DAM BREAK UNSTEADY FLOW

[Richard Schneider]

I am modeling dam break with unsteady flow. I am confused as to how to input data for the storage behind the dam. I understand the reservoir (storage) can be modeled with x-sections or using volume of the reservoir. Problem I have: is how are either of these methods actually input into the Hec-Ras unsteady flow model?

Dick Schneider, P.E.
Project Manager
KAPUR & ASSOCIATES, INC.
10101 Market Street, Ste C20, Rothschild, Wisconsin 54474
main 715-359-9668 Ext. 4005 | fax 715-359-4844 | cell 715-573-1269
http://www.kapurengineers.com

[Anonymous]

A tutorial for developing the input data for modeling a dam breach with RAS using a storage area to depict the reservoir was published by the State of Colorado a few years ago. Their document can be found at http://water.state.co.us/DWRIPub/Documents/GuidelinesForDamBreachAnalysis.pdf
That document describes how you enter the data for using a storage area to describe the reservoir. An example of the data structure for describing the reservoir with cross sections is included in the example data sets with RAS 4.1 (Bald Eagle Cr.).
The general approach is that the dam is described as an inline structure. If the reservoir is being modeled with cross sections, just continue with them upstream. If, however, the reservoir is being modeled as a storage area, it is described with a storage-elevation table. Then, the dam (inline structure) must be connected to that storage area using the RAS geometric schematic editor. In either case, you can have an input hydrograph to the reservoir.

[Anonymous]

Thanks Mike:
This is extremely helpful

[Dilli]

I am also trying to see Dam Breach scenario to generate flood hydrograph of a mountain glacial lake in eastern Himalaya. It is to study the lake burst flood hazard assessment. Could you please guide me some process on it? Your help would be appreciated. Thanks.

best
Dilli

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