Civic & Community, Landscape Architecture, Sustainable Practice

Sustainability in Park Design

In the Pacific Northwest, the heat is literally on. Last summer, we experienced record-breaking heat in Seattle and, in Washington State, we recently adopted the Climate Commitment Act that requires a drastic reduction in greenhouse gas emissions and carbon pollution to net zero by 2050. Can investing in sustainable park infrastructure help us meet those goals?

Leslie Batten

April 14, 2022

Washington State’s recent legal adoption of the Climate Commitment Act requires a significant effort, to say the least. Climate scientists suggest that, in fact, we need to make a reduction in greenhouse gas emissions and carbon pollution sooner rather than later to avoid a warming of 1.5 degrees Celsius. By some estimates, by 2030 if not before.

It seems like investing in parks is an easy win for helping to meet the Climate Commitment Act goals. In many ways this is true. The environmental benefits of green infrastructure like open spaces and parks are numerous. The green space afforded by parks and open spaces is excellent at capturing (sequestering) carbon and greenhouse gases, providing shade and reducing local temperatures, and reducing the number of paved surfaces that can absorb and reflect heat and are a source of carbon emissions during the manufacturing process. The list of environmental benefits of parks and open spaces is long, as are the social and health benefits.

Is it possible that parks can be even greener?

Can parks lend a hand in helping Washington State reach the goals of the Climate Commitment Act, perhaps sooner than 2050? Could 2030 be an achievable goal? We think with the right amount of planning, leadership, and enthusiasm, there are a number of ways to achieve net-zero parks.

Consider Existing Infrastructure

As designers, we get excited about the prospect of a new park to design or plan. The possibilities seem endless and the opportunities to engage and discuss ideas with the community are invigorating. But equally important, if not more so, are existing parks and public spaces that may be well-established spaces in the community.

These spaces are a great place to begin to assess whether easy, low-barrier ways to introduce carbon sequestration efforts can be implemented in the near term. 2030 is right around the corner, after all.

The following are some questions we suggest asking as a place to start when assessing existing public spaces.

• What is the ratio of paved area to planting area? Can trees be added to the space without sacrificing program and function? There are several great examples of how trees can be incorporated into high-traffic public spaces without sacrificing accessible space. Tree grates have come a long way!

• Can pavement be removed (and recycled or reused elsewhere) and replaced with planting area(s)? Perhaps that strip of concrete doesn’t get used, or there is way too much pavement. More plants – especially trees – help in countless ways to enhance the space and sequester carbon.

• Can lawn be replaced with planting areas? Lawns require far more maintenance than planting areas due to mowing, fertilizers, and irrigation demands. Transitioning to a planting area can help reduce ongoing carbon emissions that arise through maintenance practices – not to mention reducing the workload of our already taxed maintenance crews.

• Can biochar be introduced as a soil amendment? We are still researching this, but it is lauded as a great way to lock carbon into the soil column and enhance soil quality.

• Can maintenance procedures be carried out manually or with electric equipment? Reducing the use of combustion engines to blow leaves around or cut blades of grass has long-lasting impacts on carbon storage, air quality, budgets, and lower sound volume preserves peace.

• Can electric vehicle charging spaces be added? Promote the use of electric vehicles by park users. Encourage people to make decisions in their day-to-day lives that tend towards our shared goals.

• Can the site be linked via a green trail program to other parks or community centers? Use the existing space to expand the green investment. Use street trees, bioswales, and bus routes to help link existing parks and provide residents opportunities to get out of their cars.

Consider Opportunities in New Parks

Of course, new parks benefit from a broad horizon of potential. Many municipal codes have requirements in place that limit the number of paved surfaces for stormwater runoff and to protect critical areas. These go hand in hand with the goals of the Climate Commitment Act but may need some additional considerations to encourage greater reductions in emissions and increased carbon storage opportunities.

The following are a starting point for how we can bring sustainable practices into new park design.

• Assess the embodied energy of the existing program elements – the paving, the structures the planting areas. Can any of these be salvaged or retrofitted or enhanced to match contemporary program needs while minimizing carbon emissions? Don’t forget that new pavement, earthmoving activities, etc. will produce carbon. Placing a higher value on embodied carbon of existing materials will go long way in the near term.

• Salvage and protect as much of the existing soils and plants as possible. Soils are a natural carbon bank. Disturbing them could mean releasing more carbon – the opposite direction of our goals. The mature plants are also banks of carbon and will help create a more welcoming experience once the park opens than any new small 1 gallon or 1½ inch caliper plants will provide.

• Use tools like Climate Positive Design's Pathfinder to assess the amount of carbon the project will emit, and how long it will take to reach net-zero through sequestration. Revise the drawings until the timeline is reasonable.

• Use locally sourced materials that don’t need to travel across the country or overseas.

• Investigate and pilot innovative materials like carbon-negative cements.

• Partner with contractors who invest in electric construction equipment or provide incentives for contractors to switch to electric equipment.

• Work with the park maintenance team to invest in manual and/or electric maintenance equipment.

• Help reduce maintenance needs with plantings that are appropriate for the location, are drought-tolerant, and do not need synthetic fertilizers or pesticides. Use low-mow turf to reduce mowing demands.

• Be open to a plant palette that may need to be revised as our weather conditions change. The list of species we call native may need to expand as our local flora is no longer able to withstand the dryer summers and colder winters without drastic intervention.

• Protect and enhance wetlands, our natural carbon vaults.

• If on a marine shoreline, assess kelp bed enhancement or establishment and, perhaps, floating wetlands.

• Include electric vehicle charging stations for park visitors.

• Include multimodal connections to link parks together with pedestrian, bicycle, and transit routes, or green belts.

This is just the beginning of our brainstorm for how we can contribute our design thinking to meeting the Climate Commitment Act in our projects. We would love to hear from you. What are you doing to help reduce greenhouse gas and carbon emissions? How can parks and public spaces help us in our goals?