A sophisticated stormwater system elevates Philadelphia’s Girard Avenue interchange.


Around the world, cities are demolishing, burying, or capping their elevated freeways, but an interstate in Philadelphia provides a possible alternative—one in which the highway stays up but connectivity, open space, and water quality are still prized. In redesigning three miles of Interstate 95 north of Center City Philadelphia, the Pennsylvania Department of Transportation planned 27 acres of park and open space, and the first phase of the $1 billion project, due for completion by 2027, incorporates examples of green infrastructure. According to AECOM, the prime consultant on the project, landscape design and green infrastructure accounted for between 5 and 7 percent of the first phase’s total budget.

At the Girard Avenue Interchange, I-95 runs parallel to the Delaware River two blocks away. Rather than whisking stormwater runoff directly into the river, overtaxing an already burdened municipal system, or funneling a deluge into a rock pit, AECOM and other experts devised a treatment scheme of basins, weirs, bioswales, and rain gardens. Ten planted acres can capture the first inch of runoff from about 50 acres of road surface. “The water design actually improves the water table,” says Christian Lynn, ASLA, a landscape architect at AECOM.

Water resource engineer Edwina Lam, also with AECOM, explains, “Water hitting the pavement runs to a gutter line and then through a drainage system to surface-street level, where it is collected in a bioswale or rain garden. We’ve built an outlet structure for a hundred-year storm.” Water not absorbed by the ground or plants goes through filtration before entering conduits that take the cleaned water to the river; weirs control water volume. The design is meant to capture water so that it doesn’t overload the city water drainage system. “The two systems are separate,” Lam says. “The city is already managing household and commercial wastewater.”

Plantings are also “meant to be placemaking,” Lynn says. “They make the underneath spaces more engaging and soften the edges.” Reconfigured entrance and exit ramps for the interchange increased the distance between highway touch-down points, expanding areas of natural light as well as pedestrian access. Still, nearly 70 percent of the open space lies under the deck, so the team conducted a sun/shade analysis and then mapped planting zones before choosing a plant palette that includes species able to withstand low light. Lynn also considered tolerance for salt, pollution, stormwater, and other urban conditions. For the planted areas, AECOM brought in a highly porous soil mix with amendments that will absorb and dissipate pollutants to protect the nearby river.

Residents, in whose back or front yards this transformation is unfolding, have had a voice and a vote in many decisions, with computer models to help them imagine the changes. Already, some residents are taking ownership of the spaces, posting pictures of butterflies in flower beds and hanging bird feeders in the young trees, which the designers and engineers take as measures of success. More official gauges are coming from several university research projects: Graduate students at Villanova University and Temple University are tracking plant health and water volumes and monitoring weather.


Click to view slideshow.

Technologist landscape architects rejoice—the November issue of LAM is packed with imagined scenarios, myth breakers, and tantalizing possible futures for urban design. Whether or not autonomous vehicles will allow for utopian cities of tomorrow depends on careful planning and policies today, says writer Brian Barth. And the future of autonomous vehicles might not look as green as we’re imagining. A new landscape by Ki Concepts on Honolulu’s Ford Island—site of the Pearl Harbor attack in World War II—weaves the richly layered history of the site into a sleek, cohesive design. And a new streetscape redesign by CRSA in the Sugar House business district of Salt Lake City turns a large thoroughfare into an inviting multimodal streetscape.

In Materials, Jane Berger discusses the stigma—and benefits—of the often-misunderstood bamboo. And in Tech, geodesign unites academics and agriculturists in the pursuit of the most optimal yield for their yearly crops. All this plus our regular Books, Now, and Goods columns. The full table of contents for November can be found here.

As always, you can buy this issue of Landscape Architecture Magazine at more than 700 bookstores, including many university stores and independents, as well as at Barnes & Noble. You can also buy single digital issues for only $5.25 at Zinio or order single copies of the print issue from ASLA. Annual subscriptions for LAM are a thrifty $59 for print and $44.25 for digital. Our subscription page has more information on subscription options.

