Lake Water Quality

Lake Springfield is a reservoir built by impounding water upstream of Spaulding Dam on Sugar Creek. In general, the raw water quality of the lake is typical of many midwestern reservoirs. Rain falling directly on Lake Springfield is one source of water supplying the lake; however, the predominant supply is runoff from the 265-square-mile watershed that lies primarily southwest of the lake. The watershed is the system of drainage ways, most notably Lick and Sugar Creeks and their tributaries, that collect runoff water and groundwater from as far west as Waverly and as far south as Virden. The land use in the watershed is approximately 88 percent agriculturally oriented with the row cropping of corn and soybeans predominating. Given the agricultural nature of the watershed, the lake is very much influenced by the soils, land uses, and human activity occurring within the watershed. These influences, seasonal changes, and the dynamic nature of the lake ecosystems all contribute to the quality of water in the lake.

CWLP's Lake Water Sampling Programs Read More

CWLP biologists and chemists regularly collect lake samples in cooperation with the Illinois Environmental Protection Agency's Volunteer Lake Monitoring Program. Parameters such as pH, temperature, dissolved oxygen, clarity, conductivity, alkalinity, nutrients, and suspended solids are measured and recorded in a database for use in comparing trends over time. In 1999, the utility initiated an E. coli monitoring program. Taking a lead from the Illinois Department of Public Health, which uses high levels of E. coli as an indicator of potential health concerns at bathing beaches, CWLP monitors regularly for E. coli at five locations around the lake.

Monitoring has indicated that E. coli levels rapidly increase after rainfall events and then subside within a few days. Recreational users now have the opportunity to use this monitoring information to help them decide where and in which areas of the lake they choose to recreate at any given time.

Lake Oxygen and Temperature Readings Read More

Many sport fishermen use dissolved oxygen levels and water temperatures to determine the best depth for finding fish. The measurements are taken at one to two foot depth intervals and the most recent readings are recorded on a map that is available for viewing in the documents section.

Approximately every two weeks from spring through fall, CWLP measures dissolved levels and temperature at five different locations on the lake:

- Near the water intake tower, near Spaulding Dam
- In the main basin of the lake, midway between Lindsay Bridge and the C&IM Railroad bridge
- Just west of the C&IM Railroad bridge
- In the upper (Lick Creek) arm, between Woodside Bridge and the I-55 bridge
- In the lower (Sugar Creek) arm, near the Wildlife Sanctuary

(Updated 11/3/2025) (Updated 10/9/2025) (Updated 9/9/2025)

E.Coli Monitoring System Read More

E. coli is a naturally occurring bacterium that originates in the intestines of humans and other animals. It can be found virtually everywhere, including in raw water supplies. While some strains of E. coli are "friendly" to humans and are a necessary component of our digestive process, others can cause serious illness or even death. E. coli is ubiquitous (found virtually everywhere) and its presence is easy to test for. The presence of large quantities of E. coli is often considered to be an indicator of the possible presence of high levels of other, potentially harmful, microorganisms, including Leptospira, the bacteria that causes leptospirosis.

Under normal conditions, CWLP tests for E. coli in the raw lake water every two weeks from the spring through the fall. If readings are abnormally high, more frequent samples will be taken. Test results are also shown on an E. coli map.

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Map (PDF)

E.Coli Readings 10-30-25.pdf

E.Coli Readings 10.8.2025.pdf

E.Coli Readings 9.9.2025.pdf

E.Coli Readings 8.19..2025.pdf

E.Coli Readings 7.29.2025.pdf

E.Coli Readings W Triathlon Route 7.23.25.pdf

E.Coli Readings 7.9.2025.pdf

E.Coli Readings 6.23.25.pdf

E.Coli Readings 6.2.25.pdf

E.Coli Readings 5.15.25.pdf

Micro-Organisms Read More

Recreational users of any lake, river or other body of fresh water should be aware that they are not swimming in a chlorinated pool, but rather in a natural environment complete with fish, aquatic insects, and naturally occurring microorganisms such as bacteria and protozoans. While most of these organisms are not harmful to humans, quantities of pathogenic (disease-causing) bacteria might be present at certain times, particularly after heavy rainfalls.

