Some remarkable healing is happening at a teaching hospital in the state capital, and it’s not only the result of modern medicine. This particular cure has to do with restoring the health of a previously ill-treated water source. A creek that meanders between the hospital’s buildings and that serves as a tributary of the Colorado River is being restored, rainwater is being captured and reused, and stormwater is being managed to mitigate erosion and avoid flooding. Thirsty non-native and invasive species that have long choked the creekbanks have been removed and replaced with water-wise native and adaptive plants.
The Dell Medical School and its teaching hospital, Dell Seton Medical Center, are part of a 16.2-acre development located in central Austin on the University of Texas campus. The three buildings and a garage that comprise the development are situated in an ecologically sensitive area astride 6.6-mile-long Waller Creek, which flows through north-Austin residential areas, bisects the UT campus and continues through the heart of Austin’s central business district before emptying into the Colorado River. Plagued by flooding and sorely neglected for years, Waller Creek (named for the city’s first mayor) has recently been the beneficiary of intensive public and private restoration efforts to ensure the long-term viability of this urban tributary. The section of the waterway that runs through the Dell Medical School campus is a significant part of that restoration work.
Using a combination of rain gardens, pervious pavers, rainwater harvesting, invasive-species removal, native-habitat restoration and a green roof on top of the garage for the hospital’s outpatient clinic building, the landscape’s water-saving focus allows it to manage rainfall onsite and prevent runoff for as much as 46,939 cubic feet of water during a rain event. Now, 85 percent of rainwater remains onsite, rather than overflows into the creek and contributes to flooding downstream.
Saving water was a guiding goal from the start of the Medical School’s development. Recognizing the importance of the landscape’s contribution to that effort and including it in the planning process informed an innovative approach that has seen benefits at every phase of the project. The waterway that wends its way between the hospital and school buildings was a major consideration from the get-go. Waller Creek is a natural riparian corridor, and by conserving and reusing salvaged native plants and restoring more than 3,000 cubic yards of soil, the project has helped reestablish the tributary’s ability to function as nature intended.
The Sustainable SITES Initiative is a national rating system that assesses the sustainable design, construction and maintenance of landscapes. SITES awarded the Dell Medical School development its first Gold Certification in Texas and summed up the project this way: “Prior to construction, approximately 70% of the vegetative canopy along Waller Creek was comprised of invasive species. Restoring the creek was an 18-month process that included the removal of invasive species, stream-bank stabilization and the revegetation of over fifty diverse native-plant communities. Formal planting areas around the buildings prioritized the usage of native vegetation, which helped reduce irrigation by over 75%.”
One of the main aspects of the development’s water-saving efforts is a 20,000 square-foot green roof on top of a seven-floor parking garage, attached to the Health Transformation Building, which houses a variety of outpatient clinics. By replacing a large, impermeable surface with plants and soil that absorb and retain rainfall, water that would otherwise drain off and inflict damage as floodwater is saved and reused. The old adage describing weather in Texas as “drought punctuated by flooding” is becoming even more prescient due to climate change. With more intense storms causing more rainfall in less time, anything that can mitigate runoff and flooding from impervious surfaces is a bonus.
The green roof is made up of 6,500 individual native plants: prickly pear (Opuntia ellisiana), red yucca (Hesperaloe parviflora) and manfreda (Manfreda maculosa), over-sewn with a mix of Texas bluebonnets (Lupinus texensis) and plains coreopsis (Coreopsis tinctoria). The placement of the green roof above a parking garage takes advantage of the garage’s inherent weight-bearing structure. Furthermore, the roof serves as a capture area for rainwater that is filtered and collected into a 27,000-gallon cistern positioned at the base of the parking garage below. A separate, 7,000 square-foot strip of roof garden runs along the opposite side of the seventh-floor offices, but it is not connected to the water-collection system.
The overall model for the roof gardens is based on Ladybird Johnson Wildflower Center research plots that have been surviving without irrigation since 2014. The growing medium for the roof gardens is a special soil mixture that was specifically designed by the Wildflower Center for green roofs in hot climates. This lightweight soil, along with a gravel perimeter for drainage, the use of native species and the load-bearing capacity of the parking garage below the garden, allow plants to be installed in a full foot of the special soil mix, which provides greater insulation from heat and enables retention of rainwater.
Not only does the green roof reduce heat and save water, it also serves as a living research laboratory for the University to collect data on the efficacy of the system. After the soil was in, but before the native vegetation was planted, drip irrigation was installed with special soil sensors that tie to the University of Texas irrigation system. Although the ultimate goal is for the green roof to thrive without supplemental moisture, the sensors monitor soil moisture and assess watering needs on an ongoing basis, providing data for continuing research.
An added benefit is that the green roof can be seen from hospital rooms in the Dell Seton Medical Center across Waller Creek. Research has shown that green spaces can facilitate faster recovery in hospital patients and improve the well-being of staff and visitors. By combining architecture and ecology into the design of the development, the Medical Center provides those who come to the hospital with an opportunity to connect with nature in an otherwise increasingly urbanized environment.
Justin Hayes is the Landscape Supervisor of the Dell Seton Medical Center. It is his job to oversee the installation and ongoing maintenance of the many softscape aspects of the development. He brings years of experience and an interesting backstory to the task.
In 1993, Justin was a 12-year-old kid in Lubbock who wanted a Sony PlayStation in the worst way. His father told him to get a job and earn the money to buy one. So, he started mowing lawns at $10 apiece (gas was a lot cheaper back then). It wasn’t long before he had a regular customer base of 70 yards per week, some with signed contracts. Justin got his PlayStation, of course, but in the process, he got something else: a nascent familiarity with urban landscapes, a budding interest in sustainability and a lifelong career path. In 2008, a move to Austin to be near family members led him to a job as a gardener at the University of Texas campus. He steadily worked his way up the ranks, learning from mentors, attending conferences and developing a passion for working with nature to create sustainable landscapes within an urban institutional environment.
Justin’s approach to managing the site is all about working with nature, which dovetails perfectly with the development’s goal of sustainability. “When I think about what to plant and where, I always ask myself the WWND question — What Would Nature Do? — and then let the answer guide my actions,” he says. “That often requires delayed gratification. You have to let natural succession happen. What starts out with wildflowers might transition to prairie grasses, then next comes small woody plants and so on. Now that the site has the basic elements in place, we try not to do too much engineering of the project other than invasive-plant removal. We let nature take the lead.”
In the process, the Dell Medical Center landscape, with its focus on Waller Creek and the crucial importance of water conservation, has become an urban oasis that provides environmental and human health benefits to patients, their families, medical professionals, students, educators and the entire Austin community. tg
Suzanne Labry, B.A., B.ED.
Volunteer Billie L. Turner Resources Center Herbarium
University of Texas at Austin