NOAA Great Lakes Environmental Research Laboratory

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From safe drinking water to sustainable fisheries, NOAA GLERL’s Experimental Lake Erie Hypoxia Forecast is even more useful than anticipated

Four years ago, NOAA’s Great Lakes Environmental Research Laboratory (GLERL) and the Cooperative Institute for Great Lakes Research (CIGLR) began providing an Experimental Lake Erie Hypoxia Forecast Model to warn stakeholders of low-oxygen upwelling events that can cause water quality problems for over 2 million residents of northern Ohio. Now in its fifth year, this forecast model has turned out to serve additional purposes that NOAA’s scientists hadn’t even considered – including maintaining sustainable fisheries and solving a smelly mystery!

Water intake crib off the coast of Lake Erie in Cleveland, Ohio. By forecasting potential hypoxic upwelling events that could impact water quality, NOAA GLERL’s Experimental Hypoxia Forecast Model helps drinking water plant managers be prepared to adjust their treatment processes as needed.

Providing critical warnings to keep drinking water safe

Hypoxia – a state of low oxygen – occurs in the deep waters of Lake Erie’s central basin in July through September of most years. Low-oxygen water is an unfavorable habitat for fish, and may kill bottom-dwelling organisms that provide food for fish. While the hypoxic water generally stays near the lake floor, changes in wind and water currents can create upwelling events, in which this zone of low oxygen is brought to the surface along the coast.

Once it creeps into shallower parts of the lake, hypoxic water can upset drinking water treatment processes at water intakes along the shoreline. Hypoxic upwelling events cause rapid changes in water quality variables such as temperature, pH, dissolved organic matter, iron, and manganese. To maintain the quality of treated water, plant managers must adjust treatment in response to these changes. NOAA GLERL’s Experimental Hypoxia Forecast Model provides several days of advance notice that water quality is changing, so that drinking water plant managers can be prepared to adjust their treatment processes as needed.

This infographic from NOAA GLERL describes how hypoxia occurs in large bodies of water like the Great Lakes.

Plot twist: Benefiting more than just our water supply

NOAA GLERL’s Experimental Lake Erie Hypoxia Forecast has proven to be incredibly successful in its original goal – but our scientists were surprised to learn that its usefulness didn’t stop there. Recent stakeholder interviews conducted by CIGLR Stakeholder Engagement Specialist Devin Gill revealed that, in addition to helping manage the drinking water treatment process, the forecast has also become an unexpectedly vital tool for managing Lake Erie’s fisheries. 

One agency that makes use of the experimental hypoxia forecast is the Ohio Department of Natural Resources (DNR). The Ohio DNR is responsible for generating population estimates for Lake Erie’s yellow perch and walleye – estimates that ultimately help determine official catch limits to maintain the lake’s sustainable fisheries. 

“Large aggregations of fish may seek refuge at the edges of the hypoxic zone,” says Ann Marie Gorman, a fisheries biologist with the Ohio DNR’s Fairport Harbor Fisheries Research Station. “Our office tracks the location of the lake’s cold bottom water using the NOAA GLERL Hypoxia Forecast Model, and we may modify the timing of some of our surveys to minimize the potential impact of hypoxia on the results. Overall, the NOAA GLERL Hypoxia Forecast Model has become an integral tool for our survey planning.”

Understanding fish behaviors in response to hypoxia is important to conducting accurate population surveys of Lake Erie’s fish species. The ability of NOAA GLERL’s hypoxia forecast to warn fisheries managers of potential survey bias from these hypoxic events helps to save time, money, and energy that may have otherwise been used to conduct unsuccessful trawling surveys in hypoxic zones.

NOAA GLERL’s Experimental Hypoxia Forecast Model helps to guide the planning of trawling surveys like this one conducted by the Ohio Department of Natural Resources. Consulting the forecast helps the Ohio DNR to minimize the potential impact of hypoxia on survey results, which are used to set catch limits that keep Lake Erie’s fisheries sustainable. Photo credit: Ohio Department of Natural Resources.

Richard Kraus, a supervisory research fish biologist with the United States Geological Survey (USGS) Great Lakes Science Center Field Station in Ohio, also uses the experimental hypoxia forecast for his work with Lake Erie’s fisheries. Kraus explains that in Lake Erie, several cold-water fish species rely on finding refuge in colder, deeper waters of the lake – waters that are not impacted by warmer summer air temperatures. However, the presence of hypoxic zones in these deeper waters can impact how much refuge is available for these fish. As hypoxia reduces refuge habitats for cold-water species, chronic effects on growth and reproduction may develop, and in severe circumstances fish kills sometimes occur. The NOAA GLERL Hypoxia Forecast Model is instrumental in predicting where these potential ecosystem impacts could occur, in turn helping fisheries managers determine sustainable catch limits for each fish species in question.

