Delavan Township Park, Turtle Creek Watershed (LR01)
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Delavan Township Park, Turtle Creek Watershed (LR01)
Delavan Township Park (793600)
0.03 Miles
0 - 0.03
Natural Community
Deep Lowland
Year Last Monitored
2025
Good
 
Walworth
Trout Water 
No
Outstanding or Exceptional 
No
Impaired Water 
No

Fish and Aquatic Life

Current Use
Deep Lowland
Attainable Use
Default FAL
Designated Use
Default FAL

Overview

Lake Delavan is a moderately large eutrophic lake in Walworth County. A dam on Swan Creek, the lake's outlet stream, elevates the lake level by three feet. Due to excess nutrients the lake has been plagued for years by poor water quality, severe blue-green algae blooms, excessive populations of rough fish, anoxic conditions and fishkills. Construction of a municipal sewer system eliminated septic systems surrounding the lake by 1981 and a complete restoration was attempted in the late 1980s and 1990s. The restoration included dewatering, pesticide application for carp removal, and extensive alum treatments. However, tons of phosphorus and nutrient-rich sediments remain in the lake.

Although the lake's excess nutrients no longer result in the large blue-green algae mats of the 1970s and 1980s, an overabundant fishery and excessive populations of Eurasian water milfoil are now problematic. An Aquatic Plant Management Plan was completed for the lake in 1993 by Aron & Associates. In 1975, more than 15 percent of the lake's direct drainage was urbanized; today this percentage is likely higher. Plans for a new dog track and numerous new subdivisions in the direct drainage area ensure that stormwater management, construction site erosion, and hydrologic modification will be top concerns for this lake in the coming years.

The Lake Restoration Project implemented by local citizens, governmental units, the University of Wisconsin, WDNR, U.S. Geologic Survey and U.S. Environmental Protection Agency in the 1980s and 1990s included the following milestones: short-circuiting the mixing of nutrients coming into the lake from Jackson Creek; drawing down the lake for treatment of rough fish (carp) with the chemical rotenone; and application of aluminum sulphate on the lake bottom to reduce nutrient exchange between lake sediments and lake water. The plan also included reducing nutrient and sediment loads through wetland restoration and creation. About 125 acres of existing wetland and farmed wetlands at the confluence of Jackson Creek and its major tributary were selected for restoration/creation (Helsel and MacKinnon 1995). An 85-acre wetland was constructed to reduce sediment and nutrients entering the lake. This Lake Renewal Plan, funded by U.S. EPA's Clean Lakes Program, was implemented in coordination with the activities funded under the Turtle Creek Priority Watershed Project.

Rock River Water Quality Management Plan, Lower Rock River Appendix. WT-668-2002. South Central Region, WDNR.

Date  2002

Author   Aquatic Biologist

Historical Description

A large natural lake managed for largemouth bass, pan fish, and walleye. Major management problems are carp and pollution. Rough fish removal has since both state and town roads border the pond. Only one farm has frontage and there are no recreational facilities.

Surface Acres = 2,072, S.D.F. - 2.77, Maximum Depth = 56 feet.Source: 1961, Surface Water Resources of Walworth County,WI: WI-DNR Delavan Lake, T-2-N, R-16-E,

Date  1961

Author   Aquatic Biologist

Natural communities (stream and lake natural communities) represent model results that use predicted flow and temperature based on landscape features and related assumptions. Ranges of flow and temperature associated with specific aquatic life communities (fish, macroinvertebrates) help biologists identify appropriate resource management goals. Wisconsin Natural Communities.
This is the most recent date of monitoring data stored in SWIMS. Additional surveys for fish and habitat may be available subsequent to this date.
Trout Waters are represented by Class I, Class II or Class III waters. These classes have specific ecological characteristics and management actions associated with them. For more information regarding Trout Classifications, see the Fisheries Trout Class Webpages.
Wisconsin has designated many of the state's highest quality waters as Outstanding Resource Waters (ORWs) or Exceptional Resource Waters (ERWs). Waters designated as ORW or ERW are surface waters which provide outstanding recreational opportunities, support valuable fisheries and wildlife habitat, have good water quality, and are not significantly impacted by human activities. ORW and ERW status identifies waters that the State of Wisconsin has determined warrant additional protection from the effects of pollution. These designations are intended to meet federal Clean Water Act obligations requiring Wisconsin to adopt an 'antidegradation' policy that is designed to prevent any lowering of water quality - especially in those waters having significant ecological or cultural value.
A water is polluted or 'impaired' if it does not support full use by humans, wildlife, fish and other aquatic life and it is shown that one or more of the pollutant criteria are not met.
The use the water currently supports. This is not a designation or classification; it is based on the current condition of the water. Information in this column is not designed for, and should not be used for, regulatory purposes.
Deep lowland lake describes the depth and location of the lake in a watershed. These variables affect the lakes response to watershed variables.
The use that the investigator believes the water could achieve through managing "controllable" sources. Beaver dams, hydroelectric dams, low gradient streams, and naturally occurring low flows are generally not considered controllable. The attainable use may be the same as the current use or it may be higher.
Fish and Aquatic Life - Default Waters do not have a specific use designation subcategory but are considered fishable, swimmable waters.
This is the water classification legally recognized by NR102 and NR104, Wis. Adm. Code. The classification determines water quality criteria and effluent limits. Waters obtain designated uses through classification procedures.
Fish and Aquatic Life - Default Waters do not have a specific use designation subcategory but are considered fishable, swimmable waters.