Why they call them Marshfield and Swampscott

Milton Brasher-Cunningham limns the view out the window of his Marshfield home:

...This morning we could see
the flooded road
from our kitchen window.
"Why do you think
they call it Canal Street?"
she asked, smiling.
The tide was coming in
again as I left for
work, thankful to have
four wheel drive. ...

On the North Shore, New in Swampscott describes, photographs coastal flooding:

... Both me and the wife had today off for Patriots Day, but I spent the better part of it watching my sump pit fill with water. After the high tide at around 11 am, we still hadn't overflowed the pit and then the sun came out, saving the day. ...