The experimental forecast was also found to be useful to commercial and recreational fishers, who use the forecast to gauge the distribution of yellow perch in relation to hypoxic zones. Fishers can utilize the forecast on a daily basis to determine where to launch their boats, and where to search for aggregations of fish, depending on the hypoxia forecast for that day.

Plus, it’s not just routine fisheries management and recreation that the Experimental Hypoxia Forecast helps improve. In early September, it helped solve the mystery of a strange, foul smell coming from Lake Erie near Cleveland, Ohio, and fish kills associated with it. These phenomena resulted in many public inquiries regarding suspected gas leaks or pollutant spills. Thanks to the forecast, public officials knew that an upwelling of hypoxic water had recently occurred, likely carrying sulfur and nitrogen compounds that caused the stench, and were able to quickly eliminate other possible causes.

Half a decade in the making

Since it began in 2017, this NOAA project has grown into much more than just a computer model. The Experimental Lake Erie Hypoxia Forecast model was developed as a five-year project (2017-2021) with funding from NOAA’s Coastal Hypoxia Research Program, and is an extension of the Lake Erie Operational Forecasting System at NOAA’s Center for Operational Oceanographic Products and Services. Co-led by NOAA GLERL research scientists Drs. Mark Rowe and Craig Stow, and CIGLR’s Dr. Casey Godwin, project scientists provide an email update to public water systems, fisheries managers, and other stakeholders ahead of likely hypoxic events that contains links to the experimental forecast website and other useful NOAA webpages.

Map from the NOAA GLERL Experimental Lake Erie Hypoxia Forecast Model showing predicted change in Lake Erie temperature (top) and dissolved oxygen (bottom) during a three-day hypoxic upwelling event from August 31 to September 2, 2021.

Partners on this project include Ohio public water systems (including the cities of Cleveland and Avon Lake), NOAA’s National Ocean Service, and the Great Lakes Observing System. Special thanks to Devin Gill from the Cooperative Institute for Great Lakes Research for contributing stakeholder interview findings for this article.

photo of building in water with skyline of city in backgroun


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NOAA and partners team up to prevent future Great Lakes drinking water crisis

A new video SMART BUOYS: Preventing a Great Lakes Drinking Water Crisis released by Ocean Conservancy describes how NOAA forecast models provide advance warnings to Lake Erie drinking water plant managers to avoid shutdowns due to poor water quality.

An inter-agency team of public and private sector partners, working with the Cleveland Water Department, are addressing drinking water safety for oxygen depleted waters (hypoxia). By leveraging NOAA’s operational National Weather Service and National Ocean Service forecast models and remote sensing for the Great Lakes, NOAA’s latest experimental forecast models developed by its Great Lakes Environmental Research Laboratory can predict when water affected by harmful algal blooms and hypoxia may be in the vicinity of drinking water intake pipes. Advance notice of these conditions allows water managers to change their treatment strategies to ensure the health and safety of drinking water.  

“Hypoxia occurs when a lot of organic material accumulates at the bottom of the lake and decomposes. As it decomposes, it sucks oxygen from the water, can discolor the water and allow for metals to concentrate,” explains Devin Gill, stakeholder engagement specialist for NOAA’s Cooperative Institute for Great Lakes Research, hosted at the University of Michigan.

Low dissolved oxygen on its own is not a problem for water treatment. However, low oxygen is often associated with a high level of manganese and iron in the bottom water that then leads to drinking water color, taste, and odor problems. In addition, the same processes that consume oxygen also lower pH and, if not corrected, could cause corrosion in the distribution system, potentially elevating lead and copper in treated water.

“Periodically, this water with depleted oxygen gets pushed up against the shoreline and the drinking water intakes pipes,” said Craig Stow, senior research scientist for NOAA’s Great Lakes Environmental Research Laboratory. “We have buoys stationed at various places and those guide our models to let us know when conditions are right for upwellings that would move this hypoxic water into the vicinity of the drinking water intakes.”

NOAA provides advanced warning of these events so that drinking water plant managers can effectively change their treatment strategies to address the water quality, which is a huge benefit in the water treatment industry.

For more information on NOAA GLERL’s harmful algal blooms and hypoxia research, visit www.glerl.noaa.gov/res/HABs_and_Hypoxia.

