Skip to content

Fish ladders: Power dissipation

This tool is an aid for the pre-dimensioning of a fish ladder: it allows to calculate the missing value of the four quantities:

  • the fall between the basins (\(\Delta H\)) in m;
  • the flow rate (\(Q\)) in m3/s;
  • the volume of the basins (\(V\)) in m3;
  • the power density (\(P_v\)) in W/m3.

The formula for calculating the power dissipation is then:

\[P_v = \frac{\rho \mathrm{g} Q \Delta H}{V}\]


  • \(\rho\): the density of water;
  • \(\mathrm{g}\): the acceleration of the Earth's gravity = 9.81 m.s-2