Green Infrastructure: Using and Mimicking Nature for Climate Resilience

Rain gardens on Michigan Street in Grand Rapids are eye-pleasing and effective at minimizing stormwater runoff. Photo courtesy West Michigan Environmental Action Council.

By Henry Ludwig, Milliken Law and Policy Intern at FLOW

At FLOW, I have spent time this summer thinking about how we can help municipalities across the Great Lakes region create green infrastructure solutions. A few weeks ago, I found myself stuck in a downpour in the streets of Grand Rapids, Michigan, and witnessed green infrastructure in action. To me, it was like seeing a movie star.

Green infrastructure is a different way of thinking about a city’s stormwater system.

The growth of cities has created thousands of acres of impervious surfaces where water has nowhere to go. Buildings, roads, and parking lots prevent rainwater from seeping into the soil where it falls, creating runoff. Traditional city design has used “gray infrastructure,” miles of storm sewers and drainage ditches that aggregate and funnel stormwater and discharge into surface water. This runoff water picks up pollutants like oil from cars, road salt, and fertilizers, which harms our lakes, rivers, and streams. Stormwater runoff is a significant non-point source of pollution to urban waterways.

Green infrastructure is merely a flashy name for when cities design solutions for stormwater and flooding that involve or replicate nature. In nature, a water droplet hits the ground and is absorbed into the soil until saturated and either percolates into groundwater or is taken up by a nearby plant and evaporated. The goal of green infrastructure is to infiltrate, evaporate, or otherwise mitigate stormwater as close to where it falls as possible.

Green infrastructure relies on decentralized, nature-based solutions. Some examples of green infrastructure projects include rain gardens, green roofs, permeable pavement, street trees, and infiltration ditches landscaped with native plants.

Some green infrastructure solutions—think permeable bricks and asphalt and green roofs—seek to increase permeable surfaces. In effect, these solutions reduce the total amount of runoff that a stormwater system must handle. Green infrastructure takes a two-fold approach: (1) it seeks to reduce runoff at the source by eliminating impervious surfaces where droplets fall, and (2) it aims to infiltrate runoff in a decentralized system, wherever possible.

While it may seem new and radical, green infrastructure represents a return to nature with hopes of fixing the problems of a human-centered world. The infrastructure solutions take a step back from the traditional vision of civil engineering. Rather than attempting to exert control over water, it gives water natural places to flow.

Green infrastructure can play a crucial role in coping with the increasing effects of climate change in urban environments. Gray infrastructure is inflexible; the projects are designed to handle a certain amount of runoff and are difficult and expensive to expand. City engineers develop these projects to handle the worst-case rainfall that historical data can predict. But rainfall events are worsening, with 100- and 500-year flood events becoming more common. Historical data cannot predict what will happen in the future with a changing climate. With these significant storms, gray infrastructure faces bottlenecks and failures. These failures have caused significant damage across Michigan cities.

The damages caused by these increased rainfalls are not only a problem for urban areas. Rural and coastal areas have also experienced extreme flooding and associated damage. Green infrastructure presents a flexible, project-by-project approach that can alleviate the risk posed by extreme rainfall events without the need for a major, costly gray infrastructure project.

Besides efficient stormwater mitigation and reductions in pollution, green infrastructure has many carry-on benefits. Among these benefits are increased property values, greater access to parks and nature, cooler cities, and safer roads. Green infrastructure increases green spaces in cities. These solutions can be integrated into parks or used along roads to improve curb appeal. The use of native plants in green infrastructure projects allows the projects to blend in sustainably with a neighborhood. Using permeable pavement and increasing tree cover from street trees can avoid the heat-island effect caused by artificial surfaces absorbing and radiating the sun’s heat. Permeable asphalt has been shown to reduce ice build-up in the winter, leading to safer driving conditions. These additional benefits position green infrastructure as a potential collaborative approach among numerous city departments and goals.

I was in Grand Rapids when Michigan saw days of intense rain. While large parts of Detroit were flooding, Grand Rapids was not. I witnessed water running down street corners into sunken rain gardens rather than pooling around overflowing storm drains. Though the rain in western Michigan was just as heavy as it was in southeast Michigan, there were solutions in place for it.

Things were not always so rosy in Grand Rapids. In 2014, days of heavy rains led to widespread flooding in the city. This event culminated in extremely high river levels, which nearly led to catastrophe if bridges or floodwalls had failed. This event served as a wake-up call spurring the acceleration of ongoing green infrastructure implementation.

Grand Rapids has led the charge in Michigan and the nation to adopt green infrastructure solutions. Former Mayor George Heartwell made green infrastructure a priority for the city by leading the charge in rewriting city ordinances to eliminate barriers to its adoption. The city again sought to mimic nature when rebuilding and shoring up floodwalls on the Grand River in the aftermath of the 2013 flooding. Rather than building larger concrete walls, the city worked with engineers to design a system of many small levees, walls, and rocky shoals to increase both public, recreational access to the river and its banks, and the river’s aesthetic value. The city’s Vital Streets initiative has also sought to replace parking lanes with permeable asphalt and implement other green infrastructure solutions whenever doing substantial work on city streets. In short, the city has made it a priority to incorporate nature into the city, and it has paid off.

Non-governmental groups have also played a critical role in the success of green infrastructure in Grand Rapids. The West Michigan Environmental Action Council (WMEAC) has done crucial work in public education on the implementation of green infrastructure solutions. WMEAC has also participated in research on the costs and benefits of green infrastructure and created a tool called Rainwater Rewards to help citizens perform a cost-benefit analysis of green infrastructure solutions on their property. The Lower Grand River Organization of Watersheds (LGROW) has also been instrumental in providing resources to guide private developers in the use of green infrastructure and imagining a green infrastructure future for the whole watershed.

In FLOW’s neck of the woods up in Traverse City, The Watershed Center Grand Traverse Bay has installed green infrastructure around the region. The Watershed Center has installed 18 rain gardens and nearly ¾ miles of infiltration trenches to reduce stormwater flow into Suttons Bay, reducing the risk of bacterial contamination of nearshore waters caused by nutrient runoff. Additionally, the Watershed Center has installed infiltration trenches in Traverse City to reduce nonpoint-source pollution of Kids Creek, which is on Michigan’s Impaired Waters List.   

At the end of the day, however, green infrastructure is just infrastructure. While it may seem new and radical, green infrastructure represents a return to nature with hopes of fixing the problems of a human-centered world. The infrastructure solutions take a step back from the traditional vision of civil engineering. Rather than attempting to exert control over water, it gives water natural places to flow.

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