Utilities and Climate Scientists Team Up to Prepare for Bleak Water Future

Alliance is helping U.S. water utilities integrate climate models into long-term planning to better adapt their operations to global warming

San Francisco's Oceanside wastewater treatment plant/Credit: Christina B. Castro

Ten of the nation's largest water utilities have teamed up to connect climate scientists and water providers so utilities will have the information they need to prepare for the harmful effects of global warming.

Climate change will create a host of challenges that affect water supply, water quality, stormwater drainage and flood control. Utilities on the coast may need to prepare for rising sea levels. Utilities in the Southwest could face more intense droughts.

But there's a gap between most climate research and the kind of information that utilities need. Current climate models tend to work best with long-term trends and over large geographic areas. Water utilities, on the other hand, need specific information about how their water supplies and local rainfall patterns will be disrupted before they risk investing their customers' money in new infrastructure.

"It's inherently difficult for water utilities to make heads or tails of how they're going to be affected by climate change," said Kathleen Miller, a scientist at the National Center for Atmospheric Research. "When you zoom in on a particular locality, the scale of global models isn't able to tell you exactly what's going to happen."

To fill this gap, David Behar, who directs the climate program at the San Francisco Public Utilities Commission, helped found the Water Utilities Climate Alliance (WUCA) in 2007.

"It really is a Wild West out there," Behar said, referring to the lack of guidance on how to make high-level science useful on a regional scale. The local data that are currently available are often scattered or hard to understand, he told SolveClimate News, leaving water utilities without a clear approach for evaluating local climate vulnerabilities.



WUCA aims to integrate climate models into utility infrastructure planning. Its members include the San Francisco Public Utilities Commission, Denver Water, Seattle Public Utilities, Portland Water Bureau, Tampa Bay Water and the New York City Department of Environmental Protection.

Miller said WUCA has become a kind of "broker" for the water industry. "They've been engaging very actively with the atmospheric science community to get a layperson's understanding of the science and how to use it [for water resource planning]."

Water utilities have typically used historic stream flows and rainfall data to gauge future water supplies, said Marc Waage, manager of water resource planning at Denver Water. But climate change will disrupt historical weather patterns and add a huge layer of uncertainty to long-term planning.

WUCA has co-authored two studies on bringing climate models into the water utility community. The first report, completed in 2009, identified how climate science can be tailored to better support adaptation needs. A follow-up report in 2010 explained methods for incorporating the science into decision-making.

The organization is now conducting a series of case studies on projected climate impacts for San Francisco, Seattle, Portland, Tampa Bay and New York City.

"The purpose is to work closely with the academic community [on issues] related to climate change modeling and how to make that information useful for utilities," said Lorna Stickel, water resources planning manager at the Portland Water Bureau. The projects are funded by the utilities and by the National Oceanic and Atmospheric Administration.

Last month, Stickel and Behar met with scientists who work with the Community Earth System Model, whose data has been included in assessments by the United Nations Intergovernmental Panel on Climate Change and which is one of three global climate models used in the United States. Behar said he and Stickel helped persuade the scientists to create a new work group focused on connecting climate model results with the needs of decision-makers. The group's first area of focus, said Behar, will be the impacts on water resources.

In addition to WUCA's efforts, individual utilities have turned to "no regret strategies" for climate change adaptation, such as conservation, water recycling and diversifying their supply sources. The term "no regret" refers to the fact that the methods are useful even in the absence of damaging climate change impacts, Behar said, "but they will also make us more resilient to the effects of climate change, whatever they are."

As useful as these no regret strategies are, however, they won't solve all the problems caused by climate change. As water utilities tackle these deeper structural problems, Behar said their biggest challenge will be making changes at the right time, in the right place and at the right cost.

San Francisco's Public Utilities Commission is one of the few WUCA members investing in a major project driven exclusively by a need to adapt to climate change. Over the next five years, Behar said, San Francisco will install equipment to prevent rising sea levels from pushing seawater back into the city's wastewater treatment facility. The project is funded by ratepayers and will cost $20 million to $40 million.

Despite the enormous price tag, the program will fix a pernicious and costly problem that has persisted for years.

During very heavy rainstorms, when the stormwater collection system can't handle the large volume of water, stormwater flows into the sewers and out of the overflow pipes that discharge into San Francisco Bay. At high tide the pipes become inundated, allowing saltwater to flow into the wastewater treatment system. The saltwater can then kill the microorganisms that clean up wastewater and reduce the facilities' efficiency.

Behar said the saltwater flows currently occur only four to seven times a year. As sea levels continue to rise, however, they will increase, so "it makes sense to invest in protecting ourselves from that problem today."

Seattle Public Utilities has also launched a small adaptation project. Earlier this year, the utility partnered with the University of Washington to create Seattle RainWatch, a $70,000 online forecasting tool that projects local rainfall patterns for the next hour.

RainWatch allows the utility to respond to storms ahead of time, said Paul Fleming, manager of climate and sustainability at Seattle Public Utilitites. If RainWatch forecasts heavy precipitation in one part of the city, for instance, employees could be sent out to clear debris from storm drains before the rain hits.  

The program hasn't made a dramatic difference at this point, Fleming said. But if the West Coast receives the intense storms that some climate researchers are predicting, Seattle will have one more tool at its disposal.

Like the other WUCA members, Fleming said Seattle remains focused on understanding the climate impacts that will influence its resource planning. The utility is researching the effects of local sea level rise and hopes to commission another study on the impacts of erosion, water quality and forest fires.

Fleming said that it's tempting to think "enough already, let's do something." More action does need to be taken, he said, but the utility needs to better understand and analyze localized climate data before committing to a course of action.

The slow pace of climate change is working in the utilities' favor, Behar said. "Unlike mitigation policy, where we need to act now, we have some time to consider what we know and don't know [about our] vulnerability to climate change and to plan adaptation measures in a more careful and time-consuming way."

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