European Rewilding Network
ERN2101

Sigma Plan

Restoration of river Scheldt and its tributaries

The Sigma Plan allows the Scheldt river to overflow in a controlled way, while letting the natural rhythms of the tides breathe new life into floodplains and tidal areas.
Yves Adams
The rewetted floodplains along the Scheldt river are boosting biodiversity.
Wesley Poelman
The marshes and mudflats in the Scheldt Delta are a natural form of flood protection while absorbing carbon and hosting a myriad of life.
Yves Adams
To restore the ecosystem of the river Scheldt the area of tidal marshes needs to increase by 2,000 hectares, with alluvial forests restored on a large scale alongside a variety of wetlands, creating fertile conditions for viable populations of species such as bittern, corncrake, otter, beaver and great loach to thrive.
Yves Adams
The Sigma Plan is a unique integration of water safety and nature development.
Yves Adams
Sigma Plan will create 14,000 hectares of connected nature-friendly habitats by 2030.
Cascades at Kruibeke De Vlaamse Waterweg.

The Sigma Plan protects Flanders from floods. In storm weather conditions, the tidal river Scheldt and its tributaries can reach dangerously high water levels and can even overflow their banks. That is why the Sigma Plan invests in sturdier and higher levees and in a chain of natural flood control areas in the river valleys. Areas like these can catch excess river water and this gives the rivers room to flow and to overflow in a controlled manner.

At the same time, in these areas, a vast nature area of 14 000 ha is created with wetlands. Tidal river creation is made possible by flood control areas with controlled reduced tide, specifically created for densely populated areas. Along the river, tidal nature is subject to the full range from sea water to fresh water, resulting in a broad variety of habitats. The marshlands, maintained by large herbivores are popular breeding grounds for birds such as little bittern, blue throat, marsh harrier and common bittern. After decades of absence, otter and beaver have returned to the river valley. Because of the investments in a better water quality, removal of physical barriers and creating better habitats, fish such as eel and twait shad migrate freely now.

After a long and difficult period of acceptation and because of hard work and a lot of consultation, people living and recreating in the valley, start appreciating and enjoying the nature development. The modular system of inundation areas is, up to a certain level, easily adaptable to future predictions of rising sea levels. Since we are simultaneously investing in wetlands, it is a ‘no regret’ measure against climate change. In recent years we have been dealing with long drought periods in the summer, as a result of which we raised the water level in winter and now use the wetlands as storage for rainwater.

A detailed monitoring of physical and biological parameters helps us to combine the different needs such as flood risk reduction, wetland restoration, shipping and sand extraction, living and recreation.

Specification Description Achievements Exchange
Project: Sigma Plan
Region: Belgium/Flanders
Type of protection: Mainly Natura 2000 network. By Decision of the Flemish Government, all areas have the status of nature area and will have an approved nature management plan. Most parts will receive the status of nature reserve.
Habitat types: • Salt and fresh water tidal mudflats and marshes
• Salt and fresh water marshlands
• Tidal willow forest
• Alder woodlands
• Tidal river
Type of project: Creating space for wilder nature, Fostering the development of nature based economies, Increasing interest in the wild through communications, Supporting wildlife comeback
Aim and vision: The flood of 1976 was the impetus for creating the Sigma Plan. To prevent disasters like that, the Belgian federal government launched an ambitious plan – a plan with the S from Scheldt and one that was analogous to the Dutch Delta Plan. In 2005, the Sigma Plan was updated to include the latest scientific insights. Since then, the Sigma Plan has also made important contributions to the European conservation objectives for Flanders.

