Evening star. [volume] (Washington, D.C.) 1854-1972, 1895-08-09
WASHINGTON AQUEDUCT
Report of Major Knight of the Operations
During the Month of July.
Break In the Conduit and It's Repair
Raising the Great Falls Dam
Testing the Tunnel.

Maj. Knight las made a report to the
chief of engineers of operations on the
Washington aqueduct and accessories dur
ing the month of July. During the month
prior to the break in the by-conduit of the
receiving reservoir, the level Of water IN
the distributing reservoir varied between
six and twenty-five inches below it's level
when the reservoir is full. After the
break, the supply to this reservoir was cut
of before being restored. and the level of
the water fell to seven feet nine inches be-
low the full stage but at am, July 81
it was five feet and six inches below that
stage. At the same time, the water in the
receiving reservoir was six inches higher
or five feet six inches below it's overflow
lire.
The Break in the Conduit.
About 3 o'clock am, July 81, Thomas
Harper discovered a break in the by-con-
duit of the receiving reservoir and gave
an alarm. By 3:45 m. Waterman Fergu-
sen had taken the necessary measures to
prevent loss of water in the distributing
reservoir, which would have occurred by
its flowing back through the break. Infor-
nation of the break and warning as to the
necessity of economy in the consumption
of water was given to all government de-
partments the officer in charge of public
buildings and grounds, and by the COOP
through displayed bulletins. At pm. the
next day the flow Of water into the dis
tribnting reservoir was resumed, the wa
ter having, by that time, fallen there six
feet Mai knight says that both reser-
voirs are now slowly filling, and that be-
fore many days the normal level of water
will be regained.
Raising the Great Falls Dam.
During the month quarrying cutting and
transporting Of stone was continued IN
execution of the project for increasing the
water supply of Washington by raising the
height of the dam at Great Falls. Major
Knight says that about $500 blocks of
stone will be required for this work. OF
this number 444 have been cut and brought
down from the Seneca quarry for storage
between the canal bank and the Maryland
channel near the dam About 200 more
blocks have been Quarried. Bids have been
received for the construction OF suSpen-
sion cable way and necessary towers and
engines for. use in raising the dam. The
operating span will be about 1900 feet in
the clear The lowest bid for the work
was $1o,245. The award of the contract
has been deferred pending action on e.
port concerning the necessity for protect
ing the canal tow path and its slopes be-
tween locks 20 and 81, for distance of
about two miles Immediately above the
dam A barge will be built for carrying
stone across the Maryland channel, and
preparations are being made for reopening
the government quarry on the Virginia
shore at the dam to obtain granite to
crush for concrete work.
Testing the Tunnel.
The approved project for testing the
Lydecker tunnel conduit contemplates
pumping out the tunnel closing the four
easterly shafts and filling the tunnel with
water. In regard to this work Maj.
knight says: Pumping was continued
with one pump at Champiain avenue and
two at Howard University shafts until
July % and "a, respectively. having ceased
at Rock Creek and Foundry Branch shafts
June and 10, respectively. the masonry
closure of Rock Creek shaft was finished
June 80; that of Foundry Branch shaft,
July Is, and that of Champlain avenue,
July %. At Rock creek it has a minimum
thickness of nine feet, consisting of one
two-ring brick arch and one siX-ring brick
invert with concrete between. July 81
there were nineteen feet six inches of ;eep-
age water resting the top of this ma
scnry. At Foundry branch the masonry
has the same thickness and consists Of a
two-ring brick arch, then two feet of con-
crete, then six-ring brick invert and
four feet of concrete. On this at the close
of the month there were fourteen feet of
seepage water. At Champlain avenue
eleven feet of masonry consists of a two
The water seeped into the shaft in such
quantities as to make satisfactory work
on the six-ring brick invert extremely
difficult. Hence, this invert was not plac-
ed. The concrete was covered with twenty
three feet six inches of water at the close
of the month.
This water will assist the masonry to sus-
tain the upward pressure when the tunnel
is under pressure by exerting a downward
pressure of from six to ten pounds to the
square inch. At Howard University shaft
the brick curb has been carried up sixteen
courses with Flemish bond true to the
curve of the base of the standpipa for
which it is now ready. Put-lock holes in
the brick lining of the shaft were closed.
Slowly Filling With Seepnge Water.
1.-The tunnel is now slowly filling with
seepage water. AS soon as the Potomac
water can be spared it will be used to
gradually reinforce the seepage water. In
quiries have been made as to level of wa
tiers in wells in the vicinity of the conduit
line. Measurements and computations of
amounts of masonry and other work re-
quired to complete the tunnel, exclusive of
shafts, have been finished. The probable
operations for August are to continue plac-