The Sun.
London, England, 1856-12-03 00:00:00

1,000,000 cubic feet.

" The bottom of the reservoirs would be two feet
above Ordnance datum, or at the level of the ebb tide at
2:41 hours after high water, that being the period when
the discharge of sewage into the river would cease.
"The level of the overflow weir would be 16i feet
above datum, and the mean depth of the reservoirs
would be 14 feet. The reserv,ir on the north side would
cover about 10 acres, and contain about 6,000,000 cubic
feet when foil ; that on the south would cover about 4,'2
acres, and contain about 2,750,000 cubic feet when full;
so that the average daily flow of sewage during dry wea-
ther would about half fill the reservoirs in eight hours.

" In order to arrive at a more accurate idea of the
time and mode of discharging the sewage from the reser-
voirs, I have obtained au abstract of the quantity of rain
which fell last year, as observed at this office. From this
it appears that there were 226 days in that year up oi
which there was no rain, 90 days upon which there was
less than 1-10th of an inch, and 21 days upon which
there were rainfalls varying in depth between 1-10th and
1-sta of an iacb, making 337 days upon which less than
1-sth of an inch of rain fell, and 28 days upon which
that quantity was exceeded.
"Upon the 226 dry days the reervoirs would, as
already shown, be on the average only half full at the
end of eight hours; therefore it would be not only uli-
necessary, but also impossible, to discharge any portion
of their contents into the river during the last hour of
flood-tide ; because the tide would during that period be
above the level of the sewage in the reservoir, and the
tide would then be allowea to flow into the reservoir,
diluting its sewage, and raising its level to that ot high
water in the river. The discharge of sewage would on
those 226 days commence immediately after high water,
andewould be completed within 21 hours, by which time
the tide would have ebbed below the bottom of the
reservoir. Upon the 90 days of minimum rainfall it ap-
pears that, after making the necessary deductions for the
amount of evaporation, absorption, and the time occupied
by the rain waters in flowing from remote portions of the
district to the point of crded, the reservoir would not be
more that; about two-third. full, and therefore the period
of discharge would ou those 90 days also take place only
during the first 22 hours of ebb tide. Upon the 21 days
the reservoir would probably be nearly filled during
the 8 hours, and the discharge would then commence
1i hours before high water. Upon the remaining 28
days of heavier rain the discharge would take place at
earlier periods, varying with the amount of rain that bad
fallen.
"The reservoirs, as at present designed, will there-
fore always contain a sufficient amount of reserved
space to hold the metropolitan sewage, estimated as
being due to the anticipated increase of the population
and water supply in future ages, and produced within
eight hours ; taking also into consideration the unequal
low of that sewage during different portions of the day.
The reservoirs might, however, be added to hereafter,
from time to time, without difficulty or disadvantage, if
considered necessary ; and this mode of enlarging them
—by adding a second basin—would be preferable in an
engineering point of view to now constructing one basin
ot increased area. Ido not, however, recommend any
enlargement of the reservoirs beyond the dimensions now
named, in order to inciiide within eight hours the rain-
fall due to the 28 days per annum, because to do this
would spread the sewage for 337 days over an unneces-
sarily large space, while on the 28 days it would be
considerably diluted, and the storm overflows into the
river would on some portion of those days necessarily
come into .action at higher points in the river.
"Since September last, when I prep.,red a design
for carrying the lower portion of the outlet+ sewer on
the north side of the Thames in a direct route across
the mouth on Dagenham Gulf to point B, I have ascer-
tained that a company has been formed and an act ob
tamed last year for the conversion of this gulf into a
dock, and it is stated that preparations are now being
made to effect that object. I have now, therefore,
diverted the northern (Jutted sewer round the north side
of the gulf, instead of across the entrance. This altera-
tion has somewhat increased the length, diminished the
fall, and necessitated a corresponding enlargement of the
