Mud Lake, Lower Crawfish River,Beaver Dam River Watershed (UR02, UR03)
Mud Lake, Lower Crawfish River,Beaver Dam River Watershed (UR02, UR03)
Mud Lake (831500)
116.80 Acres
Natural Community
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.
Shallow Lowland
Year Last Monitored
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.
Suspected Poor
Trout Water 
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.
Outstanding or Exceptional 
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.
Impaired Water 
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.

Fish and Aquatic Life

Current Use
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.
Shallow Lowland
Shallow lowland lake describes the depth and location of the lake in a watershed. These variables affect the lakes response to watershed variables.
Attainable Use
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 - waters that do not have a specific use designation subcategory assigned but which are considered fishable, swimmable waters.
Designated Use
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.
Default FAL
Fish and Aquatic Life - Default Waters do not have a specific use designation subcategory but are considered fishable, swimmable waters.


Mud Lake, in the Beaver Dam River and Lower Crawfish River Watersheds, is a 116.80 acre lake that falls in Dodge County. This lake is managed for fishing and swimming and is currently not considered impaired.

Date  2011

Author   Aquatic Biologist

Historical Description

Source: 1965, Surface Water Resources of Dodge County Mud Lake T9N, R14E, S19

A shallow, muck bottomed widespread lake on the Beaver Dam River. Annual winterkill precludes the establishment of a permanent fishery, although carp, bullheads, northern pike and channel catfish may enter the lake from the river during periods of open water. Its greatest value lies in its attractiveness to wildlife, particularly waterfowl. For this reason it was included in the Wisconsin Conservation Department acquisition project which at the present consists of 2,909 acres in the area. Expansion to 6,762 acres is anticipated, along with control structures on the river which would allow manipulation of water levels on the lake and adjacent area. Almost all of the 1.4 miles of shoreline is in public ownership, and although no boat launching facilities exist, navigable water access is possible via the Beaver Dam River, and hunting is permitted. Mallards, black ducks, blue-winged teal, wood ducks and coot have raised broods on and around the lake, and large numbers of waterfowl visit the lake during the migrations. Upon occasion in the spring, up to 500 ducks, 200 coot, 50 swans and 100 geese have been seen on the lake, which may swell to over 3,500 acres during periods of high water.

Surface Acres = 94, S.D.F. = 1.03, Maximum Depth = 3 feet

Date  1965

Author   Surface Water Inventory Of Wisconsin

Mud Lake, Lower Crawfish River,Beaver Dam River Watershed (UR02, UR03) Fish and Aquatic LifeMud Lake, Lower Crawfish River,Beaver Dam River Watershed (UR02, UR03) RecreationMud Lake, Lower Crawfish River,Beaver Dam River Watershed (UR02, UR03) Fish Consumption


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.



Shoreland Ordinance
Dodge County Planning & Development Department is interested in revising the Dodge County Shoreland Zoning Regulations and adopting a "waterway" classification system to better regulate and manage the county's water resources.

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 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

Mud Lake is located in the Lower Crawfish River watershed which is 177.65 miĀ². Land use in the watershed is primarily agricultural (66.50%), grassland (11.20%) and a mix of wetland (10.70%) and other uses (11.60%). This watershed has 331.66 stream miles, 1,780.53 lake acres and 12,199.86 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.

Natural Community

Mud Lake is considered a Shallow Lowland under the state's Natural Community Determinations.

Natural communities (stream and lake natural communities) represent model resultsand DNR staff valiation processes that confirm or update predicted conditions based on flow and temperature modeling from historic and current landscape features and related variables. Predicated flow and temperatures for waters are associated predicated fish assemblages (communities). Biologists evaluate the model results against current survey data to determine if the modeled results are corect and whether biological indicators show water quaity degradation. This analysis is a core component of the state's resource management framework. Wisconsin's Riverine Natural Communities.

Shallow lowland lake describes the depth and location of the lake in a watershed. These variables affect the lakes response to watershed variables.