National Republican., 1883-02-13
LETTERS TO THE EDITOR.
THE WATER SUPPLY.
In me Edifor

To The Editor.
The queries submitted by " Subscriber" in
your issue of the sixth instant, under the
head of "Want of Water" can best be an
swered by brief statement.
The conduit built by Con. Meigs for the
supply of the city extends from its head on
the Maryland shore of the Potomac, a few hun
dred yards above the Great falls, to the re-
cciving reservoir, thence to the distributing
reservoir, at Drovers rest, just above George
tOwn--a distance in all of about twelve miles.
From the latter the mains carry the water
for the supply of the city.
These mains consist of two 4S-inch iron
pipes, which may be seen where they cross
Rock creek on Aqueduct street.
These mains are tapped before reaching
the bridge for the supply of the high service
reservoir near Seventh and High streets, and
below it for the supply of the standpipe ON
Sixteenth street road.
A few feet below the head of the conduit
the dam commences, crossing portion Of
Falls island and extending TO the lower end
of Conn's island, having total length Of
about 100 feet.
Between the western shore of Conn's island
and the Virginia shore there is no dam, and
between these two shores the great volume of
the Potomac flows. At ordinary tide, or when
the water just flows over the dam, the nine
feet conduit is about one-half full and affords
fair supply of water to the city. The act of
July 10, 1882, contemplates the extension and
completion of this dam across Conn's island to
the Virginia shore, and the raising of the en-
tire dam a sufficient height to keep the con-
duit full at all stages of water.
Asit is, however, the river frequently gets so
low that the water will not ruin over the DAM
At such times the supply in the city becomes
scant, and to remedy this the expedient is re-
sorted to of building temporary dams at the
head of Conns island and closing up the
openings between certain small islands so as
to force an additional supply into the channel
leading TO the conduit. These dams are COM
posed of earth, broken stone, and brushes,
very temporary in their character, and have
to be watched, repaired, or rebuilt at every
low water stage, and this has been going on
more or less ever since the conduit was built
and will have to be continued until the dam
is completed.
One of the results of this attempt to force
the current is that at q certain distance down
the island an eddy or counter current is
formed along the eastern shore of Conn's
island which runs up stream with consider
able velocity and around its head into the
Virginia channel. Between Conn's island
and the Virginia shore are large number of
islets on mats, as they are called up there,
which have been built up since the dam was
made, and OH points formerly above water,
chiefly by the accumulations due to the
slackening of the current by the dam of
earthly matter, dead leaves and branches,
drftwood and grass, which, in periods of low
water, when the current is most sluggish. and
especially in the hot season, more or less
effect the purity and wholesomeness of the
water delivered to the city.
Pressure upon the mains depends upon
elevation and power applied by artificial
means, and not upon increase of volume, as
some otherwise intelligent people conceive.
Hence the raising of the dam sufficiently to
keep the conduit full would have scarcely
any apprecabe effect upon the pressure. The
filling of the mains and keeping them full by
an ample supply at the head would, however,
have n very material effect upon the amount
available for distribution. WAT.