KWR collaborated on the book “Het vroon ontrafeld”

Het vroon ontrafeld -The vroon unravelled- describes how ecosystems in the Middel- and Oostduinen wet and dry dunes on the South-Holland island of Goeree-Overflakkee have spectacularly recovered since the 1980s. The dunes are under the aegis of the Evides Waterbedrijf, which radically modified the approach to water abstraction in the area. Instead of conducting dune infiltration with untreated surface water, Evides Waterbedrijf switched over to the concept of ‘Open Infiltration New Style’ (OINS), which involves the infiltration of pre-treated surface water coupled with the nature-friendly design of the infiltration area. As a result of redesign and nature restoration measures, both nature values – including a spectacular increase in the number and diversity of orchids – and the drinking water production were boosted. The book also shows how the bird and mammalian fauna has changed over the past forty years.

Aerial view of Middel- and Oosterduinen dunes during the restoration in 2000 (Goeree) (photo: Evides Waterbedrijf)

Long-term monitoring

The Middel- and Oostduinen are among the most studied and best documented dune areas in our country. Many of the results of these efforts are used to describe and understand the developments that occurred in the area. Marten Annema, who works for Evides Waterbedrijf and is the book’s principal author, has managed the water abstraction area since 1978. As a result of the long-term monitoring of flora and fauna, and many hours in the field, he succeeded in collecting a treasure of information. André Jansen (Bargerveen Foundation) and Camiel Aggenbach (KWR) also collaborated on the book. Both conducted considerable research in the area, and much of their knowledge about ecological restoration of dunes derives from this work.

Green and blue objectives

The OINS concept implemented in the Middel- and Oostduinen dunes employs artificial dune infiltration to pursue a combination of ‘green’ and ‘blue’ objectives. The green objectives relate to the durable preservation of nature values appropriate to the area concerned. While the blue objectives involve achieving a more efficient drinking water production with reduced space requirements, costs, maintenance and energy consumption. Het vroon ontrafeld describes how this concept was fleshed out by means of far-reaching measures, how these measures were implemented, and how all of this ultimately impacted the water management and the restoration of the dune ecosystem. Both the success factors and the failures in the nature restoration are discussed.

Flower rich vegetation in a wet dune slack (photo: Marten Annema)

Unique glimpse

The combination of the manager’s personal experiences together with the scientific analysis of this special dune area gives us a unique glimpse. It shows how, over the last few decades, the vision on the management of nature and abstraction areas has been drastically transformed by interweaving the interests of nature and water abstraction. It presents a fascinating example of the development that nature management and dune water utilities have gone through together in dealing with dune areas.

Het vroon ontrafeld is written for dune managers, students and interested laypersons. The book has 288 pages, contains a rich variety of photos, maps and charts, and costs € 29.95 (Uitgeverij Natuurmedia).