Using Google Street View, I found that in October of 2012 the stream was not yet "daylighted", although the orange barrels suggest it was around then that it happened.

If it is really beavers, you should see some indication of a dam/lodge close by. They don't haul all that timber very far :-) And trees felled by beavers are pretty distinct in their appearance........

One of the universities in my city is a Tree Campus USA and has amassed an arboretum-like collection of trees, many of which are very unique, even rare. Urban Beavers have, over the years, done hundreds of thousands of dollar's worth of damage to the collection along a stream front.

They finally had to place steel gates in the culverts to prevent their access to campus, but still had to trap one or two a year. They are incredibly destructive, not only in their tree damage but in the flooding they can cause in the urban setting by their dams.

There is a 2 acre pond behind our property. (Used to belong to us, but we sold it). There is a nice concrete dam/spillway on it. We don't have beavers in this area, but one came in from somewhere, following the flood. He has raised the dam by 3 ft. I kinda get a kick out of walking back there and checking his progress every now and then.

A video making the rounds on Facebook was shot by a motorist watching a beaver haul a tree trunk across a road. Beavers must be pretty strong!

I will just add to what others have said in that work incredibly fast and efficiently in destroying a good sized tree (meaning 6-8” diameter). A smaller one doesn’t have a chance.

We have a small creek down below us. The closest neighbor to the creek had portions of her pasture flood numerous times. While her DH was alive, he broke up many dams and had trappers come out. After he passed, DH and another neighbor broke up 7 small dams but could not deal with a larger one. She had to have someone come out to work on it. Improved the draining tremendously. You can’t ignore the drainage too long.

I walked past again on the way to lunch, and a University grounds worker was there picking up gnawed-off branches. He confirmed that it was a beaver problem.

Look out for the beaver shoes!

We had a beaver in the wet area behind our house. It (they?) chewed off so many young trees, leaving pointy 2 to 3 inch diameter stumps sticking about 6 inches out of the ground. Easily concealed by fallen leaves ... imagine falling and being impaled, yikes! My sister thought my daughter was warning her about beaver footware ... not beaver chews.