The Trimbelle River and Isabelle Creek Watershed drains 221 square miles in Pierce County. The character of this watershed has changed dramatically from pre-settlement times to the present. Forested acreage was dramatically reduced from 96% to less than one-quarter of the watershed area. As in the Rush River Watershed, increased runoff rates have led to reduced infiltration of precipitation and thus decreased stream habitat and increased water temperatures. Historic forest cover contributed to greater rates of infiltration, allowing greater spring flow to streams.
This watershed contains almost 63 miles of trout streams, some of which are either threatened or could be improved. There are no lakes in this watershed, except for backwaters found along the Mississippi River.
Population, Land Use
Land use in the Trimbelle River and Isabelle Creek Watershed is dominated by agriculture with 61% of land devoted to farmland. Only a quarter of the watershed’s area remains under forest cover. Open water, wetlands, and suburban areas encompass most of the remaining area in the watershed with eight percent, three percent, and two percent, respectively. Grasslands make up one-half of a percent of the watershed’s total area, while urban land use is minimal with only about one-quarter of a percent.
Nonpoint and Point Sources
The Trimbelle River and Isabelle Creek Watershed is listed as a high priority overall for nonpoint source (NPS) pollution due to its listing as a high priority for groundwater and stream NPS pollution.
The Trimbelle River and Isabelle Creek Watershed is located in two Ecological Landscapes: the Western Coulee and Ridges and the Western Prairie.
The Western Coulee and Ridges Ecological Landscape in southwestern and west central Wisconsin is characterized by its highly eroded, driftless topography and relatively extensive forested landscape. Soils are silt loams (loess) and sandy loams over sandstone residuum over dolomite. Several large rivers including the Wisconsin, Mississippi, Chippewa, Kickapoo and Black flow through or border the Ecological Landscape.
Historical vegetation consisted of southern hardwood forests, oak savanna, scattered prairies, and floodplain forests and marshes along the major rivers. With Euro-American settlement, most of the land on ridgetops and valley bottoms was cleared of oak savanna, prairie, and level forest for agriculture. The steep slopes between valley bottom and ridgetop, unsuitable for raising crops, grew into oak-dominated forests after the ubiquitous presettlement wildfires were suppressed. Current vegetation is a mix of forest (40%), agriculture, and grassland with some wetlands in the river valleys. The primary forest cover is oak-hickory (51%) dominated by oak species and shagbark hickory. Maple-basswood forests (28%), dominated by sugar maple, basswood and red maple, are common in areas that were not subjected to repeated presettlement wildfires. Bottomland hardwoods (10%) are common in the valley bottoms of major rivers and are dominated by silver maple, ashes, elms, cottonwood, and red maple. Relict conifer forests including white pine, hemlock and yellow birch are a rarer natural community in the cooler, steep, north slope microclimates.
The Western Prairie Ecological Landscape is located on the far western edge of the state just south of the Tension Zone; it contains the only true representative prairie potholes in the state. It is characterized by its glaciated, rolling topography and a primarily open landscape with rich prairie soils and pothole lakes, ponds, and wet depressions, except for forested areas along the St. Croix River. The climate and growing season are favorable for agricultural crops. Sandstone underlies a mosaic of soils. Silty loams that can be shallow and stony cover most of the area. Alluvial sands and peats are found in stream valleys.
Historic vegetation was comprised of dry to mesic prairie grasses in the rolling areas and wet prairies in the broad depressions. Open oak savannas and barrens were found on the hilly topography, with small inclusions of sugar maple-basswood forest in small steep sites. Prairie pothole type wetlands were mainly found in St. Croix and Polk counties. Barrens were found along the river terraces of the St. Croix River. Almost half of the current vegetation is agricultural crops and almost a third of the area is grasslands, with smaller areas of open water, open wetlands, and urban areas. The major forest types are maple-basswood and oak-hickory, with smaller amounts of lowland hardwoods and lowland conifer.
Streams within the Trimbelle River and Isabelle Creek watershed have changed dramatically over the past century. Most streams during pre-settlement conditions likely contained self-sustaining native brook trout fisheries. During the early European settlement period, this region saw some logging for timber production and small dam building from milling operations. Following the logging and mill dam era, in the early and mid 1900’s, intensive agricultural practices and severe flooding degraded stream habitat conditions and the health of the native coldwater fish communities. Flash floods have always been a problem on streams in west central Wisconsin due to the steep topography. Flooding conditions likely still impact stream resources, but they are not considered a main limiting factor because other streams within west central Wisconsin experience similar flood events and support very healthy coldwater fish communities. Within the past decade many streams in western Wisconsin have been improving. Changes in land use practices along with the installation of Best Management Practices (BMPs) in this portion of the state appear to be aiding in the recovery of coldwater fish communities.
