The Lower Big Rib River Watershed lies entirely within Marathon County and ends at its confluence with the Wisconsin River. Well-developed systems of ephemeral (seasonal) and perennial (present all year) streams that drain the land surface characterize the Lower Big Rib River Watershed. There are nine named perennial streams in the watershed, which have a combined length of about 85 miles. These streams support warm water fish communities and maintain at least a small continuous flow throughout the year. The Big Rib River is the predominant surface water feature. The portion that lies within the watershed project is located from a point just below the confluence with Black Creek, in northwestern Marathon County, and flows southeasterly approximately 24.4 miles, where it drains into Lake Wausau.
Groundwater is the only source of drinking water in the Lower Rib River Priority Watershed. It is stored in porous spaces and cracks within the sub-surface soil and rock layers. The unconsolidated materials and rock layers saturated with water and capable of providing adequate quantities of water are defined as an aquifer. The top of the uppermost aquifer is called a water table. Aquifers receive and store water in the ground and discharge this groundwater to lakes, streams and wetlands.
Population, Land Use
Incorporated areas in the watershed include the City of Wausau and the villages of Edgar and Marathon. Public lands within the watershed include Marathon, Rib Falls, and Sunny Vale County Parks, and part of Rib Mountain State Park.
Land uses and/or management practices elevating nitrate and pesticide concentrations in groundwater include: poor manure and nutrient management practices; increased pesticide use and amounts, and poor disposal practices; poorly sited and/or constructed and mismanaged manure storage facilities, and; improperly abandoned wells.
Nonpoint and Point Sources
The Upper Wisconsin River Task Force Nonpoint Source Pollution Management Plan identified the Lower Big Rib River Watershed as serious affected by NPS pollution from livestock waste runoff. Problem areas are confined to tributaries o the Big Ri g River. The towns of Cassel, Rib Falls, and Stettin lie within the Lower Rib River Watershed. Soil erosion rates range from 3.1 - 3.8 tons/acre/year (Kaatz). These soil loss rates are high compared to other areas of Marathon County. Low dissolved oxygen from runoff has affected the Wisconsin River dissolved oxygen levels down to the DuBay Dam.
Water quality problems include diurnal shifts in dissolved oxygen, nutrient loading, high fecal coliform bacteria counts and biotic index scores showing poor to very poor water quality in certain streams.
The watershed was ranked per the Nonpoint Source Priority Watershed Selection Criteria. Based on NPS impacts on surface water quality, the watershed ranked "Medium" for NPS pollution control work. The ground water portion of the watershed rank "Low".
Numerous sand and gravel washing operations can be found on or near streams in the watershed. Zmuda (1987) , indicates there were 75 excavation sites disturbing nearly 900 acres of the upper and lower Big Rib River Watershed. This acreage is increasing. The long-term cumulative impacts to this riverine system caused by sand and gravel excavations is unknown.
Edgar and Marathon City have municipal wastewater collection and treatment systems discharging effluent to surface waters in the watershed. Although these treatment plants are capable of producing effluents low in biochemical oxygen demand (BOD) and total suspended solids, they are sources of nutrients discharging to surface waters. The facilities are not designed and operated for nutrient removal. Cheese factories are also a potential source of nutrients if washwater is discharged to surface waters.
The Lower Rib River Watershed is located in the Forest Transition Ecological Landscape which lies along the northern border of Wisconsin's Tension Zone, through the central and western part of the state, and supports both northern forests and agricultural areas. The central portion of the Forest Transition lies primarily on a glacial till plain deposited by glaciation between 25,000 and 790,000 years ago. The eastern and western portions are on moraines of the Wisconsin glaciation. The growing season in this part of the state is long enough that agriculture is viable, although climatic conditions are not as favorable as in southern Wisconsin. Soils are diverse, ranging from sandy loam to loam or shallow silt loam, and from poorly drained to well drained.
The historic vegetation of the Forest Transition was primarily northern hardwood forest. These northern hardwoods were dominated by sugar maple and hemlock, and contained some yellow birch, red pine and white pine. Currently, over 60% of this Ecological Landscape is non-forested. Forested areas consist primarily of northern hardwoods and aspen, with smaller amounts of oak and lowland hardwoods. The eastern portion of the Ecological Landscape differs from the rest of the area in that it remains primarily forested, and includes some ecologically significant areas. Throughout the Ecological Landscape, small areas of conifer swamp are found near the headwaters of streams, and associated with lakes in kettle depressions on moraines. Ground flora show characteristics of both northern and southern Wisconsin, as this Ecological Landscape lies along the Tension Zone.
Groundwater flows from recharge areas such as hills and exposed bedrock to discharge areas such as lakes, rivers and wetlands. In the watershed, groundwater flow is local and follows topography with groundwater discharging into the Big Rib River and Lake Wausau (Kendy, 1988). The time between groundwater recharge and discharge is relatively short. Regional groundwater flow in western Marathon County is southeast toward the Wisconsin River (Bell, 1974).
Principal aquifers within the watershed are the Shallow Sand and Gravel Aquifer underlain by the Crystalline Granite Bedrock Aquifer. In most of the watershed clay outwash deposits that do not serve as an aquifer overlie the granite bedrock aquifer. The aquifer of choice is typically the shallow sand and gravel aquifer where available. This aquifer exists primarily in the far eastern portion of the watershed, and intermittently along river channels.
The portion of the river within the watershed begins just below the confluence with Black Creek, in northwestern Marathon County. The River flows southeasterly for 24.4 miles where it enters Lake Wausau, a 1,918-acre impoundment formed by the Big Rib, Eau Claire and Wisconsin Rivers. Other primary streams in the watershed include Einert, Pine, Omar, Scotch, Soda, Artus, Kennedy and Pet Brook Creeks. Only the Big Rib River and a 3.8-mile stretch of Scotch Creek from the mouth upstream, support a warm water sport fishery. The remaining streams support limited aquatic life, warm water forage, and limited forage fish communities.
Smaller tributaries including 54 miles of unnamed streams within the watershed are only known to support forage/minnow communities due to the flashy nature of the systems. Flashy systems exhibit conditions of high rates of run-off for short periods during rain events, but low sustained base flows; in some cases the streambeds are persistently dry. Human activity in the watershed, such as deforestation, draining of wetlands, nonmetallic mining and spring development has contributed to low baseflow conditions.
River and Stream QualityAll Waters in Watershed
The Big Rib River and other streams are not reaching their highest potential use due to low baseflow conditions and the resulting low levels of dissolved oxygen, and pollution from nonpoint sources. Eroding croplands, streambanks and improperly managed livestock operations are the major sources of nonpoint pollution in the watershed. The primary causes of streambank erosion are due to a combination of livestock grazing of streambanks, historic in-stream sand and gravel mining and high flows during spring run-off events. It is common to observe scarring on trees five feet above base flow water levels in some of the streams. Severe streambank erosion leads to deposition in pools, the filling of spawning substrate within riffle areas, and the elimination of streambank cover.
Date 2002 Watershed Trout StreamsWatershed Outstanding & Exceptional Resources
Lakes and Impoundments
Impaired WatersList of Impaired Waters
Monitoring & Projects
Projects including grants, restoration work and studies shown below have occurred in this watershed. Click the links below to read through the text. While these are not an exhaustive list of activities, they provide insight into the management activities happening in this watershed.
Monitor biology on WBIC: 1454400
Conduct biological (mIBI or fIBI) monitoring on Unnamed, WBIC: 1454400, AU:12458
Big Rib RiConfirm FCA
Confirm FCA 1451800 name Big Rib River TMDL ID 44 Start Mile 0 End Mile 13.52