The Ordway new era., 1914-03-20

The Ashokan reservoir, from which
the water will flow its 96-mile trip to
the city. is 1873 miles square.
The Catskill watersheds have an
area of 800 square miles. They In
clude the valleys of the Esopus. Ron
dout, Schoharie and Catskill creeks.
1t is estimated that, when everything
is in working order. these sources will
yield an average supply Of 660.000.000
gallons daily.
In the peaceful valley OF the ESQ
pus. where 10 villages once nestled
along the stream, is a natural hollow
that biologists say was an inland lake
in prehistoric times, before some
mighty convulsion of nature opened
the rift through which now flows the
majestic Hudson. This natural basin
Is now the bed of the great Ashokan
reservoir. The principal wall of the
dam ia nearly two miles in length,
and over 200 feet in height, with a
breadth of 800 feet at the base. slop-
ing to width Of 60 feet at the top.
The huge aqueduct Is an under
ground channel of concrete and steel.
ranging in diameter from IL to II feet,
built to last forever and to carry the
water In continuous descent from the
high level of 900 feet at Ashokan res
ervoir to 1856 feet at Kensico, where is
located main storage reservoir. for
maintaining very large store of
water near New York, and delivering
It to the filtration plant at Scarsdale.
1t 10 the largest tunnel In the world.
The water is carried through this
aqueduct wholly by gravity. 1t has n
theoretical slope sufficient to cause
flow at the rate of about five miles an
hour. The aqueduct follows the con.
tour of the land as much as prac-
ticable. curving up and down as well
as sideways. 1t goes down and up
again on the siphon principle. but
never rises above the theoretical slope
called the hydraulic gradient. since
this would involve pumping. .,
Course Of the Aquedust.
Sometimes the route lies through
tunnels, and sometimes 1t bridges
streams. curves around the crests OF
hills. and dips down across valleys.
The general course is southerly from
Ashokan dam, across Rondout valley,
through Waikiki and Plattskill val
leys. and down west OF the Hudson, to
a point near Storm King. which is a
little above Peekskill. Here it crosses
under the river by huge concreted
siphon or rock tunnel; thence 1t
passes through the Peekskill water
shed, crosses Croton lake and valley
In a deep siphon and discharges into
Kensico reservoir; thence on to Scars
dale filtration plant, and to Hill View
reservoir, near Yonkers. from which
Manhattan and the Bronx will be sup
piled; thence 1t continues in pipe lines
to the waters of the East river, cross.
ing above Wards island to the
borough of Queens. continuing to For
est Park reservoir. to supply Brook
lyn: thence conduit will extend
through South Brooklyn and beneath
the bottom Of the Narrows over to
Staten Island. where a distributing
reservoir will supply Richmond
borough. The total length of the works
from Staten island up to the most re-
mote reservoir in the Catskill noun
tains Is 150 miles.
The mtst unique feature of this
aqueduct is the stupendous siphon un-
der the Hudson at Storm King. This
Is feat of tunneling that puts to
blush all the tunnels around New York
city. The subways go down 80 feet be-
low the water. but the Storm King
siphon sinks $50 feet below the sur.
face Of the water and 1900 feet below
the aQueduct gradient, crosses under.
meath the river and then starts on to
New York again, gradually rising to a
point within several hundred feet of
the earth's surface. II this were built
on the air.pressure principle, used in
the East river tunnels. the workmen
would perish from the pressure as
soon as the work had gone 100 feet
under the water. For this reason the
engineers decided to go SO far down
below the river bottom that the tunnel
would be in solid rock and no water
would leak in. thus dispensing with
the necessity Of working under pres
sure from compressed air.
The .Kensico reservoir has been
greatly enlarged so that 1t may serve
as an equalizing and storage reservoir
permitting repairs to the So miles OF
aqueduct above, or even the entire
shutting down Of the Ashokan supply
for two months at time 1t Will hold
a supply for Greater New York for sc
days.