Keep an eye out here on the blog, on the LAM Facebook page, and on our Twitter feed (@landarchmag), as we’ll be posting November articles as the month rolls out.

Credits: “The Retraining of Salt Lake City,” CRSA; “Before and After Pearl Harbor,” Alan Karchmer; “Dream Cars,” Illinois Institute of Technology; “Raising Canes,” OvS; “Models of Collaboration,” Len Kne. 



An asphalt coating could help cool Los Angeles. Will the benefits offset the costs?


Initially, the product was for the military. Marketed as CoolSeal, the light gray-colored asphalt seal coat was developed to reduce the surface temperature of runways so that they would be less visible to infrared satellites. A few years ago, Greg Spotts, the assistant director of the City of Los Angeles Bureau of Street Services, wondered what would happen if you painted every street in the city with CoolSeal. Could you reduce the urban heat island effect, a phenomenon that has been estimated to cost the city $90 million each year in energy bills?

Now, with $150,000 in public funding, Spotts is testing the coating at locations in each of the city’s 15 council districts. The coating, which is just 15 microns thick, goes on in a brilliant gray, far lighter in color than a typical asphalt street, though Spotts says it soon fades to more of a “battleship color.”

By this fall, all 15 streets should be complete, and according to the city’s asphalt testing lab, even in the afternoon on the hottest days, the surface temperature of the coated pavement is, on average, 10 degrees Fahrenheit cooler than the uncoated pavement. The city also will monitor the coating to test how it performs over time, Spotts says.

Allen Compton, ASLA, a principal at SALT Landscape Architects and the cochair of the Los Angeles Department of Transportation’s Pedestrian Advisory Committee, is curious to see the results. But he also wonders whether or not there might be urban side effects, such as a decrease in the visibility of road striping, or troublesome glare.

The biggest question may be to what extent a local reduction in temperatures helps the world at large. A 2017 study conducted by scientists at the Department of Energy’s Lawrence Berkeley National Laboratory, which has consulted with Los Angeles on its pilot, compared traditional pavement and coatings like CoolSeal and found that the additional energy and emissions needed to produce the latter exceeds any energy savings achieved through lower surface temperatures. In other words, these coatings could have a net-negative environmental impact.

Even if the coating were carbon neutral, Spotts acknowledges that the CoolSeal would represent an extra layer, and therefore an extra cost, in street construction. But his hope is that the project will signal to manufacturers that there is a demand for cool pavement products. Right now, a standard asphalt street in Los Angeles gets something called a slurry seal, a three-eighths-inch rubberized coating that seals it from water intrusion, Spotts says. “If there was a light-colored slurry seal, that’s a solution we could take to scale with existing funding. But there isn’t one.”

Timothy A. Schuler, the editor of NOW, can be reached at and on Twitter @Timothy_Schuler.


As part of an ongoing effort to make content more accessible, LAM will be making select stories available to readers in Spanish. For a full list of translated articles, please click here.

Click above for a full PDF of the translated text with English text available below.



Among Southern California landscape architecture firms, Los Angeles-based Studio-MLA (formerly Mia Lehrer + Associates) is arguably highbrow. Known for public spaces like the 1,300-acre Orange County Great Park and Vista Hermosa Park in an underserved section of Los Angeles, and transformative master plans for infrastructuralized landscapes like the Los Angeles River and the Silver Lake Reservoir, the firm has a serious approach to the needs of Southern California and the services landscape architecture can provide. It’s complex, civic-minded work built out of decades of engagement in the community.

So it’s somewhat unexpected to see some of Studio-MLA’s recent work diversify into the mass market world of professional sports. The firm is currently working on three separate sports stadium projects in the Los Angeles area, starting with a reimagining of Dodger Stadium in 2012, a stalled urban development turned National Football League stadium in 2014 in Inglewood, and the stadium for a Major League Soccer expansion team, the Los Angeles Football Club (LAFC), in Exposition Park. Within five years, Studio-MLA has become the unofficial stadium landscape architect of Los Angeles.

