Surface Water Quality Monitoring & Assessment Programs

River and Stream Monitoring Programs

The Illinois EPA conducts a wide variety of water quality monitoring programs which have sampled approximately 3,300 stream stations. At least 850 of these stations are sampled for biological, chemical and instream habitat data as well as stream flow. Water quality monitoring programs consist of a combination of fixed station networks and intensive or facility-related stream surveys in specific watersheds.

Illinois EPA operates an Ambient Water Quality Monitoring Network (AWQMN) consisting of 213 fixed stations to support surface water chemistry data needs. Integrated water column samples are collected on a six week sampling frequency and analyzed for a minimum of 55 universal parameters including field pH, temperature, specific conductance, dissolved oxygen, suspended solids, nutrients, fecal coliform bacteria, and total and dissolved heavy metals. Additional parameters specific for the station, watershed, and/or subnetwork within the ambient network are also analyzed. Major subnetworks include a pesticide monitoring subnetwork, an industrial solvents subnetwork, and a mining subnetwork. Where stream flow is available from the U.S. Geological Survey (USGS), water quality data are analyzed for flow-adjusted water quality trends.

Illinois has more than 580 navigable miles of Mississippi River shoreline. Until 1999, the Agency only maintained four active AWQMN stations along this entire river segment. Samples were collected frequently at stations at Fueton, Elsah and Thebes, and nine times a year at Keokuk. Beginning in 2000, seven additional monitoring stations were located on the river, with approximately 50 miles between each station. Above St. Louis these stations are located at locks and dams, while the river below St. Louis is sampled from existing boat access ramps. All stations are sampled on a quarterly basis.

• Program Contacts

Since October 1985, Illinois EPA has operated a Pesticide Monitoring Subnetwork to expand screening for toxic organic substances. Fifteen common herbicides and organophosphate insecticides currently used in agricultural production practices are included for water column analysis. The Pesticide Monitoring Subnetwork consists of 30 AWQMN stations that are adjusted annually to provide additional monitoring coverage in conjunction with the Intensive Basin Survey program. Sampling is conducted during three of the nine AWQMN sampling cycles and consists of one pre-application collection (March to mid-April) and two samples collected in the post application period (mid-April to July). Post pesticide application collections are coordinated with farming activities occurring locally near the AWQMN collection site.

• Program Contacts

Illinois EPA conducts Facility-Related Stream Surveys consisting of the collection of macroinvertebrate, water chemistry, stream flow and habitat data upstream and incrementally downstream from municipal and industrial wastewater treatment facility discharges. Facility-Related Stream Survey information is used to evaluate water quality impacts and the need for additional wastewater treatment controls. Data are also used to characterize the existing and potential aquatic resource of the receiving stream, determine whether there is significant biological impact on the receiving stream and to support the Bureau of Water's National Pollutant Discharge Elimination System permit reissuance activities.

• Program Contacts

Intensive river basin surveys are conducted on a five-year rotational basis in cooperation with the Illinois Department of Natural Resources (IDNR). These intensive river basin surveys are a major source of information for annual 305(b) assessments. Illinois has 33 major river basins within its borders. Stations sampled by Illinois EPA and IDNR are selected on the basis of where intensive data are currently lacking or historical data need updating. Water chemistry and biological (fish and macroinvertebrate) data along with qualitative and quantitative instream habitat information including stream discharge are collected to characterize stream segments within the basin, identify water quality conditions, and evaluate aquatic life use impairment. Fish tissue contaminant and sediment chemistry sampling are also conducted to screen for the accumulation of toxic substances.

• Program Contacts

The Agency has used toxicity testing as a form of environmental exposure and physiological toxicity monitoring for approximately 15 years. The Bureau of Water (BOW) utilizes toxicity/bioassay information for identifying municipal and industrial wastewaters that have potential for toxic chemical contaminants and toxicity to aquatic life in receiving waters. Toxicity testing also supports BOW Permitting and emergency response activities, and assists in the identification of streams selected for biological monitoring in conjunction with the Agency's Facility-Related Stream Survey program.

• Program Contacts

Fish samples collected at intensive river basin survey stations are analyzed for 14 chemical contaminants as part of the Fish Contaminant Monitoring Program. Fish samples are collected and analyzed from approximately 50 stations on Illinois' rivers and streams on an annual basis.

Biocriteria are numerical values or narrative expressions that set the standard or attainment goals for biological communities. In Illinois these biocriteria or "biological expectations" are based on a regional reference site approach that enables within-region comparisons between the aquatic community at any stream site and the reference expectation. The regional reference site approach is a key component of biocriteria which ensures reasonably attainable biological goals that recognize and account for the unique combination of regional land form, land use, and physical habitat characteristics which influence the distribution of fish, macroinvertebrates and other aquatic organisms. Illinois is currently developing this framework, which includes refinement of existing biological assessment tools and, where needed, development of new state-of-the-art monitoring approaches.

Illinois EPA is working with the Illinois Department of Natural Resources (IL DNR), U.S. EPA, members of the agricultural, industrial, academic and regulated communities as well as outside contractors and other interested parties to develop biological criteria (biocriteria) for streams and rivers. This approach to biocriteria will enable Illinois EPA to better assess the ecological/environmental quality of Illinois rivers and streams and should allow the Agency to continue to update and refine the stream use designations contained in Illinois' water quality standards.

• Program Contacts