The daily union. [volume] (Washington [D.C.]) 1845-1857, 1854-01-22
From me senuasl.

III is evidently OIL lnc huch
Creek scheme. and quotes Colonel Hughes's report ia
regard to the difficulties OF bringing from the Great
Falls 1t also quotes Captain Megs's report, taking
passage in which he speaks OF the costly nature OF the
works he obliged 10 devise for bringing water from
the Little Falls, an open canal necessarily placed near
the level OF the river and exposed to lis floods and APP
plying very unfairly 10 the project from the Great Falls
which has been, under the authority vested in him by
Congress- adopted by the President. aud which, owing TO
the great descent of the river its point Of begin
ming is in very short distance, out OF reach OF its
freshets.
Had the writer been disposed quote fairly he would
have taken the following passage
The traveller, ascending the bank of the Potomac
from Georgetown 10 the Great Falls, would conclude that
unpromsing region Tor the construction OF an
aqneduct could not be found Supported by high walls
against the face OF jagged and vertical pecpces, con-
nua danger of being undermined by the foamlng tor
rent which bos below, the canal is monument OF the
energy and daring OF engineers The route seems
occupied and mode OF BRING the water except by
iron pipes secured the rocks laid in the bed OF the
canal seems practicable. Such my impress
sions and though knew that in this age with money
any achievement OF engineering was possible, thought
the survey would be needed only to demonstrate by
figures and measures the extravaganza of such work.
% But when the levels were applied TO The ground,
found to my surprise and qualification, that the rocky
precIpces and difficult passages nearly all below the
line which, allowing uniform grade, would naturally
be selected Tor our conduit and that, instead OF demon
stratng The extTavagance OF the PROPOSAL became
ties and afordng no opportunities for the exhibition OF
any trIumphs OF science or skill.
. Indeed the nature of the country is such present
less than The ordinary difficulties TO be expected in such
undertaking There enyera unnels OF average
length OF only 220 ee but three bridges, and only
Of these large enough 10 make its erection object of
ambition to engineer. The line runs on the slope Of
the hills. which is generally moderate, and such
afford choice of ground Il has been located
form the surface and requires very light excavation and
ing maps, is very direct liDe OF remarkably easy
curves, much less crooked than the line COM
PEELED to adopt on Rock creek, though longer; with
BRIDGES and those, except in instance, less
costly The distance, IN right line from the beginning
OF the conduit 10 the north end oil the Georgetown
aqueduct, is eleven and ,hreequarer miles; the length
OF the conduit is about fourteen miles including the
reservoirs and the pipe, to this same point"
And then he would not have been able to cay " these
facts and admissions sufficient 10 prudent men
10 pause"
Since Colonel Hughes's report was made, the expe.
rience of Boston and New York has shown that much
larger supplies of needed in those north
cities. than be calculated upon Boston using in.
stead OF 2Si gallons daily 10 each inhabant,
days nearly 80 gallons,
The question of supply is fully discussed in Captain
Megss report, and sufficient given for adopt
ing plan which, at moderate expense, gives very
ample II is there shown that an aqueduct, to make
the best of Rock creek, including the Of dsrbu
ton to public buildings, navyyard, &C., with proper
storage and reservoirs, will cost, not $4,000, but
and a.quarter millions
This difference results from providing larger reservoirs
larger aqueduc and nearly $780, 600 worth of pipes TO
the various public establishments, which were not pro-
vded for at all in Colonel Hughess estimate
But, after all. the supply from Rock creek is rela.
BILE, and those who have lived on it's banks, George
town, will testify that during the past il has been
almost los, n the pebbles OF its bed.
Another party desires TO lay an iron pipe from the
falls. thinking that this will save great expense in
grading.
They do not make the distinction between delivering
water in a reservoir at height not much below the
source, and drawing it of the level OF Pennsylvania
for example. lhree-feet pipe from the Great
Falls would deliver on Pennsylvania avenue a vast
quantity water but much on Inc attic floor of the
Capitol.
Exclusive OF digging and covering from Frost single
three-feet pipe will cost quite much the brick
arch Of the aqueduc nine feet in diameter and will not
deliver one-naih much water.
The digging and grading necessary 10 lay one pipe AT
such depth in the rocky soil to be secure from frost
will cost FAR more than these suppose the TOP
OF the pipe be three feet under ground as it must be 10
be from frost, il will require six feet of excava
lion And 1t would take more than nine three feet pipes
to deliver at the distributing reservoir the same quantity
the nne-feet conduit.
Indeed to supply reservoir in Washington. one hun
dred ahd oTiyhve feet above tide, by iron pipes viii,
The quantity OF water will be delivered by the
nine feet aquedue, would cost nearly nine times as
much. These assertions will SURPRISE but little cal.
cuahos and study OF The subject will bring any engineer
to this conclusion.
New York built her squeduct OF masonry, and very
extensively Boston did the same. more economical
plan, after several years OF study and comparison of
projects from many engineers Albany has since follow.
ed the example. Is il likely that all the eminent engi-
consulted these great works have been wrong as
to materall
Is worth while build, those cities have all DONE
a work which in ten years will be Insufficient and re-
que enlargement or entire rebudingi
Are these people that iron is liable 10 rust
What iron pipe laid under ground will be capable of
resisting the pressure OF water hundred years hence
Masonry squeducis properly constructed and covered
thousand years old still continue TO supply The cities
which built them,
word as 10 The danger OF injury to the Washington
squeduct from the Great Falls by floods
The dam crossing The river will be the only part of il
within reach OF the foods. The moment the conduit
leaves the dam passes under the canal and them at
depth oil twenty feet buried in rock excavation il
proceeds TO the first tunnel When it comes from under
the hall at the end OF the tunnel has passed the Glea,
Falls, and the river is some sixty feet below H.
IL Is perfectly safe from the rivers foods The pas.
cage quoted in the article which called thus forth re-
lated TO the project for work al the Lue Falls which
was open canal outside Of the present one and ne
cessay exposed to the violence Of The river and there
fore requiring, for safety, very expensive construction
NJ.