Milwaukee Riverkeepers: OUR MISSION & VISION

Our mission is to protect, improve and advocate for water quality, riparian wildlife habitat, and sound land management in the Milwaukee, Menomonee, and Kinnickinnic River Watersheds.

We envision a future in which people from all walks of life can enjoy the healthy waterways of the Milwaukee River Basin.

Milwaukee Riverkeeper is a licensed member of the Waterkeeper Alliance, an international coalition ensuring clean water and strong communities.

Milwaukee River basin

The Milwaukee River Basin is an 882.3-square-mile area housed within Milwaukee, Waukesha, Washington, Ozaukee, Fond du Lac, Sheboygan, and Dodge Counties that includes the Milwaukee, Menomonee, and Kinnickinnic River Watersheds. Together, these watersheds contain approximately 500 miles of perennial streams, more than 400 miles of intermittent streams, 35 miles of Lake Michigan shoreline, 57 named lakes, and over 1.3 million people.

The Milwaukee River Basin is divided into three main watersheds:

  • Milwaukee River Watershed
  • Menomonee River Watershed
  • Kinnickinnick River Watershed

The Milwaukee River Watershed is also divided into four main subwatersheds:

  • North Branch Milwaukee River Subwatershed
  • East & West Branch Milwaukee River Subwatershed
  • Cedar Creek Subwatershed
  • South Branch Milwaukee River Subwatershed

The Milwaukee River Basin also includes the Milwaukee River Estuary.

The Natural Heritage Inventory has documented 16 endangered, 26 threatened and 65 special concern plant and animal species and 30 rare aquatic and terrestrial communities within the basin. The Southeastern Wisconsin Regional Planning Commission (SEWRPC) identified over 18,000 acres of high-quality natural communities and critical species habitats remaining in the basin. About 18% of the land area of the basin is covered by urban uses, while the remainder is considered rural. Agriculture is still dominant in the northern half of the basin.

Lake Michigan supplies drinking water to about 70 percent of basin residents as a function of population size. The remainder of the population receives their drinking water from groundwater sources. As people move to the more rural areas of the basin, groundwater quantity and quality issues will become more important.

Milwaukee River Basin’s Past

Before intensive settlement, the Milwaukee River Basin was much different than it is today. Historic settlements of four Native American groups—the Fox, Mascouten, Potawatomi, and Menominee—were documented along the Milwaukee River, and remained in the area for a short time after their lands were ceded to the United States around 1833. Some of these groups became involved in the fur trade with French explorers during the 1700 and 1800s. Pere Jacques Marquette was the first European explorer known to have visited what is now Milwaukee. He and the other explorers who followed found an area rich with upland forests of maple, beech and basswood, and lowland areas dominated by tamarack, cedar and ash.

In addition to the forests, the basin was water and wetland rich. The abundant resources of the forests, rivers and lakes were catalysts for the first settlers’ attempts at economic development in the basin. The southernmost portions of the basin, now known as the Milwaukee area, were soon settled and incorporated, while many of the forested riverbanks were cut for lumber or cleared for farming. Further north in the basin the land was rapidly deforested and cleared for agriculture. The relatively flat landscape and rich soils formed by the glaciers in many areas of the basin allowed for farming a variety of crops. By the mid-late 1800s, farming was the main activity in the upper basin,while mill operations were the first industries. The Milwaukee River and Cedar Creek provided excellent hydropower for the mills.

River Inhabitants

The number of fish found in the Milwaukee River Basin vary depending on if you count Lake Michigan species or not. Some studies count Lake Michigan species that enter the river such as Coho and Chinook salmon, but do not count fish that might stray into the lower part of the river such as lake trout. A rough cross-reference reveals 54 different species of fish.

There other inhabitants than fish in the Milwaukee River Basin however. Invertebrates play a significant role in the ecosystem of a river. In fact, the types of critters you might find can help determine the health of a stream.


Senior water advocacy.

The Senior Water Advocacy Network is a network of adults aged 50 and older who come together to learn and become advocates for Lake Michigan and Milwaukee’s rivers.

Upcoming Events:

Join Milwaukee Riverkeeper SWAN members and attend one of our fun, interactive bus tours, lunch seminars, and workshops on current issues affecting our rivers and Lake Michigan:

Project History

SWAN (the Senior Water Advocates’ Network) was formerly known as the Water Advocacy Institute for Seniors (WAIS). The first began August 21, 2007, with a three-day training program attended by 24 participants. Through speakers, tours of water-related facilities and projects, and instruction on becoming water advocates, participants learned about critical water problems and ways to get involved in helping to solve these problems. Each water advocate wrote a “plan of action” indicating what he/she intended to do in the months ahead to work actively on specific issues. A reunion meeting was held on March 19, 2008, where participants heard a talk concerning the effects of global warming on water.