Sources of these organisms can be wildlife, sewage treatment plants, livestock facilities, and failing septic systems. Although the source was never identified, an outbreak of leptospirosis (a bacterial infection) occurred among recreational users of Lake Springfield in 1998. This is the only identified outbreak of its kind in Lake Springfield, and it appeared to be related to a period of extensive rainfall. Since that 1998 occurrence, no one has come down with the illness after using the lake.

Swimming Read More

Swimming and wading are permitted in Lake Springfield only in designated areas. Rules and regulations regarding this type of water activity must be followed at all times. CWLP has the authority to prohibit these activities at any time in order to prevent pollution or injury to the lake or to prevent disease or danger to human life.

Swimming from boats on Lake Springfield is permitted, but only between sunrise and sunset and only in "no wake" zones adjacent to non-leased marginal lands.

Swimming within 150 feet of the shoreline of marginal lands that have been leased by the City to lake-area residents and private organizations is permitted under certain conditions, but only with the lessee's consent.

Under certain circumstances, CWLP's general manager may also approve swimming in areas other than those noted above. Before such approval would be granted, however, prerequisites, including the availability of experienced lifeguards and sanitary toilet facilities, would have to be met. For some more information, click below.
Swimming

Health Advisory Read More

When using a lake, river or any other body of fresh water for recreation, there are risks of infection from a variety of microorganisms that are naturally present in freshwater habitats. An example of such an infection is leptospirosis, which struck a number of triathletes and recreational users of Lake Springfield in summer 1998.

Leptospira interrogans is a bacteria that is spread from infected mammals to humans, usually by exposure of the eyes, nose, open mouth, or cuts to water that has been contaminated with the urine of an infected animal. Direct contact with the urine, blood or tissue of an infected animal is another avenue of exposure. Both wild and domestic animals can be infected with, and be the source of, the bacteria that causes leptospirosis.

Symptoms of leptospirosis can include fever, chills, vomiting, headache, muscle aches, diarrhea, abdominal pain, eye pain, red eyes, and dark urine. Symptoms usually begin within two to 10 days of exposure, although it is possible for onset to take 30 days or more. The illness can be treated with antibiotics, but, if left untreated, more serious complications could occur.

Exercising certain precautions when using bodies of fresh water can help reduce your chance of becoming infected by Leptospira interrogans and other disease-causing microorganisms. These precautions include avoiding:

- water skiing, jet skiing, swimming or wading when you have cuts, scrapes or athlete's foot

- swallowing the water

- swimming in muddy water, particularly after heavy rainfalls

To help reduce the possibility that infectious diseases will be spread through the lake water, persons with any type of contagious diseases or skin infections are not permitted to swim in the lake for the duration of their condition.

To better allow swimmers in Lake Springfield to judge the potential health risks posed by the lake water at any given time, CWLP regularly tests the water for the presence of the E. coli bacteria. The Illinois Department of Public Health uses high levels of E. coli as an indicator of potential health concerns at bathing beaches. High levels of E. coli are believed to indicate the potential for high levels of other harmful microorganisms, including Leptospira interrogans, for which there is no reliable test.

Source Water & Watershed Protection Activities & Milestones Read More

In an effort to improve Lake Springfield source water protection, an alliance was formed between CWLP and the Sangamon County Soil and Water Conservation District (SCSWCD), along with land owners, producers, educators and independent agricultural educators, which led to the formation of the Lake Springfield Watershed Resource Planning Committee (LSWRPC) in 1989. In 1990 the first watershed resource management plan was written. A sampling of just some Lake Springfield watershed protection efforts and milestones to date are as follows:

