India Brook Mendham:

[thmyorke1]

So the coordinates,
40 47.47,-74 37.156

point to the stretch of india brook that's right in the park. Ive been to that spot myself just last winter. So do plenty of hikers. I remember some private property on the east side there. but no divergence I have no idea why they are diverting it. But I think the park used to be some operation (mining, logging, or water treatment?) in the past, and there were old divergents and structures that are still sort of left over. That's why you see the wall in the third picture, but that divergent is clearly new.
You can see in the third picture, it would normally flow to the right, towards the camera. But looks really bad and dried out. The divergent is in the background of the third picture, as it comes around the wall a bit.

Hope the brookies and browns are ok. Water was low enough already.
Who knows why the guy diverted it, and even thought it was a good idea to do it like that and get away with it.