Once road and de-icing salts wash into surface and groundwater, there is no feasible way to remove the chloride, which means that chloride will continue to accumulate in the environment over time. More than 1 teaspoon of chloride per 5 gallons of water is toxic to fish, aquatic bugs and amphibians. When the road density in a watershed exceeds 18%, water quality problems are likely. In Minnesota there are over 40 surface waters that exceed the water quality standard for chloride and another 50 that are approaching the standard. 75% of Minnesotans rely on groundwater for drinking water. High amounts of salt in groundwater cause drinking water to taste salty, which could restrict its use for drinking, because the cost to remove salt from drinking water using reverse osmosis is expensive. Currently 30% of Twin Cities' drinking water wells have high levels of chloride. Chloride also corrodes road surfaces and bridges and damages reinforcing rods, increasing maintenance and repair costs. Deicing salt accelerates rusting, causing damage to vehicle parts such as brake linings, frames and bumpers.
Report chloride water quality monitoring under BPA 19.1.
Find additional information related to chloride management at water and wastewater facilities under BPA 20.4.
Smart Salting Training and Certification:
Partnering with others, the MPCA has created and offers a Smart Salting certification program, which has a section on gravel road maintenance and use of dust suppressants, and a web-based winter maintenance assessment tool to help winter maintenance organizations assess operations, identify opportunities to reduce salt use using proven BMPs, and to track progress, which always includes cost savings. The goal is to maintain performance while reducing salt use and saving cities money.
The City of Minneapolis offers a free online Salt Mini-Course for residents to learn how de-icing salt impacts the environment and the best practices to reduce use.
The city of Edina developed a model contract for snow and ice management that embraces best practices to minimize environmental impacts from salt and other chemicals. Property owners can adapt the model contract to suit their needs and to ensure their contractors are protecting Minnesota waters from chloride pollution.
See model snow and ice management policies - for city-hired snow and ice management services, that mandate best practices to minimize environmental impacts from sand, chlorides and other chemicals - and for private snow/ice service contractors signing agreements with customers - developed in 2016 by snow and ice management professionals from cities and counties in diverse areas of Minnesota, watershed districts, the Minnesota Pollution Control Agency, the Minnesota Nursery and Landscape Association, and other stakeholders. These policies balance public interests including public safety, equipment and material cost, and environmental impact. See also a shorter model Snowplowing Policy from the League of MN Cities.
The MPCA partnered with the Nine Mile Creek Watershed District, TetraTech, several local cities and watershed organizations to develop a suite of model ordinances that communities can choose to implement. There are several options to consider which are intended to assist with reducing salt pollution.
Pervious concrete use in roadways both reduces stormwater infrastructure and salt use, with Shorewood as a national exemplar.
The biggest salt-reduction action, which is also the most effective way to prevent/melt ice and snow, is to apply liquid pre-wetting and anti-icing solutions to roads. These brines spread more evenly, stay put and begin working immediately because the salt/other components are already in solution. In Minnesota, cities that have switched to tanker trucks have reduced salt use by up to 70% and have paid back their equipment investment in a year or two.
Note that this salt action was previously an erosion control action (replaced because erosion control is almost always required of cities).
Certify primary winter maintenance staff through the MPCA's Smart Salting Level 1 training (for city snowplowing, and for parking lots, service roads & sidewalks) and/or Property Management training; follow training recommendations; certify new staff and keep certifications current; actively promote a model contract that private snow/ice service contractors would sign with customers; report decreased use of CaCl dust suppressants and alternative dust measures.
Certify the city at Smart Salting Level 2 by using the MPCA's Smart Salting Assessment Tool to complete a best management practices assessment; redo assessment at least every 3 years; develop or adopt an existing chloride/salt management plan; modify and adopt a model contract for city-hired snow and ice management services that mandates best practices to minimize environmental impacts from sand, chlorides and other chemicals; host a free training for private property managers and contractors.
Adopt a Chloride Reduction ordinance; report use of pervious concrete/paving and resulting salt-use reduction; complete two of: track salt usage; report salt reduction progress in the 30% to 70% range (over one year for 30%; over more years for 70%); track implementation of best management practices using the winter maintenance tool; educate residents about the environmental impacts of salt and provide information on how to reduce their personal salt use. Report reduction in residential/commercial water softening salt use and wastewater chloride monitoring and improvements under BPA 20.4.
Who's doing it
Bloomington - 3 star
Date action report first entered:
Date of last report update:
Year action initially completed: 2019
Bloomington has certified primary winter maintenance staff through the MPCA's Smart Salting Level 1 training (for city snowplowing, and for parking lots, service roads & sidewalks), certifies new staff, and keeps certifications current. Bloomington uses efficient plows with brine tanks and has certified the city at Smart Salting Level 2, and has developed a chloride/salt management plan.
Bloomington currently tracks salt usage using a calibrated software on trucks, and has issued educational material to residents about the environmental impacts of salt on how to reduce their personal salt use.
