Environmental flow as a criterion for evaluating the potential of small hydro schemes

Flow regime features, including magnitude, frequency, duration, timing, and rate of change, are of significant interest when estimating the potential for the development of small hydro. Currently, assessment of water availability, biodiversity, and ecosystem conservation is used to classify waterways by environmental objectives, with consideration given to annual water volume and seasonal or monthly flows. This helps in the selection of appropriate hydro generation technologies that reduce impacts and maintain connectivity throughout the network of tributaries in the basins. In this paper, the authors analyse hydrological and geographic features of sub-basins of the Rio Verde in the state of Oaxaca, Southwest Mexico. Selected hydrological indicators are presented of the flow regime, and components of the environmental flows associated with potential small hydro projects are also reported.