The second Water Advocacy Institute for Seniors took place on August 12–14, 2008 with 21 participants. A reunion meeting was held March 23, 2009, for participants from both 2007 and 2008. Here, Sharon Cook from the Alliance for the Great Lakes talked about the legislative agenda for the Great Lakes at the federal and state levels.

Classroom Programs:

Milwaukee Riverkeeper provides free, in-classroom lessons and activities for 4th-9th graders. Our program is designed for students to interact with local rivers, use professional-grade testing equipment, and analyze live water samples without leaving school grounds.

Students become scientists in their own classroom! We prioritize schools without resources for off-campus field trips. Students leave with an understanding and appreciation for local freshwater resources and exposure to STEM future careers. Most importantly, students will gain a better understanding of how they personally can affect our waterways and become environmental stewards.

Program Goals:

  • Provide meaningful, hands-on learning opportunities in classrooms
  • Connect students from all around the Milwaukee River Basin to their freshwater resources
  • Develop knowledgeable and active lifelong environmental stewards through hands-on exploration of their waterways
  • Create a sense of student ownership and respect for a brighter freshwater future in Milwaukee

Available Classroom Programs:

  • An Introduction to Water: How much water is there? Why is water important? What makes the city of Milwaukee special? Who is affected by water quality? What does Milwaukee Riverkeeper do? Students will learn about freshwater on Earth by helping the presenter with a simple but effective demonstration showing the scarcity of freshwater. They will identify the major water sources in Wisconsin by looking at a map, define what “riverkeeper” may mean, and finish the lesson with a discussion about freshwater.
  • Watersheds 101: What is a watershed? What are rivers’ role in a watershed? What watershed do you live in? In addition, students will do a classroom ‘stream tour’ where they investigate which physical, chemical, and biological characteristics are affecting our rivers. This lesson includes a watershed modeling hands-on activity. Finally, students will be able to take a peek and do some work with our yearly publication: the Milwaukee River Basin Report Card.
  • Riverkeeper for a Day: What indicators and characteristics do Milwaukee Riverkeeper scientists and volunteers look for when testing water in the field? Why? What equipment do they use? Why is dissolved oxygen so important? How about pH or turbidity? What happens if too much salt gets into our rivers? Too much phosphorus? Students will use our equipment to test their own water samples and become a Riverkeeper for the day! Note: This lesson can be broken into two different days for classrooms that are interested in going into further detail about water quality indicators.
  • Living Things in our Streams: Students will become familiar with all of the creepy-crawly bugs that are living in our waterways. They will address the following questions: What are macroinvertebrates? Why are they important in determining water quality? What is a biotic index? What do mussels do? Why are they important? This is a fun lesson that allows students to see how the presence/absence of bugs and animals can indicate the health of our rivers.
  • Hidden Harms: Emerging Contaminants in Our Waters: In this lesson, students explore the chemicals in everyday products polluting our rivers. Students also hear from real scientists to learn how these contaminants cause problems for our fish and wildlife.  Together, we’ll find ways to keep these pollutants out of our waters.  Since many students are learning online today, we made sure these concepts could be explored from home, activity-centered, and engaging. 
  • Plastics: An Audit: Are your students interested in learning about the increasingly plastic world around them? Milwaukee Riverkeeper provides a free, in-classroom lesson and audit that will help students understand the lifecycle of plastic, how the process of creating plastics causes pollution, and how their disposal leads to problems in our ecosystems. Along with a lesson, students can conduct an audit with their own plastic wastes, discuss problems and patterns with plastics, as well as reflect on solutions through their own lens.


I-94 Expansion: More highways, poor waterways.

In July 2020, Governor Evers expressed support for a Walker-era policy to add two more lanes to a 3.5 mile stretch of Interstate 94 between 70th and 16th Streets. 

So, what’s the problem with that? 

There are three main issues, let’s look at each in detail:

1. Environmentally harmful: The proposed expansion of I-94 would contribute to climate change, pollute our air, and lead to more contaminated runoff in our waterways.

