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Northeast Lakeshore TMDL

A framework for water quality improvement

South Branch of the Manitowoc River
South Branch of the Manitowoc River
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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 (NEL) TMDL basins. The NEL 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 NEL 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.

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.

TMDL Study for Total Phosphorus and TSS/Sediment

The TMDL process pipeline- Development stage

Project overview


Informational Sessions

Upcoming Webinars

None currently scheduled.

Past Webinars

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 NE Lakeshore TMDL. The webinar announcement flyer [PDF] summarizes the topics of each webinar. Recordings and PDFs of the webinar presentations are below.

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

Draft datasets and reports

Current Comment Periods

The DNR is accepting comments on the draft NEL TMDL report and associated appendices through COB on March 3, 2023. Comments can be emailed to Please use the subject line "NEL TMDL Comments."

All comments received will be addressed with appropriate changes to the TMDL report and a written response that will become part of the TMDL document (Appendix N: Response to Preliminary Comments). Note: Six of the appendices have previously been posted for comment but are being included again in this comment period for completeness.

Report for Review

Past Comment Periods

Stakeholder Review - January 2022

The draft lake modeling report and allocation tables can be found here:

Stakeholder review – March/April 2021

The SWAT watershed model was developed by CADMUS, under a contract with US EPA, and quantifies the baseline stream flows and pollutant loads.

The draft watershed model report is available here for stakeholder review. Comments were accepted through April 16. 2021.

Stakeholder review - September/October 2020

The SWAT watershed model is being developed by CADMUS, under a contract with US EPA, and will quantify the baseline stream flows and pollutant loads.

A portion of the draft watershed model report is available here for stakeholder review. Comments were accepted through October 16, 2020.

Stakeholder review - July 2019

Below is the first round of draft products that the DNR has made accessible for stakeholder review. These products will contribute to the development of the watershed model. Additional datasets will be posted for review as they are developed. Please review the instructions document below for more information. Comments were accepted through July 12, 2019. Data sets were revised according to stakeholder comments and updated in January 2020.

Project Resources

Projected project milestones

Map and spatial data viewer

Stream Monitoring

Agricultural Land Use and Management