By Jason T. Berner
The University of Arizona at Tucson campus takes the RainWorks Challenge.
Tucson receives 12 inches of rain a year, and much of that rainfall evaporates or “evapotranspires” through its plantlife. Future climate change scenarios going out to 2099 expect increased temperatures will likely reduce snowpack, which will impact streams in the spring by reduced surface water runoff entering streams, according to the EPA. And with future amounts of precipitation projected to decrease during the spring, available water resources to meet high summer demands of a growing population will be reduced. Also, with limited existing surface water and future projections of decreased precipitation for Arizona, it makes sense that universities, such as the University of Arizona at Tucson, focus on water conservation efforts using rainwater, gray water, and condensate collection systems.
Sustainable landscape projects at the university have influenced the city, which now has a municipal rainwater-harvesting ordinance, requiring 50 percent of water used for irrigating landscapes to originate from onsite sources.
The university has a recent history of designing and building sustainable landscapes that conserve limited water sources, including the Sonoran Landscape Laboratory, which uses 83 percent less potable water than similar Tucson landscapes. Sonoran Landscape Laboratory landscape architecture professor Ron Stoltz has provided 3,000 tours annually, teaching community members about capturing rainwater from rooftops, collecting water from air conditioning units, and reusing gray water from drinking fountains for arid landscapes. Tucson and the University of Arizona have a mindset for water conservation and always look for ways to limit the use of turfed landscapes.
In 2012, the EPA announced the first annual Campus RainWorks Challenge, a design competition open to all universities in the United States to submit green infrastructure designs for their campuses. Design teams were composed of students of various academic backgrounds, including engineering, landscape architecture, urban planning, and environmental sciences, mentored by a faculty advisor. The competition was intended to encourage students and faculty to think creatively about how to manage stormwater runoff using green infrastructure, including green roofs, permeable pavement, cisterns, and bioretention practices for their campuses.
Stoltz and students from the master of landscape architecture program, Micaela Machado and Rayka Robrecht, redesigned an existing 70,000-square-foot parking lot (equivalent to the size of one-and-a-half football fields) into a community gathering place—which includes underground cisterns that collect condensate water from nearby buildings and retention basins. The green space design will be the second largest on campus. Parking spaces lost will be replaced with parking garages located throughout the campus. The design’s intention was to educate the public about the use of rainwater and water conservation—for example, water collected by the cisterns for irrigation would reduce normal annual irrigation needs by 87 percent (610,000 gallons saved).
The students approached the design problem in multiple layers, including engineering, ecological, social, education, and horticulture, creating an integrated design. The design mimics the forms of a storm and an agave plant, highlighting the movement of water. In 2013, the University of Arizona’s design was awarded second place for large academic institutions, being the only winning design for an arid landscape. The design also won an Arizona State American Society of Landscape Architects award for integrated water conservation practices. For these types of landscape projects, Stoltz has found it important to engage campus facilities staff early on in the process. Implementing a sustainable landscape project requires help from staff who are aware of existing sources of water from buildings. Facilities staff found alternative sources of existing water for the design project. And by involving them with water conservation projects, this helps to ensure annual maintenance happens, notes Stolz.
“We often work with a large number of design constraints such as budget, fire lane access, and existing utilities, which makes it difficult to envision anything past what is in front of you. A student competition affords students an opportunity to design without someone saying, ‘You can’t do that.’” Stolz will continue to use the Campus RainWorks Challenge as a design project for the master of landscape architecture students, making students solve real-world and local water conservation problems. For instance, sustainable landscape projects at the university have influenced the city, which now has a municipal rainwater-harvesting ordinance, requiring 50 percent of water used for irrigating landscapes to originate from onsite sources.
Students participating in this challenge increase the intellectual capital of the green infrastructure inside and outside of academia. The design challenge not only highlights how to conserve water in the arid west, but also shows University of Arizona students and staff how universities throughout the country adapt similar technologies under different climates. For the second annual competition, universities had the option to design master plans or site plans. This year, the EPA plans on funding implementation of selected site plan projects from the competition.