More road means more cars, and more cars lead to more greenhouse gases and other air pollution. This highway expansion contradicts Gov. Evers’ own Task Force on Climate Change, which categorized highways as “environmentally harmful infrastructure.” Additionally, more concrete disrupts the water cycle by preventing rain from entering the ground where it lands. The project would add 56 more acres of it. With more highway, more water will collect and runoff from the roads carrying harmful pollutants like road salt into adjacent waterways. What’s worse, climate scientists predict more rain and flooding for our region in the coming years.

2. Economically questionable: Many studies show that highway expansion does not reduce congestion. There are three reasons for this:

  1. Existing road users may change the time of day they travel thinking that the commute will be faster. 
  2. Those travelling a different route may start driving on the newly expanded road. 
  3. More people may switch to driving alone instead of taking the train or carpooling. 

All of these behaviors combined lead to higher demand for the road, offsetting any anticipated traffic reductions. Moreover, Census data shows that the region isn’t even congested — commute times in Milwaukee County were nearly 20% lower than the U.S. average for metro areas in 2019. The fact is, adding two lanes to I-94 would actually cost taxpayers roughly $300 million more than repairs, even more head-scratching.

3. Racially unjust: While no particular race is immune to the environmental damage that would be caused by I-94 expansion, the harm would be concentrated disproportionately among people of color. This is not new. From the very beginning with the Federal Highway Act of 1956, construction planners charted paths through predominantly black neighborhoods. If your home wasn’t demolished, you lived in the shadow of a chosen class, smothered by the toxic fumes of its highway commuters. The Biden Administration is demonstrating across the country that these expansion projects, funded with federal dollars, won’t go unchecked.    


Milwaukee Riverkeeper recognizes the need for road repairs and supports plans to sustainably revitalize the existing infrastructure footprint with green designs like adding “holding tanks” or rain basins to capture excess water from heavy storms.

We say expand transit, not highways because affordable public transportation reduces emissions, maximizes road efficiency, and creates new employment and commercial opportunities for underserved communities.

More details on a proposed alternative to expansion can be found here:

I-94 Public Meeting Handout – June 2022


With the help of our Coalition for More Responsible Transportation, WisDOT was required to provide an updated Environmental Impact Survey (EIS), delaying the project for at least a year. This is a WIN. However, expansion funding was just passed in the budget so it is almost certain that it will proceed in some form. We are working to highlight more sustainable and just transportation solutions, which are more protective of the environment.


While Gov. Evers may have signed the budget, the makeup of the state legislature gave him little bargaining power. If you don’t want to see projects like the I-94 expansion completed, you must vote for candidates that agree and speak with your legislative representatives. Without that, organizations like Milwaukee Riverkeeper are left with limited tools to prevent or delay the process. There will also be additional public hearing and comment periods as part of the new EIS process, and we encourage you to get involved!!

MKE County Grounds: 

5 Things You Need To Know about the County Grounds:

  1. The County Grounds is located in Wauwatosa and is divided into four quadrants with Highway 45 dividing it into a western and eastern half and Watertown Plank Road dividing it into north and south. The northeast quadrant is the last remaining quadrant that has yet to be fully developed.
  2. The County Grounds is the largest remaining open space in Milwaukee County and home of the confluence of the Menomonee River and Underwood Creek. The County Grounds also consisted of prairie and oak savanna, which provided important habitat for birds, monarch butterflies, owls and other wildlife.
  3. In 1997, the Milwaukee County Board of Supervisors proposed selling the Northeast Quadrant of the Milwaukee County Medical Complex to developers. Public outcry calling for preservation of the land quickly forced the County to call a moratorium on development plans.The Wisconsin Department of Natural Resources conducted a feasibility study for creating a State Forest on the land and decided 60 to 235 acres could be used as a State Forest, with an emphasis on forestry education. The Commission ultimately recommended preserving 235 acres in the northeast quadrant as a State Forest, and developing 50 acres along Watertown Plank Road.
  4. The County Board approved this proposal in 1997, but the County Executive vetoed the Commission proposal, offering an alternative instead that would preserve only 60 acres as a State Forest. Approximately 60 acres of this quadrant north of Swan Boulevard was ultimately preserved by WDNR as State Forest. The Council also passed an ordinance establishing a new type of zoning called Conservancy, which could be used to preserve land in the City of Wauwatosa. However, the victory was only temporary, as zoning was never applied to any of the proposed sites on the County Grounds.
  5. Within a few years, Wauwatosa and Milwaukee County moved forward on efforts to create an “Economic Development Zone”(EDZ) along Watertown Plank of 70 acres (20 acres more than the Commission recommended). In 2004, the City of Wauwatosa sought public input and created a well-balanced Master Plan to develop 42 acres and preserve 28 acres of high-quality natural area of the EDZ. However, in the last 10 years that Master Plan has been largely ignored. In 2006, 90 acres of the northeast quadrant were converted to flood detention basins, and, in 2010, the EDZ was expanded to sell 89 acres to UWM for an Engineering Campus, which currently exceeds density recommendations by over 40%. Now, the City of Wauwatosa is poised to adopt a new development plan for the northeast quadrant that removes protection for any remaining natural areas and proposes the construction of a “Scenic Parkway” through critical habitat, known locally as, “Sanctuary Woods.”



