Experts warn utilities to prepare for double-whammy weather
by Elizabeth Harball at ClimateWire
Most water utilities know that extreme weather can render their product undrinkable and have developed contingency plans to deal with hurricanes, floods, droughts, fires and other trials that may come their way.
But experts are now warning water providers that as the climate changes, they must brace themselves for a new normal — extreme weather events that happen so frequently that utilities don’t have time to recover from one disaster before the next one hits.
“What we see in the latest climate change science is not only a prediction that the intensity of events will increase, but also the frequency of events,” said Ben Stanford, director of applied research at Hazen and Sawyer, a New York-based consulting engineering firm that focuses on water, wastewater and water reuse.
“Utilities in the future will have either (a) less time to respond to one event before another one comes along, or (b) they’ll have to deal with multiple events within a very short period of time, if not on top of each other,” Stanford added. “I think that is where the shifting in our thinking needs to happen.”
Stanford is the principal investigator of a new report backed by the Water Research Foundation, which examined 41 water utilities from across the United States and Australia to study how extreme weather is already threatening their operations.
One of the report’s key findings, Stanford said, was that “combinations of extreme events are much more devastating for utilities.”
For example, the report describes a long-lasting drought leading to brush fires in Australia’s southeastern state of Victoria, which was followed by a major storm event in June 2007; more than 9 inches of rain fell in some river catchments in a single day. Water surging through the state’s Upper Yarra Reservoir stirred up much more solid material than usual, and authorities deemed the water unsafe to drink, placing about 6,000 homes on a boil water notice.
From floods to droughts to toxic algae
Several U.S. water utilities have also already faced a pileup of extreme weather events. After a major flooding event in 2006, California’s Sonoma County was hit with a three-year drought, forcing local water authorities to ration water. And between 2011 and 2013, communities in the Lower Missouri River Basin saw record floods that damaged 388 wastewater systems and a record drought that spurred toxic algal blooms in their reservoirs.
When looking at what water utilities now have to cope with, “averages are really meaningless,” said Lauren Fillmore, senior program director at the Water Environment Research Foundation, who also contributed to the report.
“Fifty years ago, you would have gentle rains that fell for a reasonable amount of time,” Fillmore said, “but now, even though the average may be the same, you’re going from extreme to extreme.”
Some water utilities have already readied themselves for unprecedented circumstances — the District of Columbia Water and Sewer Authority is building a storm wall that can withstand a 500-year flood, even though the region has not seen greater than a 100-year flood in its recorded history (ClimateWire, Jan. 13).
“Planning, understanding what impacts you might have and then being ready for those impacts, is the key to dealing with extreme events,” said Kenan Ozekin, a senior research manager at the Water Research Foundation.
Bipolar weather makes preparations a challenge
But of the U.S. water utilities surveyed in the report, 76 percent of respondents thought their current risk assessment procedures were inadequate to handle extreme events, especially combinations of extreme events.
Due to limited resources and staff, utilities serving smaller populations may struggle to cope with the complexity of preparing for multiple threats, Stanford said. New infrastructure can be extremely costly — the price tag for the D.C. water agency’s sea wall is more than $13 million, and, as reported to the WRF by 18 water utilities, the median cost for future adaptive measures was $10 million.
Another hurdle water utilities face with the “drought and deluge” trend is that the public tends to have a short memory, Fillmore said, making communities less willing to back major projects to cope with heavy rainfall while in the middle of a dry spell. Moreover, spending millions of dollars to prepare for extreme weather doesn’t always make economic or environmental sense.
“Designing a collection system that would not have an overflow during a storm like Sandy would have its own massive impacts,” Fillmore said.
Despite these challenges, however, Stanford said water utilities will likely have to adapt to keep safe drinking water flowing.
“Maybe our parameters that we’ve used to say that this is the range of water quality that you can expect as a utility, therefore we’re going to design it to operate in this way — maybe those need to be readjusted to consider the impact of multiple events,” he said.
This article was reprinted from ClimateWire with permission of E&E Publishing, LLC. Go to www.ClimateWire.net for more stories like this.