A buoy near the Cleveland Water intake—approximately 3.5 miles off the Cleveland shoreline—gives researchers at NOAA GLERL the ability to incorporate water temperature, pH, turbidity, dissolved oxygen and other parameters into their Experimental Hypoxia Forecast model. This allows water treatment managers enough time to anticipate and respond to changes in lake water quality before it is drawn into their treatment plants. Photo Credit: Ed Verhamme, Limnotech
CIGLR Mechanical Technician, Russ Miller, and Research Associate, Dack Stuart retrieve a sediment core from Lake Erie, near the Cleveland Water Intake Crib. Photo Credit: CIGLR
CIGLR Mechanical Technician, Russ Miller, prepares to deploy temperature and dissolved oxygen sensors in Lake Erie, near the Cleveland Water Intake Crib. Photo Credit: CIGLR
Retrospective animation of the Experimental Lake Erie Hypoxia Forecasts from the 2018 season, showing the predicted change in bottom temperature and dissolved oxygen.
Cleveland skyline and Cleveland Water Intake Crib. Daily, about 165 million gallons of water leaves Lake Erie through the crib to the pump station, where the water will begin treatment before it flows to other water facilities. Photo Credit: Ed Verhamme, Limnotech.
CIGLR Associate Director & Research Scientist, Tom Johengen, works hard to understand more about Lake Erie hypoxia by measuring sediment oxygen demand. Photo Credit: Michele Wensman, CIGLR.
The story of hypoxia


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Update on Lake Erie hypoxia forecasting stakeholder workshop (May 23, 2017)

Researchers partner with drinking water plant managers to forecast hypoxia in Lake Erie

By Devin Gill, Cooperative Institute for Great Lakes Research and Kristin Schrader, Great Lakes Observation Systems

Lake Erie’s “dead zone” not only impacts the lake’s ecosystem, but also poses challenges for managers of drinking water treatment facilities. The Lake Erie dead zone is a region of the central basin where oxygen levels within the water become extremely low, creating a condition known as hypoxia. Great Lakes researchers are sharing their scientific expertise to help managers be fully prepared for threats to drinking water resulting from hypoxic conditions.

Scientists from NOAA GLERL, Cooperative Institute for Great Lakes Research (CIGLR) and the Great Lakes Observing System (GLOS) met on May 23 in Cleveland, Ohio with water plant managers from the southern shore of Lake Erie for a stakeholder engagement workshop to discuss the hypoxia issue. An important focus of the workshop was the development of a new hypoxia forecast model that will act as an early warning system when hypoxic water has the potential to enter intakes of water treatment facilities. The depletion of oxygen in hypoxic water occurs when the water column stratifies (separates into warm and cold layers that don’t mix). Oxygen in the lower, cold layer becomes depleted from the lack of mixing with the upper (warm) layer that is exposed to air, as well as from the decomposition of organic matter (dead plants and animals) in the lower layer. The process of hypoxia is illustrated by GLERL’s infographic, The Story of Hypoxia.

Stakeholders who attended the workshop explained that water treatment operators must be prepared to respond quickly during a hypoxic event to ensure that drinking water quality standards are met. Hypoxic water often is associated with low pH and elevated manganese and iron. Manganese can cause discoloration of treated water, while low pH may require adjustment to avoid corrosion of water distribution pipes, which can introduce lead and copper into the water.

At the workshop, researchers shared information on lake processes that contribute to hypoxia and on development of the Lake Erie Operational Forecasting System that provides nowcasts and forecasting guidance of water levels, currents, and water temperature out to 120 hours, and is updated 4 times a day. Information was also shared on preliminary hypoxia modeling results that simulated an upwelling event (wind-driven motion in the Great Lakes, pushing cooler water towards the lake surface, replacing the warmer surface water) that brought hypoxic water to several water plant intakes in September, 2016. Water plant managers reported that advance notice of a potential upwelling event that could bring hypoxic water to their intakes would be useful to alert staff and potentially increase the frequency of testing for manganese.

Dr. Mark Rowe from University of Michigan, CIGLR, researcher and co-lead on this initiative, comments on the value of this hypoxia stakeholder engagement workshop: “At both NOAA and the University of Michigan, there is an increasing focus on co-design of research, which refers to involving the end-users of research results throughout the entire project, from concept to conclusion. If we succeed, a new forecast model will be developed that will be run by the operational branch of NOAA. This can only happen if there is a group of users who request it. This workshop provided critical information to the researchers regarding the needs of the water plants, while also informing water plant managers on how forecast models could potentially help them plan their operations, and on the latest scientific understanding of hypoxia in Lake Erie. ”

Stakeholder Scott Moegling, Water Quality Manager at City of Cleveland Division of Water, also recognizes the value of  engagement between the stakeholders and the Great Lakes researchers. Moegling points out that “the drinking water plant managers not only benefit from sharing of operational information and research, but also by establishing lines of communication between water utilities and researchers that help identify common areas of interest. The end result—researchers providing products that can be immediately used by water utilities—is of obvious interest to the water treatment industry on Lake Erie.”  Moegling also views the GLERL/CIGLR research on the hypoxia forecast model as holding great potential in predicting hypoxic conditions in Lake Erie and believes that once the model is developed and calibrated, there may be a number of other possibilities for highly useful applications.

