The Liverpool Standard and General Commercial Advertiser.
Liverpool, Merseyside, England, 1844-06-25 00:00:00

THE WALLASEYPRO RANDD AND THE EVIDENCE
CON.

A pamphlet,* which has just been handed to us, arrives
most opportunely, to enable us to present to our readers,
in a comprehensive form, a description of the actual
nature of the works proposed to be formed upon the site
of Wallasey Pool; the evidence by which they have been
supported, a.,;tl carried through the ordeal of a commit-
tee of the House of Commons, together with that offered
against the passing of the Bill in its present shape. For
our entering upon this duty, the only apology which we
feel it necessary to plead, is the ignorance of the great
mass of the public of the real merits of the project, and
the cast importance of the questions at issue between its
promoters and opponents; which involve no less a con-
siderations than the very existence of this port, and the
secutity of the navigation of the river.
At the risk of being tedious, and to render more in-
telligible the remarks which we shall have to make, and
the evidence which we shall take the liberty of quoting,
we shall offer here a description of the proposed works,
RS given before the committee on the Bill, by the engineer.
Mr. Bendel describes them as consisting of "a large
basin or low water harbour of 37 or 38 acres, with 12 feet
depth of water at low water spring tides, or 20 feet 9
inches below the level of the Liverpool Dock sill. At
the head of the basin is an embankment across the Pool,
which converts Wallasey Pool into a large float, which
may be called a reservoir, or a lake. The area at high
spring tides to the grass line is about 170 acres ; but with
a high tide that would flow over the grass ;ine, it is about
208 acres. The area of what the lake would be, when
the water is lowered down to what is called the perma-
nent level, would be on an average no acres. The plan
also proposes a pair of tide gates of 70 feet opening, the
level of the sill to be 6 feet below the Liverpool datum.
Within the dam an area of 12 acres is to be excavated to
a depth of 19 feet below the permanent level line, 6 to 7
feet below the same datum; that is, an excavation down
to the level of the silt of the great gates to the extent of
12 acres. There is also a small dock close to Birkenhead
connected with a lock of 30 feet. The lock leads to a
small dock, which is particularly well placed, being close
to the leading thoroughfares of Birkenhead. The area
of this small dock is three acres, and it communicates
with the large float and also with the tidal basin by a lock
suitable for the river craft and coasters. The plan further
shows a tidal harbour of 10 acres near Woodside Ferry,
which Mr. Rendel says would be quite sufficient for all
the vessels requiring to beach on Wallasey Bank ; and
would form a harbour for steamers as well as for river
craft."
Such then is the plan of the promoters as explained by
themselves—an outer basin of 37 or 38 acres, with a bot-
tom 20 feet 9 inches below the level of the Liverpool
dock sill ; a twelve and a three acre inner dock, and an

embankment across the mouth of the pool, with tide gates
to make the upper part of it into a float. Let us see then
how it is proposed to work out this plan.

It is stf;ted.:—

" Ist. That the proposed large tidal basin could be main-
tained by the process of sluicing at the depth of 12 Pet
below low water-mark, which operation of sluicing could
be continued daily throughout the year," the great dock
or rather float forming a reservoir for the necessary water.
Upon the successful operation of this sluicing, depends,
of course, the keeping open of the outer basin and the
fate of the whole scheme, for Mr. Rendal states, that
" Unless you could have a large quantity of water to be
passed through this basin, not in the ordinary way of
scour, but rather as an artificial river (that is a subaqueous
river) running through, there would be a difficulty of
keeping open a basin of that size." The following are
his views as to the operations of such sluicing :
" A gentle current produced by the sluicing under the
vessels in the basin will be the means of keeping the basin
clear with the daily operations in running off the water.
The velocity of the water passing from the sluices is to
be 30 feet a second ; and to produce a velocity of two
miles an hour through the basin, that gentle velocity
which will take out the daily accretions, but will not dis-
turb the ground.
" The vessels in the tidal basin are to be the means
of exciting that kind of disturbance in the water, when
the water is in gentle current, which will be required to
carry out the daily accretions ; we can command that
kind of current passing under the vessels from their being
afloat, which will keep the bottom clear of the daily ac-
cretions.' "
Here 111 r. Rendel goes upon the supposition that his

