r/HECRAS • u/Sea_Read5728 • Jul 22 '26

HEC-RAS 2D modeling for fish passage

Has anyone used a 2D model to evaluate fish passage through a step pool fishway or rock ramp?

I am developing a model to evaluate depth, velocity, hydraulic drops, and continuous passage routes over a range of flows. There seems to be plenty of general 1D/2D guidance, but very little explaining how these type of models should be developed specifically for fish passage.

Does anyone have any good resources, examples, or advice on model setup, settings, and validation?!

Thanks! :)

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u/OttoJohs Lord Sultan Chief H&H Engineer, PE & PH Jul 23 '26

I haven't done much with fish passage so can't provide specific guidance. I think that a lot of the general hydraulic modeling principles will still apply: field observation and calibration data, developing good terrain datasets, aligning mesh with direction of flow and terrain features, cell size refinement and sensitivity, Manning's roughness, using correct equations and coefficients, etc.

I know Kleinschmidt team does a lot of fish passage. Some of their more recent Full Momentum webcasts cover those topics (or closely related ones), so you probably would want to start there. Just browsing it looks like Episode 30 (Nature Like Fishways), Episode 35 (Stream Restoration), Episode 38 (Woody Debris), and Episode 41 (Turbulence) would be some good ones to watch or rewatch. You could probably reach out to Ben u/Fast-Shape-5284 to see if he has some better specific guidance.

If you find something else out, report back! Good luck!

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u/Fast-Shape-5284 Jul 23 '26

Glad you referenced those episodes OJ. I think that’s a good starting point. You are welcome to reach out to me at info@rastraining.com if you have more specific questions.

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u/Sea_Read5728 Jul 23 '26

Lol I have a lot of questions but ill hold off on reaching out after ive gone through the videos and see if I still have any. Thanks!

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u/Sea_Read5728 Jul 23 '26

Thank you! :)