Water use changing with climate

Unlike her neighbors, Rachael Paschal Osborn’s yard isn’t an expanse of green grass meticulously fertilized and watered on schedule by timed sprinklers.

Paschal Osborn, a public interest lawyer who teaches water law at Gonzaga University’s Law School, doesn’t like to waste a drop. So, the grass in her west Spokane yard is brown during the summer months while drought-resistant native plants and her vegetable garden thrive on drip irrigation.

Climate experts say the rest of Washington may have to follow Paschal Osborn’s example in the future as global warming changes the way residents use water on their yards and in their homes.

The gradual warming of the Earth’s surface will have benefits and drawbacks for municipal water systems, they say.

Kurt Ungur, a hydrogeologist with the state Department of Ecology, said a warmer climate likely will produce about the same amounts of precipitation – possibly a bit more – but its timing will change from historic patterns.

In winter, more precipitation will fall as rain, rather than snow, which serves as the mountain “bank” for much of the state’s water supplies.

In spring, warmer temperatures will bring earlier runoff, leading to potential conflicts over scarce water in late summer, he said.

Paschal Osborn, co-founder with her husband, John Osborn, of the nonprofit Columbia Institute for Water Policy, said most of the state’s cities are unprepared for the consequences of global warming.

“The potential for change is dramatic. It could change the natural ecology of forests. It is also going to change the human landscape,” Paschal Osborn said. “It will change what we can grow for crops and what we can grow in our yards.”

Paschal Osborn, Ungur and others point to Seattle, which has taken the lead in promoting water conservation and planning for the effects of climate change.

It will be up to individual municipalities to adapt to global warming changes, Ungur and others said.

Heather Cooley of the Pacific Institute for Studies in Development, Environment, and Security, in Oakland, Calif., said communities could reduce their annual water consumption by 30 percent through use of low-flow devices, efficient landscaping and more efficient use of water by commercial and industrial customers.

Paul Fleming, manager of climate change initiatives for the city of Seattle’s water utility, said the key will be mitigating effects of greenhouse gas emissions, then adapting to the changes that climate change will bring.

“The impacts don’t manifest themselves for quite a while. I think we have some time to make investments to strengthen the resiliency of our system,” Fleming said. “Conservation has been a real godsend to us.”

Water storage in lean times and water drainage during increasingly frequent urban floods are two issues cities will face, Fleming and Paschal Osborn said.

“In summer, when rivers and groundwaters are normally fed by snowmelt, the snow is not going to be there,” Paschal Osborn said.

“We will tend to have water scarcity issues during the summer months. That probably will be compounded because summers will be hotter.”

Instead of building expensive storage reservoirs, the Seattle utility, which provides water to 1.3 million customers in King County, has turned to using less water per customer, spokesman Andy Ryan said.

Despite population growth, the city’s utility is using about the same amount of water it did in the 1960s, he said.

Seattle has a three-tier rate system that makes it more expensive to use large volumes of water. An entire section of the utility is devoted to promoting water conservation measures, Ryan said.

The flip side is too much water when it’s not needed, Fleming said.

It would be too expensive to rip up streets to install larger water storage vaults to accommodate excess precipitation and runoff, so cities will have to look for ways to add “little kinds of buckets” where storm water can be temporarily stored, he said.

The Pacific Institute’s Hoover said some communities in California are recycling treated wastewater for nonpotable uses, such as in landscape irrigation and industrial uses.

Unlike Seattle, many cities and towns in Washington have not made plans for potential impacts of climate change, mainly because water utilities make their living off providing more water to customers, Paschal Osborn said.

“At some point, you’d think water purveyors are going to say, ‘water is too precious to waste,’ ” she said. “We are still of the mind-set that the aquifer is so plentiful we don’t really need to conserve.”