By Malcolm Watson
University of Novi Sad, Faculty of Sciences
Most people are aware of the fact that in ancient times, rivers were essential to the rise of human civilisation. From Shang on the Yellow River, to Uruk on the Euphrates, without rivers, there would be no agriculture, and without agriculture, the earliest cities could never have developed. What is perhaps less obvious is the fact that rivers are still of vital importance even today. As we enter the late stages of the Information Age, with 3D printers becoming cheaper every year, we are still centuries of development away from the point where we will be able to use an app on our phones to download our breakfast like a portable version of the replicators from Star Trek. About half the global population depends on rivers for fishing and/or farm irrigation and billions of people world-wide continue to rely on rivers, directly or indirectly, for drinking water supply.
For example, the Danube (Europe’s second largest river after the Volga) passes through 10 different countries and serves as the primary drinking water source for more than 20 million people. In riverbank filtration systems, shallow wells are used to extract water from the first layer of aquifer near the river bed. These aquifers are directly connected to the river itself by the river sediment, with the surface water in riverbank filtration sources typically taking two to three weeks to travel through the riverbank from the river to the well. In this time, the sand and gravel within the aquifer layer serve to physically filter the river water, and also provide a home to a wealth of microorganisms which are capable of breaking down and removing various pollutants. As a result, the water which reaches the wells is a lot cleaner than the original river water, and often only requires disinfection in order to make it safe for human consumption.
Travelling down the Danube from its source in the Black Forest, you pass through many settlements which utilise riverbank filtration as their primary drinking water source, including Deggendorf/Straubing (DE), Vienna (AU), Bratislava (SK), Budapest (HU), Novi Sad and Belgrade (RS), all the way to Galati (RO) just before the Danube delta at the Black Sea. Historically, all these riverbank filtration systems have been excellent drinking water sources, but as the Danube basin feels the increasing effects of climate change, and with more and more pollution being emmited every year, all of these cities must work to protect the river. River protection would be a challenge if drinking water supply were the only issue, but like every other river in the world, in addition to its role in drinking water supply, the Danubian countries also rely on the river for irrigation, for navigation, for drainage, for electricity generation, and to support hundreds of biodiverse ecosystems across the continent, including more then 80 internationally protected Ramsar sites (wetland nature reserves) in the Danube basin alone.
The Danube is just one example. Apart from the estimated 83 million people living in the Danube basin, another 8 billion people on this planet rely on rivers for all the reasons discussed above, so its clear that in general, healthy rivers are indeed still absolutely essential for almost everyone (1).
(1) More than 100 million people in the world rely on incredibly expensive desalination plants rather than rivers, but let’s not worry about them right now.