Today, at lunchtime, I drove over to take a look. Nothing. In fact, that water hazard from frozen solid. They must have been sitting on ice last night. I continued down Salem End Road and saw a flock of ducks swimming in the water north of the bridge before Temple Street. I turned around and parked and carefully made my way back to the water (no sidewalks on this part of the road and lots of traffic).
Turns out it was a flock of Ring-Necked Ducks, mostly males, numbering about 3 dozen. There were at least two females among them, plus three Hooded Mergansers, and four Mute Swans.
Hooded Merganser (front and center)