Research Magazine 2006
Sustainable solutions

By restoring ecological relationships in urban areas, landscape architect David Hopman creates natural settings with a socially and environmentally viable future

Every time landscape architecture Assistant Professor David Hopman walks by Trading House Creek just west of the Maverick Activities Center, he experiences a blend of optimism and annoyance.

Creek? Yes, the ravine that cuts between the MAC and the Tennis Center is, in fact, the “headwaters” of Trading House Creek, the tributary that fronts the campus on the north side of Mitchell Street. From there it meanders east a half-mile to join Johnson Creek, which gurgles north to the Trinity River.

architectural rendering

Landscape architecture Assistant Professor David Hopman and his students studied Trading House Creek with hopes of making it an asset instead of a potential liability.

A pre-1900 trading house on the small stream has long disappeared, but the name persists. Never a grand waterway, Trading House Creek is better described as a willow-lined ditch, and a growing one. When it rains, the creek empties quickly from runoff, expanding a bit each time.

“The soil around it is highly erodible,” Hopman says. “If we don’t do something about it soon, we’ll have to adopt a drastic solution like rip-rap (rock and concrete linings) or even moving the surface flow into underground drainage pipes.”

Hopman prefers a more nature-friendly fix. In fact, he has emerged as one of UT Arlington’s foremost champions of sustainability, defined as meeting the needs of the present without compromising the ability of future generations to meet their own needs.

The landscape architect’s philosophy is not just to encourage endless debate about sustainability but to demonstrate practical ways to move forward. Students design at least one major ecological project each year in the site design studio he teaches.

The projects involve other faculty and staff members and volunteers from outside the University community. Students this year studied the small stretch of Trading House Creek with an eye to making it an asset instead of a potential liability.

“The beginnings of it don’t even look like a stream,” Hopman says. “We don’t have any retention or detention on campus. The water flows build very quickly and disperse very quickly, causing both erosion and low flows during dry periods.

“Right now on most of the campus during rains, we go from green (water falling on grassy or wooded areas before it drains) to gray, water flowing to hard surfaces and directly into either streams or subsurface drainage. For this project, we studied reversing that, so that water goes from concrete to green areas that can slow the flows, cool the water and remove pollutants.”

Recommendations included redesigning the creek to mitigate a large subsurface water flow draining into the campus from the north. Using the principles of low impact development, the students incorporated bioretention areas, rain gardens, water harvesting, bioswales and more into their design. The project won an Honor Award from the Texas Chapter of the American Society of Landscape Architects in the team graduate general design category.

"Addressing the actual conditions of our lives means that any, including small, movements toward future viable practices are environmental benefits worth pursuing."

Hopman believes that the quality of urban life is enhanced when cities are rooted in their natural landscapes, following seasonal cycles, feeling the angle of hills and the natural flow of water. “Reinhabitation,” he calls it—bringing nature to cultural environments.

“Addressing the actual conditions of our lives means that any, including small, movements toward future viable practices are environmental benefits worth pursuing,” he says. “Reinhabitation means working with and restoring the ecological relationships of a place and establishing a socially and environmentally viable future landscape.”

When you’re in Hopman’s company, he speaks at length about such sustainable refinements as permeable paving, rain gardens, stormwater planters, bioswales, ecological retention ponds and green roofs, like the one he helped install last year atop the Life Science Building. Although roofs covered with plantings are common in Europe and a few U.S. cities, the one at UT Arlington is believed to be the first in the Fort Worth-Dallas area.

Green roofs reduce runoff, limit the heat island effect, provide a park-like respite and are said to cut building heating and cooling costs. They use minimum soil (in this case four inches), little irrigation and low-maintenance plants to achieve the maximum environmental benefit with the smallest consumption of resources.

Hopman says the idea at UT Arlington originated with School of Urban and Public Affairs doctoral student Kent Hurst. “As it turned out, Dr. Jeff Howard, co-chair of the President’s Sustainability Committee, also had a class that was studying the idea. It was, ‘Hey, let’s go plant a green roof.’ ”

Hopman convinced the green roof enthusiasts that it was time to research practical applications. “What I found was that nobody in North Central Texas really knew how to do it, though there was a relatively new extensive green roof near the Lady Bird Johnson Wildflower Center near Austin.”

He wrote everybody he could find who had worked on such projects and in the process found two vendors willing to donate most of the materials—about $10,000 worth of soil, plants, roofing and irrigation supplies. More than 50 volunteers showed up from all over campus when the green roof was installed in spring 2008.

“The green roof has already given us a lot of data,” he says. “We have two soil systems up there, 23 species of plants, two roofing systems and all kinds of monitoring equipment. We won’t know for another year or two which of the plants will be able to survive the extreme hot weather, extended wet spells, wind and hard freezes. But thus far only three plant species have crashed and burned.”

Hopman gives a couple of green roof tours every week to environmentalists, professors from other universities, landscape architects, developers and the simply curious. “After two years, we’ll be able to tell people with more confidence what will and will not work with green roof construction. By taking the risk out of it and providing a definitive example, we will greatly increase the probability of many other green roofs being installed in this region.”

His sustainability ventures stretch far beyond rooftops. Last fall, volunteers constructed a Hopman planting design around a rather drab block of Mission Arlington downtown. The greenscape involved $15,000 worth of vegetation.

The list goes on, from the redesign of a golf course to create an environmental education center at the Heard Museum to a new master plan for the Texas A&M-owned Dallas Urban Solutions Center. A design strategy for the Lewisville Lake Environmental Learning Area converted a portion of the wilderness preserve into a user-friendly space for interpreting nature, including 400 acres of canoe paths, hiking trails and visitor structures.

Hopman’s enthusiasm for such environment-enhancing initiatives is catching.

“Projects like the green roof and the ongoing work of the President’s Sustainability Committee have drawn like-minded people out of the woodwork here at UT Arlington,” he says. “There are people who are proactive on many levels. I feel like we’re making steady progress.”

- O.K. Carter