Common Threats
Clean water in good supply is in danger and we need to conserve our water resources. The main threats to freshwater are linked to economic development and the need to meet the growing demand for water in the 21st century.
To dam or not to dam
In the 1950's dams were seen as the hallmark of development. Over 48,000 large dams are in operation worldwide. And more are being built to provide drinking water, irrigate the land, produce hydropower, and prevent floods.
Today only a third of the world’s 177 large rivers (1,000 km and longer) remain free-flowing, unimpeded by dams or other barriers.
But we have learnt that dams can cause damage as the natural flow of rivers becomes fragmented. Dams can destroy ecosystems and cause people to lose their homes and livelihoods.
In 1998, the World Commission on Dams was established to address what had become one of the most controversial areas of infrastructure development and in the words of Nelson Mandela ‘one of the battlegrounds in the sustainable development arena’.
Today only a third of the world’s 177 large rivers (1,000 km and longer) remain free-flowing, unimpeded by dams or other barriers.
But we have learnt that dams can cause damage as the natural flow of rivers becomes fragmented. Dams can destroy ecosystems and cause people to lose their homes and livelihoods.
In 1998, the World Commission on Dams was established to address what had become one of the most controversial areas of infrastructure development and in the words of Nelson Mandela ‘one of the battlegrounds in the sustainable development arena’.
The Bassano Dam is part of the Eastern Irrigation District, a large irrigation network in southern Alberta, Canada, that provides water to farms, towns, and recreation areas.
Dams can cause damage as the natural flow of rivers becomes fragmented.
Agriculture: the greatest user of water
Globally, the agricultural sector consumes about 70% of the planet's accessible freshwater – more than twice that of industry (23%), and dwarfing municipal use (8%).
Agriculture wastes 60% or 1,500 trillion litres, of the 2,500 trillion litres of water it uses each year. Between 15–35% of water used by agriculture is estimated to be unsustainable.
The main causes of wasteful and unsustainable water use are:
Agriculture wastes 60% or 1,500 trillion litres, of the 2,500 trillion litres of water it uses each year. Between 15–35% of water used by agriculture is estimated to be unsustainable.
The main causes of wasteful and unsustainable water use are:
- Leaky irrigation systems
- Wasteful field application methods
- Cultivation of thirsty crops not suited to the environment
Brazil has most of the crop area of the Amazon, followed by Peru and Bolivia
Between 15–35% of water used by agriculture is estimated to be unsustainable.
Widespread contamination
The use of pesticides, fertilizers and other agrochemicals has increased hugely since the 1950s. For example, the amount of pesticide sprayed on fields has increased 26-fold over the past 50 years.
These chemicals don't just stay on the fields they are applied to. Some application methods – such as pesticide spraying by aeroplane – lead to pollution of adjacent land, rivers or wetlands. Fertilizers and pesticides also commonly run-off from fields to adjacent rivers and lakes and contaminate groundwater sources.
Pesticides often don't just kill the target pest. Beneficial insects in and around the fields can be poisoned or killed, as can other animals eating poisoned insects. Pesticides can also kill soil microorganisms.
Unlike pesticides, fertilizers are not directly toxic. However, their presence in freshwater and marine areas alters the nutrient system, and in consequence the species composition of specific ecosystems.
These chemicals don't just stay on the fields they are applied to. Some application methods – such as pesticide spraying by aeroplane – lead to pollution of adjacent land, rivers or wetlands. Fertilizers and pesticides also commonly run-off from fields to adjacent rivers and lakes and contaminate groundwater sources.
Pesticides often don't just kill the target pest. Beneficial insects in and around the fields can be poisoned or killed, as can other animals eating poisoned insects. Pesticides can also kill soil microorganisms.
Unlike pesticides, fertilizers are not directly toxic. However, their presence in freshwater and marine areas alters the nutrient system, and in consequence the species composition of specific ecosystems.
Agriculture is the most damning area of the country’s environmental failures
The amount of pesticide sprayed on fields has increased 26-fold over the past 50 years.
Habitat loss
Species loss in freshwater ecosystems is faster than anywhere else on Earth. There is a more than 50% decline in freshwater species populations over the past 30 years.
Protecting and restoring freshwater habitats is essential for safeguarding plant and animal species, as well as the communities who rely on them for livelihoods and other services.
However, freshwater habitats in many places are either still under immediate threat or underrepresented in current protected area networks.
In most cases, existing freshwater protected areas are fragmented and disconnected from one another, and not sufficiently large or robust enough to safeguard species and freshwater ecosystem services.
Protecting and restoring freshwater habitats is essential for safeguarding plant and animal species, as well as the communities who rely on them for livelihoods and other services.
However, freshwater habitats in many places are either still under immediate threat or underrepresented in current protected area networks.
In most cases, existing freshwater protected areas are fragmented and disconnected from one another, and not sufficiently large or robust enough to safeguard species and freshwater ecosystem services.
Until the 19th century, giant Beluga sturgeons migrated from the Black Sea up the Danube as far as Germany and were important mainstays for many fishing communities.
Dams such as the Iron Gates between Serbia and Romania have cut off the migration routes of sturgeons, causing loss of spawning habitats.
Climate change
It is thought that people will feel the impact of climate change most strongly through water, with hundreds of millions of people at greater risk of water scarcity or flooding. It is estimated that by 2025 up to two-thirds of the world’s population will be living in water stressed countries.
The impacts of climate change are most visible in the dramatic changes occurring to the planet’s freshwater resources according to a WWF report written in 2010 for the World Bank.
The report, Flowing Forward, finds both “visible” water such as rivers, lakes, precipitation, glaciers and snowpack, and water used for crops and livestock, health and sanitation services, hydroelectric and nuclear power as well as manufacturing and business are heavily influenced by climate change.
The very language of climate change — droughts, floods, desertification, famines, tropical cyclones — is the language of water.
We can no longer assume that what is sustainable now will remain sustainable in 10 years, much less 50. So a shifting climate means that the rules for water management must change too. Our current model of ‘sustainable development’ is threatened by climate change. Engineers, policymakers and resource managers need new tools to prepare for more extreme floods and droughts.
The impacts of climate change are most visible in the dramatic changes occurring to the planet’s freshwater resources according to a WWF report written in 2010 for the World Bank.
The report, Flowing Forward, finds both “visible” water such as rivers, lakes, precipitation, glaciers and snowpack, and water used for crops and livestock, health and sanitation services, hydroelectric and nuclear power as well as manufacturing and business are heavily influenced by climate change.
The very language of climate change — droughts, floods, desertification, famines, tropical cyclones — is the language of water.
We can no longer assume that what is sustainable now will remain sustainable in 10 years, much less 50. So a shifting climate means that the rules for water management must change too. Our current model of ‘sustainable development’ is threatened by climate change. Engineers, policymakers and resource managers need new tools to prepare for more extreme floods and droughts.
Dried-up lake due to drought, Patagonia, Argentina. Climate change is increasing the frequency of extreme weather events such as droughts and flooding.
The very language of climate change — droughts, floods, desertification, famines, tropical cyclones — is the language of water.
