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Road salt and water quality

snowplow MPCA recommends a low-salt diet for Minnesota waters. Doctors tell us to stick to a low-salt diet. Our lakes and streams should follow the same advice. When winter comes and snow and ice build up on Minnesota roads, parking lots, and sidewalks, one of the most common reactions is to apply salt, which contains chloride, a water pollutant.

Salt pollutes. When snow and ice melts, the salt goes with it, washing into our lakes, streams, wetlands, and groundwater. It takes only one teaspoon of road salt to permanently pollute 5 gallons of water. Once in the water, there is no way to remove the chloride, and at high concentrations, chloride can harm fish and plant life. Less is more when it comes to applying road salt.

In the news

New Report

The MPCA and its partners sample Twin Cities lakes and streams to help us manage water quality while balancing our need for road safety.

Twin Cities Metropolitan Area Chloride Monitoring (wq-iw11-06x)

A call for less salt in our roadways diet — Star Tribune, Feb. 7, 2013
KUMD Morning Show interview with Brooke Asleson, MPCA Dec. 19, 2012
Check out the article in this month's national stormwater magazine: Ice School: Melding the science and craft of winter road maintenance.
Check out this WCCO radio interview/article dated March 25, 2011: Road Salt: Essential For Winter Roads, Toxic For Lakes
StarTribune article, March 23, 2011: Road salt turning Twin Cities lakes into dead seas
Twin Cities DAILY PLANET article dated December 26, 2010: Hold the Salt
Ice management article: Ahead of the pack
StarTribune article, January 2, 2010: State's roads aim for low-salt diet
Environmental Science and Technology journal. A Fresh Look at Road Salt: Aquatic Toxicity and Water-Quality Impacts on Local, Regional, and National Scales: free download.

Chloride and our water — monitoring the mix

Tips

Follow these simple tips to protect our water!

There are many ways to reduce salt use while maintaining high safety standards.

Shovel. The more snow and ice you remove manually, the less salt you will have to use and the more effective it can be. Whether you use a shovel, snow blower, snow plow, or ice scraper, get out there as early as you can and keep up with the storm. You may even decide that salt isn't needed.
15°F is too cold for salt. Most salts stop working at this temperature. Use sand instead for traction, but remember that sand does not melt ice. Use the reference table below to apply the correct product for the conditions.
Slow down. Drive for the conditions and make sure to give plow drivers plenty of space to do their work.
Be patient. Just because you don't see salt on the road doesn't mean it hasn't been applied. These products take time to work.
More salt does not mean more melting. Use less than 4 pounds of salt per 1,000 square feet (an average parking space is about 150 square feet). One pound of salt is approximately a heaping 12-ounce coffee mug. Consider purchasing a hand-held spreader to help you apply a consistent amount.
Sweep up extra. If salt or sand is visible on dry pavement it is no longer doing any work and will be washed away. Use this salt or sand somewhere else or throw it away.
Watch a video. This video, produced by the Mississippi River Watershed Management Organization, provides tips to homeowners about more environmentally friendly snow and ice removal: Improved Winter Maintenance: Good Choices for Clean Water
Share a brochure. Read and pass along Nine Mile Creek Watershed District's brochure about residential snow and ice care. You can find it on Nine MIle Watershed District's education page.
Check out other resources. If you are responsible for snow and ice removal somewhere other than your home, please check out our training and resources tab.

Know about the salt product

Salts can range from simple table salt to calcium chloride. Salts are used because they are able to decrease the freezing point of water. Whatever product you chose, make sure you know at what temperature it stops working. We recommend using the table below as labels may be misleading. Note that pavement temperatures are usually warmer than air temperatures. To find out the pavement temperature near you, search the Road Weather Information Service.

Melting agent	Lowest pavement temperature at which product works
Calcium chloride (CaCl₂)	-20° F
Potassium acetate (KAc)	-15° F
Magnesium chloride (MgCl₂)	-10° F
Sodium chloride (NaCl)	15° F
Calcium magnesium acetate (CMA)	20° F
Blends	Check with manufacturer.
Sand	Never melts, provides traction only.

Environmental concerns

Environmental concerns about road salt

Did you know that several metro lakes and streams in Minnesota have been classified as polluted by road salt?

Winters in Minnesota bring slippery roads and the application of de-icing materials to keep our roads free from ice and safe. Road salt is the most commonly used de-icer, which contains sodium and chloride. The chloride in road salt enters our surface waters and groundwater after snow meltd and is harmful to the fish, insects, and plants. The sodium stays in the soil and reduces its ability to retain water and increases the amount of erosion. Too much salt results in costly damages and serious environmental consequences.

While progress in Minnesota has been made in these areas, there is still much work to do in order to meet water quality standards and achieve a high level of road safety. In 2010, the MPCA more than doubled the number of waters that are listed as impaired for chloride.

