Effects of Bridges on River Scour

The bridge that carries Route 381 over the Youghiogheny River has been there a fairly long time. At least in some form or another. We have often wondered if the placement of the piers have affected the river scour at this site, as there is a downward trend in the habitat quality at this particular site. The pier is directly in front of the scour and may deflect the following water from directly hitting the scour.

A bridge pier in front of the a river scour. The Youghiogheny is flowing from the right to the left.

The other side of the bridge pier from the previous photo.

Just downstream of here, one can see a lot of the grasses are bent in the upstream direction, indicating that there’s some sort of eddy operating here. I’ve seen similar eddys at the downstream end of river scours before, typically after a series of rapids.

So many interesting questions about scour hydrology!