Understanding the impact of climate change in the Zwin area

09 March 2021 - Published by Elin Ljunggren
The Zwin area is a nature reserve at the North Sea coast on the Belgian-Dutch border. As a result of climate change, sea level rise and silting are seriously threatening the tidal marches, impacting both ecology and the drainage capacity of the area. To better understand the impact of climate change from a coast-to-coast perspective, the case study carried out in the C5a project are looking at The Zwin from three different major climate challenges: heat stress and droughts, water safety and eco-system services.


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the Case study


 - Overall, measures are often implemented from a single perspective. However, involving a range of different thematic experts will allow us to better understand, value and address the whole-of-system. Therefore, per identified major climate challenge, a group of thematic experts was invited to apply their specific knowledge on Zwin whole-of-system, says Stevie Swenne project manager for C5a in The Zwin area.

In October 2020 project partner VMM (Vlaamse Milieumaatschappij - Flanders Environment Agency) carried out individual interviews with experts of each identified major climate challenge. The interviews specifically aimed at identifying the main impact of climate change scenarios for the Zwin whole-of-system. - Originally, a real-life workshop was planned to be held in April 2020. Due to covid-19, this was postponed to September 2020. As this was, again, not a real option, we decided to split the case study workshop in separate processes, says Stevie.

Three major climate challenges

Interviews with thematic experts on the topic heat stress and droughts shows it is generally expected that due to climate change an elevated average temperature and prolonged heat waves will increase excess mortality, damage infrastructure, decline quality of life and create urban heat islands. - For the urban environment around the Zwin Nature Reserve, anticipated effects are expected to even have a bigger impact because of the high, continuous buildings along the coastline preventing natural ventilation by a cool sea breeze. It also must be noted that the impact of additional pressures to the environment due to an increased local population and tourism is not exclusively negative. The additional consumption of fresh water is supplied from regions deeper inland but is discharged locally. As a result, salinization has a positive impact on water quality, says Stevie.

- However, on the rural environment in and around the Zwin Nature Reserve, long periods of drought can be particularly damaging to agriculture and nature, considerably increasing the need for additional natural water retention areas, Stevie says.

Regarding the topic of water safety, a distinction between two threats needs to be made: the impact of additional rainfall and the impact of a rising sea-level.

- Due to the typical characteristics of the landscape in the Zwin area and its environment, the potential for natural run-off of additional rainfall is very limited. In addition, taking into account the specific concerns regarding droughts, irrigation is considered to be very important. To maintain the natural value of the area and its biodiversity, a continuous water level in the nature area is required as well, says Stevie.

The third challenge is the wide variety of ecosystem services that can be identified. For the Zwin area, a selection was made identifying the services most prominent and possible impacts of climate changes.

  • Food production: climate change is expected to lead to a decreasing water table, increasing precipitation, increasing salinization and more invasive species which will all have a considerable impact on the capacity to grow crops in the rural area around the Zwin.

  • Biodiversity and natural habitats: an increased sea-level and even higher waves will jeopardize breeding facilities in the area; a decreasing water table will result in certain plant species not blooming anymore due to a lack of water; and a rise in temperatures will allow invasive species to settle in the area.

  • Historical landscape: sea-level rise could lead to the consideration of elevating the dikes present which would ultimately alter the historical landscape of the area.

  • Recreation: more winter storms could make the Zwin Nature Reserve less accessible throughout the year; in combination with more favorable temperatures in summer, could cluster visitors resulting in a bigger impact on the area.

The outcomes of the individual interviews will be summarized in a report and during 2021 work will continue in the case study. Including an online workshop with all environmental managers for the Zwin Nature Reserve where the aim is to investigate how the available assets are contributing to the three major climate challenges that have been identified, as well as take into account the whole-of-system. - The result of both exercises will lead to the adaptation pathways to make the Zwin Nature Reserve more climate resilient, taking into account the whole-of-system, says Stevie.