Skip to main content

Northeast Lakeshore TMDL

A framework for water quality improvement

A view of the water cutting through tall brush on a sunny day in the South Branch of the Manitowoc River.
South Branch of the Manitowoc River. / Photo Credit: Holly Stegemann, DNR

The DNR, together with many partners throughout the basins, is working to improve the surface water quality of tributaries, streams, rivers and lakes within the Northeast Lakeshore TMDL basins. The Northeast Lakeshore TMDL is focused on addressing surface water quality impairments from phosphorus and total suspended solids. In addition, quantifying nonpoint nitrogen loading is part of the study; however, a TMDL will not be created for nitrogen because there are no surface water standards for nitrogen. The TMDL study and implementation plan will provide a strategic framework and prioritize resources for surface water quality improvement across the basins that make up Wisconsin's Northeast Lakeshore.

The Northeast Lakeshore TMDL study area spans a portion of the Lake Michigan watershed from just south of Sturgeon Bay to Port Washington and reaches west towards Lake Winnebago (Lake Winnebago is covered by the Upper Fox and Wolf TMDL), covering 1,964 square miles, approximately 3.5 percent of the state.

Under s. 281.145, Wis. Stats., the DNR was directed to conduct a study of nutrients in the Northeast Lakeshore study area. This study took the form of a TMDL for total phosphorus and a separate watershed study for nitrogen.

A graphic displaying the TMDL process pipeline. The process moves an impaired water through to a restored water, with the four process steps being 1.) listing, 2.) TMDL development, 3.) implementation and 4.) recovery. The Northeast Lakeshore TMDL is currently in the implementation stage according to the pipeline graphic.

Monitoring And Evaluation

Approval By The EPA

On Oct. 30, 2023, the U.S. Environmental Protection Agency (EPA) approved the Northeast Lakeshore TMDL.



TMDL Resources

Map and Spatial Data Viewer

Stream Monitoring

Past Webinars

August 2023 Informational Webinar

A webinar that provided an overview of the final draft report and an opportunity to receive comments on the "Northeast Lakeshore TMDL: Total Maximum Daily Loads for Total Phosphorus and Total Suspended Solids” study. This public informational hearing included a presentation outlining the clarifying text added to the TMDL report which discusses climate change considerations, clarifies margin of safety assumptions, discusses dissolved reactive phosphorus and outlines implementation planning and monitoring considerations.

January 2023 Informational Webinar

A webinar that provides an overview or the draft TMDL report and allocations. The presentation focuses on the layout of the report, explains how to interpret the results, and highlights key sections of the report.

September 2022 Meeting with Municipal Wastewater Treatment Facilities

Meeting reviewing the allocation process and clarify how allocations are translated into effluent limits. This meeting was held in response to questions and comments received from representatives of municipal wastewater treatment facilities.

December 2021 Informational Webinar

Webinar covering lake modeling results, the allocation process, and draft allocations.

March 2021 Informational Webinar

Baseline Load Results and Allocation Process

Summer 2020 Informational Webinar Series:
The TMDL Process and Watershed Model Development

In summer 2020, the DNR presented a series of public informational webinars to introduce development of the Soil & Water Assessment Tool (SWAT) watershed model for the Northeast Lakeshore TMDL. The webinar announcement flyer summarizes the topics of each webinar. Recordings and PDFs of the webinar presentations are below.

Webinar 1: TMDL process and introduction to the Northeast Lakeshore TMDL
Webinar 2: Water Quality Data and Impairments
Webinar 3: Watershed Model Introduction and Data Inputs
Webinar 4: Watershed Model Setup

Nitrogen Study

The nitrogen study, separate from the TMDL, was conducted by the DNR to quantify and characterize the amounts of nitrogen introduced into surface waters relative to climate, land use and other watershed characteristics. The study also explores potential mechanisms to reduce the amounts of nitrogen introduced into surface waters. Unlike the TMDL, the results of the nitrogen study do not result in TMDL allocations or modification of permit limits.

Webinar Recording

A webinar discussing the nitrogen study was held on Nov. 9, 2022.