Astrid Blom on Incision on the Rhine, Gravel-Sand Transitions, and Vertical Bedform Sorting

Dr. Astrid Blom is a professor Civil Engineering & Geosciences at Delft University of Technology in the Netherlands is perhaps best known for her recent reach and rive scale work, modeling hundreds of kilometers, sometimes for hundreds or thousands of years.  These models explore the long-term equilibrium state of river responses to human modifications and the alternate potential futures associated with different climate change scenarios and management practices.

 Most of her recent work and, as you’ll here in our conversation - the work she is most passionate about – is that actionable – morphological modeling of the Dutch reach of the Rhine that can influence wise and sustainable management.

 And I’ve been interested in Dr. Blom’s work on the Rhine for a while, partially because of its similarity to the Missouri in the US – which is a river of comparable size with comparable human modifications, which is also incising. 

 But I first started following Dr. Blom’s research over 15 years ago – with work she did at the particle scale – with detailed laboratory work on the vertical mixing processes in bedforms composed of a wide range of grain sizes.

So we talked about both of these scales.  

 We mostly talked about the Rhine, because the river’s natural template, the long history of human modification, the reach scale incision, and contemporary management efforts on that system are so interesting.  

 And we covered some fundamental processes at that scale, including how gravel-sand transitions evolve on engineering and geologic time horizons on a river that size, the impacts of incision on a large, multi-use, waterway, and some of the management practices targeted to mitigate these impacts.

 But we also downscaled a little to talk about her early lab work…because it really has affected the way I look at bimodal rivers and gravel-sand transitions.

Links to Dr. Blom's papers are on the podcast website (link below).

This series was funded by the Regional Sediment Management (RSM) program.

Stanford Gibson (HEC Sediment Specialist) hosts.

Mike Loretto edited the episode and wrote and performed the music.

Video shorts and other bonus content are available at the podcast website:
https://www.hec.usace.army.mil/confluence/rasdocs/rastraining/latest/the-rsm-river-mechanics-podcast

...but most of the supplementary videos are available on the HEC Sediment YouTube channel:
https://www.youtube.com/user/stanfordgibson

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