Rhine River

Category: Inland Aquatic Biomes.

Geographic Location: Europe.

Summary: A mid-size river with vast economic and political significance, the Rhine has rebounded somewhat from long degradation resulting from river training and industrial development.

The Rhine is a Western European river with great historical, economic, and ecological significance, as well as the source of drinking water for 20 million people. Flowing through the countries of Germany, Austria, Switzerland, France, Netherlands, Luxembourg, Belgium, and even a small portion of Italy, the Rhine today is 766 miles (1,233 kilometers) long—65 miles (105 kilometers) shorter than its natural length due to river realignment projects called river training—which has been ongoing since the 19th century.

People along the shores of the river have modified the Rhine to fit population growth and industrialization. Thus, a notoriously wild river has become little more than a canal to further industry and trade. A string of environmental disasters in the late 20th century spurred efforts to increase biological diversity, as well as reduce flood risk.

The history of artificial modifications must be considered when describing the Rhine’s geography. Projects to straighten the river led to the removal of thousands of islands, as well as oxbows, meadows, and braided beds. River training also standardized the Rhine’s width to 656 feet (200 meters) at its base in Switzerland, eventually widening to 3,281 feet (1,000 meters) in Holland. Moreover, it set the Rhine’s depth to a minimum of 5.6–8.2 feet (1.7–2.5 meters).

Because the river flows through eight European countries, the seasonal weather fluctuations vary, but temperatures can dip to 30 degrees F (minus 1 degrees C) during the winter and climb to 80 degrees F (26 degrees C) in summer.

River Flow

The Rhine is part of a sprawling canal network, giving it access to the Baltic Sea (via the Herne River), into France (via the Marne), the Mediterranean (via Rhone), and the Black Sea (via Main-Danube). The Rhine has become a flowing highway crucial for regional commerce; it is the second-busiest waterway (after the Mississippi River) internationally.

Geographers divide the Rhine into High Rhine, Upper Rhine, Middle Rhine, Lower Rhine, and Rhine Delta. The Rhine’s headwaters—the Aare, Vorderrhein, Hinterrhein, and Alpenrhein streams—flow from the Swiss Alps to Lake Constance. Lake Constance to Basel, Switzerland, is the High Rhine, where a staircase of locks and dams provides energy for local industry. The Upper Rhine is from Basel to Bingen, Germany, which lies in the Rift Valley, a natural floodplain at the foot of the Alps. This is where North Sea-bound marine traffic begins—a distance of 540 miles (869 kilometers)—making Basel Switzerland’s only port.

Between Bingen and Bonn, Germany, is the Middle Rhine, where the Rhenish Slate Mountains, vineyards, and castles captivate tourists. The steepness of the surrounding canyon has spared its natural beauty from intensive development. This contrasts with the Lower Rhine, a region from Bonn to the Pannerden Canal (near the German-Dutch border) that is heavily developed for industrial and energy production.

The Rhine Delta is entirely in the Netherlands, and divides into three branches—Waal, Lek, and Ijssel. None of the branches has reached the North Sea since the 1986 Delta Project severed all of them, and diverted the Rhine’s waters into a sluice network.

Since 1872, the New Waterway Canal has connected Rotterdam, Netherlands, to the Rhine, an artery for Rotterdam’s Europoort (the world’s second-busiest port after Shanghai).

Biodiversity

The river’s geographic distinctions are based on fish population variations that no longer exist, as river training and pollution have radically changed wildlife patterns. In 1800, the Rhine boasted 47 fish species, but by the 1970s, half were extinct, and the other half were largely sustained by hatcheries. Similarly, from 1915 to 1971, the number of indigenous invertebrate macrofauna species fell from 80 to 27. These species could not adapt to the changing river.

