hi Christopher, I'm a teacher at a community college, and I enjoy my conversations with the students regarding uncertainties and risk, it's when I assign work that students can take on to vary the parameters to see how much design outcomes vary, it is also the time when I cite web sites (NTSB) and other forms of technical reports so students can see how important it is to strengthen soft skills (technical writing) and witness how important it is to continue to get involved with their respective COP's to continue to learn from others, and yes that watershed delineation is interesting to perform, we varied it a couple of times (the DEM) so we can see how dam break flood extents will vary, check it out,
https://www.sciencedirect.com/science/article/abs/pii/S0309170809000815and thank you for your input,
Humberto
Professor, East Los Angeles College
Adjunct, Cal Baptist University
Civil Engineering
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Humberto Gallegos Ph.D., P.E., M.ASCE
Professor
California Baptist University
Riverside CA
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Original Message:
Sent: 08-30-2022 01:44 PM
From: Christopher Seigel
Subject: Being Certain That Your Work Is Uncertain
In my own line of work, I sometimes teach junior staff how to delineate drainage areas (rainfall subcatchments) in predominantly urban environments. Oftentimes, new staff will get caught up trying to decide something like "does the left side of this 400 foot street drain to the intersection to the north or the south of the street?" in an area that is 100 acres in size. They are usually surprised (and even a little skeptical) if my answer is "it doesn't really matter", until they better understand the purposes of what we are modeling the area for, and better appreciate the limitations of things like the rational method and how peak runoff works.
This is an example of trying to be realistic about the inherent accuracy limitations of the particular form of modeling that we work on. With this comes an understanding of what applications this model will work for, and what applications it will not work for.
I would be interested in learning from others about where in their own work they can be inexact, and where, in contrast, high degrees of precision are required.
I'll leave this thread with a quote that a colleague uses in his email signature, and another that I remember from one of my engineering textbooks:
"all models are wrong, so honest modelers report their uncertainty first and foremost"
"Structural Engineering is the Art of molding materials we do not wholly understand into shapes we cannot precisely analyze, so as to withstand forces we cannot really assess, in such a way that the community at large has no reason to suspect the extent of our ignorance."
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Christopher Seigel P.E., M.ASCE
Civil Engineer
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