Overview

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

Koshkonong Creek (Lower) This reach of Koshkonong Creek still flows in its natural channel for most of its distance. Lower Koshkonong Creek is a low-gradient, meandering stream, which has formed a small delta at its mouth on Lake Koshkonong. The only impoundment on the creek, the Rockdale dam, was breached in September 2000 and removed in June 2001. Stream bank restoration and revegetation to reduce sedimentation downstream is in progress. The removal of the Rockdale dam will improve fish migration and habitat quality of the stream. A partnership with the University of Wisconsin-Madison will provide a detailed analysis on sedimentation movement after dam removal. The stream is classified as a warm water sport fishery, but its uses and potential are impaired by agricultural runoff. Highly intensive agricultural operations, including one muck farm, in the drainage area affect water quality. The Upper Koshkonong Watershed contributes a significant portion of nutrient and sediment loads.

Bullhead and rough fish dominate the fishery although northern pike provide a fair fishery in the lower reaches. Wetlands near the creek mouth provide spawning areas for northern pike.

Date  2002

Author   Aquatic Biologist

Overview

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

Koshkonong Creek (Upper) Rising on the east edge of the city of Sun Prairie, much of the creek's headwaters are ditched and straightened. This river exhibits natural limiting conditions as well, such as a flat gradient, low base flow, warm temperatures, and high inputs of sediment and nutrients from the fertile watershed. Agricultural land use, urban development and hydrologic modifications result in sluggish flows, river stretches clogged with debris, and overall poor water quality. Most of its tributary streams have also been ditched and are also clogged with debris. The creek's substrate consists of thick silt, probably washed from nearby farm fields, and sludge from the Sun Prairie wastewater treatment plant lying over gravel.

Above County Trunk Highway T the creek supports a few tolerant forage species. From its headwaters to Hwy. T, the river is classified as supporting limited aquatic life, or marginal surface waters. Although the stream is marginal, Hilsenhoff Biotic Index data from 1989 indicated water quality in the stream improved from “very poor” to “poor.” Base flow monitoring in 1990 showed high levels of phosphorus, chloride, fecal coliform bacteria, ammonia-nitrogen, and nitrate-nitrogen at the Baily Road monitoring site (DCRPC 1995).

Below Highway T, Koshkonong Creek is classified as a warm water sport fishery, though it is severely affected by polluted runoff and past point source discharges. Research into water quality improvements from the upgrade of the Sun Prairie wastewater treatment plant examined aquatic insects via the Hilsenhoff Biotic Index and the stream's chemical water quality. These studies showed improvement in water quality based on chemical parameters only. The biotic index indicated less improvement than anticipated, possibly due to the persistent effects of sludge deposits on the stream bottom coupled with ongoing polluted runoff.

Date  2002

Author   Aquatic Biologist

Overview

Lake Koshkonong A large shallow impoundment of the Rock River, Lake Koshkonong exhibits the same water quality problems as other impoundments in southern Wisconsin but on a much larger scale. The lake was originally a shallow and deep-water marsh; a dam constructed in 1850 created a shallow lake. The dam was rebuilt in 1917, raising the lake level an additional two feet. The lake is a major stop-over for migratory waterfowl and was renowned for waterfowl hunting. The drainage area above the lake encompasses 2,640 square miles.

Tremendous sediment and nutrient loads from the Rock River, Koshkonong Creek and other tributaries enter the lake annually. These loads are primarily from agricultural and some urban sources. In addition, shoreline erosion is severe on the lake. Failing septic systems were a problem in the past but the creation of a sanitary district around a portion of the lake has reduced the impact of this source on water quality. Carp are a widespread problem despite a large commercial carp fishery; the carp destroy habitat and increase the lake's existing level of turbidity. As a result, severe nuisance growth of algae and algae blooms are common, often resulting in fish kills.

The lake's shallow depth combined with its long fetch--the distance the wind blows across it uninterrupted-- causes serious shoreline erosion during major storms. All these conditions combined adversely affect water quality and the lake's fisheries.

The Indianford Dam, which controls the water level of the lake, is in need of repair. The allocation of repair costs among the counties and towns that border the lake has become a local political issue. One group of property owners wants a higher water level to improve boating while another group wants lower levels to protect and improve wetland habitat.Rock River Water Quality Management Plan, Lower Rock River Appendix. WT-668-2002. South Central Region, WDNR.

