Examination of Witnesses (Questions 17419
- 17439)
Ordered that Counsel and Parties be called in.
17419. Chairman: Could I remind everybody
that coffee will be available at round about quarter to 12 today,
when the Committee has been suspended to enable Members who wish
to do so to get to Prime Minister's Question Time. May I take
the opportunity to announce that the Committee will visit Woolwich
tomorrow and any Petitioner is welcome to attend. If they would
like details on the visit, perhaps they would see the clerk.
The Petition of the Fairfield Conservation Area
Mr Andy Lyon and Ms Jacqueline Bradshaw-Price appeared
as Agent.
17420. The first petition we are dealing with
today is the Fairfield Conservation Area Residents Association,
and the representative is Mr Andy Lyon.
17421. Mr Lyon: It is a dual presentation
from myself and my colleague Jacqueline Bradshaw-Price.
17422. Chairman: I will come back to
you in a second but first I am going to ask the Promoter to outline
the case.
17423. Mr Mould: You are going to hear
today not only from these Petitioners but from three or four other
Petitioners who have a common cause. They are interested in the
additional provisions you are considering in this session in relation
to the so-called H.A.M. and Wick sewer in East London and the
environmental impacts of that. It seems to me sensible if I spend
a little more time than I would ordinarily to outline that background
to you, so that the Committee sees the context in which these
Petitioners appear before you.
17424. We are concerned with the H.A.M. and
Wick Lane sewers. "H.A.M." is an acronym for Hackney
to Abbey Mills sewer. On slide 031 we can see the location.[1]
The H.A.M. sewer is running in a south-easterly alignment just
to the west of the Blackwall Tunnel Northern Approach Road. That
is shown as a red line and the Wick Lane sewer is in green adjacent
to it. Both of the sewers connect to the low level 1 and 2 sewers
running east-west and you can see that those sewers get to the
Abbey Mills Pumping Station, run by Thames Water as the statutory
undertaker. We can see the Manhattan Building, a listed building,
and Wrexham Road and Baldock Street. The members of the Fairfield
Conservation Area Residents Association are situated around the
residential area there and they also have members within the Manhattan
Building itself.
17425. The Crossrail alignment—you can
see the dotted line—has to contend with a number of existing
constraints, in particular the River Lea, which is to be seen
just to the east of the Blackwall Tunnel and also the northern
outfall sewer. The effect of that is that it is necessary for
the tunnels in this location to pass at a level which brings them
into conflict with both the H.A.M. and the Wick Lane sewers.
17426. That was a matter that was dealt with
in the original bill. Could we put up page 32, please.[2]
The original bill scheme was that both sewers should be diverted
along this alignment to outfall at the Abbey Mills Pumping Station.
The discharge would be pumped at this location because it was
not possible along this alignment to provide a gravity-based sewer.
That was the arrangement in the bill scheme. It would have been
a single 2.4 metre tunnel, diverted along the line which you see
there. It would have involved the operation of a number of work
sites—and they are shaded beige—and it would have
involved works beneath this area, the Sortex site (the old Sortex
factory), Bow Generating Power Station, and also coming into close
proximity with a residential development scheme operated by Bellway
Homes Development.
17427. As a result of further detailed works,
it became clear that the volumes of flow, particularly after storm
conditions, in relation to this proposed diversion would be substantially
higher than had been originally predicted and that it would be
necessary to increase the capacity of the pumping station at Abbey
Mills in order to cope with that. The pumping capacity that would
be required would be equivalent to pumping the volume of an Olympic-sized
swimming pool approximately every five and a half minutes and
a power supply equivalent to that used by 1,000 houses. You can
see from those simple facts that it would involve considerable
operation and energy costs associated with the lifetime of the
sewer and the pumping station..
17428. It was in the light of that factor, principally,
that firstly Thames Water petitioned against the bill scheme,
their argument being that it was unsustainable and environmentally
unfriendly in terms of the energy cost and energy loss. In the
light of that, the Promoter decided that he should investigate
alternative options, particularly those that would involve the
need for companies to rely on a gravity solution.
17429. That led to the investigation of alternatives
and that was dealt with as part of an option exercise. Could we
put up, please, 29104B-001.[3]
An options report was undertaken in order to investigate the possible
options as alternatives to the bill scheme. At page 002, the penultimate
paragraph in the Executive Summary page, you will see that the
upshot of that report was that five options were investigated,
and the fifth of those options, extended southern gravity sewer,
was identified as "the preferred solution which should be
promoted as an Additional Provision to the Bill." It continues:
"This option diverts the sewer from a site close to the Manhattan
building to a site currently occupied by a McDonald's restaurant
near Payne Road. The route of the tunnel between these two points
takes it under Grove Hall Park in which an intermediate shaft
will be located."[4]
17430. If we can turn on to 29104-035, we see
the line of that option.[5]
That is the option that is now before the Committee as a proposed
additional provision. We can see the Manhattan building and the
beginning of the diversion. There is a curve in the line. We can
see Grove Hall Park and the proposed intermediate safety access
shaft and the Payne Road site of the McDonald's restaurant, the
end of the proposed diversion. Members of the Committee who were
here yesterday will recall that this was the option about which
the London Borough of Tower Hamlets made a number of detailed
submissions, but they made clear that they accepted that this
was the most environmentally sustainable and acceptable option
for the necessary diversion of the H.A.M. and Wick sewers. They
accept the need to divert those sewers in order to enable the
Crossrail scheme to proceed and they have accepted as a matter
of principle a number of undertakings from the Promoter in relation
to the construction and environmental impact associated with building
out that option as an acceptable basis for going forward.
