The Threat of Climate Change to Urban Stormwater Infrastructure

Extreme events throughout the USA and the world have become mainstream news, causing tens and hundreds of millions of dollars in damage, not to mention the environmental impacts. The current design methodology is based on historical rainfall patterns and our aging infrastructure was never designed to meet the demands of current and future potential storms. Analysis of historical (TP-40), current (Atlas 14), and future predicted storm events for three watersheds in Minnesota (Duluth, Minneapolis, Rochester) has shown that current design philosophy is not sufficient to prevent flooding from 10-year and larger design storm events. Flood depth and duration is predicted to increase given current climate projections. To offset the increase in potential flooding, several stormwater infrastructure adaptation strategies were assessed for reducing flood depth and duration: Baseline (existing conditions), adding rain gardens (aka, Infiltration Basins), adding new surface storage (wet ponds), retrofitting existing storage with “Smart” technology, adding new Smart storage, or upsizing of stormwater pipes to convey more water. This presentation will delve into the possibilities of adapting our stormwater infrastructure to mitigate potential extreme events, minimize flooding, and adapt to climate change.