Scheldt River
The Scheldt River is a significant waterway in Western Europe, originating in northeastern France and flowing through northwestern Belgium before reaching the North Sea in the Netherlands. Spanning approximately 220 miles (354 kilometers) and draining a basin of about 8,500 square miles (22,000 square kilometers), the river is characterized by its varied nomenclature—known as Schelde in Dutch and Escaut in French—with different sections bearing distinct names. The river is both rainwater-fed and tidal, with its water levels influenced by precipitation upstream and tides downstream. Despite being one of Europe’s smaller rivers, it ranks among the top globally in terms of economic productivity, comparable to larger rivers like the Yangtze and Amazon.
The Scheldt River and its estuary support rich biodiversity, serving as a crucial habitat for numerous bird species and a variety of aquatic life, including commercially farmed mollusks. However, human activities have dramatically altered its ecosystem over the centuries, leading to pollution and habitat degradation. Urbanization and agricultural runoff have contributed to challenges such as eutrophication and sediment erosion. The future health of the river is uncertain, with climate change posing additional risks, including increased flooding and saltwater intrusion. Conservation efforts are essential to restore balance and ensure the river's ecological integrity and economic viability.
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Scheldt River
Category: Inland Aquatic Biomes.
Geographic Location: Europe.
Summary: A heavily urbanized river biome and one of the last river-tide systems in Europe, the Scheldt encompasses valuable estuary wetlands but is threatened by widespread pollution.
The Scheldt River flows from northeastern France, cuts across northwestern Belgium, and after branching out as a great estuary across the border in southwestern Netherlands, flows into the North Sea near Vlissingen. The river springs in Gouy, France, at an altitude of about 300 feet (90 meters), and flows some 220 miles (354 kilometers) to its mouth, with the entire basin covering about 8,500 square miles (22,000 square kilometers). Several tributaries empty into the Scheldt River, including the Leie, Haine, Dender, and Rupel.
The river’s name finds its origin in the old English word sceald, meaning shallow. The river is referred to as the Schelde in Dutch and Escaut in French. Different sections of the river have different localized names. From the source to the city of Ghent, Belgium, it is referred to as the Bovenschelde; between Ghent and the Belgian-Dutch border, it is called the Zeeschelde, reflecting its broad spread as it approaches the sea; and further downstream, it is dubbed the Westerschelde.
The Scheldt River is considered to be both a rainwater-fed river and a tidal river, with precipitation controlling water levels downstream to Ghent, while tides control the water levels from Ghent to the North Sea. Even though the Scheldt River is one of the smallest rivers in Europe, its economic production places it in the top 10 of the world, with a value similar to those of the Yangtse, Amazon, and Nile.
The climate here is temperate maritime, characterized by relatively warm summers and mild winters. January is the coldest month at about 37 degrees F (2.5 degrees C) on average, and July the warmest with an average of 63 degrees F (17 degrees C). In coastal areas, the proximity of the sea tends to provide lower temperatures in the summer and somewhat warmer temperatures in the winter. Because of its limited territory, the climate within the basin varies very little.
Biodiversity
The Scheldt is one of the few rivers left in Europe with an intact tide-river system comprising major saltwater and freshwater segments. The western Scheldt estuary system forms a unique hot spot for nature, with a high diversity of bird species migrating through each year. The estuary is a multi-channel system with several tidal flats both across the middle streams and along the edges.
These tidal flats are inhabited by a rich diversity of bottom-dwelling organisms, including ranges of mollusks and crustaceans, on which migratory birds feed. Mussels, snails, and oysters are also commercially farmed here. Freshwater and saltwater species can coexist as neighbors in this ecosystem; the high productivity of this estuary creates the foundation of a complex food web. Closest to the sea, seals and porpoises often prey.
Human Impact
This river has a long and turbulent history with much human intervention to facilitate shipping and habitable land creation; it is truly an urban river. The first record of the river was from the Romans, who used it for shipping. At that time, the southwestern province of Zeeland (now The Netherlands) was almost completely underwater, which resulted in thick peatlands and clay deposits. The first modest diking of the river started in the 10th century, making parts of Zeeland habitable.
Throughout the 12th century, the Scheldt River was a smallish river with minor branches. Major flood events have altered its courses many times over the centuries, connecting and disconnecting various channels, breaching dunes, overwhelming marshes, and silting up channels—resulting in great habitat destruction at times.
Currently, the Scheldt River is left largely untouched for the first 10 miles (16 kilometers) from its source. The following 85 miles (137 kilometers) are partly canalized. The remaining length of the river mainly functions as an estuary, with the influence of the North Sea noticeable as far inland as the city of Ghent.
The river basin is inhabited by 10 million people. Intense use of the Scheldt estuary has resulted in severe pollution, eutrophication, and morphological changes threatening the natural refuges in this ecosystem. The Scheldt estuary is a uniquely polluted ecosystem due to erosion, oxygen depletion, and toxic heavy-metals inputs. The dense population of the region leads to significant pollution of plastics that likely empty into the North Sea.
Erosion fills the river with sediment, creating a turbid environment. In addition, erosion contributes a substantial amount of nutrient loading (from adjacent agricultural areas) to the river. High nutrient concentrations in turn result in algal blooms, depriving the water of oxygen and threatening higher life forms, such as fish.
Since the late 1970s, awareness about the interaction between ecology and long-term economical health has become prevalent, and a push is being made to find a balance here. The future of the Scheldt River is unclear. Recovery and conservation, in terms of river health, would require a focus on three main points: returning oxygen to the river, removing toxic elements, and increasing the floodplain area to prevent the river from filling with sludge.
Climate change may impact the river by means of exacerbating hydrological extremes of low-flow and flooding along catchments in the basin. The lower Scheldt River in Belgium is particularly prone to flood risk, as coastal level changes include both sea-level rise and storm surge changes. Saltwater intrusion is also a mounting challenge as sea levels rise. Until now, the trend has been wetter winters and drier summers.
Bibliography
Baeyens, W., B. van Eck, C. Lambert, R. Wollast, and L. Goeyens. “General Description of the Scheldt Estuary.” Hydrobiologia 366 (1997).
Gilbert, A., M. Schaafsma, L. De Nocker, I. Liekens, and S. Broekx. Case Study Report—Scheldt. Brussels, Belgium: AquaMoney, 2007.
Lefebure, Arnould. International Scheldt River Basin District: Management Plan Roof Report. Antwerp, Belgium: International Scheldt Commission, 2009.
Velimirovic, Milica, et al. "What Can We Learn from Studying Plastic Debris in the Sea Scheldt Estuary?" Science of the Total Environment, vol. 851, no. 1, 2022. DOI: 10.1016/j.scitotenv.2022.158226. Accessed 31 Aug. 2022.