Storm drains on Marlborough Street drain into the Neponset?

I'm off to the Globe archives. That's a great lead.

The staff at the Charles River Watershed Association have been very helpful. We may just find an answer to this.

I'll also do an tour of plaques today to see if I find more waterways cited in the Back Bay.

In know in some areas of other cities, the drainage is governed by when a system was built more than where that system is. They put the drainage systems in place when areas were being developed and put them through to the drainage they could reach with new construction rather than the nearest waterway. That way, they didn't rip up already developed areas, or add to systems that lacked the capacity for new hook ups.

I have an unfortunate familiarity with the city drain system. There are three plaques as referenced in the article. None of them would be particularly correct for this catch basin as it is connected to a combined sewer system (the west side interceptor to be exact), meaning that most of the time the water drains to a treatment plant (in this case deer island). So that anything going into this catch basin is treated and released into the ocean outside of the harbor.

In the event that the interceptor is surcharged with stormwater, there is an overflow regulator that sends water to the Boston Marginal conduit that runs along the Charles to deer island as well. Should the BMC become surcharged, the last resort relief is MWRA CSO #18, which dumps untreated water into the Charles (on I assume very rare occasions). So the correct plaque, should read "its kinda ok to dump if there are no big storms coming because this water is treated and drains to outside of Boston Harbor. In the event that a large storm should cause the system to overflow, some really bad sewage may end up in the Charles River, but your little bag of dog poop is probably the least of the concern."