8 benefits of healthy, free-flowing rivers
The millions of kilometers of rivers and streams that flow across our planet appear to be a nearly endless source of fresh water. But rivers, streams, lakes, and ponds together make up just 0.007% of the freshwater on Earth (the rest resides in ice caps, glaciers, and groundwater), and many face serious threats from pollution, dams, and diversions — man-made evils that reduce how well these waters can help sustain humans and other species.
In many parts of the world, rivers and streams are so polluted that they can no longer support aquatic life, poisoning residents. In Africa, Australia, Russia and South America, diversion of important waterways for agriculture and other uses has altered seasonal flooding of basins to a degree that is affecting centuries-old wildlife migrations and causing changes in climate. A study published in the journal Nature 2019 found that only 37% of rivers longer than 1,000 kilometers (621 miles) are free-flowing their entire length, and only 23% flow continuously into the sea. In the United States, dams have cut off ancient spawning routes, causing alarming declines in some salmon populations and affecting entire ecosystems that depend on these species.
Fortunately, it is not too late to reverse these trends when policymakers around the world recognize the immense value of healthy, free-flowing rivers and act quickly and ambitiously to protect them. To celebrate World Rivers Day on September 25, here are eight benefits of protecting rivers.
1. Protects sources of clean drinking water.
The condition of rivers directly affects the quality of the drinking water they provide. Water from clean, healthy rivers requires less filtration than water from polluted rivers.
Rivers have played a central role in culture and history since the dawn of civilization – as trade routes, ceremonial sites and the heart of human settlements. For Indigenous Australians, rivers are living beings. Tribes in western North America hold annual salmon spawning celebrations. The ancient Egyptians held their Wepet-Renpet (New Year’s festival) on the Nile. And along the coast of Chaitén in Chilean Patagonia, indigenous people engage in ancient shellfishing, fishing, seaweed gathering and other cultural practices.
3. Preserved rWildlife reservoirs and biodiversity.
Riparian areas — the land that borders rivers — are among the most diverse, dynamic, and complex habitats on earth, according to a study published by the Ecological Society of America.
Rivers make up only a fraction of the 0.007% of the Earth’s freshwater mentioned above, but they support a disproportionate amount of biodiversity. For example, freshwater habitats are home to almost 10% of all animal species, including a third of all invertebrates. According to the International Union for Conservation of Nature “[o]Over 140,000 described species – including 55% of all fish – depend on freshwater habitats for their survival.”
Around the world, free-flowing rivers attract legions of boaters, anglers, and other outdoor enthusiasts. Chile’s Futaleufú River, like other internationally renowned whitewater trails, has become an epicenter for recreational and tourist activities. Futaleufú Riverkeeper, a local organization, created the Chicas al Agua (Girls on the Water) program to teach high school girls how to kayak and educate them about local environmental issues, producing not only kayakers but also “Guardians of the Futaleufú.” will.
Additionally, 2020 data from the US Bureau of Economic Analysis shows that outdoor recreation generated US$688 billion in economic output in the United States and supported 4.3 million jobs nationwide. Of this, boating, fishing and other river-related activities accounted for more than $30 billion of gross annual US production. This spending directly benefits businesses of all sizes and boosts economies in rural and urban communities across the country.
River channels, gorges, and floodplains form over eons to accommodate changes in water levels. Altering river flows, for example by building dams or culverts, disrupts these natural controls, separating rivers from critical floodplains and often putting communities at greater risk of catastrophic flood damage. Also, many dams are so old that they have become hazardous to nearby communities. Outages in 2017 at the Oroville Dam in northern California and the 90-year-old Guajataca Dam in Puerto Rico exacerbated storm surges and forced the evacuation of tens of thousands of people.
Rivers serve as one of nature’s most important transport systems, carrying nutrients, minerals and fine sediments to the ocean – often from alpine environments hundreds of miles away – and facilitating the transfer of other nutrients back upstream by migratory species such as salmon.
Free-flowing waterways within unaltered, connected river systems carry sediments to flood plains and provide important habitat and food for wildlife and plants. Sediments accumulating in river deltas have often created natural buffers to protect coastal areas from sea level rise. The estuaries of free-flowing rivers are home to an extremely rich biodiversity of birds, marine mammals, fish and other marine species.
These nutrient transfers can power entire industries, such as the shrimp and barramundi fisheries off Australia’s north coast.
7. Helps combat climate change.
Flooding large areas with levees can cause microorganisms to degrade organic material – for example trees and grasses that lined a river. When this process occurs without oxygen, methane, a well-known greenhouse gas, is often released into the atmosphere. A study was published in the journal in 2016 life sciences found that annual global greenhouse gas emissions from reservoirs are equivalent to what the entire Canadian nation emits – about 1.3% of man-made emissions. Removing dams and restoring and protecting free-flowing rivers can reduce this percentage.
8. Maintains a sustainable food source.
Rivers feed people – fish, freshwater snails, mussels, crabs and more. Around the world, many indigenous and local communities rely on healthy rivers as their “supermarkets”. Studies have shown that more than half of the protein consumed by many Indigenous communities in northern Australia’s river basins comes directly from fishing in rivers and hunting in the floodplains that feed them. In the US Pacific Northwest, tribes have relied on salmon as their primary food source for thousands of years.
By working to protect and restore free-flowing rivers around the world, policymakers can show their commitment to a healthy and sustainable future for their citizens and all life on earth.
Steve Ganey is Vice President and Lauren Spurrier Senior Director at The Pew Charitable Trusts.