Date  2002

Author   Aquatic Biologist

Historical Description

Koshkonong Creek (Busseyville Creek) -T5N, RI2E, Sec. 12, Surface acres = 45, Length = 32 miles, Stream order = III, Gradient = 3.8 ft/mile, Base dIscharge = 63.8 cfs.
This large stream drains lands of the drumlin-marsh area in Dane and Jefferson counties and is a tributary to the Rock River system entering at Lake Koshkonong. Small plots of wetlands, totalling several thousand acres, adjoin the stream. Mud Creek is a major tributary and Rockdale Millpond is a major impoundment. Ditching has occurred over most of its length, and many portions are now clogged with debris. The substrate consists of thlck silt over gravel, except in areas of faster water. Water quality is poor throughout the Dane County sections, but especially near the headwaters. The CIty of Sun Prairie is a major contributor of treated sewage effluent and storm sewer runoff. Although the Sun Prairie treatment plant has been recently upgraded, very few species of aquatic life are found directly below this discharge. Further downstream the Villages of Deerfleld, Cambridge, and Rockdale contribute wastewater as do several industries. Increased flow in the lower reaches of the stream dilutes pollutants, improving water quality and diversity. Carp have become a nuisance in the system and an eradication program is being considered. Northern pike provide a fair fishery in the lower part of the stream. Cam-Rock County Park on Rockdale Millpond provIdes camping and picnicking. Numerous road crossings also provide access.
Fish species: central mudminnow, grass pickerel, northern pike, central stoneroller, common carp, brassy mInnow, golden, common, bigmouth, blackchln, blacknose, spotfin, and sand shIner, southern redbelly dace, bluntnose minnow, creek chub, white sucker, golden and short head redhorse, channel catflsh, stonecat, blackstrlpe topmlnnow, brook silverslde, brook stickleback, white bass, green sunfish, pumpkinseed, blueglll, largemouth bass, white crappIe, black crappie, johnny darter, banded darter, logperch, and walleye.

From: Day Elizabeth A.; Grzebieniak, Gayle P.; Osterby, Kurt M.; and Brynildson, Clifford L., 1985. Lake and Stream Classification Project. Surface Water Inventory of Dane County. Wisconsin Department of Natural Resources, Madison, WI

Date  1985

Author   Surface Water Inventory Of Wisconsin

Facilities Management

Koshkonong Creek is an effluent dominated system beginning at the Sun Prairie wastewater treatment plant on the southern border of the city. Upstream of this point streamflow is very low (currently 0.2 cfs or less). Groundwater modeling, using the regional groundwater model developed by the Wisconsin Geological and Natural History Survey, shows that baseflow in Koshkonong Creek has increased 800 percent due to municipal wastewater treatment plant discharges, compared to pre-development conditions (from 0.6 cfs to 5.0 cfs).

Date  2017

Author  Mike Kakuska

Impaired Waters

The 2018 assessments of Koshkonong Creek (miles 27.27-48.42) showed continued impairment by temperature; new temperature sample data exceeded the 2018 WisCALM listing criteria for the Fish and Aquatic Life use. Based on the most updated information, no change in the existing impaired waters listing was needed.

Date  2017

Author  Ashley Beranek

Condition

Wisconsin has over 84,000 miles of streams, 15,000 lakes and milllions of acres of wetlands. Assessing the condition of this vast amount of water is challenging. The state's water monitoring program uses a media-based, cross-program approach to analyze water condition. An updated monitoring strategy (2015-2020) is now available. Compliance with Clean Water Act fishable, swimmable standards are located in the Executive Summary of Water Condition in 2018. See also the 'monitoring and projects' tab.

Reports

Recommendations

Management Goals

Wisconsin's Water Quality Standards provide qualitative and quantitative goals for waters that are protective of Fishable, Swimmable conditions [Learn more]. Waters that do not meet water quality standards are considered impaired and restoration actions are planned and carried out until the water is once again fishable and swimmable

Management goals can include creation or implementation of a Total Maximum Daily Load analysis, a Nine Key Element Plan, or other restoration work, education and outreach and more. If specific recommendations exist for this water, they will be displayed below online.

Monitoring

Monitoring the condition of a river, stream, or lake includes gathering physical, chemical, biological, and habitat data. Comprehensive studies often gather all these parameters in great detail, while lighter assessment events will involve sampling physical, chemical and biological data such as macroinvertebrates. Aquatic macroinvertebrates and fish communities integrate watershed or catchment condition, providing great insight into overall ecosystem health. Chemical and habitat parameters tell researchers more about human induced problems including contaminated runoff, point source dischargers, or habitat issues that foster or limit the potential of aquatic communities to thrive in a given area. Wisconsin's Water Monitoring Strategy was recenty updated.

Grants and Management Projects

Monitoring Projects

Watershed Characteristics

Koshkonong Creek is located in the Lower Koshkonong Creek watershed which is 265.61 mi². Land use in the watershed is primarily agricultural (54.20%), wetland (11.60%) and a mix of grassland (10.50%) and other uses (23.70%). This watershed has 283.47 stream miles, 1,735.65 lake acres and 18,171.94 wetland acres.

Nonpoint Source Characteristics

This watershed is ranked High for runoff impacts on streams, Medium for runoff impacts on lakes and High for runoff impacts on groundwater and therefore has an overall rank of High. This value can be used in ranking the watershed or individual waterbodies for grant funding under state and county programs.However, all waters are affected by diffuse pollutant sources regardless of initial water quality. Applications for specific runoff projects under state or county grant programs may be pursued. For more information, go to surface water program grants.