St Louis River Estuary: The stories and the science

  • Recreation
  • The Stories
  • The Science

Superior beaches and forested trails

Sheltering the estuary from cold, deep Lake Superior, Minnesota Point (aka Park Point) and Wisconsin Point are considered, together, the longest freshwater sand bar in the world. This beautiful, popular beach stretches nearly 10 miles across the mouth of the St. Louis River. The bay side is used quite a bit by boaters, while swimmers utilize the sand beaches on the lake side. “Park Point is one of the most heavily used beaches in the area,” says Amber Westerbur, Coastal Program Manager in Two Harbors.

In addition to beaches, trails provide access to the many distinct habitats found around the estuary. In Wisconsin, one of the largest municipal forests, Superior Forest, provides motorized vehicle, hiking, skiing and mountain biking trails around Pokegama Bay, an area of forested wetlands, clay flats, and uplands. The serenity and natural beauty of the place has drawn Mike Anderson and his camera into the Pokegama Bay area since the 1980s, capturing golden sunsets amid tall, sky-reaching pines. His visits to the estuary are ones of renewal, providing serenity and quiet just a few miles from city activity and noise.

In 2011 the St. Louis River Estuary and Minnesota Point were recognized together by the Minnesota Department of Natural Resources and Minnesota Audubon as an Important Birding Area (or IBA). This designation recognizes the importance of the estuary and its diverse habitats for migrating and water-dependent birds. Gerald Niemi, biology professor at the University of Minnesota Duluth, has documented bird species in the estuary going back to the 1970s. A walk along the gravel path of the Western Waterfront Trail may bring you a glimpse of one of the 31 species of migrating waterfowl, or a close up view of some of the 27 species of shorebirds, as well as many raptors, waterbirds, and songbirds that move along this corridor.

The estuary is many things to many people. Individuals walk on the paths for exercise and perhaps a chance to catch a glimpse of a common tern, others paddle out away from the busy street noise, in search of quiet and solitude, while still others look for a way to relax on the beaches found within the estuary. All are enjoying what together makes the estuary unique – an amazing arrangement of water, wildlife, wetlands and forests in the heart of a very active urban area.

The Stories

Amber WesterburAmber Westerbur, a longtime Duluth resident, talks about rip currents, pollution and more. Read Amber's perspective.

Mike AndersonMike Anderson discusses the awe-inspiring beauty of the St. Louis River estuary. Read Mike's perspective.

Gerald NiemiGerald Niemi has spent most of his life studying birds and habitats in the St. Louis River Estuary. Read Gerald's perspective.

The Science

BirdingBirding: the western tip of Lake Superior is a hotspot for bird diversity. Read more.

water qualityWater Quality: we should not have to worry about medical problems from simply getting wet. Read more.

rip currentsRip currents are strong, narrow channels of water flowing away from shore. Read more.


Deep Map. Explore the St Louis River Estuary using this interactive GIS Map.

Deep Science. DIg deeper into sample design, water quality, bugs and plants.

Amber Westerbur

Amber Westerbur

Little treasures and natural amenities

audio transcript

“There’s these little treasures that I don’t think as many people are aware of, or utilize.” Born and raised in Duluth, Amber Westerbur recalls that areas like the Lester River, Brighton Beach, and a number of trails like the Munger Trail and the Western Waterfront Trail were within easy biking distance as a kid. Now as a parent, she finds that she visits those natural amenities a little less often, but they are still an attraction that keeps her in the area.

Amber loves that she gets to work on issues important to her, like assisting citizens and organizations in protecting, enhancing and restoring Minnesota’s North Shore of Lake Superior as part of Minnesota’s Lake Superior Coastal Program. She recalls a project down at the harbor mouth. “Interested individuals worked to put up rip current warning signs at Park Point, or Minnesota Point…that’s exciting to see, as it’s a heavily used beach.”

Education is another aspect of her job that Amber really enjoys, working with other state natural resource personnel in the annual Envirothon, a national program for high school students. In Minnesota local Soil and Water Conservation Districts host regional competitions that challenge high school teams from around the state in their knowledge of natural resources. She works to develop in students an understanding of how land and waters are connected. Non-point pollution is one aspect of this connection.

Non-point sources of pollution are hard in general because you can’t point to a specific source,” she notes. Water, from precipitation and snow melt, runs over roads, parking lots and rooftops and in doing so picks up and carries with it oils, pet wastes, leaf litter, and chemicals and often deposits them into the estuary or streams that flow into the estuary. “Those are issues that the estuary is struggling with…. and those working in it are going to try and address.”