River and Stream QualityAll Waters in Watershed
Most streams in the watershed are classified as either cold or cool cold based on the natural community model. Headwaters of larger stream and smaller first order streams in the watershed are typically dry run channels. These dry runs are ephemeral in nature meaning flow is present following large runoff events. The length of dry channel is dependent on annual precipitation and corresponding groundwater inputs. During wet weather periods segments of these dry runs maintain streamflow as a result of groundwater inputs. If streamflow persists long enough and connects to a perennial downstream waterbody, aquatic life can establish while water is present. During dry years these same areas can lack water and aquatic life.
There are over 66 miles of trout waters in the Trimbelle River and Isabelle Creek Watershed, including a five-and-a-half-mile stretch of the Big River classified as a Class I trout stream and a three-mile segment of Isabelle Creek, which is considered a Class III trout stream. All of the remaining trout streams are classified as Class II, including sections of Big and Trimbelle rivers and Trimbelle, Little Trimbelle, Spring, and Goose creeks. Over thirty miles of Exceptional Resource Waters exist within the watershed, with the vast majority of those miles occurring along the Trimbelle River (25 miles) and a minority along Big River.
According to the WDNR’s Register of Waterbodies (ROW) database, there are over 794 miles of streams and rivers in the Trimbelle River and Isabelle Creek Watershed; about 108 miles of which have been entered into the WDNR’s assessment database. Of these 108 miles, over 56% are meeting Fish and Aquatic Life uses and are specified as in “good” condition. The condition of the remaining stream miles is not known or documented.
Date 2011 Watershed Trout StreamsWatershed Outstanding & Exceptional Resources
Lakes and Impoundments
The WDNR’s ROW database shows that there are over 1,162 acres of Mississippi River backwaters in the Trimbelle River and Isabelle Creek Watershed, including Dead Slough, Goose Lake, Mud Lake, Lily Pond, and 92 acres of Lake Pepin. Reservoirs and flowages, including Gantenbein Lake, total 137 acres and unspecified open water accounts for another 667 acres within the watershed. Approximately 1,584 acres of riverine backwaters, two and a half acres of impoundments, and less than one acre of lakes are entered into the state’s assessment database. No lakes, impoundments, or riverine backwaters in the watershed have been assessed for fish and aquatic life use or any other use.
The Trimbelle River and Isabelle Creek Watershed is located in central Pierce County and runs slightly into St. Croix County. An estimated two percent of the current land uses in the watershed are wetlands. Currently, about 35% of the original wetlands in the watershed are estimated to exist. Of these wetlands, the majority are forested wetlands (59%), which include bogs and forested floodplain complexes characterized by trees 20 feet or more in height, such as tamarack, white cedar, black spruce, elm, black ash, green ash, and silver maple. Another 31% of wetlands in the watershed are emergent wetlands, which include marshes and wet meadows.
Of the 6,791 acres of estimated lost wetlands in the watershed, the vast majority (97%) are considered potentially restorable based on modeled data, including soil types, land use, and land cover (Chris Smith, DNR, 2009).
Currently, there are no waterbodies listed as impaired within the Trimbelle River and Isabelle Creek Watershed.
Date 2011 List of Impaired Waters
Aquatic Invasive Species
Zebra mussels have been verified and vouchered in Pepin Lake and the Mississippi River since 1991. Curly-leaf pondweed has also been documented in Pepin Lake since 2006.
Fish Consumption Advice
Wisconsin’s fish consumption advisory is based on the work of public health, water quality and fisheries experts from eight Great Lakes states. Based on the best available scientific evidence, these scientists determined how much fish is safe to eat over a lifetime based on the amount of contaminants found in the fish and how those contaminants affect human health. Advisories are based on concentrations of the following contaminants along with angler habits, fishing regulations, and other factors.
Pools 3 and 4 of the Mississippi River have had a specific fish consumption advisory in effect for polychlorinated biphenyls (PCBs) and perfluorooctanesulfonic acid (PFOs) since 2009.
