Sue Bednarz Interior view of Portlands $464-million East Side Big Pipe project. For officials in Portland, Ore., the Big Pipe project is no longer a dream. The recently completed $1.4-billion, 20-year combined sewer overflow (CSO) control program was implemented in response to an Oregon Dept. of Environmental Quality order to reduce significantly CSO events by December 2011. Thanks to large-diameter underground tunnels installed along the Columbia Slough and on both sides of the Willamette River, the city now meets the overflow frequency criteria set forth in 1991 by the DEQ. Annual CSO volume to the Columbia Slough and the Willamette
The 2016 Summer Olympics boating and swimming events have put an international spotlight on what has been a long-running problem in Rio de Janeiro—untreated sewage and trash are clogging up major bays and waterways.