What If highway noise barriers were repurposed as vertical gardens?

Urban food deserts - areas lacking access to fresh and healthy food - are a persistent problem in many cities in the US and worldwide. The lack of access to healthy food contributes to health disparities and economic inequality, as well as exacerbating the impacts of climate change.

A solution to this challenge may lie in an unexpected place:

What If highway noise barriers were repurposed as vertical gardens?

By transforming these utilitarian structures into vertical gardens, we can combat urban food deserts and contribute to a greener, healthier, more sustainable city environment.

The Problem of Urban Food Deserts

Urban food deserts are areas where residents have limited access to affordable and nutritious food due to the absence of grocery stores or other fresh food providers.

Food deserts are characterized by limited access to fresh, affordable, and nutritious food. These areas often have a high concentration of fast food restaurants, convenience stores, and liquor stores, which offer unhealthy, processed food options.

The prevalence of food deserts is associated with increased rates of obesity, diabetes, and other diet-related health problems in affected communities.

The Vertical Garden Solution

Vertical gardens, also known as living walls or green walls, are structures that support the growth of plants, creating a lush and productive garden in a limited space. These innovative gardening systems can be built using various materials, such as recycled plastic bottles, fabric pockets, or modular hydroponic systems.

Highway noise barriers are built to mitigate the noise pollution caused by traffic and are typically made of concrete, brick, or other solid materials. When highway noise barriers come to mind, the image is the highway-facing surface while driving past them on the highway.

We overlook the other side facing the communities bordering the highway. That’s where the sweet spot lies. (Like any vinyl fan knows, sometimes the “B side” is the better one.)

By retrofitting the community-facing sides of these structures with vertical gardens we can create spaces for urban agriculture and help address the issue of food deserts in under-served communities.

Benefits of Vertical Garden Noise Barriers

1. Local Food Production: Vertical gardens can be used to grow a variety of fruits, vegetables, and herbs. This can provide a source of fresh, nutritious food for residents in the surrounding areas, alleviating the effects of food deserts.
   

2. Environmental Benefits: Vertical gardens can help reduce air pollution by absorbing carbon dioxide and producing oxygen. They also reduce the urban heat island effect by preventing barrier walls from getting heated by the sun and promoting water evaporation into the air.
   

3. Space Utilization: By utilizing existing structures, vertical gardens on noise barriers can take advantage of underutilized space to create a productive, green environment in urban areas.
   

4. Aesthetic Improvement: The introduction of greenery can have a positive impact on the appearance of urban areas, transforming dull, gray noise barriers into lush, vibrant spaces.
   

5. Mental Health Benefits: Exposure to green spaces has been linked to improved mental health and wellbeing. Transforming noise barriers into vertical gardens can contribute to this effect by providing calming, natural environments for residents to enjoy.
   

6. Noise Reduction: While the primary purpose of highway noise barriers is to reduce noise pollution, adding vertical gardens to these structures can further enhance their noise-absorbing properties.

Let’s anchor this “What If…” in reality.

Los Angeles is one of many US cities with numerous communities living within a food desert. Los Angeles also has a lot of highways, and a lot of noise barriers running along them.

Last year I did some consulting for a candidate for Los Angeles City Council who wanted ideas on how to improve the ecology and quality of life in Los Angeles’s under-served communities. It was a chance to go deep into the issue of urban food deserts and explore solutions. One area I looked at is Nobel Street in the heart of one of LA’s food deserts:

Running along the side of the street is this noise barrier shielding residents from the 710:

That’s a lot of wasted space and surface area. Imagine if this space could grow food for the local community. Here’s a few benefits this current-food-desert community could experience if the noise barrier walls and foreground were converted to grow food:

1. Improved food access: fresh, locally grown produce easily available to a community that does not have easy access to fresh fruits and vegetables.

2. Reduced food miles: Locally grown produce reduces the distance food must travel to reach consumers - and the distance consumers must travel to get food, reducing emissions and removing barriers to those without transportation.

3. Air quality improvement: Plants absorb carbon dioxide and produce oxygen, which can help improve air quality in this area with high traffic volume and emissions.

4. Education and community involvement: The growing areas can serve as hubs for educational programs and community engagement, fostering connections between local residents and giving inner city residents a knowledge of growing and agriculture.

5. Job creation: Establishing and maintaining the growing areas could create new job opportunities in urban agriculture and related fields.

Noise Barriers as Rainwater Catchment Areas

For water-scarce regions like Los Angeles, the noise barriers could hold a significant additional benefit to provide the key element needed for growing healthy food: water.

If a rainwater-capturing channel 18” wide were installed at the top of the barrier for half a mile, 37,000 gallons of rainwater could be captured per year (based on the average annual rainfall for LA of just under 15”- I did the math; get in touch if you want the full rundown.)

So… converting half a mile of highway noise barrier into food growing areas with rainwater capture/storage functionality begins to make a lot more sense than a, well, blank hot wall with scrub growth.

Transforming highway noise barriers into vertical gardens is a speculative idea to combat urban food deserts, but it is one that would simultaneously provide environmental, aesthetic, and mental health improvements.

It’s also one that needs to be taken seriously.

By making use of existing infrastructure and limited urban space, vertical gardens can provide communities with fresh, nutritious food options while offering a range benefits. Reimagining the role of these structures in our cities gives us a chance to create a more sustainable, equitable, and healthy urban environment for all.

Get in touch if you want to continue the conversation or explore converting under-utilized assets in your community for growing food.

References for Further Reading

^{Akbari, H., Pomerantz, M., & Taha, H. (2001). Cool surfaces and shade trees to reduce energy use and improve air quality in urban areas. Solar Energy, 70(3), 295-310.}

^{Bendtsen, H. (2005). The Nordic Prediction Method for road traffic noise. Science of the Total Environment, 340(1-3), 161-170.}

^{Breyer, B., & Voss-Andreae, A. (2013). Food mirages: Geographic and economic barriers to healthful food access in Portland, Oregon. Health & Place, 24, 131-139.}

^{Despommier, D. (2010). The Vertical Farm: Feeding the World in the 21st Century. New York: St. Martin's Press.}

^{Gallagher, M. (2008). Examining the impact of food deserts on public health in Chicago. Chicago: Mari Gallagher Research & Consulting Group.}

^{Grahn, P., & Stigsdotter, U. K. (2003). Landscape planning and stress. Urban Forestry & Urban Greening, 2(1), 1-18.}

^{Nowak, D. J., Crane, D. E., & Stevens, J. C. (2006). Air pollution removal by urban trees and shrubs in the United States. Urban Forestry & Urban Greening, 4(3-4), 115-123.}

^{Ulrich, R. S., Simons, R. F., Losito, B. D., Fiorito, E., Miles, M. A., & Zelson, M. (1991). Stress recovery during exposure to natural and urban environments. Journal of Environmental Psychology, 11(3), 201-230.}

^{Yang, H. S., Kang, J., Choi, M. S., & Kim, J. K. (2008). Acoustic effects of green roof systems on a low-profiled structure at street level. Building and Environment, 43(4), 623-634.}