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 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.

To learn more about Lake Springfield's raw water quality, select any of the topics listed below.

SOIL EROSION
NUTRIENTS AND ALGAE PRODUCTION
ATRAZINE
MICROORGANISMS
SAMPLING PROGRAMS
E. COLI MONITORING RESULTS
AQUATIC ORGANISMS
UNDESIRABLE AQUATIC ORGANISMS
LAKE SPRINGFIELD WATERSHED PLANNING COMMITTEE

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Soil Erosion

The nature of the eroded soils from the lake watershed results in water clarity being limited to about one foot of depth from the surface in the upper areas of the lake, the Sugar and Lick Creek arms of the lake west of the I-55 bridge. Clarity improves to about four feet near Spaulding Dam. These upper areas have also acted as sediment basins. Although they hold only about 10 percent of the volume of lake water, these areas retain approximately 50% of the sediment that enters the reservoir.

Nutrients and Algae Production

Water clarity is also affected by the amount of algae production in the lake. Some of the nutrients, specifically nitrogen and phosphorus, that are applied as fertilizers to farm fields, enter the lake with eroded soils and runoff water. The result is that products intended to grow healthy corn and soybeans end up fertilizing aquatic vascular plants and algae, creating a rapid growth situation that results in algae "blooms." These blooms can often be seen as films on the water or as a green or brown coloration of the water. The blooms mostly consist of single-cell algae forms, and their contribution to reduced water clarity can actually have a beneficial impact on the lake because it prevents the extensive growth of submersed vegetation that is the source of boating concerns in some lakes.

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Atrazine

One agricultural chemical that has received a lot of attention in recent years is the herbicide atrazine, which is used extensively to prevent broadleaf weed growth in corn fields. While not a concern from a recreational contact perspective, its seasonally varying concentrations in the lake can, if high enough, become a drinking water issue. Fortunately, though at great expense, CWLP is able to treat the raw water with powdered activated carbon to ensure Springfield's drinking water will comply with governmental standards.

Microorganisms

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. Though 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. No one has come down with the illness after recreating in the lake since the 1998 occurrences.

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Sampling Programs

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. A new program initiated in 1999 was 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 now also monitors regularly for E. coli at five locations around the lake. Results of the E. coli monitoring program are detailed in the table below.

Monitoring has indicated that E. coli levels spike (rapidly increased) 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.

E. COLI MONITORING RESULTS

Under normal conditions, CWLP tests for E. Coli every two weeks from the spring through the fall.  If readings are abnormally high, more frequent samples will be taken.  The standard used by the State of Illinois calls for bathing beaches to be closed when E. coli levels exceed 235.

Testing stations are located as follows: (A) near the water intake tower near Spaulding Dam; (B) in the main basin of the lake, mid-way between Lindsay Bridge and the C&IM Railroad bridge; (C) just west of the C&IM Railroad bridge; (D) in the upper (Lick Creek) arm, between Woodside Bridge and the I-55 bridge; (E) in the lower (Sugar Creek) arm near the Wildlife Sanctuary.  A map showing the location of each test site and the most recent reading for each site is available.

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Aquatic Organisms

Lake Springfield provides habitat for all shapes and sizes and types of creatures that typically live in or near an aquatic environment. The greenbelt of trees and other vegetation around the lake and the presence of a water source also attracts significant numbers of terrestrial wildlife species to the area. Migratory waterfowl and other animals use the lake as a stopping off and refueling point on their way to other destinations.

The types of animals present are largely a reflection of the habitats that are available. The greater the diversity of habitats, the more species will be found. The upstream wetland areas in the Lick and Sugar Creek arms of the lake are physically quite different and more diverse than the large open expanses of the main lake basins. Also, the nooks and crannies along the shoreline areas provide important habitat for fish and other aquatic organisms.

The building blocks of the lake's ecosystem are algae and zooplankton, followed by numerous aquatic insects like the immature larval or nymphal stages of dragonflies, midges and mayflies. Fish like largemouth bass are often thought of as the top predators in Lake Springfield's ecosystem, but even they can be gobbled up by aquatic birds like great blue herons, which are often seen in the quiet areas around the lake.

A full description of the lake ecosystem and management challenges is available in a publication called Lake Springfield Ecology and Management: A Leaseholder and Community Guide. The publication discusses septic systems, dredging, erosion control, lake-area construction, permitting, yard maintenance, fuel storage tanks, boating, and other issues that can influence the quality of the lake. To obtain a copy, or for answers to any lake management questions, call Michelle Nicol, at (217) 757-8660 ext. 125.

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Undesirable Aquatic Organisms

Fortunately, at present, Lake Springfield is relatively free of undesirable aquatic organisms. One way you can help preserve our healthy lake ecosystem is to never stock exotic species or dump unused fish bait into the reservoir.

The zebra mussel, a small exotic clam that is found in the Illinois River and other bodies of water, has, so far, not made its way into Lake Springfield. This mussel is problematic for boat motors, plant intake structures, and native mussel populations. The most likely means by which the zebra mussel would enter Lake Springfield would by in the bilge water of boats and attached to boats, boat trailers and bait buckets that had been previously used in infected waters. When traveling between waterways, please take care to decontaminate your equipment prior to entering Lake Springfield.

Lake Springfield has a host of native aquatic plants, such as algae, duckweed, American lotus (lily pads), cattails, and creeping water primrose, which provide habitat and food for many animals. Gardening catalogs and garden centers offer many kinds of water lilies and other exotic plants. One in particular is the attractive purple loosestrife which is invading and causing environmental havoc in many wetland areas north of Springfield. Never stock or plant any exotic plants into Lake Springfield or any other natural areas.

Lake Springfield Watershed Planning Committee

A volunteer organization, the Lake Springfield Watershed Resources Planning Committee meets regularly to discuss and implement strategies for reducing sediment and chemical runoff to the lake. This diverse group of farmers, resource professionals, utility representatives, chemical and fertilizer dealers, farm managers, and other individuals concerned about the preservation of Lake Springfield and its watershed always welcomes fresh faces with new ideas focused on enhancing the resources. This group has written legislation, sponsored research, and made recommendations to resource agencies to implement strategies aimed at maintaining and improving the quality of Lake Springfield. For more information, call the Sangamon County Soil and Water Conservation District at (217) 241-6640 ext. 3.

Last update: 07/03/08

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