Wetland restoration: a nature-based solution for Europe’s security?

Russia’s full-scale invasion of Ukraine, now into its third year, changed geopolitical reality in Europe dramatically. While Europe is rethinking its defence strategy, both conventional military strategies as well as more synergetic measures are being proposed. Among the more surprising measures currently under discussion by the EU, is the restoration of drained wetlands, particularly the rewetting of peatlands, as they hinder movement across terrain in the event of military conflict. A European Wet Defence Line could contribute to both Europe’s military security and its climate and nature conservation efforts, but it must be handled with due responsibility and poorly planned rewetting must be avoided. 

Header photo: Wetlands in Slovenia © Dragoncello via Getty Images

Wetlands as a military’s obstacle for ground troops 

Wetlands have long helped in military defence along the Russian border. As a prime example, Napoleon’s army struggled in Russia’s peatlands and marshes. During World War II, major military operations through the wetlands were only carried out in winter, when the soil and water were frozen. These operations also relied on the help of peatland experts to navigate through the challenging terrain^[1]https://www.aeco.earth/blog/peatlands-as-natural-defence-an-innovative-approach-to-europes-security. Wet peatlands and marshes are too soft for any military vehicle to cross. Whether naturally wet or rewetted, they may stop tanks, slow down soldiers, and force armies into narrow paths, making them easier to defend. 

Although the use of airplanes, long-distance missile equipment, and drones has diminished the effectiveness of such natural defence lines, they still entail significant strategic value. Given that Russia’s ground forces have been most heavily engaged in the war in Ukraine, this prompts us to think about the rewetting drained wetland areas along Europe’s borders. Wetlands, particularly those in border regions, could serve as natural barriers that hinder military movement and provide strategic advantages in the event of conflict. 

The Pripet Marshes: a natural military buffer zone during wintertime 

The Pripet Marshes, or Polissya in Ukrainian, are a large area of roughly 270,000 square kilometre of wetlands stretching from Poland to Russia, across northern Ukraine and southern Belarus^[2]https://universalium.en-academic.com/178510/Pripet_Marshes">https://en.wikipedia.org/wiki/Pripet_Marshes. The temperature plays a military factor for Russia’s tactics to invade this area. During the winter, these soppy flatlands freeze over, providing a more stable terrain for heavy military vehicles that would otherwise get stuck in the mud^[3]https://www.washingtonpost.com/world/interactive/2022/ukraine-russia-invasion-geography-weather/. Experts say the frozen ground, usually present in February, provide Russian troops with the best window to cross into Ukraine. The terrain becomes very muddy again around March-April when the frozen marshes thaw. While more roads have recently been built throughout the marshes, having the option of crossing the open terrain is still strategically important if the roads are blocked^[4]https://www.kyivpost.com/opinion/13527.

Historic example of the Hollandse Waterlinie

The “Hollandse Waterlinie” (Dutch Waterline) is an example of the active creation of wetlands for military purposes. The Dutch first used strategic flooding in 1584 to fight the Spanish by breaking dikes and flooding land. Though they could not stop the fall of cities like Antwerp, the idea lived on. In 1672, Dutch forces opened locks to stop the French army near Flanders. This led to a smart defence system using canals and locks, which was used several times, including in World War I and II.  

After World War II, the Dutch government redesigned the idea of a waterline to counter a possible Soviet invasion. This new version of the Water Line was focused more to the east of the Netherlands at the IJssel River (the IJssel Line) and in the province of Gelderland. In case of an invasion, the water of the Rhine and the Waal were set to divert into the IJssel, flooding the river and bordering lands. The plan was never tested, and it was dismantled by the Dutch government in 1964. Today the original water line is still more or less intact. On 26 July, 2021, the line was added as a UNESCO World Heritage Site due to the unique nature of the line^[7]Hollandse Waterlinies | Stichting Werelderfgoed Nederland .

Figure: Map of the Hollandse Waterlinie © Stichting Werelderfgoed Nederland^[8]https://www.werelderfgoed.nl/nl/werelderfgoed/hollandse-waterlinies.

Mapping Europe’s strategic borderlands for rewetting 

Key areas for rewetting in Europe from a military perspective include Ukraine, where it could help defend against Russia and possibly Belarus, as well as Poland, the Baltics, Finland, and Romania, where rewetting could serve as natural barriers along NATO’s eastern flank. Germany’s eastern border region is also identified as a potential backup defence line for Western Europe. The European borderlands could form together the modern “European Waterline”. 

For these areas to effectively function as defence mechanisms, two types of wetland landscapes are of strategic interest. Firstly, large intact wetlands, which are often found near country borders; and second, fragmented drained wetlands that have been converted into farmlands. While the latter are more built-up, they could still be useful for defence purposes if rewetted, though roads and buildings may influence their effectiveness^[9]https://www.aeco.earth/blog/peatlands-as-natural-defence-an-innovative-approach-to-europes-security .

