Water and Nature
" More than one-half of the world’s major rivers are being seriously depleted and polluted, degrading and poisoning the surrounding ecosystems, thus threatening the health and livelihood of people who depend upon them for irrigation, drinking and industrial water. "
World Commission on Water for the 21st century. | 
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What are the interactions between water and nature?
Water is life and is necessary for all ecosystems. Sound ecosystems ensure balanced communities of species and rich livelihoods. Rich and diverse livelihoods are fundamental for our well-being and for the survival of the poorest. Currently, around 1,9 million species are described in the world and million of others are still to discover (Source:IUCN).
Our meals, our health and our livelihoods depend on biodiversity. Food resources from agriculture or fisheries, the diversity of medicinal herbs, water-consuming industries, or tourist activities developed next to lakes and rivers demonstrate that water resources are vital to nature and Human. In addition, nature plays a role of regulation and purification of water resources, thus contributing to better water supply and quality.
Regulating the water flows:
Some ecosystems such as wetlands or forests have strong water retention capacities. Water penetrates into these ecosystems, is stored, then restored. During wet periods, these ecosystems contribute to peak flow mitigation. During dry seasons, water is progressively released, which maintains a base-flow . Hence the necessity of preserving these zones. Improving water quality:
When polluted water percolates into the soil, it is naturally filtered. This treats a certain amount of pollutants, which will not need human treatment afterwards. Wetlands and forests are particularly useful for this purpose.
Preserving ecosystems presents interests of ethical, social and economical nature. Experts from the European Union estimate the financial value of goods and services provided by ecosystems at more than 26 000 billion euros per year, namely almost twice the value of what Human beings produce every year.
What are the current threats on this equilibrium between water and nature?
Growth in human populations, increasing consumption, infrastructure development, land conversion, poor land use and massive use of pollutants in water all threaten the ecosystem functions that produce our freshwater resources. Ecosystems evolve far too slow to adapt to quick and brutal changes, and cannot play their purifying and regulating role anymore.
· Pollution: With urbanization and industrialization, the quality of rivers, lakes, and aquifers may deteriorate seriously. This phenomenon has accelerated since 1970’s, due to the increase of human and industrial waste. With current water treatment systems, eliminating some toxic particles is sometimes not possible anymore. Surface water as well as groundwater run the risk to be neither proper to human consumption, nor to ecosystems.
· Biodiversity under threat: Today, a growing number of species and habitats are disappearing. According to the 2004 IUCN Red List of Threatened Species, a total of 15,589 species of plants and animals are threatened, facing a high risk of extinction in the near future, in almost all cases as a result of human activities. Since the beginning of the century, 50 % of wetlands have disappeared. Since 1990’s, deforestation concerns 19,4 million ha each year.
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· Water scarcity: Water resources depletion generates tensions among water users and sometimes between states or countries. Every country wants to maintain sovereignty on its resources and to maximise its storage and withdrawals. Water scarcity already affects one third of the total world population (World Water Vision)
· Flood and drought risks: Ecosystems degradation, especially in wetlands or in the upstream patch of catchments, reduces their role on flood or drought mitigation.
What kind of measures could mitigate these impacts?
First, simple everyday gestures can reduce the phenomena threatening water resources. All actors from the water sector should get involved, namely farmers, industrials, but also individuals. A responsible water-saving behaviour, a reduction in pollutants in agriculture can slow down the disappearance of water resources and the changes in ecosystems. Collective measures should also be enforced. Spaces arrangements and water resources use should be taken in hand. Regulating natural river flows, carrying out soft changes and adapting water consumption to its availability may have much more sustainable and efficient effects than increasing the pressure on the resource, leading to short-term solutions. A effective cooperation should exist among actors, to ensure a consistent and environment-friendly water management.
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