Mike Anderson

Mike Anderson

Serenity and solitude

audio transcript

“I can watch hawks and eagles flying and feel that connection to nature. How powerful is that?” Michael Anderson grew up in Superior, Wisconsin but it wasn’t until adulthood that he began to explore the sheltered bays of the Superior Municipal Forest by canoe. He hunts not for game or fish, but rather for the essence of the place. To capture the beauty, the silence, the awe-inspiring sunsets and clouds dancing upon the waters of the estuary is his goal, as he sets out with camera in hand.

The fact that such a place as the estuary can exist so close to an urban center, minutes from a busy port, is what makes this place special. Sure, the Boundary Waters are awesome, but a trip up there takes planning. Here Michael can throw his canoe atop his pick-up truck, grab some carrots from the garden and a jug of water, and sit listening to birdsong on some wooded point, away from it all in less than 30 minutes. “It’s a wonderful wilderness experience,” he notes.

For a time, Michael guided others out into the estuary, sharing his special places and offering people an opportunity to gain experience and familiarity with Pokegama Bay. “I consider myself a naturalist and basically guiding people into nature, so that they have an opportunity to discover what they will discover.” He no longer guides, and doesn’t make it out on the estuary as much as he would like these days, but it will always be a place he returns to for renewal. “This place is spiritual, nurturing.”

Gerald Niemi

Gerald Niemi

It’s a fantastic place...”

audio transcript

Dr. Gerald Niemi speaks from experience, having spent most of his life, and a large part of his research work at the University of Duluth studying birds and habitats in the St. Louis River Estuary.

His suggestion for those interested in adding birds to their life lists is to come in mid-April, after ice-out, through the latter part of May. “The birds, when they come flying up, generally don’t cross large bodies of water so they’ll move right along Wisconsin Point or Minnesota Point and fly along the edges.” Hawk Ridge, in the hills over Duluth is well known to birders, however fewer are aware of the more than 230 species of birds that occupy the wetlands, beaches, bays and forested areas of the St. Louis River Estuary. Walk along the Munger Trail or the Western Waterfront Trail, or better yet, use a canoe or kayak to paddle along the sheltered shorelines to catch a view or two of the many birds to be found there.

Colonial nesting birds, those that nest in large groups such as gulls, terns, herons and piping plovers are probably the most sensitive bird species in the harbor. They often use islands in the estuary, but prefer those with limited or no vegetation. “When we were sampling there [Interstate Island] in the 1970’s it was full of willow trees.” Islands such as Interstate and Hearding, both created from dredge spoils, and areas of Barker's and Hog Islands could possibly be restored to support threatened species such as the piping plover, now extinct in the harbor, and common tern, barely hanging on.

Controlled growth and planning is critical” Gerald notes, if we are to bring these species back.

Photo courtesy of Carrol Henderson. Click to zoom.

Photo courtesy of Carrol Henderson.

Birding in the St. Louis River Estuary

by Annie Bracey, NRRI

Duluth has long been a destination for bird watchers.

The western tip of Lake Superior is a hot spot for bird diversity. Some of the best bird watching opportunities occur during migratory periods when bird density increases significantly, as birds avoid crossing Lake Superior and concentrate along the shoreline. Because of the funneling effects of Lake Superior this migratory corridor is among the most well-known migration routes in the western Great Lakes for both spring and autumn migrants.

Impressive list of species

Although much of the area that surrounds the St. Louis River is urban, there is still a lot of minimally disturbed aquatic and terrestrial habitat making the list of species commonly observed impressive. According to the National Audubon Society's ornithological summary of the area, an annual list of around 238 species is common ( The St. Louis River Estuary and Minnesota Point are two of the most popular birding locations in Minnesota and have been collectively designated an Important Bird Area, a globally recognized location that contains important habitat for the conservation of bird populations.

