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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.

The Wisconsin legislature supports the TMDL and has provided funding for the NEL TMDL. See s. 281.145, Wis. Stats. [exit DNR]

The project is currently in the TMDL development stage.

The TMDL process pipeline- Development stage

Project overview

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 data sets and reports

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.

Please limit comments to this portion of the watershed model report as additional comment periods will be available to address the next phases of the watershed modeling and TMDL development process.  All relevant comments will be considered and modifications to the modeling report will be made as appropriate.

Review instructions:

  • Comments will be accepted through October 16, 2020.
  • Written comments on this portion of the draft watershed model report can be submitted via e-mail to Kim Oldenborg (
  • Please reference page numbers in the report when possible.

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.

Projected project milestones

Map and spatial data viewer

Agricultural Land Use and Management