EPA’s Approval of Ohio’s Maumee Watershed Nutrient Total Maximum Daily Load
Summary:
This notice announces the U.S. Environmental Protection Agency’s final review and approval of the Maumee Watershed Nutrient (MWN) total maximum daily load (TMDL) submitted by Ohio EPA on June 30, 2023. EPA determined that Ohio EPA’s MWN TMDL satisfies all statutory and regulatory requirements of an approvable TMDL.
Background:
A TMDL is the calculation that establishes the maximum amount of a pollutant that can enter a water body so that the water body will meet and continue to meet water quality standards for a particular pollutant. It is a planning tool for restoring water quality. The Clean Water Act gives states primary responsibility for developing TMDLs for impaired waters. EPA reviews state TMDLs to ensure consistency with Clean Water Act requirements and federal regulations. EPA’s detailed basis for approval is found in the Decision Document (link below).
Ohio EPA developed total phosphorus (TP) TMDL to address impaired conditions in three areas of the Western Basin: shoreline, open waters, and island shoreline. The TMDL addresses recreational use impairments due to excessive algae, public drinking water use impairments due to excessive algae (cyanotoxins), and aquatic life use impairments due to excessive nutrients. Algae responsible for HABs can produce toxins that affect drinking water and recreational uses. The blooms can negatively impact aquatic species by decreasing dissolved oxygen concentrations within affected surface waters. The MWN TMDL sets the total amount of phosphorus that the western basin of Lake Erie can receive and still protect its health and allocates this load between point sources (e.g., wastewater treatment plants) and nonpoint sources (e.g., runoff from agricultural lands). The MWN TMDL also identifies activities, programming and funding resources for stakeholders to utilize in order to reduce nutrient inputs to local surface waters that drain to the western basin of Lake Erie. Given the substantial phosphorus reductions required, meeting the loading targets in the MWN TMDL will require the immediate, concerted and sustained efforts of all western Lake Erie stakeholders.
Documents related to EPA’s approval of Ohio’s MWN TMDL are available here:
- Transmittal Letter For EPA’s Approval of Ohio’s Maumee Watershed Nutrient TMDL (pdf)
- Decision Document For The Maumee Watershed Nutrient TMDL, In All Or Parts Of 18 Counties in Northwestern Ohio (pdf)
- Attachment #1 of Decision Document: Maumee Watershed Nutrient TMDL Tables (pdf)
- Attachment #2 of Decision Document: EPA Review of Dissolved Reactive Phosphorus Information (pdf)
- Attachment #3 of Decision Document: EPA Review of Concentrated Animal Feeding Operation Information (pdf)
- Maumee Watershed Nutrient TMDL FAQs (pdf)
We are in the process of ensuring these documents are accessible to all audiences. If you need assistance accessing a document, or any materials on the Maumee River Watershed Nutrient TMDL approval webpage, please contact David Werbach at Werbach.David@epa.gov or Paul Proto at Proto.Paul@epa.gov.