Natural climate buffer, the river Hunze
In the middle course of the river Hunze, measures have been taken in the Torenveen subarea, which covers 180 hectares. The plans developed and implemented for this area are based, among other things, on objectives set down in the “Hunze Vision”. This vision was drawn up in 1995 by the Drente Landscape Foundation, the Groninger Landscape Foundation and the World Wide Fund for Nature.
Results
The course of the river Hunze in the Torenveen area is 4.5 kilometres long and serves as a link in the entire course of the stream. In the past, the Torenveen area was used for farming. Recently it was transformed into a natural area. Several areas have since been transformed to meet objectives from the Hunze Vision. In consultation with people in the region and many partners, more areas will be tackled, which will transform the current canalised Hunze into a meandering, lowland stream with its system features. The Manderlanden area was completed in 2013 and the Oudeweer area will be redesigned in 2014.
The goal of the Torenveen area and the other links in the Hunze Dale is to realise a natural low-lying stream system that also provides the preconditions for emergency water storage, the retention and supply of water during low rain periods, the improvement of surface water quality, a way to combat desiccation, the preservation of drinking water supply, the promotion of recreation, the improvement of the living climate and the improvement of the parcel structure in agriculture.
The current route of the Hunze has remained, but is followed by a meandering, separated route through which approximately 50% of the water discharge runs. To restore the meandering nature of the stream, its historical course of ca. 1900 has been chosen as a template. At the places where the meanders cross the current course, broad dams have been placed with a height that is roughly equal to the level of 50% of the discharge. That means that, when the discharge is higher, the sections of the current course will help carry the discharge and limit a rise in the water level, because they provide additional storage and a wider discharge profile. The parts of the current course that do not fulfil a discharge function at low discharge levels will either be branched into on the downstream side or be maintained as a pool. In the Torenveen area, extra space has been created for water by creating flood areas near the Hunze. These low-lying areas can be flooded at high-water levels and therefore serve as a buffer. Reconstruction of geographic relief and the possible lowering of terrain along the stream have made this flooding possible. The Climate Buffer proved its worth in January 2012, when the low-lying terrains were deployed during high water. It was flooded for a couple of days and then the water slowing drained through the Hunze down to the Zuidlaardermeer lake.
Contact person
Teddy Bezuijen
Stichting Het Drentse Landschap
+31(0)593-333058
t.bezuijen@drentslandschap.nl