Draft PPS18: Renewable Energy
E24. During operation of a small hydro scheme, water is abstracted over a short stretch of the river. Hydroelectric schemes do not pollute or consume water and usually return the supply to the channel from which it was abstracted. Water that has passed through a turbine is often improved by aeration and is free of debris.
Annex 1 Small Hydro Planning Issues: Hydrological Considerations