PROJECT DESCRIPTION
BACKGROUND
The Schelde estuary is one of the few European estuaries which still has a full gradient from fresh through brackish to saltwater intertidal areas. The estuary and its gradient extends over more than 250 km, along which tidal mud- and sandflats as well as marshes occur. The freshwater tidal areas, in particular, are extremely rare in Europe, which makes the Schelde estuary an exceptional habitat.
The estuary harbours various plant communities peculiar to this salt/freshwater gradient. It contains important habitats for bird species and is a crucial resting and foraging stop-over along the Western Palaearctic flyway. Twenty species of waterfowl occur in numbers exceeding 1% of their overall European population.
However, the Schelde is also one of Europe's busiest shipping channels. Its tidal marshes and other biotopes have for decades been subject to both destruction and degradation due to land reclamation, dredging, pollution and other activities. Erosion is a particular problem threatening the freshwater tidal marshes.
OBJECTIVES
The main objective of the MARS project was to undertake restoration work of degraded tidal marsh along the River Schelde. Actions were foreseen at four sites, totalling 200 ha: Lippensbroek, Groene Meirsch and Kijkverdriet (Belgium) and Kaloot in the Netherlands.
The most important component of this project was to reduce the erosion eating away the freshwater tidal marshes. Foreseen actions included the raising of dykes, removal of contaminated soil and restoration of tidal inlets. The project actions hoped to restore damaged habitats and to kick off the natural development of new freshwater tidal marshes which would compensate the marshes lost elsewhere.
By proving the feasibility of creating new marshes, the project sought to generate a model which could be employed during future dyke-building plans, as foreseen in the Belgian Sigma Plan. The project’s efforts were expected to allow future flood control construction works to be compatible with the conservation of freshwater tidal areas.
As a joint effort between public bodies in Belgium and the Netherlands, the project hoped also to provide an incentive for the elaboration of a cross-border management plan for the Schelde.
RESULTS
The small tidal creek in the sand dunes at Kaloot was successfully restored, but only a few other objectives were achieved in the time-frame of the project, because the preparatory site investigations revealed high levels of soil pollution, mainly heavy metals and PAHs (poly-cyclic hydrocarbons) at the three Belgian sub-sites. This had major technical and financial implications for the project.
The project conducted preparatory actions including geotechnical investigations and soil analysis. Significant problems with soil contamination were identified at Lippensbroek, Groene Meirsche and Kijkverdriet, with the following implications:
Lippensbroek - the soil problems were resolved and the competent authority indicated that permission would be granted to use soil for raising the dykes following an environmental impact assessment, but this was after the timeframe of the project.
Groene Meirsche - the cost of clearing and cleaning the contaminated parts of the site were prohibitively expensive (€3.3-5 million) and this site was dropped from the project.
Kijkverdriet - the estimated cost of cleaning up the site was substantially less expensive and it was decided to continue with the planned restoration work.
Habitat restoration actions at all three Belgian sub-sites were thus at the very least delayed until after the conclusion of the project. There were no problems with soil contamination at Kaloot (NL) and a tidal creek was successfully restored (re-opened) by the project. The project successfully purchased 20.7 ha of target land at all sites except Groene Meirsche, to enable the current or future restoration actions.
Newsletters, brochures and Information Boards to raise public awareness of the restoration project were produced as planned.The small tidal creek in the sand dunes at Kaloot was successfully restored, but only a few other objectives were achieved in the time-frame of the project, because the preparatory site investigations revealed high levels of soil pollution, mainly heavy metals and PAHs (poly-cyclic hydrocarbons) at the three Belgian sub-sites. This had major technical and financial implications for the project.
The project conducted preparatory actions including geotechnical investigations and soil analysis. Significant problems with soil contamination were identified at Lippensbroek, Groene Meirsche and Kijkverdriet, with the following implications:
Lippensbroek - the soil problems were resolved and the competent authority indicated that permission would be granted to use soil for raising the dykes following an environmental impact assessment, but this was after the timeframe of the project.
Groene Meirsche - the cost of clearing and cleaning the contaminated parts of the site were prohibitively expensive (€3.3-5 million) and this site was dropped from the project.
Kijkverdriet - the estimated cost of cleaning up the site was substantially less expensive and it was decided to continue with the planned restoration work.
Habitat restoration actions at all three Belgian sub-sites were thus at the very least delayed until after the conclusion of the project. There were no problems with soil contamination at Kaloot (NL) and a tidal creek was successfully restored (re-opened) by the project. The project successfully purchased 20.7 ha of target land at all sites except Groene Meirsche, to enable the current or future restoration actions.
Newsletters, brochures and Information Boards to raise public awareness of the restoration project were produced as planned.