The executors of the Sigma Plan are De Vlaamse Waterweg nv and Natuur en Bos (Agency for Nature and Forests). In addition to water safety, the Plan also focuses on the development of river nature, recreational facilities and local economies
Sigma Plan is a unique tandem of water safety and nature development aiming to makes Flanders safer, greener and an ever more splendid natural experience.
Uniqueness of the project: Since 2006 a modular flood control system combines with nature creation and recreation. To create tidal nature in a densely populated area a specific flood control system was invented with controlled reduced tide. The Sigma Plan is a perfect example of a ‘no regret’ measure against climate change.
Other activities: Community involved, Eco tourism, High-impact communications, Recreational activities, Research
Results you aim to accomplish in 10 years from now on: The Sigma Plan is finished. By lowering flood risk, retaining water for release during dry periods, supplementing the ground water and serving as an air cooler, Flanders is better prepared against climate change. The Scheldt estuary is a healthy ecosystem and has become a National Park.
Results so far: Many of the flood control areas and managed retreat areas are ready, have already served to control floods and give room to wetland ecosystems. The river Scheldt transformed from a death river to a living and loved
one. A detailed monitoring of physical and biological parameters helps us to combine the different needs of the partners such as flood risk reduction, shipping and sand extraction, wetland restoration and recreation.
The river Scheldt is important for birds, such as little bittern, blue throat and marsh harrier. After decades of absence, otter and beaver have returned to the river valley and fish as eel and twait shad use the river to
migrate. The people living and recreating in the valley, appreciate the nature development.
Inspirational value: - How to create a flood control area with controlled reduced tide and tidal nature creation<br /> - Different types of fish migration passages<br /> - The benefits of an integrated project<br /> - Creating social support and co-ownership in a densely populated area<br /> - Art and nature<br /> - Islands for breeding birds
Experience you would like to share: Flood control by nature creation in a densely populated area
How to evolve from NIMBY to ‘please in my backyard’ and create co-ownership
How to manage an integrated project
Monitoring methods and results
Fish migration passages
Experience you would like to gain: Reintroduction and management of large herbivores, carnivores<br /> Wetland bird habitat creation<br /> Managing draught<br /> Carbon sequestration<br /> Peatland restoration<br /> Climate adaptation of wetland ecosystems
Map
Country
Belgium
Start year
1976
End year
2030
Size (ha)
14000
Area type
River, Wetlands
Natural process
Flooding, Natural grazing, River dynamics, Wetland dynamics
Flagship species
Beaver, Otter, Roe deer, Water buffalo, White-tailed eagle
Sigma Plan
Sigma Plan
Sigma Plan
The Sigma Plan allows the Scheldt river to overflow in a controlled way, while letting the natural rhythms of the tides breathe new life into floodplains and tidal areas.
Yves Adams
The rewetted floodplains along the Scheldt river are boosting biodiversity.
Wesley Poelman
The marshes and mudflats in the Scheldt Delta are a natural form of flood protection while absorbing carbon and hosting a myriad of life.
Yves Adams
To restore the ecosystem of the river Scheldt the area of tidal marshes needs to increase by 2,000 hectares, with alluvial forests restored on a large scale alongside a variety of wetlands, creating fertile conditions for viable populations of species such as bittern, corncrake, otter, beaver and great loach to thrive.
Yves Adams
The Sigma Plan is a unique integration of water safety and nature development.
Yves Adams
Sigma Plan will create 14,000 hectares of connected nature-friendly habitats by 2030.
Cascades at Kruibeke De Vlaamse Waterweg.

The Sigma Plan protects Flanders from floods. In storm weather conditions, the tidal river Scheldt and its tributaries can reach dangerously high water levels and can even overflow their banks. That is why the Sigma Plan invests in sturdier and higher levees and in a chain of natural flood control areas in the river valleys. Areas like these can catch excess river water and this gives the rivers room to flow and to overflow in a controlled manner.

At the same time, in these areas, a vast nature area of 14 000 ha is created with wetlands. Tidal river creation is made possible by flood control areas with controlled reduced tide, specifically created for densely populated areas. Along the river, tidal nature is subject to the full range from sea water to fresh water, resulting in a broad variety of habitats. The marshlands, maintained by large herbivores are popular breeding grounds for birds such as little bittern, blue throat, marsh harrier and common bittern. After decades of absence, otter and beaver have returned to the river valley. Because of the investments in a better water quality, removal of physical barriers and creating better habitats, fish such as eel and twait shad migrate freely now.

