HILDEN DORF.- Fluctua twns in Water-l evel of Artesiam Wells.
ART.
491
the
XLII.- Fluctuations in the Water-level of some A'l1esian Wells in
Ghristck1.lrch Area.
By F. W.
HILGEN DORF,
D.Sc.
r, 1916; received by
[Read before the Canterbury Ph~lo8opl~~cal In,st~tute, 6th Septembe
December, 1917.]
Ed~tors. 30th December, 1916; iS8ued separately, IOtA
the
IN 1896 Hutton recorded the fluctuations of two artesian wells at
of
one
on
tions
observa
the
ed
continu
Chl'istchurch Museum. * Speight
copies
the wells in 1910,t and since then ha,s taken occasional readings, 1911
of which he has kindly given me for the purposes of this paper. In
I took a series of readings on a 340 ft. well at Lincoln College, fourteen
s ever
miles south-west of Christchurch,t and have taken monthly reading
urch
since. From 1912 till the present time Mr. A. D. Dobson, Christch a
e,
Merival
at
well
ft.
217
a
on
tions
observa
City Surveyor, has taken
his
illJle and a quarter north-west of the Cathedral, and l!as given me
Hutton
the
from
grant
a
by
aided
I,
and
Symes
readings. In 1914 Mr.
depth
Fund, erected a continuous-record machine on a well of uncertain
(see
al
Cathedr
the
of
est
north-w
miles
three
about
on Papanui Road,
here.
this volume, p. 493), and the readings of this well have been used _in
The graph shows the fluctuations in the static level of the water
these four wells. The comparatively small variation in the three Christwell
.church wells as contrasted with the large variation of the Lincoln
affords conclusive proof that the wells in the neighbourho~ of Christchurch have a relatively constant source of supply, while the well at Lincoln
of this
has a relatively intermi ttent one. The most reasonable explanation
•
artesian
lirch
Christch
the
of
supply
main
the
that
is
feature of the graph
supplied
is
well
Lincoln
the
wells comes from the Waimakariri River, while
which
chiefly by the rainfall direct, or by percolation from ~e Selwyn River,
rains.
heavy
III Its middle course flows only during or after
There are two facts that might be used to controvert this explanation
were the evidence of the present graph not so overwhelming.
and'
(1.) The Christchurch wells do, as was pointed out by Hutton
their
is
rainfall
the
that
but
rain,
Speight, respond very rapidly to a day's
ss
chief source of supply is rendered improbable by their relative steadine
the
either
of
e
influenc
no
be
can
There
.
during the dry years 1914-16
rainfall or the Selwyn River that would not be more distinctly felt at Lincoln
Trans.
than at Christchurch, as will be shown by a glance at the map in
kept
N.Z. Inst., vol. 44, 1912, p. 146. If either of these in1luences, then,
steady
well
Lincoln
the
kept
have
should
they
the Christchurch wells steady,
the
too, and therefore we are driven to conclude that percolation from
supply.
urch
Christch
the
of
source
Waimakariri is the chief
tion is
(2.) The second observation that does not support this supposi
of the
flow
the
or
level
the
e
influenc
not
do
ariri
that floods in the Waimak
* F. W. HUTTON, On the Behaviour of Two Artesian Wells at the Canterbury
Museum, Trans. N.Z. In.'3t., vol. 28, 1896, p. 654.
t R. SPEIGHT, A Preliminary Account of the Geological Features of the Christ·
church ArteSIan Area, Trans. N.Z. Inst., vol. 43, 1911, p. 420.
in some .Artesian
iF. W. HILGEID>ORF, Fluctuat ions ill the Level of the Wa.ter
142.
Wells in the Christchurch Area, Trans. N.Z. Inst., vol. 44, 1912, p.
Transactwns.