Five sedimentation surveys have been conducted since 1948. These surveys have helped guide local efforts to protect the Lake, and have been key resources for dredging efforts and sedimentation loading estimates in the lake over time.
1982, first Lake Springfield Source Water Protection Plan was initiated when CWLP began its Lake Springfield Maintenance and Restoration Program.
From 1987-1990, the City spent $7.8 million to dredge a portion of Lake Springfield.
In 1991, the City approved the Land Use Plan for Lake Springfield and Its Marginal Properties to define uses and management of the Lake and marginal lands. It was updated in 1994, 2005, 2012 and 2014.
In 1995, an addendum to the 1990 Plan to address high levels of the herbicide atrazine in the Lake was approved. With great cooperation from Lake Springfield Watershed producers and local agricultural retailers, action items were successfully implemented.
1995 – The City received an IEPA 319 grant to demonstrate the need for and use of urban erosion control practices in a developing subdivision.
1997-2002 – An “Assessment of Best Management Practices’ Effectiveness on Water Quality and Agronomic Production in the Lake Springfield Watershed” began. Results determined that the BMPs most effective for improving surface water quality and reducing movement of sediment, nutrients and pesticides from agricultural fields were filter strips along streams and no-till farming practices.
2003-2005 – The City received an IEPA 319 grant to establish filter strips and riparian buffers throughout the LSW. Almost 600 acres of filter strips were established along 29 miles of unprotected stream corridors.
2008 – The City received a Protecting Water Quality in Urban Centers in Illinois IEPA 319 grant, the SCSWCD hosted an Urban Water Quality BMP tour for government leaders from Springfield and Sangamon County. The Sangamon County Board and the City of Springfield adopted sediment and erosion control ordinances in 2009 and 2012, respectively.
2013 – A Priority Lake and Watershed Improvement Project grant from IEPA was awarded to the City of Springfield to reduce sediment runoff and nutrient loading into Lake Springfield. Rip rap was installed on 2,756 feet of highly eroded Lake shoreline at the confluence of Lick and Sugar Creeks.
2013-2016 – A nitrogen management program/study was initiated in the LSW. Partners included the IL Council on Best Management Practices (CBMP), SCSWCD, CWLP, Lincoln Land Community College (LLCC), local agricultural retailers and LSW producers. The program was funded 50/50 by the National Fish and Wildlife Foundation (NFWF) and CWLP.
2014-2016 – A Maximum Return to Nitrogen (MRTN) Rate was established for the LSW. This was the first Illinois watershed to have its own MRTN recommendations. The nitrogen recommendation for soybean-corn rotation is 166 N units and 202 N units for planting corn after corn.
2015 – Two USGS water monitoring stations were installed on the two main tributaries (Sugar Creek and Lick Creek) of Lake Springfield with financial support from IL Corn Growers Association. Real-time water monitoring for nonpoint pollutant sources became available 24/7.
2014-2016 – The City received an IEPA 319 Grant for the development of a watershed-based management plan (LSWMP) and for implementation of agricultural and urban BMPs throughout the LSW. Resultant pollutant load reductions totaled 14,888 pounds of phosphorus, 24,210 pounds of nitrogen, and 20,119 tons of sediment over the lifespan of the BMPs.
2016-2017 – The SCSWCD implemented a cover crop program in LSW. Thirty-five LSW producers planted 1,400 acres of cover crops in the fall of 2016.
2017 – The final Lake Springfield Watershed-based Management Plan was completed.
2017 – The final Total Maximum Daily Load (TMDL) study was completed.
2017-2019 – The City received an IEPA 319 Grant for agricultural and urban BMPs throughout the Lake Springfield watershed. A total of 4,370 feet of Lake Springfield shoreline protection was completed.
2020 –CWLP is one of three water systems in North America awarded the American Water Works Association’s Exemplary Source Water Protection Award. For the award, AWWA noted programs and planning in place to reduce and remove sediment and nutrient loading into Lake Springfield, including shoreline stabilization, cover crops, conservation tillage and split/reduced fertilizer application.
2020-2023 Over 15,000 feet of Lake Springfield shoreline protection was completed by CWLP and lake leaseholders.
2021 -- The United States Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS) Regional Conservation Partnership Program (RCPP) provided by the 2018 Farm Bill, awarded nearly $1.3 million to provide agricultural producers funding for conservation practices, and for education and outreach in the Lake Springfield Watershed. Partner-pledged contributions for the RCPP totaled over $2 million at the time of the announcement.
2021 – Under the 2020 NRCS RCPP grant two USGS continuous water quality monitoring stations have been installed on the two feeder creeks of Lake Springfield, Lick and Sugar Creek
2022 CWLP submits its Lake Springfield Source Water Protection Plan geared to meet objectives of nutrient reduction to the IEPA. This plan overlaps with the 2017 Lake Springfield Watershed Management Plan.
2022—The fifth in the state, a woodchip bio-reactor is installed on CWLP leased property at 2626 East Lake Dr. There are 80 acres of organic tillable that acres drain into the bioreactor, allowing the nutrients and sediment to be trapped by wood chips before leaving the bioreactor and flowing to Lake Springfield. The partnership making this project possible includes the Illinois Farm Bureau, the Illinois Land Improvement Contractor’s Association, Inc. (ILICA), the University of Illinois, and NRCS.

