Harger- en Pettemerpolder Climate Buffer

Results

The subsidy application submitted to the Ministry of Infrastructure and the Environment focused on the overtopping capacity of the Hondsbossche Zeewering sea wall. The intention – as defined in Chapter 6 of the Natural Climate Buffers Vision published in October 2006 (see illustration) – was to use the area behind the dyke for overtopping. This would eliminate the need for dyke improvement. At the same time, the area could be adapted to create recreational opportunities along the coast, which would reinforce the region’s socio-economic structure. Even though it was initially welcomed by the district water board and the province, and despite lobbying by Natuurmonumenten, this idea was eventually dropped from the coastal defence planning process.

Why no overtopping dyke?

The sandy seaward concept ties in best with the vision propagated by the Delta Programme, and this has been a ponderous argument. An overtopping dyke scores poorly when it comes to feelings of safety (it is absolutely fine in terms of flood risk management). Local resistance has instilled a certain fear in this regard among administrators. Furthermore, the manner in which the design of the overtopping dyke has been elaborated in the Environmental Impact Assessment Report is quite unattractive (retaining wall, et cetera).

The district water control board, the Province, and Rijkswaterstaat have elaborated the sandy seaward solution. From a financial perspective, this option now appears less costly than an overtopping dyke, on account of plummeting sand prices. Natuurmonumenten has indicated its preference for this sandy seaward strengthening over dyke improvement.

The authorities have now opted for a sandy reinforcement of the coast, involving large-scale sand replenishment in the direction of the sea. The dyke will lose its water-controlling function, but will be retained as a line element.

The planning and decision-making procedures have been completed, as has the tendering process. The contractor and the plans were announced on 11 December 2013.

The improvement outside the dyke involves an elongated expansion of intertidal land with a surface area of some 300 hectares. The expansion stretches over a coastal length of some 11 km and is widest at the mid-section. This area offers excellent opportunities for Nature and recreation. The downside is that significant existing natural values will disappear. The situation as of the autumn of 2013 is as follows (Schepers 2013):

• Natuurmonumenten has been given a substantial role in optimising the sandy seaward coastal reinforcement. Also, on behalf of other nature organisations it has conducted interviews with the tendering market parties in order to raise ambitions with respect to Nature, and to ensure that Nature will be a functional component of the sandy reinforcement.
• A main zoning plan has, in principle, been agreed with entrepreneurs in the recreational sector, the municipal authorities, Rijkswaterstaat, and the Hollands Noorderkwartier district water control board, outlining the main Nature and recreational functions, but it has not yet been endorsed.
• Joint studies and calculations conducted by coastal morphologists and ecologists have led to the conclusion that the development of wet Nature (dune valleys, beach lagoons, et cetera) will yield the most added value to the natural quality of the coast, whilst enhancing habitability, reducing sand drifts, and boosting recreational use.
• The Nature zone will be subject to amended standards for very low frequency maintenance replenishments.
• The tender comprises important financial incentives to foster natural qualities and habitability among the market parties through strict requirements and through the so-called MEAT method (Most Economically Advantageous Tender).
• Together with entrepreneurs in the recreation sector, initiatives have been taken to realise a coastal perception centre in the recreational zones. The aim is to realise beach lagoons in these zones as well, featuring high natural and amenity values.
• The district water control board is still working hard on mitigating measures for the existing natural values that will be lost. In its final permit application, it has included a set of measures to mitigate the Turnstone and the Oystercatcher, and set down plans for the sustainable maintenance of saline natural values in the Harger en Pettemer polder. A covenant has been concluded to this end.

The district water control board and Natuurmonumenten have agreed to increase their efforts for the natural environment and therefore seek collaboration. In this context, they are currently planning and negotiating an additional set of measures. A declaration of intent has been set down and the parties intend to sign a collaborative agreement to this end.

Contact person

Luc Berris
Natuurmonumenten
+31(0)35-655 9609
l.berris@natuurmonumenten.nl