Concerned about green infrastructure applications in the winter? You’re not the only one.

Winter can take its toll on everyone and everything. With proper planning and selection, your green infrastructure applications can withstand the harshest winters and provide years of water quality and quantity benefits. 

According to the U.S. Environmental Protection Agency (EPA), “Green infrastructure is a cost-effective, resilient approach to managing wet weather impacts that provides many community benefits.”

Green infrastructure is an alternative to gray stormwater infrastructure. Gray infrastructure uses conventional piped drainage and water treatment systems to move urban stormwater away from the built environment. Instead, green infrastructure reduces and treats stormwater at its source while delivering environmental, social, and economic benefits. 

Visit the EPA’s website for detailed information on green infrastructure and its benefits.

Each year, we can see how winter impacts our infrastructure—especially in northern states—through cold temperatures, snow, and ice. Roads need repair, pipes freeze, and many other issues plague us during the cold weather. Green Infrastructure is not immune to these effects of winter.

Cold temperatures can cause issues with our green infrastructure, such as plants dying out or having hardscape features being affected by freeze and thaw. But the biggest arch nemesis of our next generation infrastructure? The continued use of salt. Salt is used in many locations to melt the ice and make the areas safer for pedestrians and drivers. The use of salt has been a common practice for over 50 years, it is relatively cheap, and it’s still plentiful.  The environmental impacts is something that we are just now seeing as it relates to the contribution to our water tables and surface water pollution.

Since green infrastructure typically directly interfaces with our roadways and sidewalks, the salt used for safety can also cause issues with green infrastructure. For example, trees play a critical role in many green infrastructure solutions. While the use of salt makes it safer for people, unfortunately, it’s not quite as friendly on trees. Salts damage plants in two ways: salt in the soil and salt in the air, both of which have different effects on a tree.

Fortunately, green infrastructure can take on winter just like gray infrastructure. The key is planning. By considering your climate, knowing the types of soil, and having an executable operation and maintenance (O&M) plan, your green infrastructure project can get through winter without issues.

Some key items to consider:

1. Use alternatives to traditional sodium chloride. When temperature are above 5˚ F, use magnesium chloride. When temperatures are below -5˚ F, use calcium chloride.
2. Use liquid forms of either instead of the solid form.
3. Educate your maintenance staff on proper application techniques to reduce over-application.
4. Choose trees and shrubs that are more tolerant of salt. Silver maple, white ash, and birches are just a few examples of species that are relatively tolerant to salt exposure.
5. Flush in the spring. When the spring weather arrives, flush sidewalks, beds, and water harvesting systems. Time the flushing after the last ice event and before plants begin to bud. Don’t forget to wash the tree canopies!
6. Use large quantities of well-draining soil in the area. Well-draining soil gives the tree a large buffer against salt concentration and significantly reduces the impact of water-born salt.
7. If trees are planted in poorly draining subsoils, install subsoil drain lines to improve the drainage rates.

The use of green infrastructure has been around for over a decade, but there are still a lot of questions of its functionality during colder months. Many individual studies have been conducted on this. Fortunately, the Science Policy Exchange (SPE) developed comprehensive review of several efforts to provide a good understanding of green infrastructure functionality during the winter. Click here to download “Green Infrastructure: Lessons from Science and Practice.”

Switching over to green infrastructure from traditional methods can be a bit intimidating. But with the right, knowledgeable, partner and proper planning, your green infrastructure project can be destined for success.

While we can’t make the winter weather any easier on you, we can make it easier for your green infrastructure project. Let’s talk about your next project. Whether it’s a new project or developing a success O&M plan for existing green infrastructure, the ms team can help.

Contact Kari Mackenbach at kmackenbach@msconsultants.com for more information.