Large numbers of migratory birds

During spring and autumn migration large numbers of migratory birds utilize the estuary as a stopover location to rest and forage en route to breeding or wintering grounds. The unique habitats within the St. Louis River support the diverse species that inhabit the region at different periods of time throughout the year. Migrating shorebirds regularly occupy the sandy banks and mudflats in the estuary and there are also significant concentrations of waterfowl that congregate in both open water and wetland habitats. Waterbirds such as grebes, herons, and terns can also be found during both migratory and breeding seasons. In recent years, observations of American White Pelican have increased in the estuary and in the spring groups of these conspicuous birds are common. The abundance and diversity of songbirds that move through the area is incredible. During peak migration, daily counts of warbler species alone can number greater than 20 species and thousands of individuals. Peak spring migration for songbirds is mid-late May and peak fall migration is late August- mid September. Raptors can be observed here throughout the year, but also peak during migration when hundreds of raptors can be observed on any given day. It is difficult to visit the estuary without spotting at least one Bald Eagle, whose nests can be found along the shoreline and on islands within the river. In winter keep an eye out for Snowy Owls in the harbor as well as some of the more uncommon gull species that can be found in colder months including Glaucous Gull, Thayer's Gull, Iceland Gull, and Great Black-backed Gull.

70 species that breed in the area

Photo courtesy of Ed Zlonis. Click to zoom.

Photo courtesy of Ed Zlonis.

Although use by migratory birds contributes significantly to the areas high species diversity, there are over 70 species that breed in the area. One notable breeding species is the Common Tern. A breeding colony on Interstate Island has been monitored annually since the late 1970s. In June 2013, 15 Common Terns were fitted with geolocators, devices that record changes in ambient light levels to estimate location. With this technology, the migratory routes and over-wintering areas of individual birds from this population can be estimated and this information can be used to answer many questions about their entire life cycle such as identifying locations that are important to them while away from the St. Louis River Estuary. .

A substantial amount t of valuable information has been gained from birding activities in the estuary. Much of the information collected, including individual species accounts, can be used to document abundance and diversity to better understand the biological significance of the St. Louis River estuary to migrating and breeding birds. If you have not been actively birding in the area and would like to, a good way to become involved is by joining a local bird organization such as the Duluth Audubon Society and Hawk Ridge Bird Observatory. Here you can meet experienced and friendly local birders and quickly be on your way to enjoying the great bird diversity that people from all over the world come to experience in our back yard.

Recreation and Water Quality

We should not have to worry about medical problems from simply getting wet.

Although many people are happy to enjoy the St. Louis River Estuary at arm’s length, many others choose to immerse themselves in it, or at least enjoy a variety of water recreation activities. For people who intentionally or unintentionally get wet, water quality must be good enough that there is only a small risk of getting sick if they (or their pets) swallow any. They certainly should not have to worry about medical problems from simply getting wet. Yet, there have been sites along the river (Hog Island, Newton Creek, Crawford Creek in Wisconsin, and the US Steel and Interlake Superfund sites in Minnesota) where industrial contamination by chemicals in the water column was hazardous enough to cause these areas to be posted with “No Swimming” signs. Most of these problems have now been fixed and the sites are in various stages of restoration, although “No Swimming or Body Contact” signs remain at the US Steel Superfund site in Morgan Park, which is not yet remediated.

Disease-causing organisms are now the major cause for human health concerns in the estuary and AOC. Historically high levels of fecal coliform bacteria, an indicator of feces from warm blooded animals, were dramatically reduced after 1978 when the Western Lake Superior Sanitary District (WLSSD) was formed to collect and treat most of the industrial organic matter and domestic wastewater load from municipalities and industries in the region. Since that time, Superior and other municipalities discharging into the Wisconsin side of the estuary have also greatly upgraded their treatment facilities. Nevertheless, chronic risks to public health, as indicated by wastewater bacterial indicators, have continued to cause areas of the estuary to be posted with swimming advisories on occasion, presumably due to sewer overflows caused by extreme rainfall events, sewage spills, discharge from boats, and failing septic systems.

Since the early 2000s, considerable progress has been made by Superior, WI and Duluth, MN to upgrade sanitary sewer infrastructure and provide temporary storage designed to reduce discharges resulting from equipment failure and overflows caused by rainfall-associated inflow and infiltration. These projects are expected to be completed in 2016 (source: MPCA BUI 7 Blueprint. Similarly both states continue to upgrade rules to improve on-site wastewater treatment systems, although this is a long-term process.

In 2003 both Wisconsin and Minnesota initiated summer bacteria monitoring and advisory programs at public beaches. When indicator bacteria levels exceed state and federal criteria the public is warned against swimming via advisory signs, website warnings, and through various media outlets.

