McBreach Probabilistic Dam Breach Modeling - Free Webinar

ICEWaRM will be hosting this free webinar where I'll be discussing the software program McBreach and its application to probabilistic dam breach modeling.  Come join in!  Please note the the webinar start time for your particular time zone.  Starts at 10:30 AM local Sydney Australia time on Wednesday, Nov 6th.  That is 3:30 PM on Tuesday, Nov 5th if you live on the west coast of the USA.  Find your local time.  After the webinar, get your free copy of McBreach and the User's Manual here.

Manage risk by leveraging the power of HEC-RAS through Monte Carlo simulations

Introducing McBreach! Faced with aging infrastructure, limited resources, dynamic weather events, and the uncertainty of climate change, today’s dam owners must manage risk to protect the lives of the public and our built environment. The free McBreach program, quantifies uncertainty and informs better decision making before an event.

“McBreach takes dam breach modelling and analysis to the next level. By complimenting the traditional deterministic dam breach methods, McBreach’s probabilistic approach provides a more meaningful and more genuine way to communicate the potential effects from a dam or levee breach.” says Chris Goodell, Principal Consultant for Hydraulics & Hydrology, Kleinschmidt.

Dam Breach Class Boston, MA May 1-3, 2013

Written by Chris Goodell | WEST Consultants

Hi everyone. For those of you who are HEC-RAS dam breach enthusiasts, I will be teaching a 3-day course on dam breach modeling with HEC-RAS in Boston in a few weeks. The course will be held next to the historic MIT campus overlooking the Charles River and downtown Boston, May 1-3. In this course you'll learn all the standard and some of the not-so-well-known techniques for stabilizing and improving the accuracy of very dynamic and stubborn unsteady flow HEC-RAS models (dam breach models are notorious for this). You'll also learn state-of-the-art approaches to dam breach modeling, including level-pool versus dynamic reservoir drawdown and probabilistic techniques for dam breach modeling. Hope to see you there.

Check here for more information:
http://mylearning.asce.org/diweb/catalog/item/id/78019/q/c=79&t=2116&t=2122

If you can't make this one, the next one is in Denver September 11 - 13, 2013. 

Chris

Probabilistic Methods for Dam Breach Modeling

Written by Chris Goodell, P.E., D. WRE | WEST Consultants
Copyright © RASModel.com. 2010. All rights reserved.
I would appreciate any feedback from you all on this topic. It's something I've been thinking about for a while now. My biggest concern with the current practice of dam breach modeling is the overwhelming uncertainty associated with dam breach parameters. Not only the ultimate breach shape and development time, but things like the initiation mechanism of the breach, the discharge coefficients (both weir and orifice), and the progression rate. The deterministic approach we use leaves a bit to be desired in my opinion. Sensitivity analyses have shown that the breach outflow hydrograph can easily vary by 100% or more, based on the set of parameters used. I've been considering ways to generate a breach outflow hydrograph based on probabilistic methods. The idea being instead of providing our "best conservative guess" for the breach hydrograph, we can produce a 95% (or whatever percent) conditional non-exceedance hydrograph based on both overall peak discharge and also timing. Meaning, this is the dam breach hydrograph that will not be exceeded in peak value 95% of the time, given a dam failure for a given failure mechanism (overtopping or piping). This is done by assigning probablity distribution functions to each breach parameter, then run a Monte Carlo simulation using random assignments (within the minimum and maximum bounds and following the prescribed distribution function) for each breach parameter. Then we can plug the resulting 95% hydrograph (or the associated set of breach parameters to create that hydrograph) into our HEC-RAS unsteady flow model and resume our deterministic approach. At least we have taken the deterministic selection of breach parameters out of the analysis. I suppose at some time, the entire model could be approached with probabilistic methods, but first things first. In fact, HEC is currently working on implementing Monte Carlo simulation capabilities into HEC-RAS for a future release.

I wonder if any state Dam Safety office is ready for this type of analysis for preparing inundation maps for emergency action plans. I think it makes more sense.