The County Grounds consisted of prairie and oak savanna, which provided important habitat for birds, monarch butterflies, owls and other wildlife. It was an important remnant of an ecosystem that has been largely destroyed–99.3% of prairies and 99.9% of oak savannas have been lost in Southeastern Wisconsin (per the SEWRPC Natural Areas Plan, 1997 and 2009). The County Grounds continues to experience loss of habitat associated with construction of flood detention basins (90 acres) and several stormwater ponds, the UWM Innovation Park, the County Research Park, the Wisconsin Lutheran College Sporting Complex, and the Zoo Interchange project (17 acres).

MKE River Estuary area of concern

In the early 1970’s, following massive algae blooms and fish kills, newspaper headlines declared that Lake Erie was “dead”. Articles about extreme pollution in the Cuyahoga River in Northeastern Ohio were often accompanied by photos of the famous Cuyahoga River fire, a three day period where the river itself caught fire due to high levels of contamination. By the late 1960’s and early 1970’s, the Great Lakes and their surrounding watersheds had been subject to such extensive environmental degradation that it became apparent a binational and multi-state solution would be necessary.

In 1978, government officials from the United States and Canada drafted the Great Lakes Water Quality Agreement. The agreement emphasized the need for collaborative efforts to restore the ecological health of the Great Lakes by focusing on key pollutants of concern. A major component of the Agreement was also the designation of 43 Areas of Concern (AOC’s) throughout the Great Lakes Region. Areas of Concern, such as the Milwaukee River Estuary (Figure 16), were designated based on the observed and anticipated ecological impacts associated with historic industrial activity and legacy pollution in each of the 43 locations. In other words, sites listed as AOC’s were considered to be critically degraded as compared to other similar, often urban, areas of the Great Lakes, and were determined to be in dire need of restoration to overcome existing legacy contamination.

To track those ecological impacts, and the progress of restoration and cleanup efforts in each AOC, the Agreement included a list of Beneficial Use Impairments (BUI’s) associated with each AOC. A BUI can be thought of as “symptom of pollution” that can be monitored and assessed to help gauge the health of an AOC over time. Of the 14 potential BUI’s, the Milwaukee River Estuary AOC has 11, ranging from contaminated sediments and fish health issues to degradation of aesthetic value.


An area of concern is guided by its Community Advisory Committee. The intent is for the CAC to be a broad‐based, balanced, and diverse group representing public, private, and nonprofit sectors of the local community, with members from agriculture, construction, business, education, government, industry, environment, law, civic groups, and recreation interests. Membership is voluntary and open to anyone who wishes to participate. A CAC Leadership Team will be established to organize and guide the efforts of the CAC.

The CAC is representative of broad community interests in the AOC. The CAC is comprised of citizens who are concerned about their environment, especially their water resources, and who are knowledgeable or willing to become so to provide well‐informed opinions and perspectives on projects and activities in the AOC. CAC members are aware of their core objectives and roles to improve watershed health. The group will assure that delisting is meaningful and representative of the community at large. The group is committed to a diverse membership, not just “the choir.” A representative cross‐section of the community is needed to build community support for AOC projects and activities. Members must be willing and able to put in their time, and the CAC may need their involvement after delisting to achieve additional watershed health goals.

Water Conservation

The Milwaukee Wetscape & Why Conserve?

In Milwaukee, we’re lucky to have an abundance of water. This basin is home to 1000 miles of river and is bordered by Lake Michigan, which contains over one trillion gallons of water. But even Milwaukee’s vast water resources are limited and, because of this, we need to protect and conserve them.

