The Lake Superior - South watershed covers 402,371 acres. Located in the Northern Lakes and Forest Ecoregion, the soils and subsurface geology are dominated by bedrock, glacial till complexes, and erodible lake-laid clay soils. Bedrock is complex in its evolution and contributes to the spectacular mountains and ridges that slope toward Lake Superior. Numerous streams flow through the bedrock cracks forming waterfalls, cascades, and rapids. Lakes are found predominantly in the northeastern-most section. Major developed areas include the city of Duluth and towns of Two Harbors, Beaver Bay, and outskirts of Silver Bay. Significant development is also located along Lake Superior’s shoreline.
Land use in the watershed is a mix of urban and commercial, resort and rural residential. Tourism and forest products are significant components of land-use activity. Some commercial/industrial uses, including marinas, shipping ports, and taconite processing support, utilize and/or depend upon water resources.
Two major state parks, Gooseberry and Split Rock Lighthouse, are within the watershed. The smaller Tettegouche State Park is located on the watershed’s far eastern boundary.
Duluth Urban Area Streams Watershed
The Lake Superior - South Watershed overlaps with the Duluth Urban Area Streams Watershed, an area designated to address the complexity of a water-rich, densely populated urban center. The MPCA is working with a range of partners to monitor water quality in Duluth streams and develop restoration and protection strategies.
The watershed is a source of exceptional water quality in many lakes, streams and rivers. However, some streams do not meet water quality standards for beneficial uses such as aquatic recreation, drinking, and swimming due to excess levels of turbidity and bacteria (E. coli). Turbidity is associated with suspended sediment. Additional stressors such as elevated stream temperatures in recent summers and lack of persistent flow have become sources of concern for resource managers.
Major developed areas include the city of Duluth and towns of Two Harbors, Beaver Bay, and outskirts of Silver Bay. Significant development is also located along Lake Superior’s shoreline.
The watershed’s southwestern area is the most densely populated; this includes Duluth and an urbanizing fringe of smaller, adjacent communities and townships. Continued development pressures increase the potential for pollution problems in area streams. However, this area is also regulated through Municipal Stormwater Permits which contain specific requirements for stormwater discharges for the greater Duluth Metropolitan Area.
What's being done
Monitoring and assessment
- Lake Superior South Watershed Stressor Identification report (wq-ws5-04010102a)
- Lake Superior Streams Sediment Assessment - Phase I report (wq-b2-04)
- Lake Superior Streams Sediment Assessment - Phase II report (wq-b2-05)
- Lake Superior South Watershed Monitoring and Assessment Report
- Summary — Lake Superior South Watershed Monitoring and Assessment Report
Strategies for restoration and protection
- Lake Superior South Watershed TMDL report (wq-iw10-10e) (EPA approval 2/22/2019)
- Lake Superior North and South TMDL: Appendices A-D (wq-iw10-10f)
- Lake Superior South Watershed TMDL: EPA approval letter (wq-iw10-10g)
- Lake Superior North and South TMDL: Watershed Model Development report (wq-iw10-10o)
- Lake Superior South Watershed WRAPS Summary (wq-ws4-41b)
- Lake Superior South Watershed WRAPS report (wq-ws4-41a) (MPCA approval 8/2/2018)
- Knife River turbidity TMDL: Fact sheet (wq-iw10-01a)
- Knife River turbidity TMDL report (wq-iw10-01e) (EPA approval 7/2/2010)
- Knife River turbidity TMDL: EPA approval letter (wq-iw10-01g)
- Knife River turbidity TMDL implementation plan (wq-iw10-01c) (MPCA approval 12/9/2011)
- Lake Superior Streams
- South St. Louis Soil and Water Conservation District
- Lake County Soil and Water Conservation District
- Watershed project manager Tom Estabrooks, 218-302-6608