The Hawaiian gazette., 1896-07-03
Total Rainfall

Total Rainfall. 625 ,6'4, 742, S57
The greatest interest attaches to the
underground discharge. How much of
it can be approximately accounted for?
A given volume can be fairly closely ap-
proximated as the output of the arte-
sian we'll system in use; and a further
volume more accurately estimated by
actual "cubic-second" measurements
that have been made of certain springs
and streams nothing is better calcu-
lated to show the utter uselessness of
casual observation than the compari-
son of the amount of water discharged
even by a big stream with the total
rainfalD.
Gallons.
Total underground
~ Estimated output
OF 209 wells .43 800 000.00
springs. 4s, 49,, $50 600 s5.9S, 200
Balance 1853 81. .144
All of the water from the measured
springs is flowing into the sea. 1t in
cludes waters used for mechanical pur-
poses (rice mills, etc.), but not any
waste from rice fields or the kind. AL
though only 85,932, $50, 900 gallons are
actually accounted for, there is a fur
Their large discharge taking place un-
der our eyes, from rice fields, banana
plantations, and unmeasured visible
springs. We are persuaded, however,
that a great body of the underground
discharge occurs further out, and un-
der the sea level, either through the
coral in shallow water, or, forced by
the pressure of the mountain head, out
beyond the reef The locality of Pearl
Harbor affords ample illustration of
this.
Although the underground discharge
is visibly occurring in localities dis
tant from each other, the topography
of the two chief surface water sheds in
dicates the direction of main discharge.
the surface of the lands showing what
were the directions of the lava flows
and the consequent strata structure of
the underground. The great water
shed converges to Pearl Harbor The
next important one includes the short
er dip of the lands, formed from the
great range, towards Waialua, supple
mented by the Waianae attitudes, but
it is apparent that the great body of
the underground discharge seeks the
sea around Pearl Harbor.
According to the showing that has
been arrived at it is seen that, in round
numbers, some 200 900, 5000 gallons of
water are leaving the island without
rendering service. How can the pow
er-equivalent of this water be estima-
ted? In the first place, one-fourth of
the total amount may be taken off as
the portion of discharge from and in
Guiding Nuuanu avenue to Makapuu
Point, and this may be set apart to
meet the most eXorbitant demands that
the future expansion of the city. with
its coming sewerage system, and ex-
tensive garden cultures, can make. This
amount is not only more than can be
required; it is, we believe, more than
the actual discharge of that region.
Another one-fourth is deducted to COW
er the unmeasured wastes occurring
along the windward and around the
Kahuku sides of the island. The Wal
mea and Kawailoa streams and springs.
which yield large volume, are includ-
ed in the total of measured waters.
Some small portion of these wastes are
conducted over rice fields, but rice, it
may be said in passing, is a crop that
makes small actual use of the water
given to it, as it wastes by seepage, and
this seepage, moreover, is most
threatening foe to public health of
city, as it gradually fills up land
depressions and forms permanent
swamps. We have then 0,O0G, 900, 900
gallons of water remaining which is
discharging into the sea, probably
three-fourths around Pearl Harbor.
and one-fourth of it in the vicinity of
Waialua. The question is repeated.
How can we express the power
equivalent of this huge balance of vast
ing water?" The great plantation at
Eva suggests one mode of expression.
If we allow 100000 gallons of water
(this volume is equal to a flow of one
cubic foot per second to about fifty
acres, and is based on actual irrigation,
work. to one acre of cane, then the
total volume is capable of irrigating
10000 acres. At five tons of sugar per
acre, this area is equal to 100000 tons of
sugar. But as the cane requires one and
one-half years to mature, the power
equivalent is reduced to $4,000 tons
But setting aside all niceness of calcu-
lations and allowing for all future de-
mands of the city, of small cultures,
ETC., there appears to be water-power
going to waste annually upon this Is
land, which may be represented safely
by $4,000 tons of sugar. And there are
available lands which are capable of
putting into service this vast waste of
water energy.
One observation made as a result of
this investigation, whose showings may
be far from the. actual, is the apparent
fitness of the water supply to the area
of cultivatable lands. 1t appears that
there is an abundance, ample for every
sanitary need and expansion CT the city,
for the increase of small industries and
for raising the sugar production of
Oahu to, speaking safely, three times
its present proportion.
WALTER MAXWELL.
Director Hawaiian Experiment Station.