In recent decades, human demand and climate change have placed unprecedented pressure on our national water resources. And while some regions have experienced higher than average rainfall, many parts of the US are suffering record dryness. Notably, in September of 2007 nearly half of the country was experiencing drought, and major bodies of water like the Great Lakes, including Lake Michigan, have been showing significantly reduced water levels.

Water Conservation Tips

In the Bathroom:

  • Turn off the water while brushing your teeth.
  • Turn off the water while shaving, and instead fill the bottom of the sink with a few inches of water to rinse your razor.
  • Install a low-flow shower head. It may cost you some money up front, but your water conservation efforts will save you money down the road.
  • Fix those leaky faucets. You may think that a constant drip is just annoying, but it’s also a huge waste of water (you can lose about 20 gallons of water per day from a single drippy faucet!).
  • If you’re in the market for a toilet, buy a low-flow model they use as little as half as much water as normal toilets. Also, look into the water-saving dual flush toilets that are currently used around the world.

In the Kitchen:

  • When washing dishes by hand, don’t leave the water running the whole time. If your sink has two basins, fill one with water for washing, and another with water for rinsing. If you only have one basin, lather up and scrub a bunch of dishes, then turn the water on to rinse them all at once.
  • Only run the dishwasher when it’s completely full.
  • Scrape dishes into the trash rather than rinsing. New dishwashers don’t even require pre-rinsed dishes.
  • Boil food in as little water as possible. You just need enough to submerge your pasta and potatoes and, with less water, you keep more flavor and nutrients in your veggies.
  • Use the water left over from boiling to water your plants (just let it cool down first!).
  • Eat meat and dairy foods fewer times a day, or just in smaller portions. The amount of water used to produce animal products far exceeds the amount used for growing vegetables and grains.
  • When grocery shopping, try to buy more whole foods like vegetables, rice and potatoes. Processed foods and beverages like chips, candies, pre-made meals, and sodas take a lot more water to produce than foods that come straight from the farm.

Lawn & Garden:

  • Water your lawn during the cool parts of the day, like in the early morning or late evening. This helps to prevent evaporation that happens during the hot hours of the day.
  • Don’t water the lawn on windy days, because wind increases evaporation.
  • Set up your sprinklers so they are not spraying the sidewalk or driveway.
  • Use a drip irrigation system instead of a hose or sprinkler to water your garden.
  • Hand-water your lawn or garden instead of using sprinklers when possible. You’t use less than half as much water this way.
  • Get a rain sensor for your automatic sprinklers, or just make sure to turn them off on days when rain is expected.
  • Set lawn mower blades one notch higher. Longer grass means less evaporation.
  • Direct the water drain line from your air conditioner to a flower bed, tree base, or onto your lawn.

Rain Barrels

Set up a rain barrel under a rain gutter outside your house. You can catch hundreds of gallons to use for watering the lawn, washing the car, etc. Just don’t drink it, and make sure to keep it covered with a screen so it doesn’t breed mosquitos. Check your local municipal regulations to see if a rain barrel is allowed.Click hereto learn more about rain barrels.

Great Lake Compact

Milwaukee Riverkeeper worked in collaboration with groups locally and throughout the Great Lakes Region to advocate for passage of the Great Lakes Compact, to protect Lake Michigan and the Great Lakes from water diversions and other threats to lake health. We continue to monitor the implementation of the compact locally.

Enforcing the Compact: Sign the Pledge!

The Great Lakes Compact, signed into federal law in 2008, is a historic agreement developed to protect the Great Lakes by regulating how its waters are used and managed. According to the agreement, the waters of the Great Lakes must stay within the Great Lakes Basin and must be managed to meet the needs of all citizens who live there.

The Compact allows for only a few narrowly defined exceptions to the ban on diverting water outside the Basin. Diversion applications that do not meet the Compact’s strict criteria for exceptions to the ban cannot be approved. Failure to enforce the Great Lakes Compact by allowing unlawful diversions will jeopardize the integrity of this important legislation and the Great Lakes.

When you sign this pledge, you send a message to policy makers and elected officials that you support the Great Lakes Compact and expect them to do the same.


Passing the Great Lakes Compact

Milwaukee Riverkeeper worked with state and federal partners and with our members to advocate for passage of a strong Great Lakes Compact, and in 2008 the Great Lakes-St. Lawrence River Basin Water Resources Compact was signed into law.

