The availability of water will be a critical issue in the future and a better monitoring of water resources is a priority. The calculation of low flow characteristics constitutes a basic requirement of water resources assessment. According to the French water law, the Mean Monthly Annual Minimum discharges (MMAM) is used to summarize and to assess low flow. In fact, other indices can also be used to manage water resources during drought period and a broad range of different low flow indicators are available. This paper intends to review the variety of low flow definitions, indicators and regulatory thresholds
