Ecosystem services, a useful concept for the restoration of estuaries?

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Patrick Meire, Tom Maris, Stijn Temmerman

Monday 29 june 2015

11:45 - 12:00h at South America (level 0)

Themes: (T) Special session, (ST) Scheldt Estuary physics and integrated management

Parallel session: 1J. Special session: Scheldt Estuary physics and integrated management

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In the Scheldt estuary, since more than 1000 years, land reclamation leads to a reduction in tidal areas. As shipping became more important dredging works further changed the morphology of the estuary. Waste water discharge leads to a dramatic decrease in water quality. Environmental legislation led to improved water quality and habitat restoration and flood prevention measures are undertaken. Although some clear objectives are formulated for water quality standards, nature conservation, flood protection and depth of the fairway there is a lack of more integrated objectives. Indeed there is a close relation between estuarine morphology, tidal characteristics and water quality. Restoring tidal habitats might impact both tidal characteristics as well as ecological functioning. The concept of ecosystems services, a useful, unifying concept allows to formulate more integrated objectives leading to more integrated projects. We describe the ecosystem services delivered by estuarine habitats and species and how to use the concept to define objectives. Examples are reducing the nutrient load, reducing the increase in high water levels, reducing wave height. These objectives are translated in types and surfaces of habitat that should be restored to achieve these objectives. This approach led to a restoration plan for the estuary of over 3000 ha of new habitat. This approach led to the development of concepts combining flood protection and marsh restoration. A pilot project is monitored since 2006. During storm tides, water is stored in the polder, reducing high water levels. During normal tides a limited amount of water enters the polder leading to a reduced tidal amplitude but all major ecological processes like nutrient retention still take place, integrating several objectives. In this presentation, the advantages and possibilities as well as the disadvantages of the use of the ecosystem services approach will be discussed based on the application in the Scheldt estuary.