Former Landfill Becomes Park!

A Los Angeles firm turns to super-light interventions for a landscape bent on change.

A Los Angeles firm turns to super-light interventions for a landscape bent on change.

From the September 2016 issue of Landscape Architecture Magazine.

It’s been nearly three years since Los Angeles County Waste Management’s fleet of rumbling trash trucks ceased their daily climb up and down the massive landfill in Puente Hills, for years one of the nation’s largest. Now, the 640-acre site is poised to become a public park, and despite its proximity to an area rich in outdoor amenities like the picturesque Powder Canyon and Arroyo Pescadero Trail, it lacks easy access and infrastructure that would allow surrounding working-class San Gabriel Valley communities a chance to experience its spectacular views and raw terrain.

“When the county came to us, they wanted us to think big, and they wanted the public to think big,” says Bryan Matsumoto, a landscape design associate at Withers & Sandgren Landscape Architecture and Planning in Montrose, California. On behalf of the Los Angeles County Department of Parks and Recreation, Withers & Sandgren worked with Auburn, Alabama-based Hillworks Landscape + Architecture and other consultants to develop a careful strategy of maximizing the site’s abrasively atypical features and orchestrated a series of surprisingly creative and lively community workshops to promote the master plan process. “We were bracing ourselves for conflict and uncertainty. People are skeptical and unsure of the environmental aspects of the site, but we were up front about the challenging aspects by saying, ‘Here are the constraints,’” Matsumoto says.

Moderate settling is characteristic of most landfill-to-park remediation projects, but Puente Hills’s dramatic elevation change will be precedent setting. Portions of the site will continue to settle over the next 75 years, resulting in a negative elevation change of up to 125 feet. The settling makes even the most basic improvements, like lighting stands or trees, an impossibility across wide areas of the future park. “This is a highly engineered and very disturbed landscape,” Matsumoto says of the mountainous terrain, which is 1,000 feet high in places. “The constraints for ball fields, for example, are significant: We’d have sinking trees, dangerous divots, and rolls. We can’t have turf. Water can’t percolate down through the site, or else we’ll create leachate.”

By identifying and deciphering where “islands” of nonfill land could accommodate structures such as posts and foundations, the team could propose a precious few structured amenities that might also neutralize or enhance the huge elevation change of the site. In the process of the community workshops, groups of schoolchildren, teachers, organizers, business owners, and hikers all responded positively to fun features like a zip line, slides, and a trail lift (imagine a gondola ride). Then it was determined which adjacent, lighter amenities could populate the larger, surrounding areas of ever-settling fill. For the design team, it was key to promote the plan’s passive elements as much as its few permanent features.

During a recent workshop (the fourth of five) at a local elementary school in La Puente, homeowners with families in tow, environmental activists, city boosters, and groups of teens were asked to choose one of three visions for the park, developed based on previous workshop feedback. Out of three schematic concepts, attendees chose a design that featured a more ecological approach instead of solely recreational or educational proposals. With a strategy of ephemeral and super-light interventions such as picnic areas, a dog park, and “hedgerows” of wildflowers to define edges and boundaries, locals felt it struck a balance. Sophia Espinosa, a park supporter and returning attendee, said, “I won’t be alive 70 years from now, but I see this as that I’m leaving my mark.”

Now covered with up to 12 feet of dirt, the former landfill and its master plan await a vote by Los Angeles County’s Board of Supervisors, which has pledged support for the park. “This is a park for all in the 25-mile radius it serves, so it can’t be habitat reserves only,” Matsumoto says. “On the other hand, we don’t want it to be Disneyland. And in a sense it can’t be.”

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