National Water Information System (NWIS) and National Ground Water Monitoring Network (NGWMN) Annual Low Flow and Drought Statistics

Groundwater Annual Drought Metrics -------------------------------- Percentile Annual Metrics -Total duration below threshold: The number of days of the year where flow percentiles are below the threshold. -Longest Duration below threshold: The longest continuous period in a year where flow percentiles are below the threshold. -Total volume below threshold: The volume of days of the year where flow percentiles are below the threshold. -Largest volume below threshold: The largest volume of a continuous period in a year where flow percentiles are below the threshold. -Minimum percentile: the lowest flow percentile in a year. -------------------------------- Percentile Event Metrics -Total drought volume: Annual volume of drought. Note [...]