Revitalizing Park Infrastructure: Part 2

Preserving and enhancing natural elements

By Laurel Raines and Gretchen Wilson

Parks serve so many vital purposes in our communities. They connect us to one another and to nature. They support mental and physical health and well-being. They serve an important function in the local ecosystem, providing a habitat for plants and animals, cooling urban heat islands, filtering stormwater, and improving air quality. And most of the dozens of benefits parks provide hinge on one essential element: the natural infrastructure.

Beyond considerations for physical infrastructure ( covered in Part 1 in PRB March), a thoughtful examination of an aging park’s design involves looking at the health and lifecycle of the existing species, seeking opportunities to increase ecological function and biodiversity, and planning for how the park’s natural infrastructure can be more efficiently and sustainably maintained now and well into the future. 

Assessing And Restoring Natural Infrastructure

The existing natural (and unnatural) conditions of a park drive everything in its revitalization. At the onset of each project, it’s important to look at major environmental factors, such as microclimate and history of the site, as well as drainage, existing trees and their age, size and quality, wind and sun exposure, shade studies, and root zone extent. Soil and water quality also factor heavily into the equation, as many older parks, especially in urban environments, are built on top of what today are considered brownfields. In these instances, careful attention must be paid to removing or remediating contaminants or ensuring they remain safely sealed below the surface.

The 80-acre Carpio-Sanguinette Park in Denver’s Globeville neighborhood is a good example. Situated along the South Platte River, which was itself an illegal dumping ground for years, the park was suffering from neglect and augmentations to the natural infrastructure of the upstream watershed, which led to a high level of pollutants flowing into the river. Restoring the ecology of the site while repairing water quality became the driver of the design. One strategy for restoration was designing a new stormwater-management system using vegetation, soil, and mechanical measures to intercept and infiltrate the stormwater runoff, which will result in improved water quality, reduced sediment-loading to a nearby pond, a new habitat, and a more native, drought-tolerant, and resilient landscape.

Vienna Vitek

At Paco Sanchez Park, a 30-acre area on the former site of another unsanctioned urban dump site in West Denver, a portion of the site had been capped with fill material. Understanding that digging too far down into the ground may disturb contaminated materials (and necessitate an expensive mitigation and removal), the design team had to be exceedingly cautious with any grading, adding fill material along the way to prevent unearthing contaminants.

At Stout Street Children’s Park, a pocket park in an urban neighborhood of Denver, designers worked with existing large trees and even existing paved areas, carefully incorporating them into the new plan wherever possible. By not removing pavement and adding new concrete, the team was able to prevent additional carbon from being released, and the roots of the adjacent trees were not disturbed.

Increasing Biodiversity And Ecological Function

Once an assessment of existing conditions is complete, the goal is to restore the natural ecology as much as possible, increase biodiversity, and find efficiencies that will ultimately lower maintenance costs and requirements. 

In some cases, this means injecting nature back into the park, from pollinator-friendly species to deep-rooted plants that create a cooling effect. This is true even for smaller spaces. At Stout Street Children’s Park, the design team had a scant .25 acres, but was able to select and plant 13 different plant species to provide a multitude of habitats and ensure nectar/food availability throughout every season. This strategy also considered aesthetics to give the public more educational opportunities to learn about and get used to biodiverse planting design. 

If the budget allows, one of the significant opportunities for increased water conservation in older parks is replacing the irrigation system. Newer systems allow for a higher degree of control and responsiveness to changing weather conditions. 

At Paco Sanchez, the Dig team was able to replace the entire irrigation system. It was more cost-effective to replace it with something more efficient than to continue operating and maintaining the existing system. However, at Stout Street Children’s Park, budget constraints meant strategically replacing elements of the system while preserving others, such as the backflow controllers.

Paul Wedlake

Engaging The Community

While the first goal is always preservation, sometimes it’s necessary to remove elements to restore a healthier ecology. Any time significant changes are being made, a successful process hinges on strong public engagement and education.

In the Western U.S., where Dig Studio primarily works, older parks were often designed with an aesthetic that doesn’t work well in today’s climate. They’re heavy on turf and non-native species, and their maintenance is water-intensive—a luxury most of the West can ill afford.

For many residents, a lush, green lawn is still preferred, and the heritage trees that have been added to this arid, high-desert landscape now provide desirable shade and a myriad of other benefits, like cooling and carbon reduction. The challenge becomes how to find a more sustainable balance.

At Denver’s City Park Golf Course, as part of a significant preservation and restoration effort associated with a stormwater-drainage infrastructure program, an extensive on-site evaluation was conducted to confirm health status and determine which trees might require removal or significant pruning.

To ensure a successful execution, substantial resources were devoted to educating the community about the age, health, and condition of the existing trees and the process by which they were being evaluated. The design team conducted walking tours of the park to help the public understand why certain trees required removal, and what the plans were for reforestation. The team made sure to highlight how the park would be reforested with new trees that would better support longevity while providing flood protection for downstream neighborhoods. This allowed the team to selectively remove the necessary trees and plant 760 new trees of hardier and more diverse species.  

At Carpio-Sanguinette, the most heavily vegetated area on the site was a channel along the waterway. While the dense tree growth on this part of the site was a much-loved feature in the community, it divided the 80-acre park and created a visual barrier that also made residents feel less safe. Working closely with an ecologist, the Dig team identified invasive species along the channel and took a surgical approach to clearing out what was not serving the site, opening it up and creating new views while keeping a healthy vegetated, native channel as a habitat for birds and other species.

Balancing Nature And Programming

From amphitheaters to art installations, runnels and splash pads, the list of amenities that communities want from their parks has grown substantially beyond just green space. It’s important to balance the desire for ever-more programming and amenities with the value of an uninhibited experience in nature. 

In determining the number and type of amenities, it’s helpful to look at the current parks system as a whole to see where the gaps exist. For example, at Carpio-Sanguinette Park, basketball courts existed at a nearby park; therefore other types of programming could be explored, such as a pump track that better fit the native aesthetic and offered opportunities for bike visitors to further explore the natural area’s loop trails.

The goal for the natural infrastructure is to find opportunities to orient new programming to maximize the impact of the experience and increase opportunities for nature play. At Paco Sanchez Park, while the physical infrastructure had been neglected, the park had beautiful heritage trees uncommon in Denver. The design prioritized saving and ensuring the proper care of those trees while also strategically locating park features to take advantage of the experience they provided. The entire upper plateau, for example, was designed around a stunning silver maple. At the bottom of the slope, two beautiful Austrian pines became the frame for the performance stage. In another area, the design team worked with a steep, existing 10-percent grade, building in a slide within a large gramophone-inspired play structure that brings children into a nature play area. 

Whether a park-revitalization effort is a major undertaking or a quick refresh, the biggest takeaway is that the natural infrastructure of parks represents one of the most powerful opportunities communities have to enhance the health and well-being of both people and environment.

Laurel Raines and Gretchen Wilson are both Principal Landscape Architects leading Dig Studio’s downtown Denver studio. They have planned and designed award-winning parks across the U.S. with a particular focus on the Rocky Mountain West and Southwest.