Table 5 Indicators of hydrological alteration (32 IHAs).
Group | Group description | Hydrological indicators |
|---|---|---|
Group 1 (12 IHAs) | Magnitude of monthly flow | Average flow of each calendar month |
Group 2 (11 IHAs) | Magnitude and duration of annual extreme flows, and the base flow condition | Annual minimum 1-, 3-, 7-, 30-, 90-day means Annual maximum 1-, 3-, 7-, 30-, 90-day means Base flow index |
Group 3 (2 IHAs) | Timing of annual extreme flow conditions | Julian date of annual 1-day minimum Julian date of annual 1-day maximum |
Group 4 (4 IHAs) | Frequency and duration of high and low pulses | Number of low pulses each year. Mean duration of low pulse with each year. Number of high pulses each year. Mean duration of high pulse with each year |
Group 5 (3 IHAs) | Rate and frequency of flow changes | Rise rate. Fall rate. Number of flow reversals |