Left: Hundreds of trees were added to Dodger Stadium’s massive parking lot. Right: Public entrances emphasize the soccer stadium’s connection to downtown and Exposition Park. Credit: Hunter Kerhart, left; Gensler, right.

Given sports stadiums’ tendency to end up as fortresses ringed by excessive parking lots, they may not seem the most adventurous project type for a conscientious landscape architect. But despite a long history of problematic and divisive development, the form is beginning to change, moving away from the suburban big box approach and toward a more urban, connected, parklike feel. That’s created new opportunities for inventive design and, according to Mia Lehrer, FASLA, the firm’s president, a chance to undo some of the mistakes of stadiums past.

“The way some of these stadiums are developing and the way they’re integrated and knit into the community, they actually bring a tremendous infusion of energy,” Lehrer says.

Though it would be a stretch to call any of these stadiums public spaces, given their private ownership, ticketed entry, and business operations, Lehrer says they can still serve a public purpose. In L.A., privately owned public spaces such as the faux-city mall complex The Grove and the pedestrianized Third Street Promenade in Santa Monica are some of the most visited, and arguably the most successful, of the city’s publicly accessible spaces. Like shopping, sports have a broad appeal, and they’re able to pull in big crowds. The new LAFC soccer stadium will be able to seat 22,000; Dodger Stadium sells out at 56,000; the NFL stadium in Inglewood—the design still under wraps—could accommodate up to 80,000. For Lehrer, those numbers made the potential impact of good landscape design outweigh any reservations about the troubling history of stadium projects.

“I had to allow myself to understand the typology of these projects to make sure we weren’t selling our soul,” she says.

At roughly 15 acres, the site of the LAFC’s 22,000-seat, Gensler-designed soccer stadium is a tight squeeze, and that’s partially on purpose. Located near the southeast corner of Exposition Park and scheduled to open in 2018, the stadium will add to an already packed 160-acre park space that includes facilities originally built for the 1932 Olympics, a string of museums, a school, a historic rose garden, the site of the future George Lucas Museum of Narrative Art, as well as the Studio-MLA-designed gardens and learning environments outside the Natural History Museum of Los Angeles County. But even inside this heavily programmed complex of a park, the LAFC’s corner touches on an urban mix of residential and retail along a major north–south corridor. Among the firm’s stadium projects, Lehrer says this is “the most intensely nestled into the city fabric.”

Public spaces around the stadium will encourage festivities and tailgating. Credit: Gensler.

As bulldozers grade and cranes lower the massive concrete supports for the grandstands, Studio-MLA principal Benjamin Feldmann, ASLA, walks to the northwest corner of the construction site and points out where the main public space of the stadium will sit, totaling about eight acres. An open and programmable plaza looks down on the field and links to ancillary buildings housing a team store, dining facilities, and a roughly half-acre roof terrace designed by Lehrer’s firm. It opens out to a preexisting tree-lined space in Exposition Park used by fans for tailgating before games at the adjacent Los Angeles Memorial Coliseum, the temporary home of Lehrer’s other type of football client, the Rams.

About 215 sycamore, ash, and sweet gum trees were removed for construction and will be replaced around the site’s perimeter, along with some seemingly obligatory palms. Studio-MLA’s design specifically worked around one existing tree, a 90-year-old sycamore on the street side of the stadium. Planters and hardscape are to be installed around the tree, which is designed to become a signature gathering space at the main entrance for those not arriving in cars—a group the firm hopes will be significant. This corner of the site was designed to open directly to the sidewalk, opening views of downtown from inside the stadium and, more important, views into the stadium from the corner of the street. Feldmann notes that the team’s owners—a group that includes the Basketball Hall of Famer Magic Johnson and the actor Will Ferrell—wanted the stadium to feel connected to the city, so people could walk right up to it without passing through any gates, like an English soccer stadium woven into the urban fabric.