To date, advisories have been rare for the Lake Superior beaches, and infrequent for most, but not all, of the estuary “beaches” (most are actually small boat landing and docking sites).

More than 10 years of research by University of Minnesota scientists using state-of-the-art genetic fingerprinting techniques has shown that exceedances at some of the sites with chronic advisories appear to be a result of the indicator bacteria E.coli coming mostly from bird feces from the large flocks of gulls and geese that inhabit the estuary (details here). Further, measurements of pathogenic genes associated with E. coli and several other waterborne disease-causing bacteria have indicated extremely low risk and were not correlated with beach advisories from the routine monitoring. Nevertheless, although human pathogens may not usually be much of a risk at these “chronic” sites, it is unclear to what extent bird or other wildlife diseases associated with these high indicator values might pose a significant risk to humans. As of 2014, four sites in the SLR AOC that have been designated as “impaired” by Minnesota and Wisconsin have been targeted for more in-depth study using DNA fingerprinting technologies to better identify E.coli sources (Barker’s Island Inner Beach and Wisconsin Point Beach #2 in WI, and the Clyde Avenue and Leif Erickson Park sites in MN.

Monitored Beaches in the St. Louis River Area of Concern. Source: SLR AOC Implementation Framework: Beneficial Use (BUI) Blueprint, July 2013. Click to zoom.

Monitored Beaches in the St. Louis River Area of Concern. Source: SLR AOC Implementation Framework: Beneficial Use (BUI) Blueprint, July 2013.

Impaired St, Louis River AOC beaches targeted for microbial source tracking to determine if pathogens are of human origin (i.e. controllable). Source: SLR AOC Implementation Framework: Beneficial Use (BUI) Blueprint, July 2013. Click to zoom.

Impaired St, Louis River AOC beaches targeted for microbial source tracking to determine if pathogens are of human origin (i.e. controllable). Source: SLR AOC Implementation Framework: Beneficial Use (BUI) Blueprint, July 2013.

Throughout the Great Lakes, stormwater runoff has been shown to increase water-borne disease risks as indicated by E.coli monitoring. A consistent public education message is to:

…. minimize, or avoid water contact in general, in streams and lake coastal areas following rainstorms, since pathogens washed in from the watershed typically increase.

Large investments in sewage infrastructure and temporary storage are only recently bringing this problem under control during big rainstorms and high spring snowmelt runoff years.

Attempts have been made to accurately predict E. coli exceedances in real-time, that is – when people are planning to leave for the beach. These predictions, based on rain, wind, and water clarity (estimated using sensors that measure turbidity), have been useful for Ohio beaches in southern Lake Ontario (see Ohio Nowcast) and are being developed and tested for other Lake Michigan and Lake Huron metropolitan area beaches Lake Michigan and Lake Huron metropolitan area beaches . Thus far, the ten years of data for the lower St. Louis River Estuary have not been very promising in terms of generating such predictive “forecasts,” because the data are highly variable. Perhaps the two biggest limitations to improving the accuracy of the warning programs include: (1) The testing requires 24-48 hours to culture bacterial colonies, which means some advisories are not posted until a day or days after the exceedance occurred; and (2) Actual illnesses due to water contact at “advisory sites” are not likely to be reported to health providers unless symptoms are severe. Health officials and scientists are working on both of these issues, and rapid DNA testing kits are likely to provide more timely advisories in the next few years. Epidemiological studies that link illness to actual water contact at a particular beach will likely be based on Great Lakes-wide surveys, since the incidence of traceable symptoms in our region is rare.

Recreational experiences in the “pre-WLSSD“ days were also marred in many areas by taste and odor problems, industrial foam, oil slicks and sheens, tar balls, grain or grain dust, taconite pellets and residue, coal, etc. These issues seem to have largely disappeared as a result of the many remediation projects carried out in the past two decades. Noxious scums of algae, such as the blooms of tiny blue-green algae that are suspended in the water on occasion in Lake Erie or the massive piles of attached filamentous algae that have plagued the shoreline of western Lake Michigan for the past decade or more, have not been observed in the estuary. Since nutrient levels in the St. Louis River Estuary are sometimes high enough during the ice-free season to support large algal blooms, algal growth is likely limited by other factors. These include low levels of sunlight penetration caused by naturally dark, root beer-colored water and occasional muddiness caused by high suspended sediment loads. This “potential” for excess algal growth in the SLRE (as well its effects on Lake Superior) is the reason that new research efforts are underway to learn more about how changes in nitrogen, phosphorus, and light availability affect algal growth in the estuary (see the research here and here ).

