Breach growth formula (Water Overlay)
Revision as of 11:04, 15 April 2019 by Frank@tygron.nl (talk | contribs)
Breaches can grow when water flows from the virtual external water source into the hydrological model[1].
First, the difference in height of the water on either side of the breach is calculated.
- H = abs( max(0, we - Hb) - max(0, wb - Hb) )
Using the height difference, the breach width increase is calculated.
- ΔB = 1.3 * ((g^0.5 * h^1.5) / csb ) * log10 (1 + (0.04 * G / csb ) * Δt / 3600)
The current breach width is then equal to the last calculated breach width, plus the calculated additional breach width.
- Bnew = Bold + ΔB
Where:
- B = The total calculated breach width, initially equal to Wb.
- Δt = Computational timestep.
- ΔW = The calculated width increase of the breach.
- Δh = The difference between the height of the water columns on either side of the breach.
- fm = Material factor, set to 1.3 (average for sand and clay levees)
- g = Acceleration factor of gravity
- Hb = The BREACH_HEIGHT attribute of the breach.
- Wb = The BREACH_WIDTH attribute of the breach.
- csb = The critical BREACH_SPEED attribute of the breach.
- wb = Current water level at breach.
- we = Current water level at entry area (external or internal).
See also
References
- ↑ Verheij, H.J. ∙ Aanpassen van het bresgroeimodel in HIS-OM: Bureaustudie ∙ found at: http://resolver.tudelft.nl/uuid:aedc8109-da43-4a03-90c3-44f706037774 ∙ (last visited 2019-03-08)