OSU researcher connects lake science to Stillwater’s water future

By Jemella Zhang

STILLWATER, Okla. – Stillwater depends on a single pipeline from Kaw Lake to bring water to its treatment plant for homes, businesses and surrounding communities. If that line is out of service for repairs or due to an emergency, the city has less than one day of water available for treatment and use.

To help remedy this scenario, Stillwater is adding Lake McMurtry as a second source for city water. Water would be pumped from the lake to the city’s treatment plant before it reaches customers, creating an estimated four weeks of reserve supply and reducing the city’s reliance on one pipeline.

Before Lake McMurtry takes on this important role, Oklahoma State University environmental science doctoral student Narges Taravatrooy is building the information water managers will need to protect the lake and the city’s water supply. Her research asks three practical questions:

• How much water does the reservoir hold?
• How does its water quality change?
• What could happen when the city begins drawing from it?

Taravatrooy conducts the research with Scott Stoodley, assistant director of research in Environmental Science. The project combines measurements taken at the lake, laboratory tests and satellite observations.

“Water quantity and water quality tell different parts of the same story,” Taravatrooy said. “Alone, they do not provide a complete picture.”

Water level shows how much water is available. Water quality helps researchers assess whether conditions support aquatic life and future water use. Studying both can help managers prepare for drought, heavy rainfall, rising demand and changes in how the reservoir is used.

Taravatrooy combines lake level readings with observations from NASA’s Surface Water and Ocean Topography satellite, or SWOT, which measures the elevation of the water surface from space. When paired with a map of the lake bottom, those observations help researchers estimate how much water is stored and how that amount changes over time.

Along with Taravatrooy taking measurements at the lake, the satellite provides researchers with another way to track changes across the reservoir and helps monitor other lakes where frequent field visits are difficult or costly.

Water samples add information that cannot be seen from above. Researchers test for nutrients and measure temperature, dissolved oxygen, clarity and chlorophyll. Those results help show how conditions vary across the reservoir and from the surface to the lake bottom.

Water quality monitoring began several years ago, and researchers are still building a baseline of what normal conditions look like over time. That baseline will help water managers distinguish seasonal changes from drought, extended heat, heavy rainfall or increased water use. It can also help them evaluate whether drawing more water from Lake McMurtry or transferring water into it from another reservoir changes water quality or aquatic habitat. Managers can also identify unusual changes sooner, decide when more testing is needed and adjust how the lake is used before problems occur.

“Every lake has a story to tell,” Taravatrooy said. “It is our job as scientists to understand that story before it’s too late.”

Putting lake data to work

While the Lake McMurtry study is building a baseline for future decisions, Taravatrooy’s work at Lake Carl Blackwell shows how the same approach can guide action when a problem is already visible.

Yellow floating heart is an invasive aquatic plant that forms thick mats across the water. It can interfere with boating, crowd out native plants and affect aquatic habitat and water quality. At one point, the plant covered more than 55 acres of Lake Carl Blackwell. Treatments reduced the area to less than 3 acres before higher water levels helped it spread again.

“People don’t usually think of plants as invasive, but this one is beautiful on the surface and destructive beneath it,” Taravatrooy said.

The research team used airboats, satellite images, drones and field surveys to map the plant and target treatments. As the remaining patches became smaller and more scattered, drones allowed the team to treat them more efficiently.

Taravatrooy brought seven years of experience in water resources to OSU. She has published eight journal articles on water quantity and water quality.

“Narges’s research provides the City of Stillwater with definitive water quality and water quantity data that will aid them in water resources management moving well into the future,” Stoodley said. “Her research is cutting-edge and will contribute to NASA’s better understanding of the accuracy of two of their newly deployed satellite sensors.”

OSU Ag Research is Oklahoma’s premier research and technology development agency in agriculture, natural resources and the life sciences.

 

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