Fish and Aquatic Life
Decorah Lake is a 104-acre impoundment of the Lemonweir River formed by a dam at Mauston. A heavy nutrient load to the lake has resulted in excessive aquatic plant growth. The plant growth, coupled with sedimentation and turbidity, has caused stunted panfish populations. In 1988, a proposal suggested a run-of-the-river hydropower operation be established at the dam.
Author Aquatic Biologist
Decorah Lake is an impoundment of the Lemonweir River formed by a dam at Mauston.
Heavy nutrient load to the lake has resulted in excessive aquatic plant growth. The plant
growth coupled with sedimentation and turbidity has caused stunted panfish
populations. In 1988, a proposal sugested a run-of-the-river hydropower operation be
established at the dam (WDNR, 1991).
Author Surface Water Inventory Of Wisconsin
Source: 1969, Surface Water Resources of Juneau County Decorah Lake, T15N, R3E, Section 12
This medium hard water, drainage impoundment is located on the Lemonweir River primarily within the City of Mauston. The dam is owned by the city. The water has a light brown color, is alkaline, and has a low transparency. Walleye, northern pike, largemouth bass, bluegill, crappie, perch, pumpkinseed, and bullhead are the significant game fish species. Access is possible from a multiple-use area (park) in Mauston as well as navigable water access from the Lemonweir River. Muskrat are significant and beaver are present. Nesting mallard, teal, and wood duck may be noted. Migrating coot, diving and puddle ducks also use the flowage. In addition to the park (boat landing present), other developments include 42 dwellings.
Surface Acres = 104, S.D.F. = 4.05, Maximum Depth = 15 feet
Author Surface Water Inventory Of Wisconsin
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.
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 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
|WBIC||Official Waterbody Name||Station ID||Station Name||Earliest Fieldwork Date||Latest Fieldwork Date||View Station||View Data|
|1304600||Decorah Lake||293073||Decorah Lake - Decorah Lake||9/29/1993||9/29/1993||Map||Data|
|1304600||Decorah Lake||10017441||Decorah Lake -- Access||8/17/2005||8/17/2005||Map||Data|
|1304600||Decorah Lake||293152||Decorah Lake - Deep Hole||4/19/2004||8/18/2020||Map||Data|
|1304600||Decorah Lake||294006||Decorah Lake - Decorah Lake||8/6/1979||8/6/1979||Map||Data|
|1304600||Decorah Lake||10003065||Decorah Lake||7/27/1999||9/11/2016||Map||Data|
|1304600||Decorah Lake||293155||Decorah Lake - Deep Hole Above Dam||4/19/2004||4/14/2021||Map||Data|
|1304600||Decorah Lake||10047645||Riverside Park & Lake Decorah Boat Launch||Map||Data|
Decorah Lake is located in the Lower Lemonweir River watershed which is 209.62 mi². Land use in the watershed is primarily forest (36.20%), agricultural (31%) and a mix of wetland (22.30%) and other uses (10.60%). This watershed has 384.35 stream miles, 558.61 lake acres and 17,722.41 wetland acres.
Nonpoint Source Characteristics
This watershed is ranked Medium for runoff impacts on streams, Low 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.