Lake Springfield Watershed Protection Programs Awarded For Excellence

CWLP was one of three water systems in North America awarded the American Water Works Association’s Exemplary Source Water Protection Award for developing or implementing the highest level of source water protection for Lake Springfield. The award was presented for a number of measures accomplished with a broad coalition of the utility’s watershed partners, which are improving and protecting the source water supply for Springfield’s drinking water. For the award, AWWA noted programs and planning in place to reduce and remove sediment and nutrient loading into Lake Springfield, including shoreline stabilization, cover crops, conservation tillage and split/reduced fertilizer application.

CWLP has also worked with federal, state and local agencies and non-governmental partners to improve the water quality of the Lake Springfield Watershed through grants and educational outreach. This AWWA award follows an announcement in April of USDA funding of $1.29 million, to be matched with CWLP and land partner resources of another $1.29 million to cover five years of programming for outreach and education as well as implementation of projects to prevent nitrogen, phosphorus and other sediment loads from entering into Lake Springfield.

CWLP partnered with the Sangamon County Soil and Water Conservation District, leading to formation of the Lake Springfield Watershed Resource Planning Committee (LSWRPC) in 1990. In 2017 the LSWRPC developed a long-range source water protection plan to address agricultural resource concerns and urban issues in the watershed. Cost-share programs between the utility and land owners have been implemented for reducing soil erosion and nutrient and sediment runoff.

Other water systems receiving this award from AWWA included the Tahoe Water Suppliers Association, a grouping of California and Nevada agencies using Lake Tahoe as a water source, and Beaver Water District in Arkansas, which uses Beaver Lake as a water source.

USDA Water Quality Project Funding Awarded for Lake Springfield

Partnerships and funding sources are continuing to grow for Lake Springfield’s Source Water Protection Project, a five year program to improve soil health and water quality in the lake’s watershed. This project, set to kick off in 2021, was made possible through the United States Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS) Regional Conservation Partnership Program (RCPP) provided by the 2018 Farm Bill. The USDA recently awarded nearly $1.3 million to provide agricultural producers funding for conservation practices, and for education and outreach in the Lake Springfield Watershed.

City Water, Light and Power (CWLP), the lead partner administering the RCPP award, and 12 other agencies are contributing funding, programs, and services as a match. Together, partner-pledged contributions now total over $2 million, up from $1.3 million in initial pledges. Work is underway by these partners on a variety of plans and programming to implement a number of Best Management Practices (BMPs) to reduce the sediment and nutrient loading entering the tributaries of Lake Springfield. These BMPs include cover crops, conservation/reduced tillage practices, grassed waterways, wetlands and other structural practices. Outreach and education of such practices to reduce nutrient and sediment loading will also be a part of the program.

CWLP Chief Utility Engineer Doug Brown says these plans and programming for the Lake Springfield watershed is a continuation of utility’s commitment to protect the lake. Brown said, “By increasing conservation and reduced tillage practices throughout watershed, CWLP hopes to increase the quality of watershed streams and reduce sediment from flowing into Lake Springfield, while also improving field profitability and soil health for the farmers.”

