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Rock-ramp fishpasses

The rock-ramp fishpass calculation module makes it possible to calculate the characteristics of a rock-ramp pass made up of uniformly distributed blocks with equal transverse \(ax\) and longitudinal \(ay\) spacings.

Schematic of a regular arrangement of rockfill and notations

Excerpt from Larinier et al., 20061

The tool allows you to calculate one of the following values:

  • The width of the pass (m);
  • The slope of the pass (m);
  • The flow rate (m3/s);
  • The depth \(h\) (m);
  • The concentration of the blocks.

It requires the following values to be entered:

  • The upstream bottom coordinate (m);
  • The length of the pass (m);
  • The background roughness (m);
  • The width of the blocks \(D\) facing the flow (m);
  • The useful height of the blocks \(k\) (m);
  • The drag coefficient of a single block (1 for round, 2 for square).

Bed roughness

  1. Larinier, Michel, Courret, D., Gomes, P., 2006. Technical guide for the design of "natural" fish passes, GHAPPE RA Report. Compagnie Nationale du Rhône / Adour Garonne Water Agency.