But South Los Angeles is far from urban England. Instead of dense streets of shops and housing, fast food restaurants and parking lots fill the space between the stadium and 16 lanes of Interstate 110 to the east, and state-owned land on two sides of the stadium will remain asphalt lots. To the south the area quickly becomes almost entirely residential, but it’s still linked to Figueroa Street, a major artery in the city and the focus of a wide-ranging streetscape improvement project, My Figueroa, that aims to improve the street for pedestrians, cyclists, and transit users. Studio-MLA’s design embraces that mission, with wide pedestrian walkways, shade trees, and plentiful bike parking on the street side of the stadium, purposely positioned in a prominent location, “not hidden behind some secret doorway,” Feldmann says. The stadium’s design also calls for a street-accessible restaurant space, adding more to the Figueroa corridor than just the wall of a stadium.

Wider promenades and plazas have augmented the original landscape. Credit: Hunter Kerhart.

“It’s helping bring our community even better development, and development we’ve wanted for a long time,” says Adrienne Kuhre, president of the North Area Neighborhood Development Council, the local city-chartered neighborhood council. She says the new spaces integrated into the stadium’s design will give the area a more lively and civic atmosphere. Compared to the barren parking lots and dead space that have dominated this section of the park, particularly since the 2016 closure and demolition of the L.A. Memorial Sports Arena, the public-focused design elements of the new stadium are welcomed. “It’s just been a plot of land sitting there for so long,” Kuhre says. “To finally have something significant there is great.”

The firm’s most established stadium work is the master planning and renovation of Dodger Stadium. Originally built in 1962, the stadium was given a $100 million makeover after the 2012 season, with new team-focused facilities, restored architectural features and signage, and upgrades to the spectator experience. Part of that budget was set aside for a new landscape plan for the 300-acre stadium site. The firm focused the master plan on improving circulation and visitor amenities.

Controversially constructed on Chavez Ravine, a Mexican American neighborhood cleared under the auspices of urban renewal and housing development, Dodger Stadium was an unconventional stadium in its time—a futuristic, almost sculptural marvel of concrete, car-oriented and disconnected from the city. Though that model of detachment would soon dominate stadium design, since the 1990s the pendulum has been swinging back toward a more connected and people-focused approach to siting and designing sports facilities. After more than 50 years, Dodger Stadium has become an example of what not to do. But as others like it were torn down and replaced, the stadium also gradually became one of the oldest ballparks in Major League Baseball. Now an icon of midcentury modern design, Dodger Stadium needed preservation, but it also needed to adapt.

The stadium’s renovation was headed by Janet Marie Smith, the senior vice president of planning and development for the Dodgers, who came to the organization after leading a string of innovative stadium makeovers that prioritized the fan experience, like Baltimore’s Camden Yards and the preservation and expansion of Fenway Park in Boston. “Today’s game experience is more than just nine innings of baseball,” Smith says.

At Dodger Stadium, Smith charged Studio-MLA with turning a stadium surrounded by a desert of asphalt into a pleasant place that could be easily accessed by multiple means of transportation. The firm focused on expanding the space surrounding the stadium gates, creating new plazas and themed gathering areas in spaces once given fully to car parking. New planters and trees were added throughout, replacing nearly 30,000 square feet of asphalt that wasn’t explicitly being driven over or parked on. More than 500 trees were added to the grounds or repositioned during construction, including 100 fruit trees. Clearly marked pedestrian walkways were added to connect the stadium to the city sidewalks beyond the parking lots, as were bike racks, drop-off and pickup zones for car-sharing services, and a well-used public transit shuttle. The ticket gates themselves were moved to create more active space within the stadium’s concourses, which included children’s playgrounds, vending zones, and seating areas. The work has been gradual and ongoing since 2012, with more development planned for the future.

