Welcome to River Monitoring!

Jump to:    Introduction   •    Analytes   •    Sites   •    Data   •    Reports


Urban and suburban rivers are - almost by definition - degraded waters. Therefore, scientists and environmentalists don't monitor them to find out if they are polluted, but rather to find out how polluted they are, and with what.

For over a decade, the River Prairie Group (Sierra Club's local chapter in DuPage County, Illinois) has monitored the water quality of three regional rivers - Salt Creek and the east/west branches of the DuPage River - as part of Sierra Club's national Water Sentinels project. Our all-volunteer effort, one of the oldest and broadest programs of its type, tests river water each month and posts it to this webpage (below) in an integrated spreadsheet/graphical format.

Test results are compiled in site-specific, chronological format dating back over ten years. Rivers benefit from such long-term monitoring by enabling their data to:



The Group is currently analyzing the water samples for the following pollutants: phosphorus, chloride, ammonia, and nitrates. The pollutant standards presented are Illinois' general use water quality standards, which would apply to the waterways monitored in this project. Please note that such standards do not exist for all of the pollutants monitored in this project.



Phosphorus is one of the key elements necessary for animal and plant growth. Phosphates (PO4---) are formed chemically through the oxidation of this element. Phosphates exist in three forms, orthophosphate, polyphosphate, and organically bound phosphate, with varying formulations involving phosphorus. Ortho forms are formed naturally. Poly forms are used in detergents and in the treatment of boiler water. Organic phosphates may result from the breakdown of organic pesticides containing phosphorus. Rainfall causes varying amounts of phosphates and phosphorus to wash from farm soils and soils treated with certain pesticides into waterways.

Phosphates stimulate the growth of algae and aquatic plants that provide food for fish. This may cause an increase in the fish population, benefiting aquatic lifeforms. Excess phosphates, however, may cause an excessive growth in algae and aquatic plants, choking waterways and using up large amounts of oxygen, referred to as eutrophication. The death of the algae and aquatic plants results in the additional consumption of oxygen. The decrease in oxygen levels can result in the death of aquatic life.

Phosphates are not directly toxic to humans or animals unless they are present in very high concentrations. Digestive problems, however, can result from high levels of consumed phosphates. The main concern related to phosphates is the potential for eutrophication.

There is no Illinois general use water standard for phosphates.



Chlorides are salts resulting from the combination of the gas chlorine and various metal ions. Chlorine alone as Cl2 is very toxic. In combination with a metal ion, such a sodium (Na), it becomes essential for life. Small amounts of chlorides are essential for normal cell function.

Despite their beneficial impacts on cell function, chlorides can contaminate fresh water streams and lakes. Fish and other aquatic life forms cannot survive in high levels of chorides. Chlorides may enter surface water from sources such as : (1) rocks containing chlorides; (2) agricultural runoff; (3) industrial wastewater; (4) oil well wastes; (5) wastewater treatment plant effluents; and (6) road salts.

The Illinois general use water standard for chlorides is 500 milligrams per liter (mg/L) for chronic (long-term) exposures (not to be exceeded by the arithmetic average of at least four consecutive samples collected over any period of at least four days).

Many winter test samples exhibit elevated levels of chlorides, the result of road salt runoff after a snowfall.



Ammonia (NH3+) is a gas which is fairly soluble in water, and reacts with it to form a weak base. One unit of water can dissolve many units of ammonia.

Approximately three-fourths of the ammonia produced in the United States is used in fertilizers as ammonia itself or as ammonium salts of nitrates or sulfates. Large quantities of ammonia are used to produce nitric acid, urea, and other nitrogen compounds used in many chemical processes. Ammonia is also used in the production of ice and as a refrigerant. An aqueous solution of ammonia is used to remove carbonate from hard water.

Since ammonia is also a decomposition product from the reaction of urea and protein, it is found in domestic wastewater. Fish and other aquatic life forms contribute to the production of ammonia in streams and other water bodies.

Non-ionized ammonia (NH3) is the principal form of toxic ammonia. It has been determined to be toxic to freshwater organisms in concentrations in the threshhold range of 0.53 to 22.8 mg/L. Toxic levels are both pH and temperature dependent. Toxicity increases with decreasing pH (as the water becomes more acidic and less basic) and as the water temperature decreases. Hatching and growth rates of fishes may be negatively affected by increases in non-ionized ammonia. Structural development detrements in the tissues of gills, livers, and kidneys may also occur with increasing non-ionized ammonia concentrations.

The State has established a total ammonia limit (measured as nitrogen, N) of 15 mg/L, and our samples show no total ammonia concentrations near this limit. The State has established seasonal chronic exposure limits for non-ionized ammonia of 0.057 mg/L for April through October and 0.025 mg/L for November through March. We monitor total ammonia, as well as pH and temperature, to allow us to determine the concentrations of non-ionized ammonia.



Nitrogen-containing compounds act as nutrients in streams, rivers, and reservoirs. The major sources of nitrogen in water are municipal and industrial wastewater, septic tanks, feedlot discharges, animal wastes (livestock, birds, mamals, and fish), fertilized field and lawn runoff, and vehicle exhausts (exhausts are sources of N2 and oxides of nitrogen). Nitrogen in water can be oxidized to nitrites (NO2-). Bacteria in water converts nitrites to nitrates (NO3-) through a process which ties up the available oxygen in water.

