Harmful algae blooms are a familiar problem for folks living along the Jordan River. But this year’s warm weather and low snowpack are setting the stage for particularly hazardous water quality.
“The Jordan River is the bottom of the entire system," says Sandy Wingert, an environmental scientist with the Utah Division of Water Quality. "Think about what's coming down the mountains, through Utah Lake, into the Jordan River, and then flowing north to the Great Salt Lake.”
The Jordan River is almost at the bottom of the Great Salt Lake Basin. According to Wingert, that means that a lot of upstream pollution ends up concentrated in the river.
“Everything that touches the landscape, from mountain tip to mountain tip, is going to make its way some way into the Jordan River,” she says.
In normal years, snow melting in the mountains dilutes pollutants in the Jordan River. But this year, the situation is much different. Normally, water from mountain runoff cleans the river, transporting pollutants out of the system. But since this has been a historically dry year, the water moves slowly and pollutants accumulate in the river. Since the water is moving slowly, it also heats up more easily.
“It's shallower," Wingert says, "and so it means that when the sun comes down, it can heat up the entire river from the top to the bottom.”
Slow, shallow, warm water is a recipe for trouble when certain types of pollutants make their way into the river.
Wingert says that fertilizer nutrients, especially nitrogen and phosphorus, are key pollutants that pose an especially high risk to water quality given current climate conditions.
Nitrogen and phosphorus are two critical nutrients for plants to grow. But they also feed algae, the single-celled plant relatives that live in the water. Excess nutrients in the water cause explosions of algae growth, called harmful algal blooms, or HABs. And when algae cells in a HAB die, they initiate a biochemical process in the water that can be devastating for wildlife.
Wingert says that the dead algae cells decomposing consume dissolved oxygen, which is critical for animals living in the water.
“And then we have the fish kills," says Wingert, "because there's no more oxygen left in the rivers for the fish. You could pretty much predict that when you have a low water year, high temperatures, and have high nutrients that are not being flushed through, you get this big HAB. Oxygen drops, and then we have the fish kills.”
Besides the harmful algae blooms, the warm, stagnant water can also cause high concentrations of bacterial toxins and harmful pathogens like E. Coli. Wingert says that while it is important to be especially cautious around the Jordan River this year, the Division of Water Quality is working to emulate natural river systems to improve water quality.
“We're doing a lot of stream bank stabilization projects on the whole watershed scale," explains Wingert.
She says that the Division of Water Quality is working to improve the sinuosity of the river. More curvature leads to sediments and pollutants being deposited on the stream banks, instead of continuously recirculated through the water.
Wingert says that they look to solutions inspired by undisturbed river systems because, “Nature has a really good way of cleaning up itself.”
Recreational water quality risks like E. Coli and harmful algae blooms are monitored at https://deq.utah.gov/dwq/recreational-water-quality.
This article is published through the Great Salt Lake Collaborative with support from the Jordan River Commission. Editorial decisions are made independently by the Collaborative and partner newsrooms.