“We tried to make it much more a place for the fans, for pedestrians, for cyclists, who actually filter into the park through a human-scale space,” Lehrer says. A buffer of between 40 and 50 feet now exists around the stadium, replacing parking spaces with plazas, plantings, and areas for fans to gather. “For a stadium to be willing to give up hundreds of spaces to end up with plazas so people can have a more pleasant, interesting arrival is pretty amazing,” she says.

The view downtown. Some parking spots were traded for pregame gathering spaces. Credit: Hunter Kerhart.

The new spaces are being used. Before a game on a recent spring weeknight, fans were milling around the new plaza spaces, waiting to meet people, carrying movable seats to shady areas, and taking photos next to a recently installed statue of the baseball legend Jackie Robinson. At Top of the Park, the plaza near the stadium’s uppermost entrance with straight-on views of downtown L.A., families paused for pictures next to a cluster of palm trees and orange and red Euphorbia. A small boy leaned over a bright blue planter and poked at the spiny stem of a crown of thorns (Euphorbia milii).

Smith says Studio-MLA’s approach is the continuation of the stadium’s original landscape design, noting that the original owner spent $1.5 million on the landscape around stadium entrances and on the hillsides surrounding the park—the equivalent of roughly $12 million today. Outside the stadium gates, a bronze plaque installed in 1963 honors the original landscape team, led by the landscape architect John T. Ratekin.

Plans for the future aren’t yet public, but Lehrer says the ongoing intervention is intended to embrace people’s connection with the stadium by making it easier for them to come and enjoy the space. This approach to Dodger Stadium has ended up guiding the firm’s thinking about its other stadium projects and how they can create better spaces for people to gather. Lehrer, admittedly not a sports person, says she has come to appreciate the role sports and sports stadiums can play. “I think they are an opportunity to revitalize cities and really bring an infusion of economic, environmental, and cultural benefits,” she says.

It’s surprising territory for Lehrer and her firm—“I didn’t go looking for stadiums, to be honest,” she says—but it’s turned out to be fertile ground for innovative landscape architecture. The populist magnetism of sports stadiums has made them into almost a new type of public space. “They are becoming parks; they have that allure,” Lehrer says. “People do go and will go to these places.” And that’s a clear mandate to make them better spaces for the people who use them.

Nate Berg is a freelance journalist based in Los Angeles.

Project Credits
DODGER STADIUM: Owner Los Angeles Dodgers, Los Angeles. Landscape Architect Studio-MLA, Los Angeles. Architect DAIQ Architects, Boston. Associate Architect Levin & Associates Architects, Los Angeles. AV Design WJHW, Carrollton, Texas. Structural Nabih Youssef Associates, Los Angeles. MEP ME Engineers, Culver City, California. Graphics Ashton Design, Baltimore. Civil Mollenhauer Group, Glendale, California. Geotech URS Corporation, Los Angeles. General Contractor Hunt Construction, Orlando, Florida. Landscape Contractor ValleyCrest Landscape [now BrightView], Calabasas, California. Concrete Contractor Bomel Construction, Anaheim Hills, California.

BANC OF CALIFORNIA (LAFC) STADIUM: Owner Los Angeles Football Club, Los Angeles. Landscape Architect Studio-MLA, Los Angeles. Architect Gensler, Los Angeles. AV Design Idibri, Addison, Texas. Structural Thornton Tomasetti, Los Angeles. MEP ME Engineers, Inc., Culver City, California. Civil KPFF, Los Angeles. Lighting First Circle Design, Costa Mesa, California. Field Consultant Millennium Sports Technologies, Littleton, Colorado. Roof Engineer Nous Engineering, Los Angeles. General Contractor PCL Construction Services, Glendale, California. Landscape Contractor American Landscape, Canoga Park, California. Concrete Contractor Bomel Construction, Anaheim Hills, California.