Flood
Recurrence
Intervals
83
171
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PROBLEMS
The
following
questions
are
based
on
the
rating
curve
(Fig.
1)
and
streamflow
data
for
Cache
Creek
(Fig.
2)
1.
Using
the
data
in
Figure
2,
calculate
the
recurrence
interval
for
Cache
Creek’s
streamflow
for
the
years
Peak
Discharge
(cms)
1980-2002.
Once
you
have
calculated
the
recurrence
intervals,
fill
in
your
answers
below
and
in
Figure
2
(round
your
answers
to
once
decimal
place):
1980:
_34
years
1981:
_1.3
years
1982:
Z.T
years
1983:
1
vears
1988:
2
vesrs
Determine
the
Flood
Frequency
Curve
for
Cache
Creek
by
plotting
the
“Recurrence
Interval”
against
“Peak
Discharge”
on
the
chart
below.
Draw
a
best
fit,
straight
line
through
the
center
of
your
plotted
data,
trying
to
have
an
equal
share
of
data
points
above
and
below
your
line.
Flood
Frequency
Curve
for
Cache
Creek,
1980-2002
e
:
e
I
——
1
2
3
4
5
6
78910
20
30
40
50
60
708090100
Recurrence
Interval
(years)
