While out on a call about an unrelated water quality complaint, a city bureau of environmental services staffer happened to notice a pipe leading from Lewis and Clark's Zehntbauer Natatorium directly into the stream. According to the DEQ, when they notified Lewis and Clark about its illegal dumping of chlorinated water, the school immediately cooperated. But it was too late! Four decades of chlorine have taken their toll on the creek: the pool water has "significantly impaired" the invertebrate and fish populations in the stream.
In 2000, the school received an award from the city thanking them for preventing pollution in Portland and boasts of its numerous green buildings. Whoops!
H/T to Lewis and Clark (and Mercury) alum Angela Webber.