" subaqueous river" will continue in a current under the
upper portion of the water in the basin until it reaches the
river. But upon this point, hear Mr. Page, the value of
whose opinion as an engineer may be estimated by the
fact that his plan for embanking the Thames has been
adopted by the commissioners, appointed by her Majesty,
to inquire into the most effectual means of improving the
a"the
divergeu-ater deliveredfrom
the pointfr m
the metropolis.s
of discharge;" he remarks, " that the idea to produce a
sluices would Mr.tPenadge to saps,
rise
current under water in a basin, and to maintain it, is
something new. My opinion," says Mr. Page, " is,that
to produce any effect by scouring in that basin, it would
be requisite to put the whole quantity of water in the
basin in motion ;" and again he says, " the velocity given
to the water in the basin would be most rapid if let out at
low water. In the London Docks they scour with water
in the lock,—at low water with five feet water in the lock
—and the whole quantity of water is put in motion there,
sometimes to such an extent that you can see the bottom
of the lock, being 45 feet wide ; the mud is carried out,
but not to any great distance, and is raked into the river
by a steam-vessel." He thinks that a river such as pro-
posed (that i- the subaqueous river) would "form a bar,
and that the water would pass out over the bar."
Mr. Vignoles, another eminent engineer, thinks that
the effect desired would not be produced, because the
large body of water which comes with a certain force
through the sluices into the bottom of the basin will soon
be very rapidly diminished, and the effect dissipated ; the
effect will be, he says, to " create a current in the oppo-
site direction, flowing inwards to the upper portion of the
water ; and, setting aside the question that no vessel
during that period would be able to lie there at all,.the
effect would be such a diminution of the whole power,
that it is not likely to flow out at more than a mile and a
half, an hour."
Another eminent engineer, Mr. Walker, after the pro-
posed mode of sluicing bad been explained to him by Mr.
Rendel himself, " does not think that the basin can by any
artificial sluicing be preserved at the proposed depth."
Again, with respect to the time at which the sluicing is
to be carried on, the promoters of the scheme say that
this will be " daily ;" that "as the sluices wi I be daily
run, any 'accumulations will be removed"—that " the
sluicing will go on every day regularly," &c. Instead,
however, of this being the case, it appears that there
would be no sluicing in this great tidal basin during seven
consecutive days of every month, and that there could
not be any discharge whatever during ninety-nine days in
the year. Accumulation, therefore,. must take place
during the seven consecutive days in each month, to re-
move which, additional force of water or. other means
must be employed. It is urged, however, by Mr. Rendel,
in reply to this argument, that on such occasions of sus-
pension of the sewer there will be neap tides, when the
water will not be so much, loaded with mud, a plea which
we leave the reader to take for What it is worth.

It is quite obvious from what we have quoted of the
evidence, that the practicability of this part of the plan is
very doubtful; and such appears to have struck the coun-
sel for the promoters ; for when addressing them in sum-
ming up the evidence, Mr. Cockburn observed—
" But -what then ; supposing the sluicing will not do,
what will be the consequence; we shall have to dredge?"
And then the learned advocate exclaims, " Is there any
difficulty in dredging in this basin more than in any
other? you dredge in almost every harbour in the world,
and we must dredge here ; supposing it should turn out
that Mr. Rendel and Mr. Cubitt are wrong in their own
view of that, we shall have to dredge, and to do that which
in 99 harbours of every 100 in the world they are obliged
to do."
'Here, then, we have the leading feature of the scheme—
the sluicing which was economically to keep open the
great tidal basin, by which such vast advantages were to
accrue.to the shipping in our river,—already abandoned
in despair, or certainly fast tending to such conclusion.
That abandonmeut, too, appears of necessity to involve
also'an abandonment of the dam and of the reservoir,
both of which were devised.purposely for an object, which
it appears willultimately have to be performed, at an ex-
pense, as stated by Captain Manghan, of the London
Docks, of between £20,000 to £30,000 a-year.
In reply more particularly to the engineering objections
urged against the scheme, it is contended by the pro-
moters—
" 2d. That there would not be an entire abstraction
each tide of the whole contents of Wallasey Pool above
the proposed dam. .
"3d. That the abstraction of tidal -water by the pro-
posed works would not injure the Victoria Bar.
" 4th. That the water to be penned up in Wallasey
Pool would, when let out (after half-ebb) scour the Vic-
toria Bar.
"sth. That the turning out of the water would instantly
affect the bar.
"6th. That the proposed .sea-wall would improve the
navigation of the river; and would, by increasing the Ve-
locity of the current opposite to Wallasey Pool, cause a
greater quantity of water to flow up the river."
We will as briefly as we call refer to each of these seria-
tim. With respect to No. 2, " Mr. Rendel says the
water is not abstracted ; but 'if the whole were ab-
stracted, we are giving you back at a time 1,600,000 yards
of water, which is more valuable for your purposes.' "
Mr. Pape. however, we conceive, places the matUr in
its proper light,- in his, reply to the following questions
put to him before • the committee :—" When you have
once penned up the water in Wallasey Pool, and got a
certain quantity in the tidal basin, you have abstracted it
once for ; you do not continue to abstract a fresh
qUantity every tide?' To which Mr. Page answers.
' Unless you allow they water to pass out at such times
that it shall operate on the sea channels of the 'Mersey,
you abstract the whole quantity of water ft'om Wallasey
Pool and the counsel again urges the point,- ' You say
that you take certain quantity from the river, and you
pen it up ; you do not mean that the penning up abstracts
that quantity of water every tide ?' To which Mr. Page
answers; 'To be sure I do. It is a clear case for this
reason—the water, if not penned up: would run out at
every tide.' ".. •
With respect to the injury to be done to the bar at the
Victoria Channel, Mr, Rendel remarks that " the actual
lois of water arising from the works, if you limit the tide
to 18 feet 3 inches, is 2,300,000 cubic yards or tons, and
that the abstraction of that quantity is not a matter! of
importance under the circumstances ;.". and lie f„rther
admits the great importance of the question, and contends!
that the embankment will he " the,
positive good." Bit
against this opinion we set the following Authorities: .
Mr George Rennie is asked if the excluslon of the
water at Wallasey Pool will be inexpedient, to which he
answers :
" The doctrine I have always, in conjunction ulth other
engineers vibe have reported upon this subject, held, is