- Brian Richter, co-lead for the Conservancy's Global Freshwater team
Everyone understands that fresh water is a necessity for all living things on Earth. But how important is protecting our rivers and lakes for biodiversity conservation?
If you compare marine and land habitats with those of freshwater, you’d find that freshwater habitats are more densely packed with species. To date, scientists have catalogued some 45,000 freshwater species.
Freshwater systems also sustain many terrestrial species — in many arid and semi-arid regions, as many as 70 to 90 percent of all terrestrial species depend on accessing freshwater habitats for water and food.
Besides providing us with water, in what other ways do freshwater ecosystems like lakes and rivers support human well-being?
Freshwater ecosystems are a critically important source of food. Fifteen percent of the fish we consume comes from freshwater habitats — the fishery of Asia’s Mekong River supports 55 million people.
But they provide more than food. Freshwater systems:
* Store flood waters,
* Purify water supplies,
* Generate electricity with hydropower,
* Produce building materials such as timber and clay bricks,
* Provide places for recreation and attractions for tourists, and
* Deliver sand to replenish coastal beaches.
We will never be able to feed the hungry or meet the needs of the billion people that lack access to clean water unless we can sustain the benefits and services that freshwater ecosystems are providing to society, free of charge.
How much of the Earth’s fresh water is actually accessible to humans?
Less than 1 percent of all water on Earth is usable by humans. The rest is too salty, frozen in polar ice caps, or too deep underground.
How can we best balance human needs like electricity, agriculture and food with keeping freshwater ecosystems healthy?
First and foremost, every human being should have access to sufficient water to meet their basic needs: Drinking, bathing and cooking. And we need to ensure that there is enough water flowing through our rivers, lakes and wetlands so they continue to supply us with essential needs like hydropower and storage of flood waters.
However, one particular concern is that when we build dams to store water for cities and farms, generate electricity, or manage floods, we must build them and operate them in a way that does not degrade river ecosystems.
By my estimate, at least half a billion people living downstream from dams have suffered because dams have destroyed fisheries, displaced people from their homes and farms, or other problems. In other words, we need to stop creating poverty with dams and move toward sustainable development.
How can protecting freshwater ecosystems help mitigate climate change?
Two of the greatest human concerns associated with climate change are that floods will become more frequent and damaging, and droughts will become more intense, threatening our water supplies.
Natural freshwater habitats such as floodplains and wetlands temporarily store flood waters and can substantially reduce downstream damages. And while they are storing water, much of it may recharge ground water aquifers, which can be a critically important source of water during droughts.
So conservation of freshwater ecosystems is an important component of climate change adaptation strategies.
Can you give us an example?
The Conservancy's Roanoke River project, in North Carolina, is buying land along the water's edge, so that as sea levels rise, wetland areas can move upslope with the water line. They are also influencing the operation of an Army Corps of Engineers dam so that it can better regulate floods and provide adequate water flows during droughts to support fish and other biota.
This project highlights the fact that freshwater ecosystems can help mitigate the two greatest threats to humanity posed by climate change: droughts and floods.
Brian Richter co-leads the Conservancy's Freshwater Conservation Program. He has been involved in river science and conservation for more than 20 years and travels worldwide helping governments, academic institutions, non-governmental organizations and private firms understand the need for and feasibility of sustainable water-management practices. He has also consulted on more than 90 river projects worldwide and has developed numerous scientific tools and methods to support river restoration efforts.