Nitrate levels in water fluctuate by season, with Spring concentrations usually higher after snowmelt. Higher nitrate levels also occur following heavy rainfall.

The major impact of nitrates and nitrites on fresh water bodies is that of fertilization leading to possible eutrophication. Nitrates stimulate the growth of algae and plankton, but excessive levels of nitrogen can cause overproduction of algae and plankton. When the algae and plankton die, they decompose and consume oxygen. The consumption and eventual depletion of oxygen can lead to the suffocation of other organisms.

There is no Illinois general use standard for nitrates.



The temperatures reported here are those monitored during the sample collection.

The temperature of the water can have many effects. First, the temperature range of the water can significantly affect which fish will survive or thrive in the water. Second, the temperature, amongst other factors, can affect the amount of disolved oxygen in the water, which in turn can affect the various lifeforms in the water. Third, the temperature of the water can affect algae growth in the water. Finally, the temperature of the water can affect the level of certain chemical ions in the water, which in turn can affect the fish within the water. Generally, relatively high water temperatures are detrimental to desirable fish populations.



Grab samples from the water column are collected at the following sites. Exact locations are denoted by [latitude, longitude].

Click here for a map (opens in new window).

Sampling at the following sites was initiated in 2000:

  • Salt Creek - Prairie Path Bridge
    Prairie Path Bridge at the corner of West Avenue and Randolph Street in Elmhurst [N41 53.169' , W87 57.571']. Denoted "SC1".

  • Salt Creek - Eldridge Park
    Eldridge Park bridge in Elmhurst [N41 51.962' , W87 57.162']. Denoted "SC2".

  • East Branch DuPage River - Churchill Woods Forest Preserve
    Churchill Woods Forest Preserve in Glen Ellyn. Sampling site was previously the shore of the river's south channel; in April 2006, it was moved to the bridge on the north channel [N41 53.191' , W88 2.555']. Denoted "EB1".

  • East Branch Dupage River - Butterfield Rd.
    Pedestrian bridge on north shoulder of Butterfield Road approximately mile east of Route 53, in Downers Grove [N41 49.912' , W88 2.858']. Denoted "EB2".

  • East Branch DuPage River - Burlington Ave.
    Sampling site was previously the shore near Ogden Avenue and Route 53; in April 2000, it was moved to the shore approximately fifty yards south of the BNSF bridge (intersection of Dumoulin and Burlington avenues). In Lisle [N41 47.707' , W88 4.789']. Denoted "EB3".

  • East Branch DuPage River - St. Joseph's Creek
    Shore of St. Joseph's Creek, approximately fifty yards south of Ogden Avenue in Lisle [N41 48.014' , W88 4.113']. Denoted "EB4".


Sampling at the following sites was initiated in 2001:

  • West Branch DuPage River - Beecher Ave.
    Beecher Avenue bridge near Lions Park (aka Riverside Park) in Winfield [N41 52.160' , W88 9.781']. Denoted "WB1".

  • West Branch DuPage River - Warrenville Grove
    Prior to its reconstruction in October 2007, sampling site was on the Prairie Path Bridge in the Warrenville Grove Forest Preserve (near intersection of Butterfield and Batavia roads), but has since relocated approximately one-third of a mile downstream to the concrete bridge in Warrenville Grove park. In Warrenville [N41 49.256' , W88 10.337']. Denoted "WB2".

  • West Branch DuPage River - Centennial Park
    Wood covered bridge connecting Riverwalk to Rotary Hill in Naperville [N41 46.265' , W88 9.314']. Denoted "WB3".


Dissolved Oxygen testing at the following sites was initiated in 2003:

  • West Branch DuPage River - Beecher Ave. (same as WB1)
  • Klein Creek - Prairie Path Bridge [N41 53.449' , W88 9.376']


Thorium testing at the following site was initiated in 2005:

  • West Branch DuPage River - Warrenville Grove (same as WB2)


graphs are best viewed with Microsoft Internet Explorer

In the following graphs, a value of zero (0) does not represent an actual monitored value of zero, but rather is used as a placeholder for "No Data," which cannot be graphed.

Salt Creek - Eldridge Park

Salt Creek - Prairie Path Bridge

East Branch DuPage River - Butterfield Rd

East Branch DuPage River - Churchill Woods

East Branch DuPage River - Burlington Ave

East Branch DuPage River - St. Joseph's Creek

East Branch DuPage River - Meacham Creek

West Branch DuPage River - Beecher Ave

West Branch DuPage River - Centennial Park

West Branch DuPage River - Warrenville Grove

West Branch DuPage River - Beecher Ave (Dissolved Oxygen Project)

Klein Creek - Prairie Path Bridge (Dissolved Oxygen Project)

West Branch DuPage River - Warrenville Grove (Thorium Project)

Special Chloride Report - Winter 2008

Parametric Data
Supporting data provides context to our research, outlining the natural and manmade forces influencing river hydrology, chemistry, and biology. (Graphics will open in new window.)


Water Monitoring Reports

The River Prairie Group has published three reports summarizing the results of its test programs. The documents were distributed to the public as well as the press. Requires Adobe Acrobat Reader.


Internal Documentation

In the interest of disclosure and the sharing of information, the group's internally generated reference material is available below. Requires Adobe Acrobat Reader.


Water Monitoring Resources


Privacy Statement: To help us better understand visits to our webpage, we use a Google Analytics cookie to collect anonymous traffic data.
Their privacy policy can be viewed at http://www.google.com/analytics/tos.html