Water quality also has indirect, but critical importance to the many types of water-based recreation linked to fish and wildlife, such as hunting, fishing, and bird-watching. High quality water is essential to maintain the healthy aquatic and wetland habitats required by fish and wildlife populations in the estuary. The good news is that tremendous progress has been made in the past 30 years to correct the worst of the problems, and funding since 2009 from the Great Lakes Restoration Initiative has created strong local and regional partnerships to fully restore the ecological condition of the estuary and all of its beneficial uses.

Figure 1. Rip currents form when water piled up between the breaking waves and the beach returns to sea forming a rip current, a narrow jet of water moving swiftly offshore, roughly perpendicular to the shoreline. Click to zoom.

Figure 1. Rip currents form when water piled up between the breaking waves and the beach returns to sea forming a rip current, a narrow jet of water moving swiftly offshore, roughly perpendicular to the shoreline.

What are rip currents?

Great Lakes rip currents are strong, narrow channels of water flowing away from shore.

Rip currents are natural phenomena that transport sand and flush surf-zone water. Unlike "undertow" (sub-surface currents) and "riptides" (currents formed by tributaries or another incoming water source), rip currents form on the surface of the water and are created by wind and breaking waves returning to the lake. Rip currents result when water rushes offshore in a narrow channel. These currents can extend up to 1,000 feet, reach 100 feet in width, and travel up to 5 mph. This is slower than you can run, but faster than you or even an Olympic swimmer can swim. They are most prevalent after storms.

When and where do rip currents form?

Rip currents form when water piled up between the breaking waves and the beach returns to sea forming a rip current, a narrow jet of water moving swiftly offshore, roughly perpendicular to the shoreline.

Figure 2. . Click to zoom.

Figure 1. Rip currents form when water piled up between the breaking waves and the beach returns to sea forming a rip current, a narrow jet of water moving swiftly offshore, roughly perpendicular to the shoreline.

Figure 3.. Click to zoom.

Figure 1. Rip currents form when water piled up between the breaking waves and the beach returns to sea forming a rip current, a narrow jet of water moving swiftly offshore, roughly perpendicular to the shoreline.

Rip currents form due to factors like wind, wave activity, shoreline structures, and weather conditions. According to MacMahan et al. (2011), rip currents tend to exist when waves are coming directly toward the beach. They report rip currents most commonly develop on beaches that exhibit alongshore variations in a sandy bottom because waves break more over shallow regions and less frequently over deeper regions. The surf-zone water is pushed onshore by the breaking waves in the shallow areas (known as shoals) and returns through the deeper rip channels. Great Lakes rip currents typically form at low spots or breaks in sandbars. They can also form at beaches with breaking waves, groynes, jetties, or piers. The sandy beaches along Lake Superior's south shore are susceptible to rip currents.

Why are rip currents dangerous?

Rip currents can pull even the strongest swimmers hundreds of yards away from shore. They average a speed of 0.5 to 1 m/s (roughly 2 feet per second) but their speeds can fluctuate. Although over 100 people die in the U.S. each year because of rip currents, surfers and lifeguards commonly use rip currents to quickly exit the surf zone. MacMahan et al. (2011) suggest, "In our opinion, increased knowledge is the best approach to making a rip current 'foe' into an 'understandable friend.' If you understand how rip currents work, and if you know how to swim and float, you may not be alarmed nor become panicked if you find yourself riding in a rip current."

Rip Currents along Minnesota Point ("Park Point")

Rip currents can form along the shores of the Great Lakes, including Lake Superior. Although these dangerous channels can occur in somewhat unpredictable places, one of the most likely locations on Lake Superior is Minnesota Point ("Park Point"), due to its sandy beach.

Aerial photos of Minnesota Point show that the lake bottom along the shore has many dips and trenches. These low spots may be remnants of past rip currents or pre-formed channels where future rip currents can appear once more.

For additional public safety along Minnesota shores, flags are flown at 4 locations along the beach that match the Duluth National Weather Service (NWS) Office's daily surf forecasts for Lake Superior beaches online. The surf forecast categorizes the risk of rip currents for swimmers as low (green flag), medium (yellow flag), or high (red flag), based on wind direction and speed, and wave height. The flags are changed daily to match the risk, and are changed to red if rip currents are spotted.