Groundwater–Surface Water Interaction: Process Understanding, Conceptualization and Modelling (Proceedings of Symposium HS1002 at IUGG2007, Perugia, July 2007). IAHS Publ. 321, 2008, 171-180.

Optimisation of nature development scenarios for the integrated nature reserve of the Hemmepolder (Belgium)

ERIc DEGAND¹, ROELAND ADAMS¹, Maurice Hoffmann², Florimond De Smedt³, Hannah Van NieuwenhuySe⁴ & Jean-Louis Herrier⁴

1 IMDC, International Marine Dredging Consultants, Wilrijkstraat 37, 2140 Antwerp, Belgium

info@imdc.be

2 Terrestrial Ecology Unit, Department of Biology, Ghent University, Ledeganckstraat 35, 9000 Ghent, Belgium

3 Department of Hydrology and Hydraulic Engineering , Faculty of Engineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Brussels, Belgium

4 Agency for Nature and Forests, Coastal Conservation Unit, Zandstraat 255, 8200 Brugge (Sint-Andries), Belgium

Abstract The Hemmepolder was created in the early 14th century by diking in an active system of creeks in the IJzer estuary. This project, financed by the European INTERREG-project FRaME, investigated the potential ecological benefits for three totally different nature development scenarios. Surface and groundwater modelling was used in order to determine the hydrological conditions, such as groundwater levels, inundation frequency and duration. These models permitted the optimisation of the needed measures and costs to create the required hydrological conditions for the development of these nature types. The nature benefits were taken into account, together with the effects on soil and groundwater in a multi-criterion analysis, allowing a choice for the saline water bound vegetation type, which shows the best nature values, but with controlled inlet of salt water for environmental reasons.

Key words nature-development; mathematical modelling; FRaME