A study conducted by the University of Minnesota determined a chloride mass balance for the Twin Cities Metropolitan Area (TCMA) and found that approximately 78% of all chloride generated in the TCMA is being retained in the TCMA. This includes all of the main sources of chloride: chloride from road salt, wastewater treatment plants, water softeners, and other industrial sources.

Chloride is a conservative ion (meaning it moves with water without being broken down or lost). Once the chloride is in the water, the only known technology for its removal is reverse osmosis through massive filtration plants, which is not economically feasible. This means that chloride will continue to accumulate in the environment. A high chloride concentration in both the aquatic and terrestrial environment has some of the following implications for human consumption, aquatic life, and plant life:

At high concentrations chloride is toxic to fish and insects
At lower levels chloride can negatively affect the fish and insect community structure, diversity and productivity
Direct road salt splash can kill plants
Sodium in the road salt destroys soil stability, decreases the soils ability to infiltrate water, and can increase soil erosion.
Some animals living near or relying on chloride polluted waters are sensitive to road salt

While research does exist that identifies the negative impacts that chloride and specifically road salt has on the environment, there are still many unknowns. Continued research will help us to better understand how chloride interacts with the environment and therefore how to properly manage our water resources.

Training/resources

For residents

Training video

Did you ever think about what happens to tons of salt that goes on our roads, parking lots, and sidewalks each winter? Most of it ends up in our lakes, streams, and wetlands. As a result, clean water in the Twin Cities is in jeopardy.

No salt, or very little salt, is needed if you've done a good job of snow removal. To learn a few easy things about tools, techniques, and products that you can use to keep your driveways and sidewalks safe while protecting our waters, watch this new video.

Improved Winter Maintenance: Good Choices for Clean Water (15 Minutes)

The MPCA give special thanks to the Mississippi Watershed Management Organization for producing this video.

Brochure

The Nine Mile Watershed District developed a useful brochure: Residential snow and ice care. You can find it on Nine MIle Watershed District's education page.

Postcard

PDF Document Salt pollutes postcard (p-tr1-45) (tips on ways to reduce salt use). Print this postcard and distribute to residents and local businesses.

Workshops

Changing our waters with salt February 1, 6:15-7:30 pm, Edina Public Library, Grandview Square. The event is sponsored by the Minnehaha Creek Watershed District, Minnesota Waters, 9 Mile Creek, and Citizens for Minnehaha Creek Corridor. For more information on the workshop, visit Nine Mile Watershed District's calendar page.

For building entrances and sidewalks

This 20-minute video will introduce you to best practices for maintaining small spaces (sidewalks, entryways, steps, etc) in the winter, including deicer material selection and application rates.

Training Video - Winter Maintenance Training for Small Sites

Part 1 (10 minutes)

Part 2 (10 minutes)

The MPCA give special thanks to the Mississippi Watershed Management Organization, the University of Minnesota, and Fortin Consulting for producing this video.

For road maintenance staff

Annual Road Salt Symposium offers help to reduce chloride pollution in Minnesota's waters

12th Annual Road Salt Symposium
February 7, 2013
Minnesota Landscape Arboretum
For more information, contact: jeanne@freshwater.org or visit the Freshwater Society's website.

MPCA Level 1 Certification: Snow & Ice Control Best Practices

Through education and outreach, applicators of road salt can learn best practices and significantly reduce their use while maintaining road safety.

Who should participate? Contractors and staff maintaining private/public walkways and/or parking lots, Property managers writing contracts, distributors of anti-icing/de-icing products, snowplow drivers— those who make it happen.

Why Is it important? This class will help:

Save you money.
Keep our parking lots and sidewalks safe.
Protect our water.
Get you certified.

For more information about the MPCA's certification program and to find out who is certified visit the MPCA's Road Salt Education Program's website.

Minnesota Snow and Ice Control: Field Handbook for Snowplow Operators (2005)

The purpose of this field handbook is to help promote the understanding of the tools, best practices, and limitations for snow and ice control. In addition, it encourages progressive changes in snow and ice control practices that will help you reduce salt/sand use and environmental impacts while meeting the safety and mobility needs of roadway users.

Minnesota Snow and Ice Control: Field Handbook for Snowplow Operators (524 KB PDF)

Parking lots and sidewalks

Road Salt Manual

Winter Parking Lot and Sidewalk Maintenance Manual (parkinglotmanual)

The MPCA sponsored the development of the Winter Parking Lot and Sidewalk Maintenance Manual in 2006. It is based on the Minnesota Snow and Ice Control Field Handbook for Snowplow Operators, produced by Minnesota LTAP, as well as on training materials used in an MPCA parking lot winter maintenance training class. The purpose of this manual is to deliver practical advice for improving operating efficiency and reducing environmental impacts to those who manage parking lots and sidewalks.