Studies indicate that people exposed to PCBs are at greater risk for a variety of health problems. Infants and children of women who have eaten a lot of contaminated fish may have lower birth weights and be delayed in physical development and learning. PCBs may affect reproductive function and the immune system and are also associated with cancer risk. Once eaten, PCBs are stored in body fat for many years. Each time you ingest PCBs the total amount of PCB in your body increases (Proposed Guidance For the Classification, Assessment, & Management of Wisconsin Surface Waters, Lowndes & Helmuth, March 12, 2007).
The following groundwater information is for Pierce County (from Protecting Wisconsin’s Groundwater through Comprehensive Planning website, http://wi.water.usgs.gov/gwcomp/), which roughly approximates to the Trimbelle River and Isabelle Creek Watershed.
Bay City and Prescott are the only municipal water systems within the Trimbelle River and Isabelle Creek Watershed to have wellhead protection plans in place. Both cities also have wellhead protection ordinances in effect. Furthermore, Pierce County has adopted an animal waste management ordinance.
From 1979 to 2005, total water use in Pierce County has increased slightly from about 4.2 million gallons per day to about 4.7 million gallons per day. The increase in total water use over this period is due primarily to increases in irrigation and industrial uses. The proportion of county water use supplied by groundwater has been consistently greater than 97% during the period 1979 to 2005.
Eighty-five percent of 379 private well samples collected in Pierce County from 1990 to 2006 met the health-based drinking water limit for nitrate-nitrogen. Land use affects nitrate concentrations in groundwater. An analysis of over 35,000 Wisconsin drinking water samples found that drinking water from private wells was three times more likely to be unsafe to drink due to high nitrate in agricultural areas than in forested areas. High nitrate levels were also more common in sandy areas where the soil is more permeable. In Wisconsin’s groundwater, 80% of nitrate inputs originate from manure spreading, agricultural fertilizers, and legume cropping systems.
A 2002 study estimated that 52% of private drinking water wells in the region of Wisconsin that includes Pierce County contained a detectable level of an herbicide or herbicide metabolite. Pesticides occur in groundwater more commonly in agricultural regions, but can occur anywhere pesticides are stored or applied. A total of 2,410 acres of land in Pierce County are in atrazine prohibition areas. Nine out of 10 private well samples collected in Pierce County met the health standard for arsenic.
Potential Sources of Contamination
There are no concentrated animal feeding operations (CAFOs) in the Trimbelle River and Isabelle Creek Watershed; nor are there any licensed landfills or Superfund sites within the watershed.
Monitor biology on WBIC: 2445000
Conduct biological (mIBI or fIBI) monitoring on Isabelle Creek, WBIC: 2445000, AU:16327
Monitor biology on WBIC: 2447600
Conduct biological (mIBI or fIBI) monitoring on Big River, WBIC: 2447600, AU:1470038
Rank Watershed High for Runoff Grant
The nonpoint source priority watershed selection committee should consider the Trimbelle River and Isabelle
Creek Watershed a high priority for selection as a priority watershed project under the Wisconsin Nonpoint Source
Water Pollution Abatement Program.
Isabelle Creek Headwater Standards Review
District WRM should conduct a water quality standards review on the portion of Isabelle Creek headwater classified
as a variance water, including macroinvertebrate sampling at Highway V.
Water Plans and PartnershipsRead the Watershed Plan
2011 Trimbelle River and Isabelle Creek Watershed (LC23) Draft Water Quality Management Plan.
Partners in this watershed are the Pierce County Land and Water Conservation Department, the Trimbelle Rod and Gun Club, and the Kiap-TU-Wish Chapter of Trout Unlimited.
Date 2011 Watershed History Note
The Village of Ellsworth with a population of approximately 3,200 people, is located in the geographical center of Pierce County, in the Trimbelle River and Isabelle Creek Watershed. As the county seat for Pierce County, it is the hub of county activity with the presence of the county courthouse modeled after the Wisconsin State Capitol building. In 1984, the former governor, Anthony S. Earl, proclaimed Ellsworth the Cheese Curd Capitol of Wisconsin.
Ellsworth's first settler, Anthony Huddleston, along with C.B. Bruce, E.M.Bruce, Wilson Kinney and their families, built homes and set up businesses and by 1857 the Town of Perry was well established. Perry was later renamed Ellsworth, after Civil War Colonel, Elmer E. Ellsworth.
Ellsworth was platted as a village in 1862 and incorporated under the laws of Wisconsin in 1887. In 1885 the Omaha Railroad established a depot one mile east of Ellsworth and the community of East Ellsworth was formed. Ellsworth and East Ellsworth operated independently from one another for some time, now they function as one village.