Blue Earth Watershed

Overview

HUC: 07020009

The Blue Earth Watershed is one of twelve major watersheds that make up the Minnesota River Basin. It is located within Blue Earth, Cottonwood, Faribault, Freeborn, Jackson, and Watonwan Counties in Minnesota; as well as Emmet, Kossuth, and Winnebago Counties in northern Iowa. There are twenty-one Minnesota municipalities located within the Blue Earth watershed with Mankato and Fairmont being the largest.

The Blue Earth watershed is approximately 992,034 acres total (1,550 square miles), of which 775,590 acres are located in Minnesota and 216,444 acres are located in Iowa. The major watershed is subdivided into 115 minor watersheds. The Blue Earth River begins in northern Iowa and converges with the West Branch Blue Earth River in Faribault, from there it flows 108 miles northwardly into Mankato to its confluence with the Minnesota River.

GIS data provided by IA DNR, IA Geological Survey, and LCC – GIS Office

Major resource concerns in the watershed are soil and water erosion, nutrient management, and water quality.

Land Use

Agriculture is the predominant land use within the watershed, accounting for approximately 86% of the land use, followed by grass/pasture/hay (5%), forest (3.5%), and lakes/wetlands (3.6%).  In general, two-year corn/soybean rotations (or corn-on-corn) comprise nearly 92% of the cropped lands within the watershed.  Native vegetation in the area prior to settlement was primarily tall grass prairie.

GIS data provided by IA DNR and MN Land Management Center

Ownership:

98% Private Landowners
1.6% State
0.10% Federal
0.05% County

Soils/Geology

Soils in the Blue Earth watershed are primarily loamy glacial till soils with scattered lacustrine areas, potholes, outwash, and flood plains. Deposits of a bluish-green clay are found along the banks of the river, for which the river, city, and county were named after.  It was formed during the Wisconsin glaciation in Minnesota with glacial till deposited from the Des Moines lobe.  The landscape is nearly level to gently undulating with relatively short slopes.

The western half of the watershed lies primarily in the Blue Earth Till Plain.  The landscape in this area can be described as a complex mixture of gently sloping (2-6%) well drained loamy soils and nearly level (0-2%) poorly drained loamy soils.  There has been extensive artificial drainage to remove water in much of the flat and depressional areas.  Water erosion potential is moderate on large portion of the lands in this areas (46%).

The eastern half of the Blue Earth watershed can be described as a mixture of glacial lake plains, till plains, and moraines.  Sections of the “glacial” Minnesota Lake Plain are located in this area of the watershed.  The landscape is nearly level with poorly drained or very poorly-drained clayey or silty clay soils.  There is extensive subsurface and surface tiling in this portion of the watershed.  Water erosion potential is considered low in this half of the watershed (58%) because a majority of the lands are not bordered by streams, lakes, or drainage ditches.

The western, southern, and eastern boundaries are end moraines, as well as various ground moraines in the eastern half of the watershed. These morainal complexes exhibit an undulating to hilly landscape with slopes ranging from 2-12%.

The majority of agricultural lands within this morainal complex are moderately steep and well-drained, although approximately one-fourth are nearly level, poorly drained soils. Water erosion potential ranges from moderate to high in this landscape area of the watershed.

Hydrology

The drainage network is defined by the Blue Earth River and its major tributaries: Blue Earth, Elm Creek, Foster Creek; other smaller streams, public and private drainage systems, lakes, and wetlands complete the whole drainage network.  Total length of streams in Minnesota is 1,178 miles of which 414 miles are intermittent streams and 764 miles are perennial streams.

Major Rivers and Streams

Middle Branch Blue Earth
West Branch Blue Earth
East Branch Blue Earth
Elm Creek
Foster Creek

Major Lakes

Fox
Walnut
George
Big Twin

*More extensive lists of all rivers, streams, and lakes in the Le Sueur watershed can be found at the MRBDC website*

Water quality information:
Monitoring stations have been established on the Le Sueur River and some of the larger tributaries. Water quality data comes from a variety of sources, such as volunteers with the Citizen Stream Monitoring Program, USGS personnel, or MPCA personnel. You can find more information on water quality data from the MPCA interactive map. In general, of the three watersheds which make up the Greater Blue Earth River Basin, the Blue Earth watershed, along with the Le Sueur watershed, contribute a majority of the total suspended solids (TSS) and total phosphorus (TP) load.  The Blue Earth River generates the highest load of N-NO3.  It is estimated that the Blue Earth River delivers around 46% of the flow in the Minnesota River, 55% of the suspended sediment load, and 69% of the nitrate-nitrogen load at Mankato (includes contributions of the Watonwan and Le Sueur Rivers).  Several of the stream reaches also have high levels of bacteria and restoration of these reaches will require an 80-90% reduction in bacteria levels.

According to the MPCA website, the Le Sueur River watershed had the following water quality estimations:

For further information check out the MPCA website here to see more water quality data.

Water quality standards have been developed for many pollutants, and often they arise due to human health concerns. They are developed by state and federal governments to indicate the extent of the pollution in a water body. This gives us threshold to determine when waters are impaired or not.  The following are several of the key water quality standards for rivers:

Resource Concerns

Many of the waters in the Blue Earth watershed are on the MPCA impaired waters list.  The major concerns are aquatic recreation, aquatic consumption, and aquatic life caused by high levels of turbidity, nutrients, and bacteria.

Check out the MPCA Environmental Data Access for more information.

 Links for more Information about the Blue Earth Watershed

MPCA Blue Earth Watershed
MRBDC Blue Earth Watershed
EPA Surf Your Watershed
MN DNR Watershed Assessment Tool

Reports and Publications concerning the watershed and/or basin

Blue Earth River Major Watershed Diagnostic Report
Blue Earth Rapid Watershed Assessment
Fecal Coliform TMDL Assessment for 21 Impaired Streams in the Blue Earth River Basin
Blue Earth River Monitoring Station Information
Minnesota River Basin 2010 Progress Report: Blue Earth River Watershed
Minnesota River Basin: Watonwan, Blue Earth, and Le Sueur River Watersheds