Tag Archives: erosion

If a tree falls in a river …

If a tree falls in a river, does it make a sound? During the recent high water event on the 20th, another big tree fell into the river upstream of the bridge. Long time observers standing on the Big River Bridge at MP 5 on the Middle Fork river may have noticed the upstream west bank has been steadily eroding for at least the last decade, and probably longer. The west bridge pier and abutment are adjacent to the Granite Creek confluence immediately upstream of the bridge, but so far they do not appear to be threatened by the river channel migration. This tree will likely be transported down river and lodge itself on the bank during the next period of high water flow which is almost certain to happen this fall or next spring.


After living on the edge for years, this tree almost certainly fell during the October 20, 2016 high water event. This photo was taken 12 days later.


A couple months ago in September the tree was seemingly clinging to nothing but air.


The tree on the left is the one that just fell, and was undercut, but did not lean. Logs jammed at the east bridge pier from the fall 2015 storms may be contributing to erosion of the bank on this side.


A view of the fallen tree showing it’s proximity to the Granite Creek confluence. All of the trees in the cluster at the confluence will probably be gone in a few years.


Closeup of the root ball that pulled out of the bank

This is not the first tree to fall recently. In 2011 another tree in the same location fell after leaning over the river for years.

In 2011 a tree adjacent to the one that just fell was leaning toward the river


And in November 2011 it fell into the river. There was no extreme high water event around this time so it must have literally reached it’s tipping point. The standing partner near it’s base would last 5 more years before itself succumbing to continuing bank erosion on the west side upstream of the bridge.