I went down last Thursday to see what was up. Back hoe in the middle of the creek course, moving boulders, big plastic pipe to divert water around the drop they were working on....
I called the project manager for the Eben Fine Park renovation project and he said it was the city utility department. I've sent them an email, but haven't heard back.
It looks like mostly what they are doing is bolstering the sides of the drops and regrouting the sides to prevent erosion of the streambanks. They haven't actually modified the pourovers or the pools themselves [too bad, IMHO], tho' they are filling in to the sides both above and below by moving rocks from downstream.
I'll post if I ever hear more from the city.