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.

WholeBlueEarthCounties

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.

wholeBlueEarthLandUse

GIS data provided by IA DNR and MN Land Management Center

Landuselegend

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%).

glaciallobesfromUSGSThe 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:

2007-2009 Blue Earth – Average Loads, Concentrations and Yields

Results

TSS

Nitrate-Nitrogen

TP

PO4

Flow Weighted Concentration (mg/L)

175.7

8.26

0.27

0.075

Load (tons/yr)

197,078

8,875

300.2

85.89

Yield (lbs/acre)

281.69

12.69

0.43

0.12

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:

Parameter

Fecal Coliform

Turbidity

Nitrate-Nitrogen

Dissolved Oxygen

Total Phosphorus*

TSS

Water Quality Standard

200 CFU/100 mL

25 NTU

10 mg/L

5 mg/L

none

~60 mg/L

*There is no federal or state standard for phosphorus, often it is dependent upon and specific to the water body; The Minnesota River is estimated that a threshold of 0.26 mg/L is needed to reduce undesirable algal growth; EPA desired goal to prevent nuisance plant growth is 0.1 mg/L

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.

Listed Stream/Reach

Impairment

Affected Use

Blue Earth River, East Branch: Brush Cr to Blue Earth R

Fish IBI, Turbidity

Aquatic Life

Blue Earth River, East Branch: Headwaters to Brush Cr

Fish IBI, Turibidty

Aquatic Life

Blue Earth River: Badger Cr to E Br Blue Earth R

Turbidity, Mercury*

Aquatic Life, Aquatic Consumption

Blue Earth River: Center Cr to Elm Cr

Turbidity, Mercury*

Aquatic Life, Aquatic Consumption

Blue Earth River: Coon Cr to Badger Cr

Turbidity, Mercury*

Aquatic Life, Aquatic Consumption

Blue Earth River: E Br Blue Earth R to South Cr

Fish IBI, Turbidity, Mercury*

Aquatic Life, Aquatic Consumption

Blue Earth River: Elm Cr to Willow Cr

Fish IBI, Turbidity, Mercury*

Aquatic Life, Aquatic Consumption

Blue Earth River: Le Sueur R to Minnesota R

Fecal Coliform*, Turbidity, Mercury*

Aquatic Recreation, Aquatic Life, Aquatic Consumption

Blue Earth River: Rapidan Dam to Le Sueur R

Fecal Coliform*, Turbidity, Mercury*

Aquatic Life, Aquatic Recreation, Aquatic Consumption

Blue Earth River: South Cr to Center Cr

Fish IBI, Mercury*

Aquatic Life, Aquatic Consumption

Blue Earth River: W Br Blue Earth R to Coon Cr

Fish IBI, Fecal Coliform*, Turbidity, Mercury*

Aquatic Life, Aquatic Recreation, Aquatic Consumption

Blue Earth River: Watonwan R to Rapidan Dam

Mercury*

Aquatic Consumption

Blue Earth River: Willow Cr to Watonwan R

Turbidity, Mercury*

Aquatic Life, Aquatic Consumption

Brush Creek: Headwaters to E Br Blue Earth R

Fish IBI

Aquatic Life

Cedar Creek: Cedar Lk to Elm Cr

Fecal Coliform*, Turbidity

Aquatic Recreation, Aquatic Life

Cedar Creek: T104 R33W S6, west line to Cedar Lk

DO, Fecal Coliform*

Aquatic Life, Aquatic Recreation

Center Creek: George Lk to Lily Cr

Fecal Coliform*

Aquatic Recreation

Center Creek: Lily Cr to Blue Earth R

Ammonia, Fish IBI, Fecal Coliform*, Turbidity

Aquatic Life, Aquatic Recreation

Dutch Creek: Headwaters to Hall Lk

Fecal Coliform*, Turbidity

Aquatic Life, Aquatic Recreation

Elm Creek, South Fork: T103 R34W S30, west line to T103 R34W S1, north line

Turbidity

Aquatic Life

Elm Creek: Cedar Cr to Blue Earth R

Fish IBI, Fecal Coliform*, Turbidity

Aquatic Life, Aquatic Recreation

Elm Creek: Headwaters to S Fk Elm Cr

Turbidity

Aquatic Life

Elm Creek: S Fk Elm Cr to Cedar Cr

Turbidity, Fecal Coliform*

Aquatic Life, Aquatic Recreation

Judicial Ditch 3: Headwaters to Elm Cr

DO, Fecal Coliform*

Aquatic Life, Aquatic Recreation

Le Sueur River: Maple R to Blue Earth R

Acetochlor, Fecal Coliform*, Turbidity, Mercury

Aquatic Life, Aquatic Recreation, Aquatic Consumption

Lily Creek: Headwaters to Center Cr

Fecal Coliform*, Turbidity

Aquatic Recreation, Aquatic Life

Watonwan River: Perch Cr to Blue Earth R

Fecal Coliform*, Turbidity, Mercury

Aquatic Life, Aquatic Recreation, Aquatic Consumption

Listed Lake

Impairment

Affected Use

Amber

Nutrient/Eutrophication

Aquatic Recreation

Big Twin

Nutrient/Eutrophication, Mercury*

Aquatic Recreation, Aquatic Consumption

Budd

Nutrient/Eutrophication, PCBs

Aquatic Recreation, Aquatic Consumption

Fox

Nutrient/Eutrophication

Aquatic Recreation

George

Nutrient/Eutrophication

Aquatic Recreation

Hall

Nutrient/Eutrophication

Aquatic Recreation

Sisseton

Nutrient/Eutrophication

Aquatic Recreation

*Approved TMDL

Check out the MPCA Environmental Data Access for more information.

Soil Quality

Sheet and Rill erosion cause sediment delivery to water bodies and remove productive topsoil from agricultural areas. It also increases the potential for gully formation.

Wind erosion physically removes lighter, less dense soil constituents such as organic matter, clays, and silts. This removes the fertile part of the soil and can lower productivity.

Surface Water Quality

Excess nutrients, sediment, and bacteria in surface water bodies degrades water quality and affects aquatic life and recreation.

Groundwater Quality

Nutrients, organics, and animal and human waste pose potential water quality and health issues for groundwater from aging septic systems, feedlot runoff, agricultural runoff, and abandoned wells.

 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