DES MOINES, Iowa — On June 27th, the third-worst flood in the history of Des Moines, Iowa’s Raccoon River, necessitated the quick and urgent rescue of “Wading Bridge,” the most recent installation by the New York-based artist Mary Mattingly. This move was the fifth of a total of nine displacements that the approximately 4,500-pound installation has endured to date. When floodwaters weren’t threatening to wash it away, it was (according to the Greater Des Moines Public Art Foundation) either the Army Corps of Engineers suddenly vetoing previously approved design proposals or the budget — insufficient to pay for a professional installation crew and equipment — that almost killed the project.