Evening star., 1896-11-03
THE WATER SUPPLY
General Craighilps Report on the
Washington Aqueduct.
OPERATIONS DURING LAST YEAR
Recommendations as to the Ly-
decker Tunnel and Reservoir.
MONEY THAT WILL BE NEEDED

Gen. Craighill. chief of engineers, in his
annual report to the Secretary of War,
tells an Interesting story about the Wash
ington a1ueduct and the efforts being made
to increase the water supply of the District
During the past year" he says, in
Guiding the numerous occasions when the
water level was lowered by the supply be-
ing shut off for the purpose of making re-
pairs CT of removing deposits from the con-
duit the extreme fiuctuation Of water level
in the distributing reservair had range
of but is feet as against Al feet for the
preceding year. This marked improvement
is due to two causes: First the effects of
the removal of deposits from the conduit;
second, from putting the Dalecarlia reser-
voir into service, thereby doubling the re-
serve supply and avoiding the throttling
effects of section of the by-conduit but
s feet in diameter.
Removin. Deposits From the Conduit.
Operations for the removal of deposits
from the conduit and by-conduits in ac-
cor!ance with the provisions of the act
approved March =, 1895. We're carried on
vigorously whenever it was practicable to
empty the conduit without Interfering with
the water supply of the District. The plan
adopted was to open up successive man.
holes along the conduit. erect derricks
operated by horse power over them, and
lower wheelbarrows. each provided with a
tub rigged for hoiSting. into the conduit.
The tubs We're filed by means of shovels,
wheeled to the nearest manholes, hCsted,
emptied and again lowered into the con-
dGit. When the bottom was too rough to
permit wheeling upon it, wheeling plank
We're used and when the water in the
conduit was too deep to permit the Use OF
wheeibarrcws. boats were used instead. BY
these methods Gs,151.E2 lineal feet of con-
duit and by-conduit were cleaned and
S.9i6 cubic yards OF deposits removed
The maximum obstruction by deposits
varied from 12.S to 1,;.4 per cent of the en-
tire area OF the cross section of the con-
dut. After the Dc posts had been removed
the conduit and by-conduts were scraped
and swept and carefully inspected for
cracks.
All cracks We're cleaned out and stop
ped With cement mortar. In all 5.iS6 lineal
feet OF cracks. varying in width from Il
to 1i2 inches, We're stopped. These cracks
were almost without exception longitudinal
ones. and occurred where the conduit rest
ed on embankInents. In order to remove
the deposits from the by-conduit around
the Daiecarlia reservoir, the serious break
of July -. 1880. was repaired by the aid of
q coi1erdam built in water Is feet deep To
give additional protection at this point a
concrete wall - feet long and Go feet
wide, and containing 10 cubic yards of con-
crete, was built inside of the coffertlam,
and 100 cubic yards of riprap reyetment
placed in the vicinity.
Consumption and Waste of Water.
Measurements of the daily and hourly
c0nSiHnp ion and waste of water were made
on June - ard 30, 1S9G, and mean estimate
of the two results gave the daily consump-
tioE as 44.113.5Ii gallons. Based upon an
ustimate OF 2Jp,Ubo consumers of Potomac
water, as given by the assistant in Charge
~ the water deDartment of the District
inns corresponds 10 a per capita daily con-
sumption and waste of IL. gallons Based
upon an estimated total population OF 2S;5,-
Ec i'll the District of Columbia Irrespective
OF their source of water supply, it corre-
spends 10 Jaily per capita of l55 gallons.
fhe great extent to which this water is
wasted is shown by the fact that during
The hours of L 10 ) am. when the con-
sumption Is least. tWo-thirGs as much wa
ter IS used as during the CORRESPONDING
period between / and IL am, when it IS
greatest.
The trunk mains leading from the dis
nlbutinS reservoir into the city are over
taxed. and While the removal of deposits
from the conduit and the raising of the
'iitln Will increase the capacity of the sys-
lem supplying that reservoir. but little
practical benefit will be experienced by
consumers in the city until some method
IS provided tor getting all additional sup
ply of water from this reservoir into the
city.
In