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Supporting Information
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Table S2. List and brief definitions of 34 flow metrics calculated in this study.
Metric
Definition
MA3
CV in daily flows
MA5
Mean daily flow/median daily flow
MA11
Ratio of 25th/75th percentiles in daily flows/median daily flow
MA41
Mean annual flow/catchment area
ML4
Mean minimum monthly flow for April
ML17
7-day minimum flow/mean annual daily flow averaged across all years
ML18
CV in ML17
ML21
CV in annual minimum flows averaged across all years
MH8
Mean maximum monthly flow for August
MH10
Mean maximum monthly flow for October
MH14
Median of the highest annual daily flow/the median annual daily flow
averaged across all years
MH16
Mean of the 10th percentile flow/median daily flow across all years
FL1
Mean frequency of low flow (25th percentile)
FL2
CV in frequency of low flow (25th percentile)
FL3
Total number of low flow spells (threshold equal to 5% of mean daily
flow)/the record length in years
FH2
CV in frequency of high flow (75th percentile)
FH3
Mean frequency of high flow (3 times median daily flow)
FH6
Mean frequency of high flow (3 times median flow over all years)
FH7
Mean frequency of high flow (7 times median flow over all years)
DL13
Mean annual 30-day minimum/median flow
DL16
Mean duration of low flow (25th percentile)
DL17
CV in mean duration of low flow (25th percentile)
DL18
Number of zero-flow days
DH13
Mean annual 30-day maximum/median flow
DH15
Mean duration of high flow (75th percentile)
DH16
CV in DH15
DH20
Mean duration of high low (25th percentile of median flows)
TA1
Constancy (Colwell 1974)
TL2
CV in the Julian date of the 1-day annual minimum flow
TH3
Maximum proportion of the year (number of days/365) during no
1.67-year floods have ever occurred
RA5
Ratio of days where the flow is higher than the previous day
RA6
Median of difference between 2 consecutive days with increasing flow
RA8
Number of negative and positive changes in water conditions from one
day to the next
RA9
CV in RA8
See the “all streams” column in Table III in Olden & Poff (2003) for the complete list.
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a
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Abbreviations for the metrics are the same as those in Olden & Poff (2003) to maintain
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consistency. SD, standard deviation; CV, coefficient of variation.
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DL16
DH20
DH15
DH13
PC2 (15%)
FL2
MA5
MH14
MA3 FH7
MH16
MH8 MH10
DL17
RA9
SDdis
MA41
Meandis
TH3
ML4
FH6
TL2
TA1
FH2
DL13
ML17
MA11
RA6
DL18
FL3
DH16
FH3
ML18
ML21
RA5
FL1
RA8
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PC1 (33%)
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Fig. S2. Results of principal component (PC) analysis on 36 flow metrics calculated in
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the present study (See Table S2 for full definitions of the metrics). The first and second
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PCs together explained 48.8% of the variation in flow metrics.