Groundwater in the new intertidal area Perkpolder
Groundwater in the new intertidal area Perkpolder
Samenvatting
Intertidal areas in the Netherlands suffer from divers pressures in the delta. The Western Scheldt has an open connection to the sea. This system is in use for the Port of Antwerp, for which dredging is required. Therefore, Rijkswaterstaat has to compensate natural areas, among which intertidal areas.
Area development Plan Perkpolder is one of these projects. In addition to the marina, houses and golf course, a 75 hectare intertidal area is created. Of these 75 ha, 40 ha is a compensation for the second dredging of the Western Scheldt. The remaining 35 ha is for the “Natuurpakket Westerschelde”, a project for the development of 600 ha of intertidal flats and salt marshes. This research focusses on describing the current situation of the groundwater and soil chemistry of the intertidal area at Perkpolder. The groundwater and soil chemistry are of high importance for the development of salt marshes because they are the most important conditions for vegetation settlement. Perkpolder’s intertidal area has been given back to nature only recently (less than one year before this research), this research focusses on the response of the area to the presence of saline water.
The research question is:
- What are the current properties of the subsurface and groundwater system of the tidal restoration area Perkpolder?
Soil water samples were taken with MacroRhizons (micro filters) and analysed on oxygen content, redox potential and salinity. Soil samples were taken while placing piezometers. The soil samples were analysed on the particle size and organic matter. The piezometers function was to register the pressure head in different groundwater layers.
The intertidal area was previously used for agriculture. The soil and groundwater was a fresh water system with saline groundwater in the deeper layers. Parts of the area suffered from saline seepage. The soil becomes completely saline again now, but the origin of the present salt in deeper layers is not determined. It could be that this is still present from floods in the Holocene.
The measurements and analysis provided data of the groundwater and subsurface. This resulted in the conclusion that the system is already influenced by the saline water, but mostly in the top layer. The influences on the deeper layers are not proven with this research and the measured parameters show no clear relation with the distance to the channel, but it seems to be depending on the soil type. These soil layers are mostly formed during the Holocene and these layers have a low permeability.
The newly settled sediment will have an impact on the groundwater system. This can be a topic for further research. This can also focus on the benthos and soil properties related to plant settlement. A thicker sediment layer can be analysed on its hydraulic properties and impact on the system.
Organisatie | HZ University of Applied Sciences |
Opleiding | Watermanagement/ Aquatische Ecotechnologie |
Afdeling | Domein Technology, Water & Environment |
Partner | Building with Nature & NIOZ Yerseke |
Datum | 2016-06-21 |
Type | Bachelor |
Taal | Engels |