7 September - With competition on the rise between humans and other species for the world's limited water supplies, governments must take environmental issues into consideration when drafting laws on the use of water to avert an impending water crisis, cautions a new United Nations report.

Although more than two-thirds of the planet is covered in water, only 2.5 per cent is freshwater, most of which is stored deep underground or in glaciers, leaving only 1 per cent available for human use.

A key challenge facing countries is how to meet the water needs of a growing human population, while maintaining freshwater ecosystems and supporting environmental sustainability, says “Greening Water Law,” the new publication launched in Stockholm, Sweden, today by the UN Environment Programme (UNEP).

Every year, nearly 1.8 million children under the age of five die from diarrhoeal diseases, including cholera, typhoid and dysentery, and these deaths are attributable to a lack of safe drinking water and basic sanitation.

If the international community does not take action to improve freshwater supplies for drinking, sanitation and hygiene, up to 135 million preventable deaths could occur in the coming decade, the report warns.

The unsustainable use of freshwater also drives biodiversity loss, it says, citing the example of North America, where nearly 30 per cent of continental freshwater fauna populations are threatened with extinction due to depleted and contaminated water sources.

“Achieving a better balance between human and environmental water needs will require significant changes in legislation – and you need legal tools to do this,” says Gabriel Eckstein, the report's lead author.

In Australia's New South Wales, for example, the Water Management Act dictates that in the event of a severe water shortage, freshwater will first be allocated to meet basic domestic and municipal needs, then in response to environmental necessities and then finally for all other purposes.

The Water Resources Act in Paraguay ranks the water needs of aquatic ecosystems as second to humans but ahead of agriculture, power generation and industry.

“These laws recognize the immense value of freshwater resources,” Mr. Eckstein notes.

The UNEP study also points to the economic gains that can be derived from having freshwater resources protected by national law.

The world's wetlands are estimated to provide as much as $15 trillion in ecosystem services through their natural ability to purify and detoxify water.