The Cleveland Water Department has launched two buoys for the season. The buoys’ sensors monitor Lake Erie 24/7, keeping track of water temperature, pH, turbidity, dissolved oxygen and other parameters to help address any changes in lake water quality before it is drawn into Cleveland’s four water treatment plants.

The buoys work with the Great Lakes Observation System, which shows real-time information for dozens of buoys in the lakes, as part of the U.S. Integrated Ocean Observing System. There are 16 buoys in Lake Erie alone.

“We can’t be out on the lake collecting data 24-hours a day,” said Cleveland Water Quality Manager Scott Moegling said in a news release. “That’s what the water quality buoys do. Each is a floating laboratory in the lake.”

Among other information, sensors on the buoys track harmful algal blooms and hypoxic water, commonly referred to as the “dead zone.”

The dead zone occurs every year in Lake Erie’s central basin, north of Cleveland.
Warmer water stratifies from the colder water below, and the oxygen gets used up by decaying organisms. Fish then flee because the water has too little oxygen for them to survive, and organisms that can’t move die and decompose, using up more oxygen. The dead zone typically grows from July until October, stretching as large as 10,000 square miles.
Because each of Cleveland Water’s four intake cribs is 3 to 5 miles offshore, staff knows four to five hours in advance if the process to treat water will need to be adjusted because of algae or low oxygen.

Data and observations being collected by Cleveland Water is being used to develop a Hypoxia Early Warning System for the Great Lakes, as part of a five-year program with the Great Lakes Environmental Research Lab and the Cooperative Institute for Great Lakes Research. The work will provide drinking water treatment plant managers an early warning system for hypoxic waters, similar to weather forecasts.

How Cleveland Water gets from Lake Erie to your tap