492
Christchurch wells, as has again been noted by Hutton. But, since the
Waimakariri is flowing always, It is probably losing water by percolation
always, and not only during floods; and the rise of water-level may be so
toned down by passage through miles of gravel as to be unrecognizable
by the time it reaches Christchurch. This is rendered probable by the
behaviour of the well at Belfast, six miles from Christchurch, as described
by me, * where a river rise of 8 ft gave a well rIse of 5 III The absence
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lit ~" l,th 'I } 0""
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'Illhes
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lye ~ ~ 4
i'I
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M] JI Sp!lv Ja Mr IlIyJu Sp Nv Ja IIIr My JI Sp IIv.ld Mr My JI Sp rh Ja Mr ,., JI Sp ftv .la IDr My JI Sp Itv Ja II'r My JI Sp ~/2
ISIO
19/1
I~IZ
1913
1~14
1315
1916
Graph showmg fiuctuatlOns
ID
statIc level of four artesian wells in or near
Christchurch.
of response of Chnstchurch wells to Waimakariri floods, then, is not
necessarily at varIance With the eVidence of the graph, that the Waimakariri
is the chIef source of the ChrIstchurch arteSIan water-supply
In 1862 or 1863, at R. Taylor's brewery, on the SIte of the present Normal
School, some pipes were driven into the ground to form a staging After
a time water was found flowing from these pipes, which thus formed the
first artesian well in Christchurch. The City Council then sank a 2 III
pipe at the corner of Tuam Street and Ferry Road to a depth of 81 ft, and
* Loc
c~t.,
p. 158.
HILGEND ORF .-Fluct uation s
in JJ'ate'1'-level of A'1'tesUl'n Wells.
493
1864,
a good flow resulted. This well was completed on the lOth February,
time
this
well,
another
started
Council
and on the 15th February, 1864, the
J.
Mr.
to
d
indebte
am
I
tion
informa
above
the
For
Square.
al
in Cathedr
years
fifty
about
for
s
onward
date
this
Lothian Wilson, of Kaiapoi. From
it was
thousands of private wells were sunk in the Christchurch area, and
suffered
ft.,
80
and
ft.
40
of
depths
to
soon found that the earlier ones, sunk
wells
a serious and continuous fall in their static level. Deeper and deeper in
,ft.
400
to
down
strata
earing
were then sunk, tapping various water-b
was viewed
depth. The fall in the static level of large numbers of wells
but the
upply;
water-s
the
of
failure
possible
a
ng
very seriously, as indicati
evidence of Hutton and Speight's long-period observations on the Museum
level
well shows that the fall has been checked, if not arrested. The static
in
was,
of the 190 ft. well abov(> Hutton'R datum
.
9 ft. 8 in. ,J Average f aI) per year, 3.5 m.
1894
_.
5 ft. 3in.)
1910
5 ft. Oin.fAverage fall per y~al', O·DIn.
1916
fall
At the time Hutton made his observations he estimated the vearlv
tw"entyla~t
the
during
reduced
greatly
been
has
rate
its
at 5·5 in , so that
two years.
Why the wells have ceased to fall is not certam. There are good grounds
of
for believing that it is due to natural causes connected with the supply
in
But
sea.
the
to
rainage
under-d
the
and
ariri
Waimak
water from the
wells,
1909 the City Council sank, within the area of an acre or two, four
similar
three
and
these
from
and
,
stratum
ft
80
the
to
r,
8 in in diamete
From
wells sunk in 1912 water is pumped to supply nearly the whole town.
this
and
ceased,
entirely
almost
wells
private
of
sinking
this date, then, the
ting
fact may have so importa nt a bearing on the static level of the pre-exis
longwells that the matter is not suitable for discussion until a new series of
period observations have been made.
ART.
XLIII.- Note on the Fluctuation of Water-level in a Okristckurck
Artes~an Well.
By L. P.
SYMES.
1916; 'I'eceweO. by
[Read before the PhilosophioaZ Inst'ttute of Oanterbury, 2nd August,
Ed",tors, 30th December, 1916; issued sep'l'l'ately, 10th December, 1917.]
writers, notably Hutton, Speight, and Hilgendorf, have disoussed
vel
the Chnstchurch artesian system, and have shown that the water-le
River
rIses every evenmg, that It rIses WIth ram, and that the Waimakariri
These
has no apparen t influence. Button also described a "Sunda y rise."
or less
results were founded on intermi ttent observations made at hourly
in confrequent mtervals. To obtain more definite knowledge the writer,
ous
junctIon WIth Dr. lIJ.lgendorf, set up an instrum ent to make continu
i,
Papanu
at
well
isolated
An
veL
water-le
in
ions
fluctuat
records of the
asceryet
not
is
depth
its
nately
not in use, was selected, though unfortu
the
tained. This note deals with some of the results obtained through
MANY