The process has been long with its first major accomplishment in 2005 when following a nearly five-year negotiation, the Governors of Illinois, Indiana, Michigan, Minnesota, New York, Ohio, Pennsylvania and Wisconsin reached agreement on the Compact. The Compact provides a comprehensive management framework for achieving sustainable water use and resource protection. The eight Great Lakes States reached a similar, good faith, agreement with Ontario and Québec.

The Great Lakes are a national treasure—important to our nation and the world as both an environmental and economic asset. Our national economy depends on the Great Lakes for industrial uses, hydropower, maritime commerce, agricultural irrigation and many other uses. The Great Lakes are also a globally unique and important environmental resource. The Compact will ensure that the Lakes are used sustainably in order to continue to provide benefits to us all.

The Compact includes the following points:

  • Economic development will be fostered through sustainable use and responsible management of Basin waters.
  • In general, there will be a ban on new diversions of water from the Basin but limited exceptions could be allowed in communities near the Basin when rigorous standards are met.
  • Communities that apply for an exception will have a clear, predictable decision making process; standards to be met; and, opportunities to appeal decisions. These processes and standards do not exist under current law.
  • The States will use a consistent standard to review proposed uses of Basin water. The States will have flexibility regarding their water management programs and how to apply this standard.
  • Regional goals and objectives for water conservation and efficiency will be developed, and they will be reviewed every five years. Each State will develop and implement a water conservation and efficiency program that may be voluntary or mandatory.
  • A broad, bi-partisan consensus has been built in support of the Compact. The Compact was developed in collaboration with regional partners who have also played a key role in its implementation. Members of Congress, Mayors, local government officials and stakeholders have all been instrumental.

Pollutants and Contaminants:

The Clean Water Act defines “pollution” as the “man-made or man-induced alteration of the chemical, physical, biological, or radiological integrity of water.” More general pollution includes any alteration in the character or quality of the environment, or any of its components, that renders it harmful or less suited for certain uses.

Point/Non-Point Pollution

Point Pollution comes from an identifiable source such as an industrial discharge pipe, an underground storage tank, sewage treatment plants or even agricultural feedlots and manure storage areas.

Non-Point Pollution does not originate from one specific location, and it often discharges over a wide area of land. For example, as rainwater flows across lawns, farms, streets, parking lots, and other surfaces, it carries salt, pesticides, fertilizers, oil, grease, and many other pollutants to nearby waterways. The source of any one pollutant cannot be identified.

5 Major Pollution Catagories

Pathogenic Organisms are disease-causing organisms that are found in human intestines and, therefore, are found in human waste. These organisms cause a variety of diseases and can be contracted when people drink water containing a sufficient number of these pathogens, which cause infection. Since the disease-causing organisms are difficult to measure in the laboratory, non-pathogenic bacteria – which can be easily detected- are measured to determine the quality of the water. These bacteria are called fecal coliforms. Fecal coliforms are harmless inhabitants of the human intestine and are present in great abundance when waters have been contaminated with sewage. When high levels of fecal coliforms are detected, there is a high probability that pathogenic organisms are also present.

Oxygen-Demanding Substances. Oxygen is required for most living things, including organisms that live in the water such as fish, insects, microscopic animals, and bacteria. Oxygen is also needed for the decay of organic matter. Decay is the process in which bacteria and microscopic animals break down and consume organic material such as flesh, leaves, or fecal matter. The amount of oxygen needed for the decay process is called the biochemical oxygen demand or BOD. When given as a concentration, such as parts per million, it is a measure of the oxygen that is needed in a given volume of water for the decay process to occur. When large amounts of organic waste material enter surface waters, bacteria multiply, and decay can occur at a rapid rate. This can deplete the oxygen in the surrounding water to levels below that which is needed by living organisms. Organic wastes can come from human and animal sewage, agricultural practices, food processing, wood and paper mills, and numerous other sources.

All living organisms require nutrients for growth. However, when nutrients are present in abundance in surface waters, nuisance or excessive growth of aquatic organisms, such as algae, can occur. When the excess vegetation decays, it uses and removes the dissolved oxygen from the water being decomposed by bacteria, resulting in high levels of BOD (biochemical oxygen demand). The nutrients of greatest concern are phosphorus and nitrogen. Both are naturally present in surface waters and both are present in abundance in wastewaters. Of the two – phosphorus is naturally in the shortest supply. When additional phosphorus is available, the growth rates of vegetation increases significantly. This can produce nuisance growths of algae and can cause changes in the species composition of aquatic plant and animal communities. It can also accelerate the eutrophication processes. Eutrophication is generally associated with increasing plant growth and the slow filling of lakes with sediment and organic materials. Nitrogen, on the other hand, often occurs in the form of ammonia and is a common constituent of sewage because it is a byproduct of the decay of organic material.