sewers, which, coupled with the deepening of the reser-
voir, has in ceased the estimate beyond what is due to
an extension from point B to W.
"The drainage fr the high and middle level areas
on the north side of the Thames would still be discharged
by gravitation, and the lifts and pumping power already
provided on both sides of the river would remain the
same as originally designed fur discharging at point A.
"The total estimate for the metropolitan drainage as
now designed will be 2,836,6001."
In reply to Mr. Turner Mr. BAZILGETTE stated that
the level of the Thames 21 hours aftr high water would
be plus feet above Ordnance datum, and the bottom
of the reservoir 2 feet above the Ordnance datum ; that
he had made careful experiments at Deptford Creek with
those results ; that there might be a slight variation at
point B*, but that, practically, there would always be
sufficient difference of level to insure the discharge. In
reply to Mr. Deulton he said the plan was not well
adapted to exension, but that its extension could be
economically carried out by starting from Barking on
the north ride, and Woolwich on the south side ; about
four miles of sewer on the north and three miles ou the
south would be rendered entirely useless. And, in an-
swer to other hon. members, he said he did not appre-
hend much deposit, but would propose to remove any
that might Le made by barges; he thought that no nui
sauce would arise ; that with regard to the sewer above
ground there were few canals in tads country which had
not iron equeducte, and no difficulty had ever
arisen with these. With regard to the effects of
cold the sewage was always warmer than the atmo-
spheric air, that it would flow fcom two to three
miles per hour, and would be from three to four
hours pas-ing through the aqueduct; that it would not
daring its progress have time to freeze, and in respect to
the flat bottoms of the reservoirs a flat bottom was not
subject to an equal flo ,v, as there would always be a
large stream. As to the capitalisation of working ex-
pensee, it would be tile same as in plain B, hut the struc-
tural expense would be greater by 103,0001. ; that it
would cost the same money to extend the sewers to the
sea whether plan B or plan 13" was adopted, but that in
the case of plan B* 103,0001. more would be lost—and
that he believed that plan B was better than plan B",
notwithstanding Cept. Bursters report, and that cast
' iron pipes bad already been tried in smaller sewers, and
had proved to be uninjured by any chemical action of
the sewage.
Mr. LESLIE said that on the grow's' of the expenses
of making long lines of fla--bottorned sewers, and on the
ground that reservoirs of 10 acres on the north side and
4? acres on the south side to pond back the sewage for
eight hours in every tide would be contrary to the act
of Parliament, he should move that the engineer's report
etthe Ist of December now just read be not received.
lie
considered the plan to commence, progress, and ter-
minateaizo
of the
tinheeBr:ovvr. It conime need error in regard to., the
te,oouttittiol6o,osr9t cubic feet. fefeete.t
erie In all previous reports the size of
h
sewersside for,
aPirispchsarte"atha3(sl 2tncucbailecufelaettepderoinuitrhiuetel,a'rntl
jotnwtalise
south 2,257 feet per minute. Itßp eyprrtohngejri planu:s progressed inoa' and
error, rruoo nrp o thesbee-1
cause it divided the metropolis into two distinct parts,
north and south, whereas
act the board in assessi by
the 170th section of the
noltthhe sums to be charged upon
alodpulKledii,uoen them. The
the city and other parts metropoliseodrainage,
the
ba
evne
erfier,-
gard to the annual value of the
case of expenditure on worksproperty, and also, in the
the several
ecall
t hpeaartttsecnft
derived front suet) expenditure h
metropolis affected thereby. R: she
ion
of the members for the Surrey
as only 32,487 ;
Dent side to what
would be the effect of the proposed
exanict Kentw side was 616,6358
acreage on the Surrey and Kent wast 45,542,
populs- '
lionwhileon iht
hlVeI iSurreyddles
on the
Middlesex side 1,745.601 ; the rent on the Se;
Kent side was 2,257,8001,, while on the Middlesex side
ald
it was 8,894,1391, As he read the act, the whole of this
11 millions odd was to be taxed together, and not
in
twe separate sums of 2 millions and 9 millions. He had
no doubt the whole of the additional work would exceed
a million of money. Ile objected to four it in 11 tt-bots
towed eeweis going into the reservoir causing deposits
and becoming title-locked. All the sewers that were