Each year, Conservation Minnesota gathers local leaders to help build connections among neighboring cities and provide opportunities to learn about what’s happening across the state. Participants come from advisory commissions that guide cities on sustainability, conservation, natural resources, and parks and recreation. In partnership with GreenStep Cities & Tribal Nations, this year’s Environment Commissions Virtual Forum theme was chloride (salt) reduction strategies. We heard from the City of Eden Prairie about their low salt design infrastructure projects, the City of Marshall about their centralized water softening and rebate program, and the Minnesota Pollution Control Agency (MPCA) about the scope of the problem, negative impacts to health, and their Smart Salting training.
MPCA chloride reduction program coordinator Brooke Asleson opened the forum by grounding us in the scope of the salt pollution problem and its impacts on human and aquatic life. Each spring, salt used to deice walkways and roads throughout the winter melts and eventually enters our lakes and rivers. This salt builds up over time and there’s no effective way to remove it from our water. Salt is toxic to aquatic life, and too much salt is bad for our health. Brooke helped us understand the scope of the problem and what resources are available to cities and community leaders to help address it.
Assistant Superintendent with the City of Marshall’s wastewater treatment facility Scott Przybilla shared how Marshall is helping lower chloride emissions through centralized water softening and a rebate program to upgrade and remove old water softeners. In 2012, the city was notified by the MPCA that their discharge was more than double the state water quality standard for chloride (230 milligrams per liter). Due to water softeners, industry, and phosphorus control, they were discharging 563 milligrams of chloride per liter into the Redwood River. The city asked the MPCA for 10 years to get their discharge under the state standard.
A feasibility study determined that centralized water softening would significantly decrease their discharge and that they could apply for a Point Source Implementation Grant (PSIG) for up to $7 million. Centralized softening also allowed industrial users to shut of their individual water softeners, saving money and greatly reducing the amount of salt entering the river.
The final aspects of the plan were to tell residents that their water was already being softened and to provide them with rebates to replace or remove their existing water softeners. The rebates occurred in partnership with the MPCA and Bolton & Menk, an engineering company that specializes in salt reduction strategies. The city has helped remove or replace about 485 water softeners resulting in a reduction of 9,760 bags of salt or 12 semi-truck loads. The city is proud to report they’re now in their fifth consecutive month of discharging below 261 milligrams per liter.
Lastly, we heard from the City of Eden Prairie’s water resources coordinator Lori Haak, who discussed how the city is looking at low salt design for future infrastructure projects and development. Eden Prairie has 18 lakes, four named creeks, over 600 wetlands, and borders the Minnesota River, so there’s much at stake. The city has been using lime-based water softening (no salt) since the 1980s, so residents don’t need water softeners. Their snowplows and city maintenance personnel follow smart salting guidelines and consider pretreatments and temperature when salting their roads.
They’ve been engaged in salt reduction for a long time, but chloride levels in their lakes and rivers continue to rise, so they are now looking into low salt design. Low salt design is a concept created by Connie Fortin at Bolton & Menk where infrastructure is designed to reduce and better manage runoff from melting ice and snow, resulting in less need for salt. Now, as the city reviews and builds new infrastructure they consider things like orientation to the sun and wind, how easy is it to plow hard surfaces, where snow will be piled in the winter, whether meltwater will run back onto hard surfaces and refreeze, where the chronic problems are, and how the meltwater comes off rooftops and awnings.
Conservation Minnesota will continue to provide opportunities for city leaders to collaborate and learn from each other.
If you’re interested in learning more about salt reduction strategies, please join us for a special event: Low Salt Design 101 with Connie Fortin on Thursday, November 20th from 10am to 11am. Connie is a leading expert on salt reduction strategies and literally wrote the manual on low salt design. Another opportunity is to join the MPCA for their Community Leaders Smart Salting Workshop on Wednesday, December 3rd from 11am to 1pm.