It’s interesting, i’ve learned that CSO’s in reality kind of get a bit of a bad rap (thanks to folks who know a lot more about this stuff than me), at least in our area. If they are done correctly (AKA big enough storage/catch tanks) they can actually direct the storm water via controlled release to the treatment facility. The alternative is a fully separate system where the storm water goes directly to the Sound, treated only by the swales, rain gardens, etc… that can offer a bit of filtration, but the majority goes into the storm drains and direct to our waterways…
CSO overflows are actually rather uncommon, i pay attention to them as a scuba diver because i don’t want to dive it poo, its the everyday storm drain runoff we should be more aware/concerned of, death of the sound by a thousand paper cuts…
the real answer is working to fix it on ‘our’ end, the people’s end, things each and every one of us can do, with rain gardens, rain barrels, cisterns, cleaning up our streets, picking up our dog poo, encouraging local businesses and city construction to put in permeable concrete and greenspace, restoring watersheds and encouraging green infrastructure! limiting the volume of contaminated water hitting the storm drains in the first place.
take a look at http://www.tox-ick.org or to see how you can help!