Rewetting gains momentum in Eastern Europe 

Russia’s war in Ukraine is changing how Eastern Europe views wetlands. The German think tank on peatlands, the Greifwald Moor Centre, recently published a policy note in which they advocate for rewetting as a defence strategy^[10] https://www.aeco.earth/blog/peatlands-as-natural-defence-an-innovative-approach-to-europes-security. Also in Poland, experts are exploring how nature can play a role in defending borders. Poland’s “Eastern Shield” plan, meant to stop military threats from Belarus and Russia, has sparked debate. So far, the plan included building a high fence through the Białowieża Forest, a measure that negatively impacts wildlife and the environment. In May, the Polish Academy of Sciences suggested that rewetting the area by raising groundwater, restoring wetlands, and allowing forests to regenerate, provide more effective border protection while also benefiting the environment^[11] https://www.politico.eu/article/poland-eastern-maginot-line-bialowieza-forest-war-defense-east-shield-program-nature-preservation/. The Polish government has shown interest and reviews the idea. For the first time since Russia’s invasion of Ukraine, the restoration of wetlands is being considered as part of national defence strategy within the EU^[12]https://internationalepolitik.de/de/die-strategische-bedeutung-von-feuchtgebieten.

An important point is that effective restoration of wetlands, especially peatlands, takes time; usually several years to decades. Wetlands are not magically restored when they are flooded for short periods for acute military purposes.

Wetlands in environmental policy

Rewetting peatlands directly aligns with the EU Nature Restoration Law^[13]ttps://environment.ec.europa.eu/topics/nature-and-biodiversity/nature-restoration-regulation_en , which requires Member States to restore and partially rewet drained agricultural peatlands, namely 30% by 2030 (of which at least a quarter rewetted), 40% by 2040 (a third rewetted) and 50% by 2050 (a third rewetted)^[14]EU Nature Restoration Law: all eyes will turn to member states | IUCN NL. Next to this, rewetted peatlands contribute to the European Climate Law (adopted on 28 June 2021) and the EU Green Deal – Fit for 55 (adopted on 14 July 2021) target to reduce emissions by at least 55% by 2030, compared to 1990 levels. The climate mitigation benefits from wetlands are huge: although occupying only 7% of the earth’s surface, they store 33% of the world’s terrestrial carbon^[15]Wetlands restoration to tackle climate change | REWET.

Restoring wetlands the right way

A key point to remember is that effective restoration of wetlands, particularly peatlands, takes time, typically several years to decades. Wetlands are not magically restored when they are shortly flooded for acute military purposes. Careful planning, science-based approaches, and participatory approaches to restoration are needed to avoid risks of long-term ecological damage and social injustice. In every case, it is recommended to apply the IUCN Global Standard for Nature-based Solutions, and for peatlands specifically the ’Global guidelines for peatland rewetting and restoration’, developed by RAMSAR^[16]https://www.ramsar.org/sites/default/files/documents/library/rtr11_peatland_rewetting_restoration_e.pdf. This ensures permanence in ecosystem restoration results, with just and equitable governance of natural resources, notably land and water ownership.  

To illustrate this, “careless” rewetting unfolded through the flood event near Irpin, close to Kyiv, during the Russian invasion in February 2022. To halt advancing troops, Ukrainian forces opened a dam on the Irpin River, flooding 13,000 hectares of former wetlands drained in the 1960s. This war rewilding move stopped the Russian advance and, for now, protected Kyiv from a land invasion^[17]Wetlands and the war in Ukraine – hope amid catastrophe – Wetlands International Europe. Historically, the Irpin floodplains were a biodiverse landscape of bogs, swamps, and reed beds, but Soviet-era drainage and subsequent housing developments had significantly degraded the ecosystem. Also just before the current war, new housing projects were being planned for the area.  

With the return of the water, spatial plans must be reconsidered. Balancing trade-offs between nature restoration and urban development will become a political choice. If wetlands restoration received political support, then effective biodiversity recovery still takes years, or even decades. Sudden reflooding does not automatically lead to successful rewilding. The mere return of water is not enough to ensure long-term ecological restoration with optimal biodiversity gains. Without ecological research, planning, and local involvement, sustainable rewetting will likely not take place. 

Wetland restoration should not justify the militarisation of nature, but should serve as a means of protecting ecosystems in the long term and supporting the diverse values for people and nature.

Shaping policies for the nature–climate–security nexus 

This is a key moment to leverage environmental diplomacy in shaping wetland restoration options in EU defence policy. As a start, a dedicated biodiversity-climate-security dialogue between member states could support prioritisation of regions or countries to shape a European waterline, balancing trade-offs between nature, climate, and security goals, while assessing related potential impacts, risks, and opportunities. 

Member states are encouraged to create policy incentives that make wetland restoration more attractive. This could include promoting a shift from conventional agriculture to paludiculture by offering targeted training, financial guarantees, and subsidies to farmers and landowners in strategically important areas. Additionally, financial incentives can be used to compensate landowners for the rewetting of defence areas. Relevant EU funding is available to support these efforts, drawing from budgets related to nature, climate, and security programmes. 

In any case, wetland restoration should not justify the militarisation of nature but serve as a pathway for long-term ecosystem protection that supports the diverse values for people and nature. The risks of poorly planned rewetting, as illustrated by the incident near Irpin, highlight the potential harm and justice implications of uncoordinated interventions. Success will fundamentally depend on long-term planning, adequate funding and support from the EU and other actors, as well as early-on involvement of affected people that live in the area.