Water, or the lack thereof, is one of the defining challenges of the 21st century. As temperatures rise and droughts become more frequent, the threat of dwindling water resources worries not just environmentalists and governments but companies and their investors, too. Nearly every industrial sector, from food and beverages to mining to pharmaceuticals, depends on water for its operations.

New research shows that wastewater recycling processes may generate more greenhouse gases than traditional water-treatment processes. Despite this finding, there are good reasons to continue keep wastewater recycling among the water-resource tools for urban areas.

The implementation of virtual water into trading deals has been suggested as a realistic solution to solving the global inequality of renewable freshwater, but new research suggests that it may not be as revolutionary as first thought.

The pristine state of unpolluted waterways may be their downfall, according to research results published in the journal Geophysical Research Letters.

The world's rivers are in a crisis of "ominous" proportions, according to a new global analysis, published today in the journal "Nature." Rivers in the developed world, including those in much of the United States and Western Europe, are under severe threat despite decades of attention to pollution control and investments in environmental protection, the study shows.Rivers o

Zebra mussels are an aquatic nuisance species being identified in Colorado; they also have been discovered in Pueblo Reservoir. "There are waters in Colorado that have tested positively," Ranger Jim Hawkins said.

Groundwater is contained in aquifers, underground layers of water-bearing permeable rock or sediment such as silt, sand, or clay. Under, and sometimes over the aquifer is an aquiclude, a solid, impermeable layer such as clay that the water cannot penetrate. The top surface of the water saturated material is called the water table.

After wind, sun, currents and tides, a company is preparing to make clean electricity by harnessing another natural phenomenon, the energy-unleashing encounter of freshwater and seawater. Taking a step further in the planet's hunt for clean power, Norway is to unveil today the world's first prototype of an osmotic power plant on the banks of the Oslo fjord.