The City's standards regarding erosion and sediment controls and requirements for permanent stormwater treatment are detailed in Title 10 (Water Resource Management) of the City Code.
The City has begun tracking the amount of salt used on city streets. 51 tons per event this years vs. 77 tons per event last year.
Additionally, the City has been working with a Green Corps member to educate residents regarding salt use. https://www.ci.rosemount.mn.us/718/Conserve-and-Preserve-blog---archive-1
Outcome measures/metrics/money saved:
The amount of salt used per event by the City's public works department was reduced from 77 tons last year to 51 tons this year. This reduction is reported to the City Council on a weekly basis during the snowy season.
City of Willmar hosted Fortin Consulting Smart Salting for Roads training in 2020, which was attended by all City and Kandiyohi County snowplow operators. City is also converting from granular salt to brine application, which has reduced the amount of granular salt used by 50% in 4 years.
Outcome measures/metrics/money saved:
Average of granular salt purchased/used has decreased from 600 tons to 300 tons annually from 2017 to 2020.
The City of Edina has reported a reduction in salt use by 30% since the year 2016. This reduction in salt was accomplished from improvements in many areas of City operations. Plow drivers and park maintenance staff are trained in Smart Salting best practices through the Minnesota Pollution Control Agency. Equipment has been upgraded as well, with the addition of a dedicated brining truck, and articulated plow blades that flex to better match the road surface. Practices also include pre-wetting to use the minimum amount of salt needed to keep roads safe. Also, Edina is a participant in the Low Salt No Salt Program and received an award in 2019 from the Salt Symposium.
Mounds View Operates three plow trucks during winter storm clearing operations. All three are equipped with 110 gallon brine tanks with one truck replaced in 2019 having a more efficient applicator along with a front, belly, and wing plow that removes more snow than trucks without the wing (front and belly only) further reducing the amount of salt/brine needed. In 2021 we will be replacing a second truck. The last truck is several more years out.
We also send our PW Director, Supervisor and any additional staff available to annual conference/seminar in managing/reducing salt during winter street clearing plow operations.
Outcome measures/metrics/money saved:
Reduction in chloride/salt onto roadways and eventually into storm/ground water
Several of the City's Street staff are trained in the MPCA smart salt classes. The Street Divison purchased new Joma plow blades that offer opportunities to reduce salt application. The City pre-wets salt to hold it on the street better.
The City's Parks Dept. has reduced the use of de-icer by 30% by purchasing better, more efficient equipment to distribute deicer's. A program has been set up to check all machinery calibrations before and during the season.
The City of Duluth faces many unique challenges when it comes to wintertime salt use. Frequent flushing of the surface water systems by snowmelt and rain events prevents chloride from building up to levels that impact aquatic flora and fauna, and concentrations in Lake Superior remain low regardless of how much is flushed simply because of the sheer volume of water the lake contains. This makes it hard to convince people that chloride use is a problem. However, test wells behind the mall near Miller Creek showed levels at 500mg/l providing a rare glimpse into just how much salt is being washed into the waterways.
Despite the challenges, Duluth is working to reduce chloride use. Pre-wet granular is used at all times to increase the effectiveness of the salt and reduce waste from bounce and scatter. Various combinations of salt and sand are used depending on temperature (current and predicted) and precipitation (type and volume). When it is too cold for salt to function plain sand is used. Plow truck guidelines require that salt be dispensed at 25mph or less to reduce bounce and scatter. The city does have one experimental liquid de-icing tank, however it requires a plow to be driven in front and is not frequently used.
Duluth's hills also present a challenge. 16% of roads have a grade of 6% or steeper, and safety concerns frequently lead to them being over salted. Fortunately the hill is South facing allowing the suns heat to activate salt at colder air temperatures. Emergency services from the growing Medical District rely on many of the steepest roads for transportation so keeping them clear is a high priority. Little research has been done on snow and ice control on such steep hills so there is little solid evidence to guide control plans. Consequently, most chloride reduction efforts are focused on the remaining 84% of roads that are not as steep.
Representatives attend the Annual Road Salt Symposium to learn about new technologies and techniques that may help reduce or more effectively apply material to the road surface.
The city built a new salt shed for storage, it includes a paved floor as well as concrete walls and covered top that prevents salt from leaching into the groundwater and waste from rain/snow melt. This allows the city to purchase less salt per year , as well as better distribution as the salt is not clumping up from becoming wet.
In 2019 the City purchased a new piece of equipment that is estimated to reduce salt use by 30 percent per lane mile. The new piece of equipment is a precision applicator that can better target the areas where being applied.
In 2021, the City served as a distribution point for resident Smart Salting Kits for the Scott County Soli and Water Conservation District.
Outcome measures/metrics/money saved:
The City anticipates that the use of this new equipment will reduce its salt usage by 30% per lane mile used. Preliminary results show the new piece of equipment is resulting in an overall reduction in salt being applied.