Suspended solids are particulate material suspended in water, making it cloudy or turbid. The matter can be composed of sediment particles such as clay or sand, or of organic material such as decaying plant or animal matter. Matter such as organic material, phosphorus, heavy metals and some toxic substances tend to adhere to suspended solids. As a result, suspended solids have various adverse effects on water. Some heavy metals, most notably lead and a majority of the carbon-based toxic substances such as pesticides and polychlorinated biphenyls (PCB’s) tend to adhere strongly to sediment particles in the water. In this way, they can be easily transported from one site to another. However, they can also be removed from the water column by settling.

Toxic Substances include heavy metals and organic chemicals used in manufacturing and agricultural practices. When present in water – even in very small amounts – these materials can produce a variety of serious human and environmental problems. Furthermore, many toxic substances do not break down or decay quickly in the environment. There are currently 17 toxic metals of particular environmental concern:Ag silver, As arsenic, Bi bismuth, Cd cadmium, Co cobalt, Cu copper, Hg mercury, Ni nickel, Pb lead, Pd palladium, Pt platinum, Sb antimony, Se selenium, Sn tin, Te tellurium, Tl thallium, Zn zinc.


What are PBTs?Persistent, Bioaccumulative, Toxic substances, or PBTs, are chemical pollutants that raise special challenges for our society because of their unique properties that require special attention.

PBTs are persistent.PBTs are chemicals that last a long time in the environment. In other words, either they do not break down into safer components, or they do not break down as easily or as quickly as non-PBT chemicals. They may even go undetected for a long period of time because their initial concentrations are so small, yet they can build up to harmful levels in humans, other organisms, and the environment.

PBTs bioaccumulate.Animals and people accumulate PBTs in their bodies, primarily from the food they eat, but also from inadvertent ingestion and inhalation of soil and dust. As these chemicals move up the food chain, they increase in concentration to levels that may be harmful to human, wildlife, and ecosystem health. Regardless of an individual’s eating habits, we as humans reside at the top of the food chain and are most at risk for increased PBT concentrations in our bodies and the adverse health effects that they cause.

PBTs are toxic.PBTs are toxic substances that can cause a wide range of adverse health effects in fish, wildlife, and humans. They have been linked to nervous system, reproductive, and developmental problems, immune-response suppression, cancer, and endocrine disruption.


Previous Uses: Commercial use of PCBs began in 1929 and was widespread. The manufacturing of PCBs (or PolyChlorinated Biphenyls) was stopped in 1977 (in the United States). Major uses of PCBs included: insulation for electrical cables and wires, coolants and lubricants, and in the production of electrical condensers.

Health Concerns: PCBs are considered to be probable human carcinogens based on its association with liver tumors in laboratory rats. Recent EPA documents have termed the findings of some human studies as “suggestive” of an association between human cancer and PCB exposure. PCBs are also associated with immunological effects in animals and some developmental effects in humans. People who have been exposed to PCBs for a long time have problems such as irritation of the nose and lungs, and skin irritations consisting of acne and rashes.

Ecological Effects: PCBs are another example of a highly persistent, highly lipophilic organochlorine contaminant. The degree of chlorination plays a role in the toxicity of PCBs to fish and wildlife. The higher chlorinated congeners appear to be less toxic to aquatic organisms but more toxic to birds and mammals. Birds appear to be more resistant to the acute toxicity of PCBs when compared to mammals but are susceptible to the reproductive effects. Sublethal effects of PCB exposure include skin lesions, wasting syndrome, immunotoxicity, reproductive toxicity, genotoxic and epigenetic effects. Growth disorders and delayed reproduction and reproductive impairment are also linked to PCB exposure.

Fish Advisory

Fishing is a great Wisconsin tradition. So is eating your catch. However, some fish may take in contaminants from the water that they live in and the food that they eat. Some of these contaminants will eventually build up in fish and in humans to levels that can pose a health risk.

Mercury and PCBs are the contaminants of greatest concern in Wisconsin’s fish. To reduce people’s exposure to these contaminants, the WDNR provides advice to help you choose what fish and how much to eat. This information is not intended to discourage you from eating fish but should be used as a guide to eating fish low in contaminants.