Winter Parking Lot and Sidewalk Maintenance Manual (p-tr1-10) (October 2010)
Winter Parking Lot and Sidewalk Maintenance Factsheet (p-tr1-20) (October 2010)

For property managers

How do I find a certified contractor?

If you hire out snow removal on your property, choose a contractor who is certified by the state in Snow and Ice Control Best Practices or encourage them to become certified.

Certified practitioners may found on the MPCA's Road Salt Education Program website. Or look for certified practitioners in the files below.

MS Excel Document Road Salt Applicators Training Certificate Holders (PDF Version) (p-tr1-01) (November 2012)

Why should I hire a certified contractor?

Many local lakes and streams have elevated levels of chloride, a common ingredient in road salt. In some cases, the chloride contamination is high enough to impact or even kill fish and other aquatic life. Winter snow and ice practices have been identified as the primary source of this chloride. Certified contractors have taken a training on how to mitigate the effects of de-icing materials on the environment, without compromising safety or effectiveness.

Voluntary certification in Snow and Ice Control Best Practices from the MPCA is given to individuals who:

Attended voluntary training
Complete and pass the associated test
Agree to voluntarily apply best management practices to reduce chloride impacts

Additional links

Activities

Metro Area Chloride Project

Chloride is a unique pollutant in that once it is in our waters there is no available technology to remove it and the primary source of chloride (road salt) is currently necessary for public safety; therefore preventing chloride from entering the environment and protecting waters from degradation while still providing public safety is critical to achieving the desired water quality.

Goals

The final outcomes of this project will be a chloride management plan which will lay out a strategy for addressing chloride impacts to our surface waters for the 7-county metropolitan area. This chloride management plan will satisfy EPA requirements for impaired waters, address waters not yet listed, and develop a strategy to protect waters that are currently meeting the water quality standards. This management plan will also include implementation activities for reducing chloride to TCMA waters as well as identify high priority areas to target implementation activities. The MPCA and the hired consultants will work with the inter-agency team, a technical advisory committee, a monitoring advisory team, and implementation plan committee and local stakeholders to develop this management plan to ensure that it is supported by our local partners and will result in ownership of the final plan.

Chloride impairments in the TCMA based on 2010 303(d)list

Chloride impairments in the TCMA based on 2010 303(d)list

Stakeholder process

The MPCA project team will develop and execute a stakeholder process that facilitates positive interactions and ownership of the final restoration and protection plan recommendations and implementation efforts. The meetings will include identification of risks and opportunities, education on modeling and scientific data, and decision-making on preferred strategies and allocations. The diagram below shows the various teams that have been created (or will be created) to engage and participate in the project at various stages. A list of the members participating on each committee can be found below.

Interactions of the seven stakeholder groups

Stakeholder process diagram

Stakeholder Team Membership List (wq-iw11-06q)

Project objectives

There are 10 tasks that have been created as part of a work plan for this effort. For a detailed description of each task, please refer to the complete project work plan available on the project website.

Task 1 Targeted chloride monitoring
Task 2 Update existing data compilation with recent data
Task 3 Categorize and define waterbodies for protection and restoration
Task 4 Develop target concentrations for non-impaired waters
Task 5 Source identification
Task 6 Modeling and analysis
Task 7 Develop Education/Outreach materials
Task 8 Write draft and final TCMA chloride management plan:
Task 9 Write draft and final implementation plan and long term monitoring plan
Task 10 Stakeholder process

Timeline

The 10 tasks are on schedule to be completed within approximately 4 years. At the conclusion of the project, the state agencies and all local partners will have the information necessary to begin implementing practices to reduce the amount of chloride entering our waters.

Project work products

Work Plan Summary (wq-iw11-06s)
TCMA Chloride Monitoring Plan and QAPP- lakes (wq-iw11-06v)
TCMA Chloride Monitoring Plan and QAPP - Streams and Stormsewers (wq-iw11-06w)

For details on the project history including the Metro Chloride Feasibility study results, the partners involved, the process, and the detailed technical information, visit Metro Area Chloride | Project history.

Other projects

Shingle Creek Chloride TMDL

Meetings

All meeting information, including agendas, minutes, presentations, and electronic handouts can be found in PDF documents below. This document is bookmarked for ease in searching for specific meeting details.

Technical Advisory Committee meetings

October 12, 2011, 12-2:30 pm
September 8, 2010, 1-3 pm
TAC meeting information (wq-iw11-06r)

Inter-Agency Advisory Team meetings

November 16, 2010
March 17, 2010
IAT meeting information (wq-iw11-06h)

Monitoring Sub-Committee meetings

October 6, 2011, 9-11 am
March 3, 2010, 9-10:30 am
October 14, 2010, 1-2:30 pm

Education & Outreach Committee meetings

December 7, 2011, 1:30-4 pm
October 6, 2011, 1-3 pm

Implementation Plan Committee meetings

No information at this time.

Outreach Group meetings