17431. Chairman: What size is the pipe?
17432. Mr Mould: It is 2.7 metres. You
can see a number of work sites associated with these sites: the
Manhattan site, where the tunnel driver will pass south-north
from the Payne Road site here and along this alignment to the
Manhattan site; the Tumbling Bay site; the Wick Lane work site;
and a number of sites associated with this utility diversion scheme.
In due course, Mr Berryman will explain in more detail, as necessary,
the operations that are going be undertaken in relation to those
sites.
17433. Could we turn, please, to page 036.[6]
We have produced three plans to give you a sense of the construction
sequence. It is a 22-month construction sequence in all. We have
broken it down into three phases. We have set out in boxes, in
summary, the works that will be associated with each of the work
sites during this time. The one thing that I would point out to
you is that during the first nine months of the construction phase
there is no work associated with Grove Hall Park.
17434. Would you turn, please, to page 037.[7]
This is the second phase, months 10-15, and shows that during
this time works do take place within Grove Hall Park to construct
the intermediate safety shaft. We have set out, where you see
the access road through the park, the proposed work site area:
a relatively small area within the park for that purpose. We have
set out in these boxes the various works and time periods for
construction within the park. We estimate that with a fair wind
that should be achieved within four to five months, but we have
allowed six months in order to be robust in relation to the time
that we need within Grove Hall Park.
17435. The upshot is that, once the works to
create the intermediate shaft to serve the diversion have been
undertaken, all that will remain at the surface within the park
will be a manhole. The precise location, as you know from yesterday,
we have agreed with Tower Hamlets is to be the subject of further
detailed discussion, but we have sought to avoid any conflict
with designated play areas and sports pitches and so forth within
the park throughout the construction works.
17436. If we turn on to page 38, this is the
third and final phase of the construction phase.[8]
We can see that the manhole is in place in the park and we have
set out the remaining works. They will consist, broadly, of the
connection of the now constructed sewer into the existing water
and sewerage network. We can come back to that later as necessary.
17437. Looking at page 28, I just ought to touch
on why the intermediate shaft is required within Grove Hall Park,
because that is a matter that is going to be touched on during
the course of hearing submissions today.[9]
Thames Water, as the undertaker, have set out, in a letter of
11 October to Cross London Rail Links Limited, a brief summary
of the reasons why the intermediate shaft is required. "The
justification for the intermediate shaft is based on two dominating
factors: the first is compliance with the law and the second is
operational necessity." There is a document which we have,
if necessary, which deals with this in more detail.
17438. The third paragraph reads: "As the
proposed Sewer Diversion will be both a place of work and a confined
space Thames Water has legal duties to comply with the Health
and Safety at Work Act, 1974, Construction (Design and Management)
Regulations 1994, Confined Space Regulations, the Management of
Health and Safety at Work Regulations 1999. There are specific
high level risks of fatality (such as encountering reduced oxygen,
or flammable or toxic gases produced by the sewage) which make
it imperative that escape routes for employees are set at a distance
that reduce the risk associated with working in the sewer to an
acceptable level."
17439. Over the page: "The Sewer Diversion,
being approximately 450 m long, requires an intermediate shaft
to provide an escape route for employees at an acceptable distance.
If Thames Water were proposing to construct the Sewer Diversion
as a consequence of its duties under the Water Industry Act (1991)
(rather then Crossrail/the Promoter proposing to construct it
as a consequence of the Crossrail tunnels), Thames Water would
not construct the Sewer Diversion without the intermediate shaft.
To the best of our knowledge, comparable sewers with shaft spacing
of 450 m do not exist within TW's sewerage system."
1 Crossrail Ref: P126, H.A.M. and Wick Lane Sewers
Diversion-Sketch 1, existing sewers with Crossrail tunnels superimposed
(TOWHLB-29104-031). Back
2
Crossrail Ref: P126, H.A.M. and Wick Lane Sewers Diversion-Sketch
2, Plan Bill Scheme (TOWHLB-29104-032). Back
3
Crossrail Ref: P126, Crossrail Enabling Works, Pudding Mill Lane
Portal-Hackney to Abbey Mills and Wick Lane Sewers Diversions
Options Report (TOWHLB-29104B-001). Back
4
Crossrail Ref: P126, Crossrail Enabling Works, Pudding Mill Lane
Portal-Hackney to Abbey Mills and Wick Lane Sewers Diversions
Options Report, Executive Summary (TOWHLB-29104B-002). Back
5
Crossrail Ref: P126, H.A.M. and Wick Lane Sewers Diversion-Sketch
5, Option 5-Additional Provision Plan and Construction Sites (TOWHLB-29104-035). Back
6
Crossrail Ref: P126, H.A.M. and Wick Lane Sewers Diversion-Sketch
6, Construction Sequence Months 1 to 9 (TOWHLB-29104-036). Back
7
Crossrail Ref: P126, H.A.M. and Wick Lane Sewers Diversion-Sketch
7, Construction Sequence Months 10 to 15 (TOWHLB-29104-038). Back
8
Crossrail Ref: P126, H.A.M. and Wick Lane Sewers Diversion-Sketch
8, Construction Sequence Months 16 to 22 (TOWHLB-29104-039). Back
9
Crossrail Ref: P126, Correspondence from Thames Water to CLRL,
Thames Water Proposed Sewer Diversions, Requirement for an Intermediate
Shaft in Grove Hall Park, 11 October 2006 (TOWHLB-29104-028 and
-029). Back
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