Between sirens, horns, speeding cars, and garbage trucks, the sounds of a city are inescapably earsplitting. At times, the quest for quiet can seem more like a fool’s errand than an attainable goal. Could better design help? Turns out that when thoughtful landscape architecture enters the picture, there’s a shot at some aural relief.
Michael Van Valkenburgh Associates (MVVA), a landscape architecture firm in Brooklyn, has spent years designing urban parks that provide aural relief from the surrounding chaos. By sculpting the land, MVVA gives cities their very own mute button.
Parks are typically viewed as an escape from the urban cacophony, but as real estate becomes scarce (and expensive) in cities, leftover parcels of land are being turned into public green space. These are often next to heavy infrastructure, like highways and expressways. In the past few years, MVVA has worked on a few of these projects like Brooklyn Bridge Park in New York, Maggie Daley Park in Chicago, and A Gathering Place for Tulsa, which is still in progress. In each of these projects, the firm has sculpted the land to tune acoustics.
“Being able to have a conversation is the measure,” Matthew Urbanski, a principal at MVVA, says of an acceptable noise level in an urban park. “If you have to yell or get really close together to talk, it’s not park-like . . . You try to lower ambient noise level so people can start to hear the insects.”
Brooklyn Bridge Park, an 85-acre waterfront park south of its namesake bridge, is located on a site that was once an industrial shipping zone. Cargo operations ceased in the 1980s, and in 2000s a master plan was developed to turn the public-private area into a park and condos. Construction began in 2008 and is still underway in some areas.
One of busiest expressways in the borough is adjacent to the park and just beyond the expressway is Brooklyn Heights, a tony residential neighborhood. When the expressway was constructed in the 1940s, engineers covered it with a cantilevered structure, which directs sound away from a residential neighborhood and toward the waterfront. When it was an industrial area, noise wasn’t a problem. But when the land was reincarnated as a park, the sound was a mood killer.
Higher frequency sound–like the sound of tires on pavement and engines–travels in a linear path that follows a line of sight. So if you put a physical object in the path, you reduce noise. Working with acoustics engineers at Cerami & Associates, MVVA created a “heat map” of noise intensity using 3D models of the park and traffic patterns around it and experimented with how changing the topography of the park could mitigate noise.
The landscape architects designed a berm–essentially a very large hill–to block sound from the expressway. The soil has mass and absorbs some of the sound waves, and its slope directs sound waves away from eye level in the park. If a person stands next to the berm, she can’t see the highway, and therefore she hears less noise than if the highway is in eyeshot. The ridged, hilly shape also ensured that sound would not reflect back into Brooklyn Heights. When a sound wave hits a surface, it reflects back at the same angle. If the berm was vertical on the side facing the neighborhood, the sound wave would travel back to the houses. Angling the berm directs the reflected wave away from the houses.
“We affectionately referred to it as a Mohawk,” Urbanski says of the berm.
Before the berm was completed this year, ambient noise in Brooklyn Bridge Park was around 75 decibels, which is approximately what a loud restaurant sounds like. (“At that level it takes on a spatial dimension,” Urbanski says. “It’s squeezing you a bit.”) With the sound berm–which is covered with grass and can be used as a seating area–the ambient noise levels were reduced to the 60-decibel range, which is comfortable for conversational speech, according to the firm’s research.
In Brooklyn, MVVA’s solution was to build higher, but for Maggie Daley Park in downtown Chicago, the solution was to go lower. The 20-acre park is next to Lake Shore Drive, a busy highway. By contouring the park like a bowl, and recessing it slightly below Lake Shore Drive’s level, the designers were able to make the space quieter for park-goers. In the Tulsa park MVVA is working on, the firm is calling for land bridges over the adjacent highway so that when visitors cross the road to the waterfront area, they can’t hear or see traffic.
The problem of noise in a city might all be relative. Public Radio International recently aired a segment about how noise sparks creativity in some individuals. And even though Paley Park is in the middle of Midtown Manhattan–one of the loudest areas in the city–it feels peaceful because of a 20-foot-tall water wall that drowns out the sounds of traffic. Sometimes the remedy to noise is more noise. In other cases, people are just willing to grin and bear it.
“I’ll tell you a funny story about noise in public space,” Urbanski says. “The Manhattan Bridge goes over a piece of the east end of [Brooklyn Bridge] park. When the trains cross over, it’s hellaciously loud. Because of the nature of the way the sound is propagated, you can’t do anything about it in terms of mitigation on the ground. But you go to [that part of] the park and it’s mobbed with people. It’s proof of how crazy New Yorkers are. I joke that it’s the perfect spot for a date. If you didn’t want to talk, you’d have an excuse!”