Ural River

Category: Inland Aquatic Biomes.

Geographic Location: Eurasia.

Summary: This river, winding through low-rainfall areas, brings life to many fish species and supports a vital migratory bird stopover where it meets the Caspian Sea.

The Ural River originates in Russia, in the southern reaches of the Ural Mountains—the river and mountains together form the dividing line between Europe and Asia—flows southwest into the neighboring country of Kazakhstan, and at its delta meets the Caspian Sea at the Kazakh harbor city of Atyrau. The total length is roughly 1,500 miles (2,400 kilometers); the catchment area is some 90,000 square miles (233,000 square kilometers).

The river first flows down the eastern slopes of the Urals, from a source on Mount Kruglaya, and south to the Russian city of Orsk, where the first major tributary, the Or, joins in as the Ural turns west to skirt the southern end of the mountains. Reaching Orenburg, the Ural is swollen by the next major tributary, the Sakmara. The third major tributary, the Illek, flows in before the final turn to the south, at the city of Oral.

Near its mouth, the Ural River enters the Caspian Depression, where it waters great mudflats and shoreline reeds. Here, the Ural forms two main distributaries—Yaik and Zolotoy—as the mainstem continues out into the still waters of the Caspian Sea, forming a digitate delta, with distinct branches channeling sediment-loaded waters out at acute and right angles. This delta as recently as 1977 extended 20 miles (32 kilometers) straight out into the sea. The Caspian surface level has risen since then, and the delta in its present-day form reaches about 8 miles (13 kilometers) into the sea.

The Ural River biome in general has a continental climate, with hot summers and cold winters; rainfall is rather low, given its location at the juncture of European dry steppes and central Asian semidesert areas. The river is at least partly frozen every winter; maximum flow occurs in April and May. Water temperature in the Ural River ranges from close to freezing to as high as 77 degrees F (25 degrees C).

Annual precipitation can average as little as 4 inches (100 millimeters), and a bit higher near the delta, at 6.3 inches (160 millimeters). Snowmelt is the most significant source of its direct and tributary flow; therefore, the flow volume of the Ural varies considerably each year. At spring flood, the Ural typically spreads up to 5 miles (8 kilometers) wide across much of its floodplain, and even double that width near the confluences with its major tributaries. The middle reaches of the Ural River basin are dotted with many small lakes and ponds; their niche habitats depend greatly on whether or not the annual spring flood recharges their waters.

Biodiversity

Flora in the Ural catchment transitions from mountain meadows and scrub to forested foothills, and to grassy steppe along much of its middle length—with treed areas fairly consistent along the river itself in its upper and middle segments, transitioning to willow shrub and finally disappearing as the river approaches the Caspian Depression.

In the uplands, conifer coverage includes Siberian pine, Siberian and Norway spruce, downy birch, and larch. Meadow communities include dropwort, clover, and grasses such as Arctic brome. The dry steppes bring a regime of saltwort, sagebrush, Siberian peashrub, and stands of poplar or willow. It its final stretch, the wetlands are a realm of saltmarsh vegetation and submerged reedbeds.

More than 40 species of fish from at least 10 families inhabit the Ural River and its tributaries. Sturgeon is the characteristic fish of the biome. Beluga sturgeon and starry sturgeon, valued for their roe, or caviar, are very high in commercial value and are managed here through harvest control and hatchery supplementation. The beluga sturgeon catch in the Ural, measured as landings, peaked in the 1960s and has since declined. At one time during the 1970s, about 40 percent of the world’s caviar came from Ural River sturgeon. By the start of the 2020s, the river’s sturgeon population had declined so much that virtually none of the fish lived upstream from the Kazakhstan city of Atyrau. The sturgeon can make its spawning migrations fairly freely here, as the Ural has not been the site of much dam construction.

The Ural hosts freshwater fish types from family Cyprinidae, such as carp, minnows, barbs, and barbels, as well as anadromous types such as sturgeon, salmon, and the occasional black-back shad or Caspian cisco which migrate upstream. Other commercial species include bream, perch, and catfish. A fish that is endemic—meaning found nowhere else—to the Ural and the neighboring Volga River system is the Volga whitefin gudgeon, an indicator species for clear, well-oxygenated water.

The wetlands and delta area, at the northeastern lobe of the Caspian Sea, form a rich feeding, resting, and nesting ground for migratory waterfowl. This vital stop on the Asian Flyway is host to at least 20,000 waterfowl; major flocks of great egret, Dalmatian penguin, great cormorant, and Pallas’s gull are perennial migrants among the more than 250 avian species recorded here. The birds are drawn by the alluvial banks and inundated marsh areas that support populations of gastropods, mollusks, and crustaceans.

The firmer land surrounding these wetlands supports modest-sized terrestrial species, including bog turtles, Caspian whipsnake, muskrat, the occasional fox or wild boar, and the endemic marbled polecat.

Threats and Conservation

Upstream parts of the Ural River are destined to be tarnished from time to time by the activities of mining operations extracting gold, nickel, bauxite, and other mineral deposits. Oil and coal production in the greater Volga-Ural region is another escalating environmental concern, joining longstanding worries about nuclear waste dumps and facilities in the southern Ural Mountains area.

Global warming trends, if they reduce snowfall in the Ural Mountains region, will have serious negative effects on the flow levels of the Ural River and its capacity to support various species. There is already evidence that the Urals are warming, and the somewhat reliable cycle of snowmelt is giving way to less-likely rainfall events. Many types of fish are quite sensitive to water temperature for triggering spawning activity; such species might migrate to cooler upstream areas of the Ural River and its tributaries, or they may sustain major population reductions as warming takes hold in this biome.

Because it is largely undammed, has generally healthy fish populations, and is a key migratory-bird wetland, the Ural River biome has attracted some worldwide attention and support on ecological matters. The Ural River Delta has been named an Important Bird Area by BirdLife International. Conservation of the sturgeon in the river is a leading goal of the Ural River Basin Project, an international effort that grew out of a 2007 workshop. The government of Kazakhstan, working with the United Nations and other bodies, in 2011 established the Akzhaiyk Nature Reserve in the delta area. Each of these initiatives is a cause for some optimism.

Bibliography

Akhmedyarov, Lukpan, and Raul Uporov. “A Disappearing River: The Fate of the Ural,” translated by Valentine Baldassari, Novastan, 29 Apr. 2021, novastan.org/en/kazakhstan/disappearing-river-can-the-ural-fate-be-averted/. Accessed 29 Aug. 2022.

Chaves, H. M. L. and S. Alipaz. “An Integrated Indicator Based on Basin Hydrology, Environment, Life, and Policy: The Watershed Sustainability Index.” Water Resource Management 21 (2007).

Jewitt, Graham. “Can Integrated Water Resources Management Sustain the Provision of Ecosystem Goods and Services?” Physics and Chemistry of the Earth, Parts A/B/C 27, nos. 11–22 (2002).

Lagutov, Viktor, ed. Rescue of Sturgeon Species in the Ural River Basin. Berlin, Germany: Springer, 2008.