UC Davis environmental research center advances freshwater watershed technology
Tahoe Environmental Research Center aims to restore Clear Lake’s oxygen quality
By ESHA KANNAN — science@theaggie.org
The UC Davis Tahoe Environmental Research Center (TERC) is an institute that combines environmental science and data analysis to better understand and conserve freshwater watersheds. Located in Incline Village, Nevada, TERC strives to incorporate limnology research — the study of inland freshwater sources — from the Sierra Nevada region within global environmental stewardship initiatives.
TERC’s research has expanded to other freshwater bodies such as Clear Lake. Clear Lake is the largest freshwater reservoir in California, spanning approximately 68 square miles of surface area. Currently, Clear Lake faces numerous ecological conditions such as excess nutrients, high mercury concentrations and low amounts of dissolved oxygen.
Cara Hollis, communications and marketing specialist at TERC, explained the center’s latest research findings.
“Our research discovered that a lot of the phosphorus that's causing some of the worst water quality outcomes is actually coming from the soil at the bottom of Clear Lake,” Hollis said. “That happens when that soil gets cut off from the bottom of the lake and depletes oxygen […] That's why we're addressing the issues clearly with an oxygenation system.”
The research center built a hypolimnetic oxygenation system (HOS) to reverse the effects of eutrophication, which occurs when nutrient enrichment causes dense algal growth. The HOS will be located in the Oaks Arm of Clear Lake because of the area’s hypoxic conditions.
Steve Camden, HOS project and construction manager, believes that climate conditions which lead to dissolved oxygen levels are attributed to stratification — the formation of separate temperature layers in the water.
“In the summer when the conditions are worse, the water surface is warm because the sun and the heat in the air and one of the bottom tends to stay colder and isolated, and when that's the case, all oxygen is gone, and that changes all the chemistry,” Camden said. “I'm thinking to add oxygen at the bottom of the lake to compensate for the loss of oxygen.”
UC Davis researchers affiliated with TERC have been involved with the project since 2018. Alongside the Blue Ribbon Committee for the Rehabilitation of Clear Lake, HOS project members are working to minimize Clear Lake’s phosphorus release and reduce its harmful algal blooms.
“We're finalizing the design of the oxygenation system now and plan to construct it over the winter and have it operated by next spring,” Camden said.
The HOS team have been using technological modeling to ensure that the project is maximally effective within all environmental circumstances once testing commences.
“We’ve been monitoring the water quality in the lake all around and will continue when we operate the system to see if there's a change from now to the future,” Camden said.
One of the hallmark pieces of technology the team is currently using is a computer simulation of the environmental conditions in the lake to optimize the HOS during construction and preliminary testing.
“You can run it to report what the weather conditions are in an instance, and it'll simulate what happens in the lake, not just with the movement of water, but in how it responds to an oxygen addition in the bottom of the lake and how it impacts the mercury and algae.”
To learn more about the HOS and the Clear Lake rehabilitation projects, details can be found at clearlakerehabilitation.ucdavis.edu.
Written by: Esha Kannan— science@theaggie.org