Evening star., 1896-07-20
ABOUT THE AQUEDUCT
Capt. Gaillard's Report Of Operations
During Last Year.
CONSUMPTION and WASTE OF WATER
Work of Raising the Dam at the
Great Falls.
THE LYDECKER TUNNEL

THE LYDECKER TUNNEL
Capt. d. d. Gaillard. the engineer officer
! In charge OF the Washington aqlsdu:t and
| Its accessories. submitted his annual report
| of operations during the past fiscal year to
| Gen. Craighill. chief Of engineers. today =
During the past year. he says mot in
cluding the numerous occasions when the
water level was lowered by he supply be-
| Ing shut Off for the purpose Of making re-
pairs or Of removing deposits from .he
conduit. the extreme fluctuation of water
level in the distributing reservoir had a
range OF but 1.S feet as against Al feet
| for the preceding year. This marked I'M
provement is due to two causes-first the
| effects of the removal of deposits from the
| conduit: second. from putting the Dalecar-
liza reservoir into service. thereby doubling
| the reserve supply and avoiding the throt-
| tling effects of a section of the by-conduit
but eight feet in diameter. The high ser
Vice reservoir in Georgetown was thorough
| ly cleaned and sixty cubic ya:is Of depos-
| Its removed therefrOm. Operations for the
| removal of deposits from the conduit and
| by-conduits were carried on vigorously
| whenever it was practicable to empty the
| conduit without interfering with .he water
supply OF the District. BY The plan fol-
| lowed. 63O51 Mneal feet of conduit and by
conduit were cleaned and S.94G cubic yards
of deposits removed.
THE maximum of obstruction by deposits
varied from 1878 to 1874 per cent Of the entire
area Of the cross-section of the conduit. All
cracks were cleaned out and stopped with
| cement t-mortar. In all 8. 1856 lineal feet of
cracks. varying in width from one-quarter
| to one and one-half inches. were stopped.
These cracks were. almost without excep-
ton. longitudinal ones, and occurred where
| the conduit rested on embankments The
total cost of removing the deposits. stopping
| the cracks repairing the break in the by
conduit. etc. was s1O.I73.12. leaving a bal
ance of 81. J26. 80 to be turned into the treas
ury.
Extensive repairs were made to the dirt
road. two and One-half miles. between the
club house and Great Falls General
pairs such cleaning out cuverts and
bitches. cutting down bushes and trimming
slopes. were made to the entire road be-
tween Georgetown and Grea: Falls
Consumption and Waste of Water.
Capt. Gaillard says that measurements of
| the daily and hourly consumption and waste
| Of water were made on June % and 30, 1896,
| and a mean Of the two results gave the daily
consumption as A. 1l3.574 gallons. Based
upon an estimate of 255.OO0 consumers of
| Potomac water. given by the assistant
! in charge of the water department of the
| District. this corresponds to per capita
| daily consumption and waste Of 173 gallons.
| bdSsu upon an estimated tOtal pOpulatlon
OF 2SD,OOU in the District of Columbia. ire
| spectiye Of their source OF water supply, 1t
| corr esponds TO daily per capita of l55
| gallons The great extent to which this
| water Is wasted Is shown by the fact that
during the hours of to am. when the
| consumption is least, two-thirds as much
| water is used as during the corresponding
| period between Z and IL am. when 1t is
| greatest. The trunk mains leading from
the distributing reservoir into the city are
| overtaxed. and, while the removal OF de-
| posits from the conduit and the raising of
| the dam will Increase the capacity of the
system supplying that reservoir, but little
| practical benefit will be experienced by
| consumers in the city until some method Is
| provided for getting an additional supply
| of water from this reservoir into the city
| commission of experts appointed by the
| Secretary Of War in November. 1885, re-
| ported that the completion Of the unfinish-
| ed tdnnel between the distributing and
Howard University reservoirs furnished
| the most economical method for bringing
| increased water supply from the reservoir
in Georgetown to Washington by pipes or
| otherwise
Raising the Dam.
In regard to the project of increasing the
| water supply of Washington by raising the
height of the dam at Great Falls. Capt.
| Gaillard says that at the close of the fiscal
| year the dam had been raised to the full
| height for distance Of 394S feet and
I
| total distance of .S25S feet. Cut stone to
| the amount of 974!S cubic yards had been
quarried or purchased. and 4.659 cubic
yards of rp-sap had been brought from
| Seneca TO Great Falls. The dam extends
from the Virginia to the Maryland shore,
crossing Conn's Island. Its total length is
| 2.S17 feet. and its top width feet . inches
in the Maryland channel and feet ) inches
| across Conns Island and in the Virginia
channel. The dam Is to be raised % feet,
| SO that at Its low-water stage the river will
| just fill the mouth Of the conduit To
strengthen the conduit against increased
| Internal pressure when the dam has been
raised the embankments over culverts Iii.
IL and ~ were widened by the addition of
1.667 cubic yards of EARTH A suspension
| galloway, purchased for S1O,245, has been
| In constant use since April. 1896 If or
| dinary conditions of the river prevail until
| winter the dam will be completed during
| the present season.
Upon recommendation Of the chief of
engineers. approved by the Secretary of
War. an officer Of the Corps Of Engineers
was appointed to meet an engineer selected
by the Chesapeake and Ohio Canal Com
| pany to form commission to report upon
the probable damage to the company by
raising the dam at Great Falls The two
| commissioners recommended that 1.-The
canal authorities release the United States
from all claims for damages to the canal
embankment and towpath by reason of
raising the dam two and one-half feet as
authorized by the act Of March 2, 1893, and
l thdI eHC SAteu oldteS pay the estimated
cost of the protection, $4,000 This recon-
mendation was approved by the Secretary
Of War. and the officer in charge of the
| aqueduct notified the general manager of
the canal that he was authorized to pay
the company $4,000 upon the condition that
the trustees should execute a paper re-
| leasing the United States from all claims
for damages on account of raising the dam
and should formally authorize in writing
| on official to receive the sum in question
These papers have not been executed by
the company, and the award is held await
| ing their presentation. 1t is believed that
the balance Of the appropriation vemaining
Is sufficient to complete the dam and
| strengthen the conduit in accordance with
the approved project, and no further ap-
| preparation for this purpose Is recommend
| ed.'
The Lydecker Tunnel.
Capt. Gaillard reviews the work Of the
expert commission which tested the Ly-
decker tunnel conduit, and recommends
that the sum Of $65O,0OO be made imme-
diately available for resuming the work Of
completing the tunnel conduit between the
| distributing reservoir and the new reser-
| VOir near Howard lTDiyorsify and for ha