In addition to sharing the latest research on hypoxia, the stakeholder engagement workshop provided a forum for water plant managers to share information with each other on how to recognize hypoxic events and efficiently adjust water treatment processes. Researchers at CIGLR and NOAA GLERL are committed to conduct research that serves society, and will continue to work with this stakeholder group over the course of the five-year project to develop a hypoxia forecast model that meets their needs.

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Lake Erie Hypoxia Forecasting Project Kicks Off With Stakeholder Workshop

A collaborative research team, led by Drs. Craig Stow of the National Oceanic and Atmospheric Administration’s Great Lakes Environmental Research Laboratory (NOAA GLERL) and Mark Rowe of the University of Michigan’s Cooperative Institute for Limnology and Ecosystems Research (CILER),  will be holding a workshop with key stakeholders for guidance on how a forecast model could help meet the needs for information on low oxygen conditions—or hypoxia—in Lake Erie. The workshop, coming up later this spring, kicks off a 5-year project that brings together inter-agency and university scientists to produce a forecasting system that will predict the location and movement of hypoxic water in Lake Erie. The project will link a hypoxia model to NOAA’s Lake Erie Operational Forecasting System (LEOFS) hydrodynamic model, which provides daily nowcast and 5-10 day forecasts of temperature and currents in Lake Erie.

HypoxiaDiagram

Hypoxia occurs in the central basin of Lake Erie in July through September of most years. Low-oxygen water is an unfavorable habitat for fish, and may kill benthic organisms that provide food for fish. It is less well known, however, that hypoxic water can also upset drinking water treatment processes. Upwelling or seiche events can bring hypoxic water to water intakes along the shoreline, causing rapid changes in dissolved oxygen and associated water quality variables such as temperature, pH, dissolved organic matter, iron, and manganese. To maintain the quality of treated water, plant managers must adjust treatment in response to these changes. Hypoxia forecasts will provide several days advance notice of changing source water quality so that drinking water plant managers can be prepared to adjust treatment processes as needed.

While the hypoxia forecasting project will help to minimize the negative impacts of hypoxia, a parallel effort is occurring to address the root cause of this problem involving nutrient loading. Universities, state, federal, and Canadian agencies are collaborating to satisfy the goals of the Great Lakes Water Quality Agreement by reducing nutrient loads to Lake Erie, a primary stressor driving hypoxic conditions.

The upcoming stakeholder workshop on hypoxia will bring the research team together with stakeholders consisting of municipal drinking water plant managers from U.S. and Canadian facilities on Lake Erie, as well as representatives of state and local agencies. The group will learn about hypoxia and its effects, hear about the goals of the LEOFS-Hypoxia project, and provide input to the research team on their information needs. As the first in a series of meetings of the project’s Management Transition Advisory Group, this workshop will help identify the most useful data types and delivery mechanisms, laying the groundwork for the research team to design a forecasting tool that specifically addresses the needs of public water systems on Lake Erie.

The workshop will be held at Cleveland Water in Cleveland, Ohio. Representatives from Ohio Environmental Protection Agency (EPA), Ohio Department of Natural Resources, Ohio Sea Grant, townships and other local governments were also invited to attend.  

The LEOFS-Hypoxia project is a collaboration with the City of Cleveland Division of Water, Purdue University, and U. S. Geological Survey, with guidance from a management advisory group including representatives from Ohio public water systems, Ohio EPA, Great Lakes Observing System (GLOS), and NOAA. The work is supported by a $1.4 million award from the NOAA National Centers for Coastal Ocean Science (NCCOS) Center for Sponsored Coastal Ocean Research by a grant to NOAA GLERL and University of Michigan (award NA16NOS4780209).

Getting to the root cause of the problem
As part of an initiative conducted under the auspices of the Great Lakes Water Quality Agreement, Annex 4, the following forums, led by Dr. Craig Stow at GLERL, will focus on the linkage of nutrient loading to water quality degradation problems, such as hypoxia and harmful algal blooms.

  • 4/5-6: Nutrient Load Workshop
  • 5/9-10: Annex 4 (nutrients) Subcommittee Meeting

Scientists attending these workshops will apply long term research results to estimate nutrient inputs to Great Lakes waters and evaluate how well we are doing in reaching phosphorus load reduction targets established under Annex 4 of the GLWQA.

Additional Resources
NOAA GLERL Hypoxia web page: https://www.glerl.noaa.gov/res/HABs_and_Hypoxia/hypoxiaWarningSystem.html

Download the NOAA GLERL hypoxia infographic, here: