Evening star., 1896-02-12
WASHINGTON AQuEDucT
Capt aaillsrd's Report of of0psrations During
the Month of January.
The Water Was Turbid for TWENTY.
seve. Day "a Break 1.
the Channel.

Capt. Gaillard has made a report to the
chief Of engineersi Of operations on the
Washington aqueduct, from which 1t ap-
pears that during the month Of January
the height Of water on the gauge at Great
Falls varied from 1855 feet to 15l feet.
The condition Of the water as regards clear
ness, he says, was very unsatisfactory
during the greater part Of the month. Ac-
cording to the scale for recording the con-
dftion, the numbers ] to Z, inclusive, corre-
spond to very turbid water; to IA, to
turbid; 10 to 2l, to slightly turbid, and
% to SO. to clear water. During the month
the water at Great Falls was very turbid
fifteen days, turbid seven days, slightly tur-
distributing reservoir effiuent gate house
curing the same period the water was very
turbid twenty days, tlrrbid five DAYS. slight
ly turbid one, and clear five days
at is necessary to state, in explanation of
this table," says Major Gaillard, that a
period of single month does not show
accurately the effect of the reservoirs as
settling basins, owing to tne yery different
rates at which the reservoirs and the river
change their condition; yet, in spite of this
and in spite of the inaccuracies which nm.
doubtedly exist on account Of the different
personal equations OF the three Observers
the table shows very clearly the small
amount of sedimentation which occurs in
cold weather from the time the water
leaves Great Falls until it passes into the
mains at the distributing .seryoir"
A Break i'm the Channel.
On January "a, at about 1880 o'clock. a
break about eight feet in width occurred In
the nine-foot channel Of the protecting
works Of the Dalecarlia reservoir about 40
feet above the head of the tunnel under
Brooks HILL Through this break the en-
tire discharge Of the channel, about thirty
cubic feet per second, was flowing. The
work of repairing the break temporarily
was commenced as soon as practicable, and
al. how through 1t was completely checked
by noon or the same day. Permanent re-
pairs were completed before the end of the
month. Capt. Gaillard says the break was
undoubtedly caused by muskrat holes
through the embankment. On the morning
OF January % it was discovered that all
of the discharge Of the fve-foot channel
OF the protecting works (Which discharge
however, was small at the time) was escaD-
ing through the bottom and under the
bank at a point about $50 feet above the
east end of the Mill Creek dam This out
flow was quickly stopped temporarily, and
permanent. repairs were made before the
close of the month
careful investigation, Capt Gaillard
says, disclosed that the trouble was due to
the fact that blasting operations, when the
channel was constructed, had shattered the
sandstone under the bed of the channel
anu pciiLltlcu tHe water 10 escape through
the shattered rock into the contiguous
seams and cracks. During the month the
fence around the 9th street pipe yard was
repaired; the wooden fiume, 14O feet in
length, at waste weir No. was completed;
the two new iron gates to replace broken
ones in the gate house at Great Falls were
put In operation; the old picket fence at the
westerly approach of tie Pennsylvania ave-
nue. bridge across Rock creek was replaced
by a new one. and repairs were made to a
portion Of the Conduit road on the Dale
carlia division.
Cleaning the Conduit.
The work of removing the accumulation
Of deposits in the conduit was continued
during the month. and the cleaning of the
Great Falls division was completed from
the gate house at Great Falls to manhole
No. 20. On the Dafecarlia division the total
distance cleaned was i.61S feet. and the
amount of sediment removed was ATS cubic
yards. The total distance cleaned on both
divisions during the month was ASS feet,
and the total amount of sediment removed
was S51 cubic yards. No cracks were dis
covered in the conduit. The total length of
conduit yet to be cleaned Is three miles.
Work on the project for raising the height
of the dam at Great Falls was suspended
December IA for the winter Authority has
been given to obtain stone for completing
the dam by contract in case it shall be
found that this method is the most economt-
cal.