Straightening the Rhine more than doubled its flow rate, increased its oxygen content, and reduced its temperature, but later industrial and energy production warmed, salted, blocked, and polluted the Rhine. Indigenous species had to compete with invaders brought along by long-distance shipping and canal connections, as well as intentional introductions, such as the zander (Sander lucioperca)—known as pike-perch—unleashed to compensate for extirpated salmon.

Since the 18th century, 45 macroinvertebrate species—such as beetles, worms, and snails—have invaded the Rhine and now compose up to 11 percent of the river’s total species. Many indigenous species, which depended on fish or flood patterns that no longer existed, simultaneously competed against invading crustaceans and mollusks better suited to the new conditions.

Some river segments host relatively healthy fish communities. In the Lower Rhine, carp, minnows, chubs, and tench still thrive, while the much-less altered Upper Rhine hosts at least 36 species of fish, including sunfish, rainbow trout, roach, carp, silver bream, burbot, and stone loach.

The Rhine’s shores have similarly changed in the past two centuries. Only 15 percent of the original floodplain remains, as the local population of 50 million humans has built farms, cities, and factories. The floodplain forests (mainly oak, elm, and lime) of the Upper Rhine are Europe’s equivalent of rainforests, due to their superlative diversity of plant and bird species. These forests now only occupy 0.75 percent of their former range in the Upper Rhine, of which 70 percent consists of tree plantations. Moose, bears, and wolves went extinct here during the Middle Ages, and insects like mayfly and caddisfly (sedge-flies) are highly sensitive to water pollution; now their populations fluctuate with the Rhine’s variable cleanliness. Floodplain forests regenerate when annual floods return, though they require 200 years to reach maturity.

The 40-mile (65-kilometer) Middle Rhine section, listed as a United Nations Educational, Scientific, and Cultural Organization (UNESCO) World Heritage Site since June 2002, is home to rare and endemic—found nowhere else—species such as the white-backed woodpecker, red kite, long-eared owl, and icterine warbler. Other birds flying over, nesting, and breeding along the Rhine include peregrines, black redstart, white stork, parakeet, eagle, goose, and lapwing.

Environmental Issues

The heart of German industry (especially energy, mining, textiles, agriculture, and chemicals) lies along the Lower Rhine, an area that bore heavy environmental costs until efforts to reduce pollution began in the 1970s. These industrial clusters are closely linked. For instance, dams and power plants both depend on and supply coal firms, while chemical factories use coal for energy, and its byproducts to make dyes and fertilizer for textiles and agriculture. Hundreds of power plants require water for cooling and return warmed water that is detrimental to sensitive organisms. Numerous dams dot the Rhine to generate hydroelectric power.

Like heat, chloride pollution may garner less attention than chemical spills, but it still unsettles the Rhine’s natural balance. Until the signing of the Convention on Chlorides in 1976, salinization posed a threat to farmers, city dwellers, and other organisms dependent on the Rhine for fresh water.

Every ton of mined coal requires thousands of gallons (liters) of water for cleaning and pumping, and Alsatian potash mines similarly dumped salty refuse. The Netherlands advocated controls on salt dumping after World War II to mitigate the impact on low-lying areas from both the North Sea and the Rhine.

Textile and, later, chemical factories dumped numerous byproducts into the river, a problem exacerbated by plant growth along the river’s banks. Some 6,000 chemicals have been identified in the Rhine, the results of dumping from the chemical industry, and agricultural runoff from artificial fertilizers and pesticides from the farms that border the river.

In 1969, Hoechst Chemicals accidentally dumped the insecticide Endosulfan into the Main River (a Rhine tributary), and in 1986, millions of gallons (liters) of water used to extinguish the fire at Basel’s Sandoz chemical factory seeped into the Rhine, killing almost all aquatic life downstream until Koblenz, Germany. These two events galvanized public opinion that pressured governments to mitigate the ill effects of industrial development on the Rhine’s ecosystem.

