Penn State Live - Reducing water footprint can positively impact global water crisis

Reducing water footprint can positively impact global water crisis

Monday, April 20, 2009

Bill Sharpe

University Park, Pa. -- Much of the world's population lacks access to safe water. Bill Sharpe, Penn State professor emeritus of emergency forest hydrology, said the world's water supply is endangered, and the possibility that the next big war will be over water, instead of oil, is very real.

While agriculture and industry are prime water users, residential water consumption also is significant and can be drastically reduced. Sharpe emphasized that it's important for everyone on the planet to conserve water now. As with a carbon footprint — a measure of the amount of greenhouse gases produced in our day-to-day lives — individuals and organizations each can leave behind a sizeable water footprint on the Earth.

A carbon footprint, he said, occurs from individual daily activities such as using electricity, driving an automobile and heating or cooling the home. Water can be linked to some of the same daily activities, but a water footprint is basically measured by how much a person uses and ultimately what happens to it after it is used.

"There are two kinds of water use — consumptive and nonconsumptive," Sharpe said. "Consumptive is when used water evaporates into the atmosphere, which reduces the quantity. Non-consumptive use is when water is returned to rivers, streams or aquifers as treated water, but it changes the quality."

Climate change also is having a big impact on the world's water availability.

"Areas that usually see a lot of rain have experienced several years of drought and are experiencing massive food and drinking water shortages," said Sharpe. "In some countries like Australia, the lack of water may be permanent."

In Africa, fighting has already begun among several countries for water supplies. Even in the United States, a number of states are arguing over river water usage. One alternative, desalinizing ocean water or removing the salt, Sharpe said, requires a massive, incredibly expensive effort to attain usable water.

California has faced water conservation issues for years and has implemented water rations in agricultural, industrial and residential uses. It leads states in water reuse for landscaping purposes by using renovated wastewater, but the state still faces water shortage problems.

Nationally, residential water use has been declining, although Sharpe said this is largely from the passage of federal legislation in 1995 mandating that new homes use more efficient water fixtures, such as toilets. Before this piece of legislation, toilets expended from 3.5 gallons to 6 gallons per flush.

"It's remarkable that despite the increase in population, there's a decrease in water use," Sharpe said. "Basically, it took federal legislation to get us there."

Sharpe said an individual's first, best and most preemptive effort to reduce his or her water footprint is to use energy- and water-saving appliances. Purchasing water-efficient, front-loading clothes washers and dishwashers will pay for themselves in savings, Sharpe said. Homes that don't already have one should install toilets that use only 1.6 gallons of water when they flush. Also, efficient showerheads are only about $10 and are easy to install.

Sharpe said residents also can reduce their water use on their landscapes. He suggests that homeowners collect rainwater in barrels to use for watering gardens. The main problem with this idea, he said, is that there isn't enough incentive to adopt it because most water and sewer bills aren't based on usage — homeowners pay a flat monthly fee. Sharpe believes if water use in homes were metered, residents would make a bigger effort to preserve water.

"The federal government doesn't see the need to take this initiative yet," Sharpe said. "People need an incentive to reduce their use and until they're actually paying more, they might not make the effort."