  
3/27/2026
WT Staff
Let us know how HABs have impacted your summer experience, call 877-52-WATER (877-529-2837), or email us at info@wtoh.us
March 27, 2026 1122 am EDT
US Bureau
Ohio Workgroup for Water Resources - the multi-agency gathering reinforces the shared clean water mission, purpose and goals. Good news, the collaborative approach is working to improve water quality.
One of the many topics presented at the 19th annual WWRM meeting in Columbus: springtime phosphorous leaching from the fields and streams of the largest watershed in the Great Lakes basin correlates to the severity of the harmful algal bloom (HAB) expected to grow in the shallow west basin of Lake Erie during the upcoming summer season. Multiple agencies are engaged in limiting the amount of phos feeding the Lake Erie HAB.
When algal toxins permeated the raw water intake pipe supplying City of Toledo Water in 2014, the HAB danger lurched into public awareness. HAB toxins defy the normal safe water protocol of boiling, as heavy metal contaminants, the toxin is concentrated by boiling. Water service was cut off to hundreds of thousands of Toledo Water customers for several days while the system was scrubbed and sanitized. The raw water intake was dropped to depth to avoid a future HAB incursion, and public drinking water facilities statewide were placed on an accelerated monitoring program for microcystins, the most common of the algal toxins.
HABs proliferate where the water is warm and nutrients flow in abundance. One of the main drivers of HABs is phosphorous, an element naturally occurring in soil, released when creeks and streambeds erode, also released from decaying organic matter such as household green waste deposited in city landfills, and released from municipal and industrial wastewater facilities, not otherwise equipped to filter it out from the effluent.
See Campbell Soup Supply Co has admitted to thousands of acts of illegal dumping in a sensitive Great Lakes watershed since 2018, here.
Surveillance of the HAB toxin is among the most diligent in the nation, with mandatory bi-weekly testing regimen beginning the first full week of June through to the first full week of December each year. Ohio EPA oversees Safe Drinking Water Act licensed public facilities, the monitoring of HABs is not part of the National Primary Drinking Water Regulations, the heightened protocols in Ohio emanate from the State regulation.
Beyond the regular monitoring of public drinking water for microcystins, multiple government agencies are engaged in a collaborative effort to identify, assess and mitigate the root of the HAB issue, working to limit the nutrients entering Lake Erie from the 4 million acre Maumee River watershed. Governments are not always swift to respond to emerging threats, however, the precedent for collaboration set in the mid 2000 era has undoubtedly contributed to the success of H2Ohio.
H2Ohio is a statewide water quality initiative, initiated by Governor Mike Dewine in 2019. Ohio Departments of Natural Resources, Agriculture and Environmental Protection mandated to work together to "address complex issues impacting Ohio's waters". From the H2Ohio online resource, the program employs a "comprehensive approach guided by science and data to reduce algal blooms, stop pollution, and improve access to clean drinking water by supporting best farming practices, road salt runoff reduction, litter cleanup, dam removal, land conservation, and water infrastructure revitalization."
Maumee River Watershed is under a phos management plan or TMDL, total maximum daily load plan, managed by Ohio EPA. During the assessment phase, OEPA reported the main point sources of phos, the municipal wastewater plants were well within their allotted limits. The non-point sources were found to contribute 90% of the excess phos reaching Lake Erie. These sources are difficult to manage, as they are related to increasingly severe weather events, heavy rains promoting erosion, which remain out of the realm of factors that can be managed. Untreated dairy, hog and chicken manure spread on farm fields is managed by Ohio Department of Agriculture, stipulating the conditions that raw manure can be applied. Manure piling up on the dairy, hog and chicken farms cannot be spread on frozen ground, cannot be applied when rain is forecast, basic steps to limit the leaching of the phos into the waterways. The application of phos fertilizer for crops is also limited in the sensitive area of the Maumee River watershed, where much of the land is drained, water moves quickly from the soil to the drainage ditches and out to the lake.
Nate Manning runs the Tributary Loading research program at Heidelberg University in northwest Ohio. Manning reported to the WWRM group Thursday, while only 5% of the water volume of Lake Erie is supplied by the Maumee River, an estimated 50% of the phosphorous load is coming in from the Maumee watershed. The goal of the research program here is to quantify the nutrients and sediments that move from the watershed and enter other aquatic ecosystems. Ohio Department of Agriculture funds the research, with water samples collected three times daily, all year round. The sampling station is visited weekly, 21 samples picked up and analyzed at the water lab for thirteen constituents, including total suspended solids, total phos and dissolved reactive phos. Manning reports, the nutrient load trend is generally down over the last five years, however the most promising results are found where the modified agricultural practises have been adopted by at least 70% of the land managers in the test zone, around Shallow Run. Here, the measured phos levels are down 38%, while the control plot, having no incentivized agriculture management changes sees the dissolved reactive phos levels increasing by 47%.
WTOH.us reached out to Prof. Manning to find out more about the agricultural management practises implemented in the successful test zone. Stay tuned for those details, to follow.
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