Urban disasters, from Hurricane Katrina to the I-35W bridge collapse in Minneapolis, were front and center at a "Town Hall Forum" led by William R. Morrish, once described as among "the most valuable thinkers on urbanism today."

Morrish, former co-director (with his late wife, Catherine Brown) of the Design Center for American Urban Landscape at the University of Minnesota, spoke Wednesday at the Minnesota History Center.

The bridge collapse, like Katrina, changed the sites where they occurred from "secular to sacred" because of the loss of life, Morrish said. And those disasters point to the need to change traditional ways of thinking about urban design.

"Disasters expose outdated ways of working, immediately," he said. "They strip away and show us the transformations already taking place," whether those changes concern race, class or changing demographics. Cities like New Orleans now must be rebuilt not "as an entertainment" (i.e., The Big Easy), but as places where people live.

Morrish raced through images, ideas and anecdotes related -- at least tangentially -- to the theme of the Minnesota chapter of the American Institute of Architects' second annual forum: "Livable Communities."

Morrish sought to distinguish between faddish green architecture and meaningful innovation. Urban design has to "reground the notion of green," he said, "or we'll all get greenwashed to death." Sustainability that has to do with "going off the grid is a cop-out," he added, "a hangover from the '60s."

Buildings and landscapes within cities must "produce something beyond" themselves that adds to our current notions of infrastructure, according the Morrish. His examples included buildings that collect water and produce their own energy; landscapes that grow food, and trees that cool houses.

Six years ago, Morrish left the University of Minnesota to join the School of Architecture at the University of Virginia.

During Morrish's tenure at the University of Minnesota, he and Brown generated such innovative projects as a plan for Phoenix, Arizona, in which public artists and public-works engineers collaborated to transform urban infrastructure into a cultural amenity. Throughout Minnesota, Morrish and Brown were known for their community design meetings, which centered on integrated design solutions displayed -- pop-up style -- inside a pizza delivery box.

Camille LeFevre is a Twin Cities arts journalist.