WATER & SOIL - These are not the droids you are looking for.

F.3 Analysis and results
tatively placed with
Region on the basis
the hydrograph for
to the Taieri River
Paerau and Loganburn at Paerau (Figure F. l0)
Southland rivers (Figure F.9).
-
than the
(see section 3.1.6). Plots with similar shape were overlaid to
form combined plots.
Flood frequency data thus plotted were found to lie in
three groups:
(a) peak lake inflows and Shotover floods;
(b) Southland floods and the pomahaka floods;
(c) East Otago floods.
Group (a) closely resembled the South Island West Coast
data
Canterbury data
(see
these two groups
were
I plots of the data
they
Support for the differentiation of the lake inflows and
Shotover from the other sites studied is also given by the
hydrographs (Figure F.8). These show that floods are frequent
and occur at the same time for each catchment. Since
the floods result from the same storms, it is an argument
for each catchment having a similar shape in its flo;d frequency
curve and for grouping them together. Also shown
in Figure F.8 is the hydrograph for Cieddau at Milford.
Finally,
-
the hydrographs (Figures F.8, F.9 F.lO) show
that the majority of large floods in the decade l97l-19g0
o-ccurred in the years 1978-1980. Figures for F.g, F.9, F.l0
also show the wide extent of the October l97g flood which
was the largest of the decade for many of the records.
F.4 Gonclusion
and the Manuherikia at Ophir (1971-1980) wirh rhe
regional clrves (Figure F.7) shows the difficulty in determining
which curve is appropriate. Central Otágo is ten_
graphs (Figures F.8, F.9, F.l0)
because the frequency of minor
ach region but not across region
ïable F.3 Co-ordinates fiom regional frequency curves.
O2.33/O
o5/o
olo/o
ozdo
o5o/o
orodo
ozoo/o
S.l. West
Coast
1.OO
1.24
1.45
1.64
1.89
2.O8
2.27
Southland
1.03
1.46
1.82
2.16
2.61
2.94
3.27
sth
Canterbury-
Otago
0.97
1.51
1.99
2.48
3.17
3.73
4.33
Acknowledgements
D. McMillan in compiling the
Miss K. Vollebregt in anatysing
owledged.
References
Fitzharris, B.B.; Stewart, D; Harrison, W. l9g0: Contribution
of snowmelt to the October l97g flood of the
Pomahaka and Fraser Rivers, Otago. Journal o!
Hydrologlt (NZ) I9(2): 84-93.
Gilbert, D.J. 1978: Calculating lake inflow. Journal o!
Hydrologlt (NZ) I 7(I): 3943.
Ministry of Works: Hydrology Annual. (No. 3, 1955 ...
No. 17, 1969). Ministry of Works, Wellington.
t2Á Water & soil technical publication no. 20 (1982)