Urban rivers restored, healthy arteries of cities

The planet’s rivers are one of the main sources of water for the world’s population, as well as being the habitat of an endless roll call of wildlife. They are home to an incalculable source of economic and environmental wealth. They are also great allies in the fight against climate change. The sediments they carry with them maintain the planet’s great deltas, naturally moderating sea levels. Some studies say that the vegetation on their banks is able to regulate water temperature.

As such, over 2 billion people depend directly on rivers to drink, 25% of world food production is served by their water, and at least 12 million tons of fish are caught in them per year.

It is becoming increasingly urgent that we invest in sanitation measures to ensure sufficient flow and cleanliness in our rivers. Some big cities are working to restore them, especially in inner city areas, which most suffer from the waste tipping, sewage and chemical residues killing them.

In Sustainability for all, we have already written about the world’s most polluted rivers. So, now, through this gallery, we are going to tell you about the positive side of this subject, showing some urban rivers that have been recovered in recent years.

Unearthing of a river 

One of the most spectacular cases of an urban river being recovered can be found in Seoul. Its Cheonggyecheon river was buried by a highway that can no longer be used. Work to demolish the road began in 1999 and the project returned the river to its former glory as the city’s nerve center.

Six kilometers of the bunged river were restored and brought to the surface again, as the artery of a 40-hectare park. Since then, according to data from the South Korean government, the area has experienced extraordinary growth in its biodiversity, has cooled down and the urban air has become cleaner. There has also been an increase in use of public transport.

Victim of an environmental disaster

The 1987 Rhine Action Program was an initiative of several local governments in cities dependent on the river, which a year earlier suffered one of the darkest episodes in its history when 20 tons of toxic chemicals spilled into its basin following a fire in an industrial building. The environmental consequences were catastrophic.

Thanks to this program to eliminate river pollution and more than 15 billion dollars invested in it, the waters of the Rhine were recovered. There is still work to do, but presently 95% of wastewater from factories is treated and there are now 63 species of fish living in the river.

A home to life once more

In 1957, the Natural History Museum declared that the Thames, London’s snaking spine, was biologically dead. At the time, it seemed to have become an infectious waste dump in which fish could no longer live, since there was no oxygen during several kilometers of its transit through the city. Wartime bombing destroyed a good part of the sewage system that kept the river clean.

Since the 1960s, measures have been taken to eliminate river pollution, rebuilding the drainage system and tightening the noose around pesticides, fertilizers and heavy metals from industry that formerly reached its waters.

Now the big enemy of the river is the plastics that end up in it from many sources. London is constantly launching campaigns for a cleaner Thames. Although the problem of sewage in the river has not been completely solved, fish have returned to the Thames and there are now 125 species living in it. Occasionally, you might even find a whale that has erred into the recovered river.

An example of re-naturalization

The Manzanares, the “apprentice river” as the writer Francisco de Quevedo called it, is another example of the restoration of waters and ecosystems. After the Madrid Río works were completed, a project began to create an ecological corridor connecting the northern district of the city, where the river is born, with its outlet into the river Jarama, focusing attention on a 7.5 km stretch crossing through the city of Madrid.

The opening of the floodgates generated an explosion of life and the sediment made possible the creation of sandbanks in which seeds carried by the river could germinate. The result is a riverbank full of indigenous floral species, reeds and bulrushes, and spontaneous growth of trees such as poplars and elms. It is now an ideal habitat for animals, too.

River water quality is also better now, with more oxygenation and a reduction in nitrates, in part thanks to the presence of all this new plant life.

Many years ago, the rivers and canals of Copenhagen received rainwater from pipes that also carried sewage, often resulting in toxic discharges into the water. From 1991 onwards, the city undertook a recovery plan of rivers and canals by which rainwater drainage channels were reformed and the sewage network was improved. The project largely managed to cut back the waste being tipped into the port, improving water quality, from filthy to crystalline, and now you can even bathe in it.

Source: BBC, Iagua, Planeta Inteligente, Kcet