Wednesday, November 30, 2011
As winter arrives, and snow begins falling across much of the country, a small army of workers will spread across America’s roads, parking lots, and walkways, dumping hundreds of thousands of tons of salt. That salt will help keep people safe, but at a steep cost. Salt stresses roadside vegetation, increases roadkills, and contaminates aquifers and surface waterways. Beyond environmental impacts, salt also damages vehicles, and all of those tons of salt cost a lot of money.
In Maine, these concerns recently spurred the creation of a group called the salt management roundtable. The group is a loosely-defined set of municipal stormwater managers, public works directors, environmental consultants, regulators, and academics, all interested in finding ways to address the environmental and non-environmental consequences of salt. We’ve met several times, with a mix of structured discussions and presentations, and through those meetings I’ve all learned some interesting things. Among the highlights:
- However you measure it, salt application is a big and growing issue, even if it’s not an issue we usually hear much about. The amount of salt applied is truly enormous (see here). It all stays in the environment, and the impacts are extensive. Here in Maine, researchers have found that salt concentrations in aquifers across much of the state are steadily rising, with average concentrations eventually likely to exceed EPA water quality standards. That’s a huge problem anywhere that relies on groundwater as a drinking water source. The surface water impacts may be similarly pervasive. A UMaine Ph.D. student doing statewide water sampling recently found that impaired urban streams in Maine nearly always have elevated salt concentrations. That doesn’t mean that chloride is the cause of impairment—there are plenty of impaired urban streams in areas with less salt use—but it is at least consistent with a fear, often expressed by urban stormwater managers, that restoring urban watersheds will not be possible unless salt impacts are somehow addressed.
- There isn’t an easy answer. Simply abandoning salt would be incompatible with current public expectations for mobility and safety. Changing those expectations is theoretically possible but likely to be rather difficult. And while less toxic alternative de-icers do exist, they’re expensive. We have opportunities to reduce use, and technologies may change. But eliminating use is a very far-fetched possibility.
- Some of most intense salt users are private landowners. Municipalities apply the most salt because they are responsible for most of the paved area. But because of the financial incentives and economies of scale associated with high-volume use, municipalities can invest in sophisticated technology designed to allow strategic applications. The municipal salt trucks you see on the road probably have computer systems that help operators continually adjust to road and weather conditions. Private landowners, by contrast, have much less incentive to use those systems, and therefore often use much more salt per unit of area. If there are low-hanging fruit to be plucked, these private landowners are a particularly good opportunity.
- Law affects salt application, and not just because water quality regulation may limit salt use. Contracts also appear to make a big difference in the amount of salt applied. A contractor paid a flat sum for salt application has very different incentives from one paid for materials used. And tort law is important. Both municipal and private landowners have repeatedly expressed fears that if they use less salt, they’ll find themselves on the wrong side of a jury verdict. A recent white paper, which one of my students did most of the work of preparing, concludes that those fears, though not baseless, are probably a little overstated. But the stormwater managers I talk to still think those fears are real impediments to reductions in salt use.
Where will the group’s work go from here? I’m not sure. So far, we’ve learned from each other, gained a clearer sense of the challenge, and identified a few opportunities. But finding effective solutions is going to take much more work.
All of that leads to a pitch. I know this blog has some student readers, and some of you may be using this blog to try to identify topics for law journal comments or independent writing projects. If you’re looking to write about an important but relatively understudied environmental issue, the law of salt may provide some potentially good option.
- Dave Owen