Some fish contain elevated levels of contaminants as a result of historical and, in some cases, ongoing pollution by humans. Small organisms absorb these contaminants in the water and, in turn, are eaten by small fish. Big fish eat small fish and, in this way, the contaminants accumulate up the food chain so that top-level predators, such as walleye and bass, contain the highest amounts of contaminants.

Since the 1970’s, the state has aggressively tested fish from Wisconsin’s waters and now fish consumption advisories for specific waterbodies are issued when the fish are found to contain contaminants at levels that may pose health risks to people who eat fish.

For information about fish advisories please visit the WDNR.

Milwaukee sewer history:

The City of Milwaukee began construction of a public sewer system more than 130 years ago to carry wastewater to the surrounding rivers and to Lake Michigan. This design was insufficient for numerous reasons: the population of the area was too great, the waters smelled horrible, and there were fears of disease and contaminated drinking water. In 1888, the government took the approach of diluting the polluted waters with clean water from Lake Michigan. They built a flushing tunnel, which pumped water from Lake Michigan into the stagnant Milwaukee River, just below the North Avenue Dam. In 1907, a similar pumping tunnel was constructed in the Kinnickinnic River.

To help relieve the odor that was being noticed in the lower portions of the Milwaukee River, the city decided to construct a flushing tunnel. This tunnel would allow the pumping of water from Lake Michigan to be diverted to the lower river. However, this unfortunately brought about the possibility of diseases such as cholera and typhoid entering the drinking water. To help alleviate these problems, city officials approved the installation of pumping stations and streets mains in 1887. This provided chlorine-treated, Lake Michigan drinking water for the city residents.

With a typhoid scare in 1909, the formation of the Sewerage Commission of the City of Milwaukee was created in 1913. Their job was to design and to build a complete treatment and disposal system for the city’s waste. The Commission was one of the first in the nation to support secondary wastewater treatment. Built in 1925, the Jones Island Wastewater Treatment Plant used the activated sludge method (using microorganisms to feed on the pollutants) to clean the water.

As the population of the area continued to grow, so did the area’s sewage system and additional treatment plants and sewer lines were built. By 1977, work began on planning and constructing Milwaukee’s Deep Tunnel system. This system of over 17 miles of tunnels, 300 feet below ground, is the cornerstone of the Milwaukee Water Pollution Abatement Program, which was designed to trap sewer overflows.

Inflow & Infiltration

Inflow and infiltration (or I & I) are terms used to describe the ways in which groundwater and stormwater enter into dedicated wastewater or sanitary sewer systems. Dedicated wastewater, or sanitary sewers, are pipes that are located in the street or on easements, which are designed strictly to transport wastewater from sanitary fixtures inside your house or place of business. Sanitary fixtures include toilets, sinks, bathtubs, showers and lavatories.

Inflow is stormwater that enters into sanitary sewer systems at points of direct connection to the systems. Various sources contribute to the inflow, which include footing/foundation drains, roof drains or leaders, downspouts, drains from window wells, outdoor basement stairwells, drains from driveways, groundwater/basement sump pumps, and even streams. These sources are typically improperly or illegally connected to sanitary sewer systems, via either direct connections or by discharge into sinks or tubs that are directly connected to the sewer system. An improper connection lets water from sources other than sanitary fixtures and drains to enter the sanitary sewer system. That water should be entering the stormwater sewer system or allowed to soak into the ground without entering the sanitary sewer system.

Infiltration is groundwater that enters sanitary sewer systems through cracks and/or leaks in the sanitary sewer pipes. Cracks or leaks in sanitary sewer pipes or manholes may be caused by age-related deterioration, loose joints, poor design, installation or maintenance errors, damage or root infiltration. Groundwater can enter these cracks or leaks wherever sanitary sewer systems lie beneath water tables or wherever the soil above the sewer systems becomes saturated. Often sewer pipes are installed beneath creeks or streams because they are the lowest point in the area and it is more expensive to install the pipe systems beneath a roadway. These sewer pipes are especially susceptible to infiltration when they crack or break and have been known to drain entire streams into sanitary sewer systems. Average sewer pipes are designed to last about 20-50 years, depending on what type of material is used. However, often sanitary sewer system pipes along with the lateral pipes that are attached to households and businesses go much longer without inspection or repair and are therefore more likely to be cracked or damaged.

Inflow and Infiltration water is called “clear water” (although it may be dirty) to distinguish it from normal sanitary sewage water in the sewer system.

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