14 June 2011
Two riverbank collapse videos – don’t miss these!
Posted by Dave Petley
Regular readers will remember that I visited the Lower Murray river in South Australia earlier this year to spend some time looking at actual and potential riverbank collapses. Riverbank collapses are hugely under-researched, and indeed the amount of data and imagery available on collapse events is poor. A few days ago Ron Dorn highlighted these two amazing riverbank collapse videos from the Missouri River to the south of Bismarck in North Dakota, USA. The first takes 30 seconds or so to get going, but do hang on in there. It is worth it:
The second is smaller but still quite dramatic:
These are quite small failure events, but are really quite interesting.
Dave Petley is the Vice-Chancellor of the University of Hull in the United Kingdom. His blog provides commentary and analysis of landslide events occurring worldwide, including the landslides themselves, latest research, and conferences and meetings.
That was really interesting to watch! Just like that, the tree and the stump fall into the river. Thanks for posting.
In the winter of 1972-73 it was raining a lot, and the large new residential subdivision, Westlake Village, CA, was in full progress, and where I lived, downstream on the local river that drained the Village and surrounding areas north, I was curious to see how the riverbank was holding up to erosion as a result of all the new construction. So upon my return from working that day, I wandered on down to the river to have a stroll and observe, as it had been raining hard off-and-on all day and was still raining lightly. The river was sooo full !!! And flowing really fast !!! Next door was a place that had lots of old abandoned cars and equipment, and one windowless ’54 Ford 4door with 4 flat tires was parallel parked right on the edge of the river bank, and I’d been keeping track of how the water was growing closer day-by-day. A week ago the water was a good 6 feet away, yesterday it was about 1 foot. Today it was 2 feet past one front wheel !!! After a few minutes I gave up on any dramatic event occurring right then and wandered further along, but shortly something perked my consciousness and I quickly went back, and just in time to see the Ford, as I approached to 20 feet away, slowly tip toward the river and the sandy banking totally give way !!!, then it hesitantly but gracefully began to float !!!! I was surprised it didn’t sink immediately ! It floated a good 50 feet downstream but didn’t move as fast as the current, for water was backing up behind it and lifting the rear end, with the front end dragging on the riverbed a little. When it got astride the big sycamore tree that overhung the river, where a large deep bowl shape had in previous years been hollowed out by fluid turbulence around a huge root going across the river, it did a slow nose-dive down, like a submarine submerging !, and completely disappeared !!! And the most mysterious thing of all is I never ever saw that car again !!!!! I expected the Ford was still in the bowl, as it didn’t show up further downstream when I went looking for it right then, or later on. Nor was it in evidence on any subsequent daily searches further downriver. I was so surprised to see the big bowl have no car in it when the water finally subsided enough that the car should show ! My conclusion was it went all the way downriver and into Malibu Lake ! , never to be seen again ! But it was quite a rush and a surprise to be granted the spectacular spectacle of witnessing its aquatic ballet demise and magic disappearing act.
Thanks for sparking this remembrance !
I’ve worked as a raft guide on the Arkansas River in Colorado for a few years, and it has given me tremendous respect for the power of the river. I have no doubt that your car tumbled along the river bed as far as the current could take it.
Thanks for the videos, they are awesome.
[…] On The Landslide Blog, Dave has posted two riverbank collapse videos. They are great images of a common, but rarely seen process. https://blogs.agu.org/landslideblog/2011/06/14/two-riverbank-collapse-videos-dont-miss-these/ […]
[…] See blog post here […]