In this issue

Be salt wise this winter
Alum makes Alimagnet Lake clearer
Fewer carp in East Lake = better water quality
What's treating stormwater under your feet?
Landscaping for Clean Water registration in January

Make it a Low Salt (or No Salt) winter

We use de-icing salt to keep our roads, driveways, and sidewalks safe during the winter. However, that salt (or chloride) can easily flow into our lakes and rivers via storm drains and harm our ecosystems. It can also seep into groundwater via pores in soil and affect our drinking water supplies. It takes only one teaspoon of salt to pollute five gallons of water forever.

The Vermillion River Watershed is lucky - we do not currently have any waterbodies impaired for chloride. Let's keep it that way! Here are some things you can do to protect your watershed from chloride pollution:

Shovel first and early. The more snow and ice you remove, the less salt you need.
Use less salt. One 12-ounce cup of salt is enough to cover 10 sidewalk squares. Leave about three inches between salt granules. More salt doesn’t always mean more melting.
Check the temperature. When it's below 15 degrees Fahrenheit, it's too cold for salt to work. Use sand for traction instead.
Sweep up any excess salt to reuse later.

Stay posted in January for more information about how you can get involved!

Alimagnet Lake gets a glow-up

Alimagnet Lake, a recreational lake in Apple Valley and Burnsville, was treated with aluminum sulfate (alum) on Oct. 15 to address its phosphorus impairments. Phosphorus is a naturally occurring nutrient. However, too much phosphorus can fuel algae blooms and create poor water quality. Alum binds with phosphorus in the water column and forces it to settle. The Vermillion River Watershed Joint Powers Organization (VRWJPO) and city partners determined Alimagnet could benefit from an alum treatment.

One way to observe lake water quality is by measuring transparency with a Secchi disk. City of Apple Valley water quality volunteers quickly measured results, with transparency increasing from 2.26 ft. pre-treatment to 7.51 ft. following treatment, all the way to the lake’s bottom! That's a threefold improvement. One resident said the lake was clearer than he'd seen it in more than 50 years.

Our consultant will monitor lake bottom conditions in the lake in 2025, with an additional alum treatment set to take place in spring 2026. Water quality improvements associated with this project are forecasted to last 10-14 years, continually improving aquatic habitat.

This project was funded in part by a grant from the Clean Water Fund, one of the funds established by the Minnesota Clean Water, Land, and Legacy Amendment approved by voters in 2008.

Photo description: A barge deposits alum into Alimagnet Lake. Courtesy of City of Apple Valley.

Check out this video!

Hydrodynamic separators clean stormwater beneath your feet

To reduce sediment loading in South Creek-Vermillion River, VRWJPO and the City of Lakeville installed a hydrodynamic separator (HDS) at the intersection of 205th Street and Hollins Avenue W. in Lakeville (pictured, courtesy of Lakeville) in October 2024.

An HDS is a stormwater device that uses swirling action in a separation chamber to remove pollutants in stormwater runoff, namely sediment. HDSs are typically under the street so you can't see them. They connect to pipes carrying water from storm drains, which lead to our lakes and rivers. VRWJPO invests in many stormwater treatment projects like this to keep sediment, leaves, and trash from harming water quality.

This HDS has a flow-through structure that diverts low-flow storm events (more frequent rainfall events that carry more sediment) to the separation chamber. The HDS should reduce sediment loading into South Creek by 1,700 lbs. per year.

VRWJPO plans to install two more HDS systems in the coming years, another one planned in Lakeville and one in Farmington. They will be retrofitted into existing stormwater pipe systems. These two will be funded in part by Watershed-Based Implementation Fund (WBIF) grants, which come out of the Clean Water Fund.

More VRWJPO Projects

You can do your part to protect the Vermillion River Watershed from stormwater pollutants like salt, sediment, and phosphorus. Adopt your storm drain today and track your impact!

East Lake carp and goldfish removal numbers

East Lake, a shallow recreational lake in Lakeville, had high levels of invasive carp and goldfish that harm water quality. VRWJPO, the City of Lakeville, and Dakota County installed a low-voltage electric fish barrier to keep the fish from leaving the lake into North Creek-Vermillion River. Then a consultant began removing the fish by electrofishing and baited box nets. They removed 2,798 pounds of fish in summer and fall 2024.

Carp population densities greater than or equal to 100 pounds/acre are shown to cause the greatest water quality problems. A 2018 study found carp population density in East Lake was 192 lbs./ac. With 2024’s efforts, carp and goldfish biomass was reduced to 89.9 lbs./ac!

But we can’t celebrate quite yet. Carp and goldfish, as invasive species, have high reproduction rates, with goldfish sometimes reproducing three times a year. Removals will continue in 2025 to further address populations.

How can you help? Don't dump your pet fish into lakes or ponds.

Landscaping for Clean Water just around the corner

Are you bored with your landscaping?

Register to attend an introductory Landscaping for Clean Water class to learn how raingardens, native gardens, and native shoreline stabilization projects attract pollinators and help keep our waters clean.

During the introductory class, you will see dozens of affordable designs that transform conventional yards into beautiful and beneficial landscapes.

Afterwards, you can sign up for a design course where you will receive help designing a plan specific to your property and learn about financial and technical assistance opportunities!

Participation in the introductory classes is free, but registration is required. Registration begins on January 13. Visit www.dakotaswcd.org or call 651-480-7777 for more details. Virtual and in-person options available.

Upcoming Events

January 23, 2025 - Vermillion River Watershed Joint Powers Board (VRWJPB) meeting, 1 p.m., Dakota County Extension and Conservation Center, Farmington

January 27-31 - Winter Salt Week, in your neighborhood and online

February 12 - Vermillion River Watershed Planning Commission meeting, 4:30 p.m., Dakota County Extension and Conservation Center

February 27 - VRWJPB meeting, 1 p.m., Dakota County Extension and Conservation Center

Collaboratively providing education, science, and support to restore and protect the Vermillion River Watershed’s natural resources for all who live, work, and play within its boundaries.

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