After a long and difficult period of acceptation and because of hard work and a lot of consultation, people living and recreating in the valley, start appreciating and enjoying the nature development. The modular system of inundation areas is, up to a certain level, easily adaptable to future predictions of rising sea levels. Since we are simultaneously investing in wetlands, it is a ‘no regret’ measure against climate change. In recent years we have been dealing with long drought periods in the summer, as a result of which we raised the water level in winter and now use the wetlands as storage for rainwater.

A detailed monitoring of physical and biological parameters helps us to combine the different needs such as flood risk reduction, wetland restoration, shipping and sand extraction, living and recreation.

Map
Country
Belgium
Start year
1976
End year
2030
Size (ha)
14000
Area type
River, Wetlands
Natural process
Flooding, Natural grazing, River dynamics, Wetland dynamics
Flagship species
Beaver, Otter, Roe deer, Water buffalo, White-tailed eagle
Specification
Project: Sigma Plan
Region: Belgium/Flanders
Type of protection: Mainly Natura 2000 network. By Decision of the Flemish Government, all areas have the status of nature area and will have an approved nature management plan. Most parts will receive the status of nature reserve.
Habitat types: • Salt and fresh water tidal mudflats and marshes
• Salt and fresh water marshlands
• Tidal willow forest
• Alder woodlands
• Tidal river
Description
Type of project: Creating space for wilder nature, Fostering the development of nature based economies, Increasing interest in the wild through communications, Supporting wildlife comeback
Aim and vision: The flood of 1976 was the impetus for creating the Sigma Plan. To prevent disasters like that, the Belgian federal government launched an ambitious plan – a plan with the S from Scheldt and one that was analogous to the Dutch Delta Plan. In 2005, the Sigma Plan was updated to include the latest scientific insights. Since then, the Sigma Plan has also made important contributions to the European conservation objectives for Flanders.

The executors of the Sigma Plan are De Vlaamse Waterweg nv and Natuur en Bos (Agency for Nature and Forests). In addition to water safety, the Plan also focuses on the development of river nature, recreational facilities and local economies
Sigma Plan is a unique tandem of water safety and nature development aiming to makes Flanders safer, greener and an ever more splendid natural experience.
Uniqueness of the project: Since 2006 a modular flood control system combines with nature creation and recreation. To create tidal nature in a densely populated area a specific flood control system was invented with controlled reduced tide. The Sigma Plan is a perfect example of a ‘no regret’ measure against climate change.
Other activities: Community involved, Eco tourism, High-impact communications, Recreational activities, Research
Achievements
Results you aim to accomplish in 10 years from now on: The Sigma Plan is finished. By lowering flood risk, retaining water for release during dry periods, supplementing the ground water and serving as an air cooler, Flanders is better prepared against climate change. The Scheldt estuary is a healthy ecosystem and has become a National Park.
Results so far: Many of the flood control areas and managed retreat areas are ready, have already served to control floods and give room to wetland ecosystems. The river Scheldt transformed from a death river to a living and loved
one. A detailed monitoring of physical and biological parameters helps us to combine the different needs of the partners such as flood risk reduction, shipping and sand extraction, wetland restoration and recreation.
The river Scheldt is important for birds, such as little bittern, blue throat and marsh harrier. After decades of absence, otter and beaver have returned to the river valley and fish as eel and twait shad use the river to
migrate. The people living and recreating in the valley, appreciate the nature development.
Exchange
Inspirational value: - How to create a flood control area with controlled reduced tide and tidal nature creation<br /> - Different types of fish migration passages<br /> - The benefits of an integrated project<br /> - Creating social support and co-ownership in a densely populated area<br /> - Art and nature<br /> - Islands for breeding birds
Experience you would like to share: Flood control by nature creation in a densely populated area<br /> How to evolve from NIMBY to ‘please in my backyard’ and create co-ownership<br /> How to manage an integrated project<br /> Monitoring methods and results<br /> Fish migration passages
Experience you would like to gain: Reintroduction and management of large herbivores, carnivores<br /> Wetland bird habitat creation<br /> Managing draught<br /> Carbon sequestration<br /> Peatland restoration<br /> Climate adaptation of wetland ecosystems
Sigma Plan
Sigma Plan
Sigma Plan
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