With global demand for clean water increasing, there is a continuing need to improve the performance of water treatment processes. A new process for water filtration using carbon dioxide consumes one thousand times less energy than conventional methods, scientific research published this week has shown.

Affluent neighborhoods with lawns — and occasionally swimming pools — use up to ten times more water than neighborhoods with higher density housing with less landscaping, according to a new study. The study points to the water-saving benefits of high-density neighborhoods such as more use of hardscaping, non-vegetative landscapes, as well as native plants in landscapes, which use less water than lawns.

Peak runoff in streams and rivers of the western United States is strongly influenced by melting of accumulated mountain snowpack. A significant decline in this resource has a direct connection to streamflow, with substantial economic and societal impacts. An international team of scientists has found that up to 20 percent loss in the annual maximum amount of water contained in the western United States’ mountain snowpack in the last three decades is due to human influence.

Researchers say that by 2050, almost half of the world’s population will live in countries with a chronic water shortage. In African drylands, it is not a water shortage problem, but an inability to capture water for food and other uses. Israeli scientists help villagers in Ethiopia, Zambia, and Uganda to identify water sources and test water quality – and also better capture and use water which is available.

Potentially explosive methane gas leaking from energy wells may travel extensively through groundwater and pose a safety risk, according to a new study. Researchers found the gas is highly mobile in groundwater, travelling far beyond the shale wells where it is drilled and changing the water chemistry. It will also escape into the atmosphere as a powerful greenhouse gas.

Wheat, rice, sugar, cotton and maize are among the essential internationally traded crops in the global economy. To produce these crops, many countries rely on irrigated agriculture that accounts for about 70 percent of global freshwater withdrawals, according to the United Nations Water program. One freshwater source is underground aquifers, some of which replenish so slowly that they are essentially a non-renewable resource.

More than half the world’s population lives within 37 miles (60 kilometers) of the coast, and three-quarters of all large cities are located in coastal areas. Many coastal communities rely on groundwater to satisfy their drinking and farming water needs. But removing too much of that groundwater can change the fluid pressure of underground aquifers, drawing seawater into coastal aquifers and corrupting water supplies. Saltwater intrusion is often irreversible. Researchers have transformed pulses of electrical current sent 1,000 feet underground into a picture of where seawater has infiltrated freshwater aquifers along the Monterey Bay coastline.

President Trump issued an executive order 28 February directing federal agencies to revise the Clean Water Rule, a major regulation published by the Environmental Protection Agency and the Army Corps of Engineers in 2015. Framers and ranchers are particularly worried that the Clean Water Rule could expand federal regulations that impact their private property rights. However, regulatory agencies and the regulated community need to know the limits of the Clean Water Act’s reach so they can take appropriate measures to protect water resources. If the rule is scrapped, we still will need to know which water bodies require protection under the law. If the Trump administration withdraws or weakens the Clean Water Rule, it is likely to leave regulators interpreting case by case whether tributaries and adjacent waters are covered, as they have been doing since 2006, and land and water owners guessing about what they can do with their resources. So in the end, repealing the rule won’t answer the underlying question: how far upstream federal protection extends.

As the world warms, mountain snowpack will not only melt earlier, it will also melt more slowly, according to a new study by scientists at the National Center for Atmospheric Research (NCAR). The counterintuitive finding could have widespread implications for water supplies, ecosystem health, and flood risk.