New-York tribune., 1884-12-15
THE NEW AQUEDUC'r.
FEATURES OF rnn GREAT srRucruRE

Mifs ~ hoek iuNktiiiNG=iiVhhs 10 NJ
TURNED thnM infiM NATURAL oouHsfs,
leW persons aside from the engineer aud others
Wh" nave been engaged ~ surveying the line ut
| the new alneduot, aud the contractors who fami-
ailHed themselves with the character of tho work
| 10 be done before putting in their bds
nave any idea of the nature of
the ground through which the aqueduct
IL 10 be constructed. Roughly speaking it may be
said that for seven-eighths of the distance the
aquednct will be tunnelled through solid rock
Most OF this is hard gneiss. Where the rock can
he cut away smoothly and is free from cracks there
VIII be no need of lining Where the contrary is
the case, the interior of the tunnel will be lined
with brick laid in cement. Only about oue-eighth
VIII be open cuts. The aqueduct will be carried
under three streams-thc Harlem, SawmIl and Po-
cantlco rivers This of itself is no small engineer
ing fcat The entire work let on Saturday must be
completed within thrty-three months from the
! time of actual beginning. Ten days were allowed
TO complete the execution of the contracts and
twenty days grace before beginning work, so that
nearly thrty-four months ars given to the job.
DETAILS OF THE WORK.
Sections and b. awarded to Heman Clark of
No. 2066 Fifth-avc. comprise that portion of he
aqueduct lying within the city limits. 1t begins on
the north side OF the Harlem River and extends to
the northern line of the city, distance of about
five miles 1t is divided about equally between the
two sections. Section A was let for 81 ,O51, ,675,
and Section for 81 O06 OGj, total Of 81 147, ,74O
Botn sections are what is known as internal work.
Beginning at the Harlem River shaft will be
driven to a depth of 115 feet below tide-water
Other shafts will be sunk at convenient distances
and the working parties will then begin tunnell-
ing toward each other. The most ap-
proved machinery and plant will be used.
he work will be continued night and day
by the aid of electric lights Grounds
for dumping the aterial taken out have been con-
dcmned, and there is apparently no reason why the
WORK sDould be delayed beyond the allotted time.
The same general style of working the other see
tons, where the tunnel passes through rock, will
Section begins on the Van COrtlandt property,
near the city llnc and extends to Palmerave., just
north of the south (onkcrs station on the New
York CITY and Northern Railroad. On this section,
at ibbetts Brook, where the Aqueduct comes TO
the surface, bOw-Oif and waste weir are to be
constructed to blow into Tibbetts Brook.
Section b'gins nj tho nor II end OF Section and
runs north to a point near the line between Green
burg and Y0nkers. The entire section consists of
rock tunncllinQ.
Section continues from Section and runs north
through rock tunnel the entire distance, ending
near the property of Cyrus W. Field Just above
Ardey station Oh the New-lork City and Northern
Railroad.
Section 6, a short section is one of the most diff
licnt on the route The difficulty to be overcome
of the Sawm River. To effect TINS the river viii
be TEMPORARILY diverted from its present bed
Lreshets of course. must be guarded against
When the inverted tunnel is finished the river will
once more be returned INTO its old bed. -
Section is also short section containing diff
G"hIt piece of work. The aqneduct will cross
tioulds Swamp south of the town of Glenville,
back of Tarrytown. Above the rock are strata of
black mud. docaylng vegetation and blue clay. 1t
will be necessary TO 90 down 10 the rock In order
10 obtain the necessary Foundation.
Section / begins south of what is known az the
coop of the New York CITY and Northern Railroad
ai farrytQwn. he aqieluct will he tnnneled
,c reachsS Here The iawnili River feat viii have
tp hc repeated. On this section are also two heavy
open cuts with two Intervening tunnels of ruck.
sertion belina near the old Sleepy Hollow
nes tu the utoon Dam. The phpe distance that
the aqneinri VIII be- tunnrei through hard tprk
ai an avpiagcsderth of 400 feet HE tfUtoh River
IL iptr hpd iisi below tho present l'h'h
Tho total amount e tho awards fof tho work doc
stiihpd "a r. VI ,uuG
inr WoHk Nol Nlf AWARDED,
Tho rans and specifications mi Section haYenot
iet been dnished but afa IA tho hands of
tho Engineers of tho Aanednet Conn
mission aud the Department oi Public Morks,
aad will bo ready in few days, They aIe
Tor "a gate-house aud bye-pass to bring the water
from above the present Croton Dam and open direct
communication with the reservoir which VIII he
created by the great Quaker bridge Dam when con-
structed The gate-b0use viii be massive slruto-
ure aud involve good deal of expense.
Detailed plans are also nearly completed for that
portion of the aqueduct between the north side of
the Harlem River and the north side of Manhattan
Valley. THIS is also a heavy piece of work
consisting in good part of an III
vertcd tunnel under the Harlem River, and
gradually rising to its proper grade at the Man
haitian Valley. After crossing the Harlem River
the tunnel Is continued through solid rock. From
Manhattan Valley to the Central Park Reservoir
the manner of construction has not been de-
termined on. Various plans are now under consld-
Grafton by the engineers of The aqueduct and the
Department of Public Works. 1t is intended that
all the work shall be com fleIed within thlrty-tonr
months from the present tme Each section vii
be in charge of Il division engineer, with staff OF
assistants. who will be held responsible by Chiei
Engineer Church for strict observance to the
specifications on the part OF the contractors.