Winter Design Considerations for Chloride Reduction
Consider the agency you represent—how do you improve winter operations without impacting the environment we all work and play in? You may have been notified or required by local agencies of the Municipal Separate Storm Sewer System (MS4) permit requirement to monitor or reduce chloride impacts to water bodies and streams through stormwater system discharge. Past winter practices included sand salt mixtures to provide traction and snow melting, or a cycle of adding studded tires to meet our transportation needs. As our population has increased, we see additional impermeable surfaces in the form of roadways and multi-modal efforts to move traffic and pedestrians effectively. Today, we lean toward straight salt, or salt with liquids, or liquids only removing sand from our de-icing practices, because it only provides traction.
Knowing these concerns, we can look for ways to reduce chloride impacts and implement effective snow removal processes.
We have an opportunity to improve winter performance through design. When reviewing design plans for reconstruction, new development, and commercial/private property feature elements, we need to make sure winter is at the table. Here are a few tips to keep in mind:
· Do pedestrian elements, required landscape, islands in road entrances, cul-de-sacs, parking lots, and stormwater features impact snow removal operations, and if so, does their existence create a net positive contribution? Winter performance is often overlooked, as other considerations traditionally get higher priority.
· Managing pedestrian access in winter may include elevation changes to improve drainage and meet ADA transitions.
· Snow fencing in wide-open areas to intercept wind-blown snow, forcing it to accumulate where wanted before it causes problems on the road.
· Additional storm sewer to omit cross-intersection flow of meltwater and potential re-freezing conditions, which require de-icing.
Low salt design is an effort to focus on change in infrastructure design by engaging design engineers and winter operations professionals to work cohesively in the review, design, and reconstruction of infrastructure.
To better vet these ideas, five Minnesota communities are engaged as low salt design pilot cities: Bloomington, Hopkins, Eden Prairie, Richfield, and Minnetonka. Through this effort and by engaging maintenance staff, all are learning what is appealing, practical, and affordable with each move forward to take on winter—while considering impacts on both public and private development projects.
The pilot program is growing and evolving as existing questions are answered and new questions arise, providing opportunities for our next generation of pilot cities to help shape design standards for superior winter performance, guided through salt/chloride reduction.
The City of Bloomington, Minnesota, presented at the recent Salt Symposium event where low salt experts provide insight into their findings and inner workings of salt reduction to meet their MS4 requirements. They have the foresight to make changes incrementally, stick with current practices, or make program adjustments.
Enlightened thought
Infrastructure designers sit in a climate-controlled office. Which way the wind blows or where the sun shines may not be what they think about. As winter maintenance pros, we think about these elements often. We have the responsibility to share our reality with those that design our future infrastructure. Time to step out of our box and make a few waves.
Original post authored in the APWA Reporter.
