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Submerged slot formula

Submerged slot diagram

Excerpt from Larinier, M., Travade, F., Porcher, J.-P., Gosset, C., 1992. Passes à poissons : expertise et conception des ouvrages de franchissement. CSP. (page 94)

Larinier (1992) suggests the following equation:

\[Q = \mu b H_1\sqrt{2g \Delta H}\]


  • b the slot width in m
  • H1 the head on the slot m
  • μ the discharge coefficient (equal to 0.65 by default).

The discharge coefficient μ may vary from 0.65 for a sharp-edged slot to more than 0.85 when the slot profile is rounded.