During the winter of 2010–2011, the Bloomington, Minnesota, school district used 187.5 tons of sand and salt mix to clear its sidewalks and parking lots. By the following winter, the district had reduced its salt use by 100 tons.
This dramatic reduction in salt use followed a school district staff member’s participation in Smart Salting training sponsored by the Nine Mile Creek Watershed District. Watershed district grants also helped the school district purchase the necessary equipment to transition from salting and sanding to liquid deicing, which involves applying a combination of salt and brine to surfaces. During the winter of 2011–12, the school district increased its use of brine to 1,364 gallons.
These efforts offer one example of the watershed district’s success in partnering with another government agency to reduce chloride pollution in local creeks and water.
Erica Sniegowski, administrator for the Nine Mile Creek Watershed District, and Elizabeth Boor, watershed specialist, shared the district’s work to reduce chloride use at the 2025 Salt Symposium. Hosted by Bolton & Menk, the August 5 event brought together professionals from throughout the world to share research, projects, and approaches for chloride management
High chloride impacts
When snow and ice melt off impervious surfaces, chloride from winter salt applications flows into storm drains—and eventually into lakes, streams, wetlands, and groundwater. High chloride levels may impact the taste and healthiness of drinking water and harm fish, vegetation, and wildlife. Salt that flushes into Nine Mile Creek in the spring generates a big spike of chloride that remains in the water.
In 2004, the Minnesota Pollution Control Agency (MPCA) detected levels of chloride exceeding water quality standards in the Nine Mile Creek Watershed District, which comprises 50 miles in parts of Hopkins, Minnetonka, Edina, Eden Prairie, and Bloomington. The MPCA called for a 62 percent chloride reduction in the watershed.
“This is a very big problem for us,” Boor said. “We know that we have to approach this in several different ways.”
Tools for chloride management
The watershed district has three tools at its disposal: a funding program, education and collaboration, and regulation. Its cost-share program grants up to $50,000 for commercial, government, and nonprofit organizations and up to $20,000 for homeowner associations for proposals to improve water quality. Funding through this program has supported equipment for more efficient snow removal and salt application, as well as low-salt design training pilot projects in Hopkins, Minnetonka, and Richfield.
The watershed district also focuses on education, targeting its messages and collaborating with partners on training, such as the MPCA Smart Salting offerings. A low-salt, no-salt toolkit helps government agencies deliver salt-reduction messages with presentations, videos, and a facilitator’s guide.
“When you have a really engaged advocate [like the Bloomington school district], we’ve seen some really nice results and big changes in implementing low-salt practices,” Sniegowski said. “We’ve also seen success in creating targeted materials for specific audiences and being able to establish new relationships and engage new audiences with these materials.”
The third tool, the watershed district’s regulatory authority, allows it to set rules. For example, a development project that triggers the district’s stormwater management rule generally must include a chloride management plan. Other watershed districts have adopted similar chloride management rules.
The path forward
Despite the progress, chloride levels remain high. The watershed district will continue to implement its current tools, advance low-salt design training for developers and engineers, and reach out to large commercial property owners to share the low-salt, no-salt message.
“We’ve done a lot of the work,” Sniegowski said. “We know we’ve had impacts, and we know there is still work we need to do.”
—Darlene Gorrill, contributing writer