Managing Chloride Pollution

Capitol Region Watershed District (CRWD) is developing a Chloride Management Plan to guide our work in reducing salt use in the winter and protecting our water bodies, natural resources, and infrastructure from chloride pollution.

Winter weather in Minnesota brings slippery walkways and parking lots. While salt melts ice and can help keep us safe, the chloride in salt harms pets and wildlife, pollutes groundwater, lakes and the Mississippi River, and damages buildings, cars, landscaping, and roadways. There is no environmentally safe option; all de-icing products cause pollution, even those labeled “eco-friendly.”

Melting snow and ice carry salt into storm drains, which flow to lakes, streams, and wetlands. Over the last 20 years, CRWD has been monitoring chloride concentrations in District lakes and stormwater. The monitoring data shows increasing chloride concentrations, which has many adverse long-term effects.

The Challenge

Chloride is a very difficult pollutant to manage. Public safety on icy surfaces is a number one concern in the winter, and salt is currently one of the tools used to reduce ice and keep us safe. While salt works as a tool to reduce ice when used correctly, it is often not used correctly. Applying too much salt does NOT provide extra protection from snow and ice, but it damages property and pollutes water. Salt also does not melt ice in colder temperatures.

The use of salt has many negative impacts:

  • Water Quality: Salt can permanently pollute lakes, rivers, wetlands, groundwater, and drinking water sources.
  • Animals: Salt can be toxic to birds, fish and aquatic bugs. It can also sicken pets and hurt their paws.
  • Plants and Soil: Salt can harm lawns, landscaping, trees, and aquatic plants. It can also contaminate soil.
  • Personal Property: Salt can cause rusting on vehicles and damage shoes, carpets, and flooring.
  • Public Infrastructure: Salt damages public infrastructure like concrete and asphalt pavements, and bridges.

Additionally, once salt enters our water resources, there is no practical way to remove it. Just one teaspoon of salt contaminates five gallons of water! Staff at CRWD have been using our resources to educate, monitor, and partner for better salt reduction, but the problem and impacts continue to escalate.

The Solution

As a watershed district, CRWD is dedicated to protecting, managing, and improving the District’s water resources. While CRWD is not a large-scale applicator of salt or responsible for public safety on roadways, we still share in the responsibility to help develop solutions.

CRWD’s 2021-2030 Watershed Management Plan identified the need to develop a chloride management plan to prevent and reduce chloride pollution in CRWD’s water bodies. The plan will outline the scope of the chloride problem in CRWD, define our role in District-wide chloride prevention and reduction, and develop targeted actions to reduce or prevent chloride use. The overall plan goal is to reduce the impact of chloride pollution to water bodies, natural resources, and infrastructure in CRWD.

Plan Updates

A Minnesota Department of Transportation orange snowplow clearing a snowy road, with visible spray of salt and snow from the rear. Sign on the back advises to
An estimated 365,000 tons of road salt is applied in the Twin Cities metro area each year.
A person kneels next to a hole drilled in a frozen lake. They are holding a plastic tube that is bringing water from the hole to a plastic sample container via a battery powered pump.
CRWD staff collect a water sample from the bottom of Como Lake to measure the chloride concentration.
A person wearing winter boots sits next to a sidewalk with a white five-gallon bucket filled with salt granules and debris on it. A broom and a dustpan are resting against the bucket.
Extra salt can be swept up and reused.
A wide sidewalk with a thick layer of salt granules near the Minnesota State Capitol building. A tidy hedge with a row of lampposts, bare trees, and a strip of snow is along with sidewalk.
Applying too much salt does not provide extra protection from snow and ice.
Rust and corrosion damage on a gray metal utility box and concrete sidewalk. The sidewalk is scattered with salt granules. A gas meter and piping are attached to the box.
Salt causes rusting on vehicles and metal, and concrete corrosion.
A sidewalk with wide splotches of brown dead grass along both sides contrasting with green grass away from the sidewalk.
Too much salt harms lawns and landscaping and contaminates soil.