7812

• UCREFRP Catalog Number: 7812
• Author: Many
• Title: Rivers, Studies in the Science, Environmental Policy, and Law of Instream Flow
• USFW Year: 1990
• USFW - Doc Type: Rivers
• Copyright Material: YES

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HYDROLOGIC REGIONS
FIGURE 5. Mean August cfsm comparisons of
eight hydrologic regions.
gage sample size (n = 3) and the wide fluc-
tuation of August discharge data charac-
teristic of that region created a high degree
of data variability. The wide fluctuations
in this region are caused by severe August
rainfall events, including hurricanes that
historically do not occur as intensely in the
Mt 3
95% COMMENCE WERVVALS
FOR EACH REGION
IC„
I n=3
rr2
rt3
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111 I1

other regions. Additional unregulated gage
data from this region would be required
to draw statistical conclusions regarding
August flow regimes. Unfortunately, no
additional gage data for unregulated
streams appear to be available at this time.
A model II one-factor Analysis of Vari-
ance (ANOVA) was performed among all
eight regions (49 gages), the Scheffe F-sco-
re results of which indicated that signifi-
cant (P < 0.05) differences exist among at
least some of the regions. Paired ANOVA
comparisons among the regions indicate a
pronounced difference between the moun-
tain windward region and nearly all other
regions (Table 4), despite the use of the
Scheffe test, which is very conservative (i.e.,
it makes it difficult to find significant dif-
ferences). Significant differences among
other pairs of regions were not pro-
nounced.
Although a total of eight hydrologic re-
gions were identifiable based on physical
basin characteristics, only two region sets
could be statistically distinguished. Figure
5 and Table 4 reflect that drainages on the
windward sides of mountain ranges form
a separate hydrologic group from the other
seven regions and suggest that 1,200 feet
elevation is close to the critical mean basin
elevation, separating mountain from lower
elevation drainages.
A comparison between mountain wind-
ward and other regions (mountain lee-
TABLE 4
ANOVA F-score comparisons among eight New England hydrologic regions
Mtn.
wind Mtn.
lee Int.
west Int.
cent. Int.
east L. I.
Sound Gulf of St.
Maine Law.
Mountain-Windward -
Mountain-Leeward 13.02,
Interior-West 3.23, 0.51
Interior-Central 9.82, 0.44 1.22
Interior-East 10.72, 0.02 0.60 0.25
Long Island Sound 2.28, 0.55 0.01 1.23 0.63
Gulf of Maine 2.02 0.23 0.01 0.72 0.29 0.01
St. Lawrence 1.71 0.90 0.07 1.64 0.98 0.03 0.07 -
Source df Sum squares Mean squ are F-test
Between groups 7 0.971 0.139 18.755
Within groups 41 0.303 0.007
Total 48 1.274
'Significant at 95%.
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