Priority watersheds for soil and water conservation

Problem

Crop fields on areas with sloping or highly erodible soils can often lead to soil and nutrients ending up in waterways from surface runoff.

Solution and result

Use of Clean Water Fund grant funds in the Rush Creek subwatershed were leveraged to construct several practices, including a grassed waterway (pictured below) to reduce the runoff. When vegetation gets established in the waterway, it slows down runoff, which helps to reduce major sources of erosion and phosphorous while ultimately keeping productive soil in its place on the fields.

The overall result is less runoff and better water quality.

Story

A farmer in rural Corcoran was having issues with runoff from a steep, sloped field. In addition to producing less crops, the slope contributed to runoff, which reached a nearby lake, leading to water quality issues.

After working with Hennepin County, the landowner was able to install a waterway, sediment control basin, and subsurface drainage. The waterway directs excess water off the fields and into the nearby lake, while the control basins allow soil to settle before running off.

Before, during, and after construction

The pictures here show the progress of the project throughout construction.

Erosion occurring next to the field before starting on the project.

View of the drain tile that went directly below the grassed waterway.

Finishing up grading the soil and burying the tile.

Completed waterway structure prior to seeding it with grass to reduce erosion.

Contact

To learn more about potential projects and funding, or to set up a field visit, please fill out this online form: Cost share for conservation interest form.

Kevin Ellis, conservation specialist
kevin.ellis@hennepin.us
612-382-3956

Every two years, the Minnesota Pollution Control Agency (MPCA) evaluates all waters within the state and creates a list of impaired waters, which are water bodies that fail to meet water quality standards. Though there are many pollutants that can contribute to a water quality impairment, Hennepin County most commonly works to address phosphorus, sediment, dissolved oxygen, and bacteria by doing water quality projects with private landowners. To determine where pollutants are coming from, Hennepin County assesses pollutant contributions to the watershed using computer models.

Hennepin County and its partners work to implement water quality projects with private landowners that reduce pollutants and move towards getting water bodies de-listed from the impaired waters list. Watershed assessments can help determine where it makes the most sense to focus efforts based on a number of factors, such as:

• The amount of pollution a project will remove from an impaired water body
• How much a project will cost
• The cost-effectiveness of the project (in other words, how much the project costs relative to the amount of pollution it will remove)

Priority watersheds are geographies that have been identified by a local or state agency as priorities for reducing pollution such as phosphorus, nitrogen, sediment, E. Coli, etc. to improve the water quality of nearby lakes, streams, or rivers. Hennepin County and its partners have completed watershed assessments to identify water quality improvement opportunities for the following priority watersheds:

• Rush Creek watershed
• Lake Independence and Lake Sarah watersheds
• Dance Hall Creek watershed
• Lake Ardmore watershed

Impaired waters

Many lakes, rivers and streams experience high levels of bacteria, sediment from erosion, and nutrients. Nutrients in water bodies can make it a hard place to live for fish, bugs, and other critters that use it as habitat. Bacteria make it unsafe for recreational uses. Areas with elevated levels of sediment, nutrients or bacteria are designated as an impaired water by the Minnesota Pollution Control Agency (MPCA).

Learn more about Impaired Waters in Minnesota at the MPCA's website: Minnesota’s impaired waters list.

Phosphorus

Phosphorus can contribute to excess algae blooms, which can reduce usability of a water body for recreation. It can also lead to oxygen depletion (eutrophication), which harms wildlife.

Phosphorus has been found in excess levels at:

• The North and South Forks of Rush Creek
• Lake Henry
• Lake Sarah
• Lake Independence
• Dance Hall Creek
• Lake Ardmore
• Diamond Lake

Sediment

Too much sediment in a water body can make the water cloudy. This can harm wildlife and cause oxygen depletion.

Sediment has been found in excess levels at:

• Diamond Lake
• Diamond Creek

E. Coli

E. Coli is a type of bacterial pollutant that can reduce usability of a water body for recreation.

E. Coli has been found in excess levels at:

• The North and South Forks of Rush Creek
• Diamond Lake

Dissolved oxygen

If dissolved oxygen is too low, it can make it more difficult for fish to breathe. If levels reach a certain point, it can cause fish to die off, which can harm the local ecosystem.

Dissolved oxygen is too low at:

The North and South Forks of Rush Creek

Diamond Creek