to increasing pressures due to local human activities. In addition, global change is affecting coastal habitats. Such disturbances impinge on goods and services provided by these ecosystems. The paper is devoted to efforts to restore environmental quality in some industrialised estuaries during the few past decades. It then compares strategies to recover damaged habitats and methods to restore lost ecological functionalities. Case studies are taken from the Seine in France, the Humber in England, the Scheldt in Belgium and the Netherlands and the Elbe in Germany. The article retraces briefly the morphological and ecological changes which have been inflicted on the estuaries over the last century. It puts into light actions which have been successful in improving their ecological functioning. Through comparing the various restoration schemes, policies are assessed. Details are given on efforts made lately in the Seine estuary which has lost more than 90% of its intertidal areas in about 150 years. Recently, losses due to an extension of harbour facilities in le Havre (“Port 2000”) have been compensated by the rehabilitation of a former mud flat and various constructions such as an artificial island for birds.
The discussion confronts the present management of tidal estuaries to future challenges, including global changes. Such changes will not only include global warming and its consequences (sea level rise, biogeochemical cycles alteration...), but also socio-economic adjustments and a possible geo-political reorganization expected to take place in relation to increased harbour activities and the increasing need for more space dedicated to natural habitats and leisure activities (sports, tourism...).
The conclusion puts together the various approaches from the considered European estuaries. Resting on a rigorous scientific approach, it proposes a synthetic approach to restoration:
1. Efficient procedures of socio-ecological evaluation,
2. A methodology to assess the ecological quality of systems considered,
3. Rigorous monitoring programs, resting on a relevant choice of indicators, and
4. Participation of local communities,
in order to define strategies compatible with conservation and sustainable development at the local, regional and European levels.