Impacts of Wastewater Planning

Environmental Impacts

Water Quality Impacts

To determine the quality of surface waters in our State, the IEPA established a biological stream characterization rating system. Under this system, the IEPA assesses water quality of streams on a 5-year rotating schedule. Those waterbodies with sufficient water quality to meet the Clean Water Act goal of "fishable and swimmable" are classified as "fully supporting (good)" by the Agency. Streams not meeting this goal are classified as either "not supporting (fair)" or "not supporting (poor)" (IEPA Bureau of Water 2006, 1). The stream classifications are identified in the state's Water Quality Report and the 303(d) List of Impaired Waterways.

In 2006, "15,424 stream miles, or 21.6 percent of the total 71,394 steam miles in Illinois, were assessed for attainment of at least one designated use" (IEPA Bureau of Water 2006, 1). The IEPA's 2006 Statewide Report illustrates the findings of this assessment.

Table 1. Percent of IL Stream Miles Assessed

Designated Use	Miles	% Assessed	% Good (2)	% Fair (2)	% Poor (2)	% Not Assessed
Aquatic Life	15,057	21.1	62.0	34.5	3.5	78.9
Fish Consumption	6,858	9.6	59.4	36.6	3.9	90.4
Indigenous Aquatic Life	85	100.0	38.2	55.3	7.1	0.0
Primary Contact	3,777	5.3	12.1	38.4	49.4	94.7
Public and Food Processing Water Supply	1,108	100.0	25.3	74.7	0.0	0.0
Secondary Contact (1)	459	0.6	---(3)	---(3)	---(3)	99.4
Aesthetic Quality (1)	0	0.0	---	---	---	100.0

Note:  Numbers and percentages may not add up due to slight rounding errors.

1. Assessment guidelines are not yet fully developed; see section C-2 Assessment Methodology.
2. Percentages of "Good, Fair, and Poor" indicate the percent of miles assessed.
3. By definition, Secondary Contact Use is "Fully Supporting" in all water in which Primary Contact Use is "Fully Supporting"; otherwise, assessment guidelines are not yet developed for determining the level of use attainment.

Based on this Report for the State of Illinois' streams, only "53.6 percent were rated as fully supporting aquatic life" meeting the goals of the Clean Water Act (IEPA Bureau of Water 2006, 2).  The map below illustrates streams in northeastern Illinois that are included in the state's 2006 303(d) List.

There are various sources of impairment impacting Illinois' streams, including "high concentrations of metals, low dissolved oxygen, high polychlorinated biphenyls (in fish tissue or sediments), high nutrients, excessive siltation, high pathogens (fecal coliform bacteria), physical-habitat alteration (other than flow alterations), and high suspended solids" (IEPA Bureau of Water 2006, 1).   Potential impairment sources within the region include those related to "agriculture, hydromodification, municipal point sources, resource extraction, habitat modification (other than hydromodification), and urban runoff/storm sewers" (IEPA Bureau of Water 2006, 1).

The above table and maps represent the widespread problem of impaired water quality throughout northeastern Illinois. One of the most endemic problems facing our waterways is the release of excessive nutrients from both point sources and nonpoint sources, which stimulate excessive aquatic plant growth such as algae blooms. These plants can lower dissolved oxygen levels, which can have adverse impacts on stream biota. Elevated or excessive algal growth can lead to eutrophication, decreased species diversity, increased turbidity, adverse impacts to fish, and increased sedimentation. The most dramatic example of this effect is Gulf Hypoxia, or a large area of low oxygen where the Mississippi River meets the Gulf of Mexico, caused by accumulated nutrients from Midwestern cities, farms, and industries. The hypoxic zone in the Gulf, measured at 7,900 square miles in 2007, is still expanding. It is absent of most marine life, and could be permanently altered if the trend is not reversed.

Usually, a combination of nutrients creates a compound effect on our waterways. Phosphorus is one of the most common nutrients found in excessive amounts, and is a key contributor to algal growth, which often occurs in "slow moving rivers and streams" (NIPC 2000). In an effort to mitigate these impacts, the Illinois Pollution Control Board (IPCB) recently issued regulations limiting the discharge of phosphorus into receiving streams to a monthly average of 1 milligram per liter for expanding or new treatment facilities with a capacity of 1.0 million gallons per day or greater.

Currently, the IEPA does not limit the discharge of nitrogen into a receiving stream, but the USEPA has ruled that all states were required to enact nutrient standards by 2004. In an effort to implement this ruling, the IEPA formed a stakeholder group to provide guidance in formulating water quality standards for nitrogen to mitigate impacts from discharging excessive levels into waterbodies. The IEPA ultimately presents findings from this group to the IPCB as support for proposed nitrogen standards.

Development and land use changes within wastewater planning areas are also associated with increased nonpoint source pollutants (both volume/quantity and rate) and impaired water quality. Impairments related to human activity not only degrade water quality, but also decrease aesthetic values, natural flows, navigation, and, at times, can lead to the extinction of oxygen-dependent organisms or animals (Fabrizi).