Portland thinks bioswales are cool, but the city doesn’t know if they’re needed, according to a recent audit, as reported in the Mercury:
[T]he audit finds that some 36 percent of the city’s over 2,000 green streets might not have been necessary to create in the first place.
Even worse, the city doesn’t know whether the bioswales work:
Auditors found that Portland does not have a comprehensive plan to identify areas that are prone to flooding and pollution, fails to consistently report on project results, and does not regularly maintain and inspect its many projects. The bureau spent $13 million on these projects this year alone.