How Water Shapes Architecture in Arid Tucson

Welcome back to The Architect's City, a monthly series inviting an emerging architect to reimagine an existing structure in his or her city, submitting a speculative proposal for Curbed readers. This month, how water concerns change architecture in Tucson, Arizona.

In Tucson, Arizona, says Jesús Robles, there's one topic that rarely recedes far from architectural considerations. "The larger conversation of this place revolves around water," he says. "Water and water security equals food security, which equals crop security, which equals economy for a region, state, a nation."

A typical year brings around twelve inches of rainfall to Tucson. After a drought crisis in the mid-1970s, water conservation became a major priority. And though the population of the area served by the city water authority has grown by more than a third since the late 1980s, water consumption has remained constant. With a handful of activist groups spearheading awareness on a more systemic level and residents increasingly choosing arid landscaping over lawns, installing rainwater recapture and gray water use systems, Tucson is at the forefront of water conservation.

Robles, who founded the Tucson-based firm Dust with partner Cade Hayes in 2007, has long worked with private clients to maximize water conservation at home. But Dust's proposal here, for the city's first permanent parklet, grew out of a request from a pair of local businesses, a cafe and a bar. The storefronts were interested in sponsoring a traditional, ecologically-minded parklet—small, impermanent, in underutilized parking spots in front of their establishments. The city, however, in the process of building an expressway that cuts through a handful of downtown neighborhoods, announced plans to update the street's storm drains and modify the curb in front of the storefronts, rendering the parklet plan moot.

Here, Robles and the team at Dust suggest working with the city's plans, rather than against them, to create a watershed catch basin masquerading as a simple parklet. It would be Tucson's first permanent parklet, and also its first micro park using exclusively native desert plants.

"By removing the concrete, planting the soil with desert materials and creating a desert compost of debris to withhold it," he explains, "you're basically slowing the water down."

Dust aims to seed the parklet with native plants, like cacti, local peppers—chile tepin, with which the coffee shop now makes a cold brew—and mesquite trees, the seeds of which would be ground down and used as a syrup for beverages. A small curb cutout (essentially, a notch sliced into the curb) provides a runoff route for excess water. Above the plants, a system of modular grates offers firm footing for visitors and maximum porosity for the plants below. The grates, made of oxidized steel, would also aesthetically shift in patina over time.

The hexagonal shape on which the team settled, Robles says, refers to honeycombs, both their structural capacity and their importance to the desert ecology. "A lot of the reason that people are gathering the rain and runoff is for the bees," he explains. "Plants are thriving, and we're getting really great desert honey out of it."

Between the park and the curb, Robles proposes parking for twenty bicycles. Tucson, he explains, is a great biking city, and residents frequently take to the streets on two wheels. Not only does the design offer parking spaces, but the parked bikes and their infrastructure serve as a buffer between the parklet and the street.

While this specific parklet would function in part as a commercial space—Robles foresees coffee-sippers sitting on the seats with their lattes and bar-goers spilling out as the night gets later—this proposal could function equally well in a more public setting. "I could see this incorporated into a bus stop," he says. "I'd really like to remove a bit of the [café] program, make it a little more public."

He points out that no other public parks in Tucson have a similar sustainable desert ecology. Local nonprofits like the Watershed Management Group and activists Brad Lancaster and Katie Bolger have fed the city's revolution in rainwater recapture—Lancaster lobbied for three years in the late 90s and early aughts to legalize curb cuts, the practice of slicing small notches in curbs to encourage rainwater runoff from streets toward plants. Clearly, it's having an impact, and citizens are following suit. But while there are catch basins, Robles points out, there's no architectural model at this scale for businesses interested in converting a similar curb or sidewalk café into water recapture-slash-architecturally interesting, possibly profitable space.

"We hope this starts a conversation about how we can start to inhabit the spaces that are reclaiming the water," he says. "As architects, we're in it, our job is to make aware and integrate as much of this [as possible] into our design."

· Tucson coverage [Curbed]
· The Architect's City archive [Curbed]