The Illinois Farm Bureau, one of the RCPP partners, sees value in the partnerships of agencies working in resource protection. “The agricultural community sees the importance of continued collaboration with drinking water agencies as we work together over the next five-years and beyond to implement best management practices that will reduce nonpoint source pollution in both rural and urban settings within the watershed,” says Lauren Lurkins, Director of Environmental Policy for the Illinois Farm Bureau. “RCPP funding opens up new opportunities for area farmers, local county farm bureaus, and local soil and water districts to work hand-in-hand to protect our natural resources.”

Todd LaFountain, CWLP Water Division Manager, says the RCPP programming will help the utility further meet its source water quality goals on multiple fronts. “Reducing the nutrient and sediment loads that enter the lake will help us reduce the risk of harmful algal blooms and other source water contamination issues, plus slow the progression of Lake Springfield water capacity loss and reduce finished water treatment costs,” he said. “The RCCP program will help CWLP achieve our own lake watershed protection plan goals and significantly contribute to State of Illinois’ Nutrient Loss Reduction Strategy (NLRS) to reduce phosphorous and nitrate-nitrogen loads.”

Since the initial funding announcement, new partners have joined including the Illinois Corn Growers Association, Illinois Department of Natural Resources Office of Water Resources, and the Sangamon County Farm Bureau. All partners include:

City Water, Light and Power (lead partner)
Illinois Corn Growers Association (ICGA) (new)
Illinois Department of Natural Resources (IDNR) – the Division of Fisheries
Illinois Department of Natural Resources (IDNR)—the Office of Water Resources (new)
Illinois Farm Bureau (IFB)
Illinois Fertilizer and Chemical Association (IFCA)
Illinois Lake Management Association (ILMA)
Illinois Pork Producers Association (IPPA)
ManPlan LLC
Northwater Consulting
Sangamon County Farm Bureau (SCFB) (new)
Sangamon County Soil and Water Conservation District (SCSWCD)
Springfield Plastics

RCPP outreach and education activities are beginning, and producer applications for funding will open later this year. To receive notifications for the RCPP such as the opening of the RCPP applications, and for information on agricultural watershed events and other grant/funding opportunities through the Sangamon County Soil and Water Conservation District (SCSWCD), please sign up to be on the Lake Springfield Watershed Notification List. To join the list, contact Sarah Lindholm, RCPP Coordinator at CWLP (217)-757-8660 x1025 or sarah.lindholm@cwlp.com) with your contact information such as name, phone number, e-mail, and address. Producers interested in installing RCPP conservation practices once applications are open, can also contact Sarah directly. More information on RCPP can also be found here, https://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/newsroom/releases/?cid=nrcseprd1629618.

About the Lake Springfield Watershed

The Lake Springfield watershed encompasses over 170,000 acres in Sangamon, Macoupin and Morgan counties; the main source waters to Lake Springfield are Lick and Sugar Creeks, and their tributaries. Approximately 74% of the watershed is row crop agriculture, while roughly 6% is urban area including Springfield, Illinois and villages and cities located to the south and west. The lake supplies drinking water to approximately 165,000 people.

Over the last 36 years, CWLP and its Lake Springfield watershed partners have invested nearly $5.5 million in source water protection measures. A number of watershed protection programs for Lake Springfield began in the 1980s. Shoreline stabilization and sediment removal, among other practices, commenced in those years. Following the formation of the Lake Springfield Watershed Resource Planning Committee in 1990, various lake land use and land management plans were developed for water quality and protection purposes for Lake Springfield and its watershed. Many cost-share programs between the utility and land owners have been implemented for reducing soil erosion and nutrient and sediment runoff over the years. Measures have also been taken to reduce atrazine, nitrogen and phosphorus specifically in Springfield’s water source. In 2020 CWLP was awarded the American Water Works Association’s Source Water Protection award for its watershed protection efforts.