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The USGS Southwest Biological Science Center (SBSC), US Bureau of Reclamation, and partners compiled a 58-year limnology dataset of historical and primary data that captures water quality parameters for Lake Powell, from shortly after the reservoir began filling, through 2021. This represents the longest known published water quality record for any human-made reservoir system.

Sunset at Lake Powell, AZ in July 2017
Sunset at Lake Powell, AZ, July 2017.

Lake Powell is a water storage reservoir on the Colorado River in the arid southwestern US. Lake Powell was created by the closure of Glen Canyon Dam, which was completed in 1963. The reservoir provides about 70% of the storage capacity for the Upper Colorado River Basin and is the second largest reservoir in the United States by maximum capacity (second only to Lake Mead). The water quality monitoring that produced this Lake Powell dataset was originally motivated by basin wide salinity concerns.

The parameters in the dataset include temperature, salinity, dissolved oxygen, major ions, and total suspended solids, as well as a 38-year record of Secchi depth (a measure of water clarity), and a ~30-year record of nutrients, phytoplankton, and zooplankton assemblages.

The dataset includes 5,208 unique site visits spanning 258 unique sites of which nine have been consistently visited. It also spans the establishment of quagga mussels, an invasive bivalve (Dreissena bugensis) which was first detected in 2012.

Given the general lack of long-term data from lakes or reservoirs in arid regions, this dataset represents a unique contribution to regional, continental, and global scale limnology studies and can be used to investigate site-specific long-term water quality trends and inform broader-scale limnology research.

This work was funded by the Bureau of Reclamation as part of an Interagency Agreement to monitor water quality at Lake Powell (see

Access the paper and dataset here: 

Deemer, B.R., Andrews, C.M., Strock, K.E., Voichick, N., Hensleigh, J., Beaver, J.R., and Radtke, R., 2023, Over half a century record of limnology data from Lake Powell, desert southwest United States: From reservoir filling to present day (1964–2021): Limnology and Oceanography Letters,

The associated data is available as a versioned data release which will be periodically updated to include newer data as it is collected: Andrews, C.M., and Deemer, B.R., 2022, Limnology data from Lake Powell, desert southwest USA: U.S. Geological Survey data release,


Nick Voichick at the winch, Lake Powell water quality monitoring
SBSC monitors Lake Powell water quality in partnership with the Bureau of Reclamation Colorado River Salinity Control Program and the National Park Service Glen Canyon National Recreation Area. Photo by SBSC, Grand Canyon Monitoring and Research Center, March 2022.
SBSC's Bridget Deemer labeling samples during a Lake Powell water quality monitoring trip
Bridget Deemer labeling samples during a Lake Powell water quality monitoring trip. Photo by SBSC, Grand Canyon Monitoring and Research Center.
U.S. Bureau of Reclamation studying temperature and water quality monitoring on Lake Powell
U.S. Bureau of Reclamation works with USGS SBSC Grand Canyon Monitoring and Research Center on water quality monitoring in Lake Powell. Robert Radtke checks a line of temperature loggers deployed in Lake Powell near the dam. Temperature loggers provide continuous (30-minute) temperature data for ~18 depths spanning the surface to the bottom of the reservoir.

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