Project overview
The storage of plowed snow has garnered relatively little attention in stormwater management owing to the general notion that the key purposes of stormwater systems are rate and volume control of rainwater, sediment removal, and nutrient reduction. It is true that salts cannot be removed by existing stormwater treatment practices. However, snowmelt from piled snow can sheet flow and refreeze across pavement. Salts are a pernicious stormwater pollutant used to remedy the refreeze hazard. Published stormwater manual guidance suggests that suitable snow storage areas are down slope from foot and vehicle traffic and in an area where debris can be recovered. Anecdotally, maintenance professionals suggest that there is often insufficient suitable snow storage area connected to their work site. While snow storage planning is a required element of development review in many locations, a lack of structured guidance for sizing relegates this requirement to a minor checkbox. Stormwater professionals must come to recognize the stormwater pollution prevention role of design in developed areas and transportation corridors. Without more informed ability to appropriately size storage areas, the refreeze-salting cycle is unavoidable. This project aims to provide a starting point for informing pollution prevention practices which leverage simple climate parameters and the size of a maintenance area (“plowshed”) to model snow storage performance. Outcomes will include tools for public works and watersheds to reduce the need for salt applications to treat refrozen meltwater.
Research questions
- What relationships exist between a winter maintenance pavement area and the dimensions of snow storage?
- What relationships exist between snow storage dimensions and weather/climate variables? Research may include snow depth observations, seasonal cumulative or event-based snowfall metrics, or modeled quantitative snowmelt, which are factors that are common outputs of climate projections.
- What relationships exist between snow storage dimensions and maintenance practices?
- Research will include observations of the equipment used to push snow, manipulate snow piles, and snow hauling activity.
Key innovations/contributions
This research will help us design snow storage areas that can prevent melting and refreezing, reducing the repeated use of deicers.
What does this mean for Minnesota?
We propose to study stored snow at sites and along corridors in the Nine Mile Creek Watershed District and the City of Duluth because we want to find out how stockpile sizes and shapes change based on weather and plowshed size in order to understand the areal requirements for stockpiling snow so that design engineers, community planners, and stormwater regulatory staff might recommend or institute climate-informed, prescriptive design outcomes and maintenance actions which reduce meltwater sprawl and limit the use of deicers during thaw-freeze events.