I love meandering rivers. This is a short post with some (I think) great images of meandering rivers and oxbow lakes.
In my previous post Google Earth and a 5 minute book review: Geology illustrated I reviewed one of my favorite coffee table books: Geology Illustrated by John S. Shelton.
The last view in that post was as close a perspective replica of Figure 137 in the book as I could get using Google Earth, showing the meander belt of the Animas River a few miles from Durango, Colorado.
What a great opportunity to create a short time lapse: a repeat snapshots of the same landscape nearly 50 years apart. This is priceless: 50 years are in many cases next to nothing in geological terms, and yet there are already some significant differences in the meanders in the two images, which I have included together below.
For example, it looks like the meander cutoff in the lower left portion of the image had likely ‘just’ happened in the 60s, whereas at the time the imagery used by Google Earth was acquired, the remnant oxbow lake seems more clearly defined. Another oxbow lake in the center has nearly disappeared, perhaps in part due to human activity.
Below are two pictures of the Fraser River in the Robson Valley that I took in the summer of 2013 during a hike to McBride Peak. This is an awesome example of oxbow lake. We can still see where the river used to run previous to the jump.
And this is a great illustration (from Infographic illustrations) showing how these oxbow lakes are created. I love the hands-on feel…
The last is an image of tight meander loop from a previous post: Some photos of Northern British Columbia wildlife and geology.
Do you know of any references that look at the in variability of channel aspect ratio along its length or as analyzed as a function of meandering over time?
Danny, great question!
I don’t have my Geomorphology book at hand (sadly’ still in a box in my basement since my last move), the only thing off the top of my head is this classic paper:
The hydraulic geometry of stream channels and some physiographic implications, Leopold and Maddock, 1953
I’d check with Zoltán Sylvester (twitter, blog).