Fish and Aquatic Life
Hahns Lake, in the Middle Rock River Watershed, is a 72.06 acre lake that falls in Jefferson County. This lake is managed for fishing and swimming and is currently not considered impaired.
Author Aquatic Biologist
Source: 1968, Surface Water Resources of Jefferson County Hahn Lake, T8N, R14E, Section 25
A small shallow lake connected to the Rock River by a wide back water. The water is clear and fertile over a silt bottom. Winterkill and pollution are recurring problems. Its fishery assets are limited to some panfish and possible spawning habitat for northern pike because of its shallowness due to siltation. Mallards and blue-winged teal nest here and in the 114 acres of adjoining acres of wetland. There is one improved access and it can also be reached by boat from the river. There are two dwellings on the lake.
Surface Acres = 79.0, S.D.F. = 1.84, Maximum Depth = 6.0 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.
Jefferson County Land and Water Conservation Department will undertake a lake classification process. The resulting lake classification system will enable the County and other lake management entities to implement appropriate lake management strategies in a priority -driven and efficient manner. It will result in the protection and restoration of the water quality and natural ecosystems of the lakes in Jefferson County.
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|
|847100||Hahns Lake||10003061||Hahns Lake||7/27/1999||9/30/2017||Map||Data|
|847100||Hahns Lake||283118||Hahn Lake - Deep Hole||6/30/1980||6/30/1980||Map||Data|
Hahns Lake is located in the Middle Rock River watershed which is 95.12 mi². Land use in the watershed is primarily agricultural (52.90%), wetland (16.60%) and a mix of grassland (12.40%) and other uses (18.10%). This watershed has 166.13 stream miles, 125.64 lake acres and 8,735.75 wetland acres.
Nonpoint Source Characteristics
This watershed is ranked Low for runoff impacts on streams, Not Available 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.