By Brian Grimmett – Kansas News Service
LAWRENCE, Kansas — It’s Trevor Flynn’s job to keep the local tap water from smelling like dirt.
It’s a pleasant enough scent after a good rain storm. It goes down less easily in glass.
Climate change makes Flynn’s job harder. It’s triggering days of triple-digit temperatures and more times when the breeze takes a holiday. That, in turn, breeds ever bigger blooms of blue-green algae.
In Clinton Lake — a source for the Lawrence municipal water supply — and ponds and reservoirs across Kansas, the pond scum is only becoming more common. Flynn has to make sure that by the time water comes out of the faucet that the dirt-tinted flavor from the blue-green algae is gone.
That requires more treatment, which increases water bills. The trick, for now, comes in figuring out how to avoid pulling in water from parts of a reservoir most contaminated by the algae.
The more experts can solve that problem, Flynn said, “the more (money) we can absolutely save.”
To get rid of the taste and odor problems, the Lawrence water treatment plant uses activated carbon. When there’s a bloom on nearby Clinton Lake, it can double the cost of chemicals needed. That’s ultimately passed on to customers.
The city has teamed up with researchers at the University of Kansas to understand what triggers blooms on Clinton Lake, how to predict them and where to put water intakes when one does form.
Research professor Ted Harris leads the project. About once a month, he and a small team head out onto Clinton Lake to take measurements and retrieve data from a high-tech buoy they’ve anchored in place.
The research is all about layers, and what type of water comes from different depths.
“The really shallow parts, you get a lot of issues with algae,” Harris said. “At the bottom or near the bottom, you get issues with sediments and decaying things that are also hard on drinking water treatment processes.”
“So,” he said, “there’s some Goldilocks zone right in the middle and that’s what we’re out here to find out.”
Onboard a pontoon boat floating near the buoy a few hundred yards from the dam, a graduate student lowers an instrument down into the water. Harris monitors a laptop nearby as colored dots corresponding to the number of different types of algae detected begin popping up on a graph displayed on the screen.
Again, it’s about the layers. The dots show a high concentration of algae down to about 5 meters, before a pretty sudden drop off.
The researchers make regular tests of temperature, how deeply light is penetrating the water, the levels of dissolved oxygen.
“So if there was a huge, lakewide bloom,” Harris said. “We’d have all this data now beforehand to go, ‘Hey, these were the things setting up the blooms.’”
So far, Clinton Lake has not had the severe blue-green algae problems found at other Kansas lakes, like Milford and Marion Reservoirs. But Harris says the trend is clear. Blooms are on the rise.
That’s partly due to climate change. A recent study shows that the number of days with calm wind conditions in Kansas is increasing. So is the number of days above 95 degrees. Add in large amounts of nutrient-rich runoff from nearby farms and Harris says it’s a perfect recipe for blooms.
“It really is that race against time,” he said. “If we have strong signals that this lake is going to start changing and getting more, unfortunately, blue-green (algae), what can we do now to help mitigate it or set up or at least have a plan so that we can be more proactive and less reactive?”
It’s even an issue for cities that don’t pull their water directly from impacted lakes and reservoirs.
WaterOne, which provides water for about half a million people living in Johnson County in northeast Kansas, pulls its water from the Kansas and Missouri rivers. But it’s downstream from several reservoirs that frequently deal with blue-green algae issues.
Before it recently spent $40 million to upgrade its water treatment facility to a more advanced system, WaterOne spent upward of $2 million a year on activated carbon.
“Anything that comes down the river, we have to deal with at our treatment plant,” said Mike Armstrong, WaterOne general manager. “If we can start with higher quality water, it just reduces our treatment processes, our expenses and any concerns with any kind of contaminants.”
He said the first major bloom that happened on Milford Reservoir in 2011 was a real wake-up call. Since then, WaterOne has joined other water users and managers along the Kansas River basin in trying to address some of the issues feeding the blooms. Armstrong said that’s because the only way to solve these problems long-term is to reduce how many nutrients are running off of farmer’s fields and into the reservoirs.
The program pays farmers to use practices such as no-till farming and planting cover crops, which can greatly reduce runoff. Because once a harmful blue-green algae bloom takes off, there’s not a whole lot that can be done to stop it from coming back — every year.
And cleaning up all that stinky water will likely end up costing city water utilities in the state hundreds of thousands of dollars extra a year.
“If the water looks bad and smells bad in the reservoir,” Armstrong said, “then there’s always going to be some concern about how effective our treatment process is going to be.”
Kansas News Service stories and photos may be republished by news media at no cost with proper attribution and a link to ksnewsservice.org.
Brian Grimmett reports on the environment, energy and natural resources for KMUW in Wichita and the Kansas News Service. You can follow him on Twitter @briangrimmett or email him at grimmett (at) kmuw (dot) org.
The Kansas News Service is a collaboration of KCUR, Kansas Public Radio, KMUW and High Plains Public Radio focused on health, the social determinants of health and their connection to public policy.