Floating evaporation stations deployed at Lake Powell — Desert Research Institute #aridification #ColoradoRiver #COriver

Evaporation monitoring platform located in Padre Bay at Lake Powell. Sensors measuring wind speed and other weather parameters along with water temperature will help researchers estimate the timing and magnitude of water lost to the atmosphere. Photo credit: The Desert Research Institute

Here’s the release from the Desert Research Institute:

In the western United States, reservoirs are critical for storing water that can later be used by cities and for agricultural applications — but evaporation can remove a significant amount of this stored water each year.

A new collaboration between the Desert Research Institute in Reno, Nev. and the Technical Service Center of the Department of Interior’s Bureau of Reclamation aims to improve our understanding of evaporation from Lake Powell and other major reservoirs of the western United States through the deployment of floating evaporation stations.

The stations monitor meteorological conditions over the water and estimate evaporation using four primary methods: eddy covariance, energy balance, aerodynamic bulk mass transfer, and the combination of energy balance and aerodynamic. Data from the stations are transmitted back to the research team via a web portal for real-time monitoring.

While there are multiple techniques used for estimating reservoir evaporation, there is little consensus on which is best for accuracy, cost, and long-term operational monitoring potential, says principal investigator Chris Pearson, Assistant Research Scientist of Hydrology at DRI.

“A key aspect of this project is to use multiple techniques, including newer and older, more traditional methods. We’ll run them all at the same time, side by side, to see how well they agree or don’t agree,” Pearson said.

Researcher adjusts the alignment of the inertial motion unit during installation at Lake Powell. 3-D wind measurements from the Eddy Covariance system will be corrected for pitch, roll, and yaw motion of the floating platform. Photo credit: Desert Research Institute

Water temperatures in Lake Powell change significantly throughout the year, as snowmelt fed runoff enters from the Colorado River and other tributaries. Temperatures also vary by depth and location around the lake. Consequently, the team has deployed measuring stations at two different locations, Warm Creek and Padre Bay, where the depth of water is around 100-150 feet.

By collecting data from multiple sites in the reservoir, the research team will learn about how evaporation rates vary both spatially and temporally throughout the year. The end goal, says Pearson, is to help scientists and water managers make accurate evaporation estimates using best available science – both at Lake Powell and elsewhere in the world.

“Eventually we’d like to integrate these data with satellite and gridded climate products, so we can provide accurate estimates with minimal instrumentation in the field, but collecting reliable and accurate benchmark in-situ data is the first step.” Pearson said.

This project is made possible with funding from the Bureau of Reclamation. Other members of the project team include Justin Huntington, Ph.D. (DRI, co-principal investigator), Brad Lyles (DRI), Richard Jasoni, Ph.D. (DRI), Mark Spears, P.E. (Reclamation, senior project lead), Dan Broman, Ph.D. (Reclamation), and Kathleen Holman, Ph.D. (Reclamation).

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