Stream power

Stream power is the rate of energy dissipation against the bed and banks of a river or stream per unit downstream length. It is given by the equation: Stream power is the rate of energy dissipation against the bed and banks of a river or stream per unit downstream length. It is given by the equation: where Ω is the stream power, ρ is the density of water (1000 kg/m3), g is acceleration due to gravity (9.8 m/s2), Q is discharge (m3/s), and S is the channel slope. It can be derived by the fact that if the water is not accelerating and the river cross-section stays constant (generally good assumptions for an averaged reach of a stream over a modest distance), all of the potential energy lost as the water flows downstream must be used up in friction or work against the bed: none can be added to kinetic energy. Therefore, the potential energy drop is equal to the work done to the bed and banks, which is the stream power.