Tag: fluvial geomorphology

Gravel Bar in the Creek

A wavelike bar of loose gravel in the creek.

In addition to clearing out the leaves, the fast flow in the creek created some interesting fluvial features. Example number one is this curious gravel bar that was not there a week ago. The gravel is quite coarse — 2-4 cm in diameter — but it’s extremely loose, which is typically of recently deposited sediment.

It seems likely that the sediment comes from beneath the fallen tree that cuts across the creek just upstream of the gravel bar. The tree restricts the stream flow, forcing the water to speed up, and when the water found it’s way through by cutting under the tree, it had enough energy to excavate a hole under the tree and deposit the resulting sediment just a meter or so away.

Constriction of the stream by the fallen tree focused flow beneath it, digging out sediment and depositing just downstream on the gravel bar.

It’s a neat piece of fluvial geomorphology.

Wandering Through the Creek

Inspecting the creek.

The rapid, snow-melt driven, flow in the creek has receded a little, but it managed to clear out most of the dead leaves that have carpeted the stream bed since the fall. Now that the rocky bottom is exposed, hopefully, we’ll be able to see some more of the benthic fauna that’s been invisible for the last few months.

Washing out the dead leaves has exposed the rocks and rapids.