The Key West citizen. [volume] (Key West, Fla.) 1879-current, 1934-09-06
Gives Bermuda Good Water
> NEUTRALITY-SUSPICIOUS.

Due to the fact that Key West
is placed in the same status as
Bermuda, which had to depend on
rain water supply entirely, the
following article will prove to be
interesting reading to the people
of this city:
(By w. D. TURNER)
Until 1929 Bermuda had to de-
pend entirely for fresh water on
rain water collected from the
roofs or specially constructed
catchments, or on importations
from New York. In times of long
continued drought these sources
naturally became depleted, and
with many thousand visitors COM
ing annually to their shores, indi-
viduals as we'll as public organiza-
tions were frequently pressed to
secure fresh water.
The small area of the islands,
less than that of Manhattan Is
land, means that there are no sur
(! face waters such as streams and
rivers. Furthermore, the islands
as group represent a porous
coral formation, and no method
had been found to collect under
ground fresh water without con-
tamination from the sea water
which permeates this coral struc~
ture.
Rain Desn't Fluctuate Seasonally
The rainfall in Bermuda does
not fluctuate seasonally, though
there are dry and wet months,
dry and wet years, and as every
tourist knows, dry and wet days.
The total annual rainfall is some
where between 40 and 60 inches,
which is comparable with the
rainfall in New Jersey. SINCE the
soil is quite porous, the water
must drop rather rapidly through
nearly vertical course unit! it
comes to a position where it floats
on top of the salt water. Being
lighter in gravity, it will not sink
through the salt, but will flow
laterally in either direction to-
wards sea level. The natural re-
sistance to flow set up by the
soil will cause a hydrostatic head
n h.
shaped stratum higher in the mid
die and tapering down to sea !eve-
ell at the edges.
Calculations of drainage area
from contour maps and engineer
ing survey. together with the esti-
mates of the probable run-off Of
the area, indicated the amount of
this fresh water lens reservoir
which must be tapped to furnish
any desired quantity of fresh wa
ter. In order to get at the water
at least expense, site was select
ed where the runoff from a rela-
lively large area would be concen
trated in a relatively narrow val
ley.
To tap this water, a trench
about 400 feet long, cutting across
the valley-like swale in the hill
side. was dug down to the fresh
water level, then through this thin
lens to within a few inches Of the
sea water level. 1t intercepted the
fresh water lens for a depth of
about 10 inches. still with trench
bottom inches above sea level.
During the excavation thousands
of tiny springs were intercepted
! which began at once to feed fresh
living water into the trench.
Central Pumping Station
This water was diverted from
! both ends to a central pumping
station in the middle. through
open joint tile laid on the bottom
of the trench on an incline of
about 1 inch per so feet. The
open joints were carefully cover
ed with coarse rock, after which
the entire trench was back-fi!led
and closely packed with coral
sand. Thus any surface water
flowing down the hillside during a
storm would flow over the trench.
or would find its way into the
trench from the surface through
at least four feet of coral sand.
Good Fresh Water
! When the test pumps were
started, the flow of water came
fresh and sweet, and in volumes
beyond the capacity of the pumps
to measure. An analysis of the
water indicated a salt content Of
about 80 parts per million. The
! hardness was found to be up
wards of $50 parts per million, eX
pressed as calcium carbonate. AS
was to be expected, only a small
amount of this hardness was mag
nesium and only a small amount
was sulphate, the hardness nat
urally having developed from the
coral limestone formation.
But since Bermudians are
used to rain water, plant fur
nishing a very hard water would
have difficulty in competing with
the individual rain water systems.
1t was therefore decided to install
a complete softening plant to take
. the water directly from the central