As the memorial required an innovative sustainable pavement system, Peter Walker and Partners called upon long-trusted paving consultant Mark Smallridge & Associates to help engineer and execute the intended design. “This included consideration of the material properties, the anticipated loading of the plaza, drainage provisions, and the environmental conditions,” says Mark Smallridge. “A complete solution was developed so that it could meet the unique conditions of the pavement substrate while meeting Peter Walker and Partners’ particular vision.”
9/11 Memorial: The Other Half
Thursday, May 23rd, 2013
By Saundra Marcel
Illustration by Spencer Matern
There’s been a grand opening, and more than six million visitors have visited, but the 9/11 Memorial site in lower Manhattan is still very much a work in progress. Landscape architect Peter Walker, co-designer of the project, estimates that after 10 years on the job, his vision is only halfway realized. More acres of the plaza need to be built and that can’t happen until the underground museum and train station are finished, as well as the surrounding streets.
Despite being unfinished, the memorial is open, and people have been coming from all over the world to pay their respects. Crowds are hustled through the maze-like barriers of this construction site before reaching its heart: the solemn memorial of two meaningful voids in the ground. Eventually, though, the experience will be completely different.
The finished product will be a memorial plus an open public space. Eight carefully planned acres that will ultimately be a contemplative and restful place, transformed by a lush forest of more than 400 swamp white oak trees. It will be one of the most sustainable plazas ever constructed. This part of the project will conclude years from now, quietly and without as much pomp and fanfare. But for generations to come, this park will ultimately be an important and reverent part of the experience.
Saundra Marcel: How did you become involved in the 9/11 Memorial project?
Peter Walker: We were called by architect Michael Arad when he was one of the eight semifinalists in the design competition. The jury liked the concept of the sunken spaces representing the missing buildings, but he had the whole eight acres in stone. That was too harsh. Our job was to make a park compatible with the voids. It would get the mood of the memorial, but operate as an open public space.
SM: The jury’s mandate was to humanize the site. Your assignment was to take this harsh concept, and without disturbing the idea, transform it to be softer and more alive. What parts of this task were the most challenging?
PW: Normally, you have an experienced architect with an experienced landscape architect, so they know what each person does and so forth. But Michael had never built anything before. I mean, he had never even done a set of working drawings. So it took a while to get our teams working in a way that we could accomplish the various ends. There were a lot of challenges in the first years. It took a lot of hard work to get all that pulled together.
SM: The landscape around the memorial is such a huge part of the experience, but in its own way, it’s minimal. What led you to this approach?
PW: One has to take the memorial function and the park function as two separate activities. People who go to see the memorial will experience the park, but not in the same way as people living and working around it. So we had to analyze which park functions should be accommodated, and which would be detrimental to the sense of dignity and honor of the memorial. We already had the rejection on the big stone plaza idea. We knew we had to introduce plant materials and softening on the ground. But we had to keep the plaza flat. The flatness is so important. When you come across a flat surface, and then suddenly these great holes cuts down, this contrast gives it power. For me, that was an interesting artistic challenge.
SM: What are your favorite details?
PW: If you look from the north or the south into the memorial, you will see the trees as woods, very soft, almost random. You have to turn 90 degrees to see them as colonnades. They change as you move through. It’s like an Escher drawing, a trick of playing back and forth between soft and hard. It’s very simple, but not so simple that it’s not interesting. If it gets too interesting—like if you have swings and slides—it would be great for a park, but it wouldn’t be great for people coming to a memorial.
SM: With such a high-profile and emotionally charged project, there was plenty of criticism levied from various parties. Was there any controversy over your landscape design?
PW: We didn’t have controversy over anything conceptual. Where we had trouble is where people differed in the details. One person liked one kind of bench, another person liked another kind. One person liked a lot of trees. Somebody else liked less. Security was a real problem. How do you keep a place open and also secure? We spent almost two years on the security issue. On the whole, we’ve won those battles, though. I don’t mean to sound bitter. It just took a long time.
SM: And how has the public received it so far?
PW: That’s right—the public. You have to decide whose interests you’re serving. Existentially, it’s the families who became the client, not that they speak with one voice. When we started this, they were hurting. We felt we had to satisfy their feelings, which were the strongest of all and the most immediate. I was worried all the way along that we would not be able to, and that would have been a real failure. At the opening, I was getting praise from some of the most active representatives of the families—and I was flying high.
Renderings by Squared Lab Design; Photos by Alan Ward; all courtesy of PWP Landscape Architecture