Worries about pollution were not new, as many had noted the Rhine’s deterioration early on. In 1901, German parliamentarians called the Rhine a “sewer,” and their commission reported the Rhine was red (because of sewage) from Ludwigshafen to Worms and yellowish near Mannheim (home to a large paper-pulp industry). Various complaints surfaced over the decades, and treaties were drawn to protect the river and surrounding areas. There were several treaties to protect salmon in the 19th century, though the fish still disappeared.

International Efforts

The World Wars and Great Depression stalled international negotiations, and it was not until 1950 that Switzerland, France, Luxembourg, Germany, and the Netherlands jointly founded the International Commission for Protection of the Rhine (ICPR). It was the Rhine’s first antipollution institution. Although the ICPR systemically measured the river’s water quality, the organization lacked funding, legal power, and even a functioning secretariat (until 1953), as fluvial states ensured a rapid economic recovery took precedence.

But by 1995, the ICPR exceeded its goals of reducing major pollutant emissions by more than 80 percent. The reintroduction of salmon became symbolic of the organization’s success, and since 1990, some 5,000 salmon have migrated between the Rhine and North Sea, a feat made feasible by the construction of fish channels to circumvent dams.

Four “once in a century” floods in the 1980s and 1990s prompted a radical reformulation of river management. A shorter and faster Rhine was more prone to flooding, because the spring melt of Alpine glaciers coincided more often with the flooding of Rhine tributaries. Instead of constricting the Rhine further with dikes and levees, the ICPR set out to combine flood reduction with re-naturalization. In 2001, it presented Rhine 2020, a plan to increase biodiversity and relieve pressure on flood infrastructure through a patchwork of revitalized fluvial ecosystems. Rhine 2020 also included more stringent pollution regulations, especially against difficult-to-detect micropollutants, which can accumulate in organisms. Acres of cropland have been converted to pasture to limit erosion and nutrient runoff from farms.

While Rhine 2020 was successful in many respects the water quality of the Rhine continues to decline. One of the goals of Rhine 2040, passed in 2020, is to reduce the discharge of pharmaceuticals, x-ray contrast agents, and pesticides into the river by at least 30 percent by 2040. However, these substances are difficult to remove and the quantities continue to grow larger.

Climate change poses another set of challenges for the management of the Rhine. In 2022, water levels significantly dropped, mainly because of a severe drought and unusually hot and dry summer. The level of the Rhine was so low in places that companies could not transport freight on the river because it was impossible for barges to pass through such shallow water.

Bibliography

Blackbourn, David. The Conquest of Nature: Water, Landscape, and the Making of Modern Germany. New York: Norton, 2006.

Cioc, Mark. The Rhine: An Eco-biography, 1815–2000. Seattle: University of Washington Press, 2002.

Disco, Cornelis. “Accepting Father Rhine? Technological Fixes, Vigilance, and Transnational Lobbies as ‘European’ Strategies of Dutch Municipal Water Supplies 1900-1975.” Environment and History 13, no. 4 (2007).

Frijters, Ine D. and Jan Leentvaar. Rhine Case Study. New York: United Nations Educational, Scientific, and Cultural Organization (UNESCO), 2003.

International Commission for Protection of the Rhine (ICPR). “ICPR Brochures.” http://www.iksr.org/index.php?id=254&L=3.

Leuven, Rob S. E. W., H. J. Rob Lenders, and Abraham Vaate. “The River Rhine: A Global Highway for Dispersal of Aquatic Invasive Species.” Biological Invasions 11, no. 9 (2009).

Novo, Cristina. "Water Quality in the Rhine River Is Declining." Smart Water Magazine, 20 Feb. 2020, smartwatermagazine.com/news/smart-water-magazine/water-quality-rhine-river-declining. Accessed 1 Sept. 2022.

Venditti, Bruno. "Visualizing the Rhine River's Shrinking Water Levels." Elements, 19 Aug. 2022, elements.visualcapitalist.com/visualizing-the-rhine-rivers-shrinking-water-levels/. Accessed 1 Sept. 2022.