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Division(s):
Banbury Grimsbury & Castle, Banbury Hardwick, Banbury Neithrop,
Wroxton.
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ITEM CA13
CABINET
– 20 DECEMBER 2005
BANBURY
FLOOD ALLEVIATION SCHEME
Report by
Head of Transport and Solicitor to the Council
Background
- Banbury has a
long history of flooding. The town is located on the flood plain of
the River Cherwell. The river’s catchment is founded mostly on impervious
clays leading to a rapid response to rainfall and a tendency to flood.
The 1998 flood is the most recent large flood to affect properties in
Banbury and it also caused a significant disruption to the transport
system. Similar scale events were recorded in 1947 and 1932.
(Annex 1 - map - download as .doc file)
- In response to
local concerns the Environment Agency (EA) is proposing to construct
a flood alleviation scheme to reduce the risk of the River Cherwell
flooding Banbury. Planning permission has been granted for the scheme
by Cherwell District Council.
- The chosen scheme
is the result of a series of studies carried out by consultants for
EA between 2001 and 2004. Various options were considered before concluding
that a combination of flood storage upstream of Banbury and localised
flood defences within the town would provide the "most sustainable,
environmentally acceptable, cost effective, socially acceptable and
technically feasible of all the flood defence options".
- The scheme also
runs into Northamptonshire. It is understood that Northamptonshire County
Council still have outstanding technical issues with the EA and therefore
the EA’s planning application for the scheme in Northamptonshire has
been withdrawn at the present time. In terms of the highway issues,
Northamptonshire County Council took joint legal advice with this Council
(detailed below). It is believed that Northamptonshire County Council
are yet to form a view as to whether it can withdraw its objection to
the EA’s compulsory purchase order (CPO).
The Scheme
- The element of
the EA’s proposed scheme with particular significance to the County
Council is a "Flood Storage Area Upstream of Banbury". This is located
to the north of the M40 and is part of the River Cherwell’s existing
flood plain. A section of both the present and former A361 (the latter
being now used as a footpath and cycle route) lie within the storage
area. A key plan is attached.
- Two storage area
layouts were considered in detail by the EA. The first entailed the
construction of a horseshoe shaped embankment to contain flood water
in the area between M40 and A361 and avoided directly flooding the A361.
In the second layout the embankment is curtailed by omitting the portion
protecting the A361 and permitting flooding of the roadway and agricultural
land to the east.
- In an Environmental
Statement dated March 2004 the EA concluded that the second layout was
to be preferred due to its greater cost saving and reduced environment
impact and because it would provide greater flood storage which in turn
would reduce down stream flood levels. In the same Environmental Statement
it was also stated that "this alignment does not seek to prevent
flooding of the A361….., which will continue to flood at a frequency
similar to that at which it currently floods". The EA have subsequently
stated that the cost benefit ratio for the first option would be insufficient
for the scheme to achieve a place in their works programme and that
the second option provided the only viable scheme.
- In the proposed
scheme, flow control structures would throttle flows on the River Cherwell
and reduce water levels in Banbury whilst retaining the remaining volume
of water. The first layout would be unlikely to be effective in dealing
with a 1 in 100 year event whereas with the second layout floods up
to a 1 in 200 year event would be stored and flows in excess of a 1
in 200 year event would be released in a managed fashion.
The Benefits
of the Scheme
- In existing conditions
a 1 in 20 year flood causes local flooding of the public highway in
Banbury and of the A423 Southam Road to the north of the town. The extent,
depth and duration of the flooding increases with the severity of the
event, with Banbury Station becoming flooded during a 1 in 50 year event
and Southam Road and other streets in Banbury becoming impassable at
around a 1 in 100 year event.
- The scheme would
reduce the risk of flooding for the residents and businesses in Banbury
and would aim to provide protection against a 1 in 200 year flood. The
1998 event was approximately a 1 in 100 year flood and would have been
prevented if the scheme had been in place.
The Effect
on the A361
- In the 2004 "Environmental
Statement" the EA conclude "There would be no increase in the frequency
of flooding in the upstream flood storage area but there would be an
increase in the extent of flooding, the depth of flooding and the duration
of flooding" and "For the worst case flood that could be stored
in the flood storage area….there would be 1.6m increase in depth increasing
flooding by 19 hours to a total of 54 hours…".
- In existing conditions
the A361 floods locally with a 1 in 50 year event but remains passable
with care up to a 1 in 100 year event. Flood maps provided by the EA
show that with the scheme in place there would be no increase in depth
or duration until a 1 in 50 year flood event. The maximum period of
closure illustrated for a 1 in 50 year event is 19 hours, for a 1 in
100 year event 30 hours and for a 1 in 200 year event 40 hours (copies
of the EA’s Flood Maps are on deposit in the Members’ Resource Centre).
Public
Rights of Way
- The scheme would
affect the footpath/cycle route along the former A361, which would flood
to the same frequency and duration as the A361 itself and to approximately
the same depth.
- The footpath/cycle
route would need to cross over the new flood embankment which would
be constructed across its route. Ramps would be provided but the gradient
could affect low-mobility users such as people in wheelchairs, people
pushing prams and those with walking difficulties.
Closure
Protocol
- There is currently
no clear protocol either for warning of the likelihood of flooding or
for dealing with the consequences regarding the highway.
- With the scheme
in place the EA would be able to provide advance warning of the likelihood
of a flood on the A361 giving sufficient time for a closure plan to
be implemented. A protocol would need to be agreed with the EA and with
neighbouring highway authorities, Northamptonshire and Warwickshire
County Councils, for providing advance warning of the likelihood of
flooding and for the closure of the A361 and the setting up and removal
of a diversion route.
The Legal
Position
- Officers of both
this Council and Northamptonshire County Council were concerned regarding
the effect that the flooding of the A361 and the footpath/cycle route
to an increased depth and duration would have on the Council’s duties
as highway authority.
- Under Section
130 of the Highways Act 1980, the highway authority has a duty to assert
and protect the rights of the public to use the highway and under Section
41 a duty to maintain the highway. It was considered that acceptance
of the deliberate flooding of the A361 and footpath/cycle route could
be in breach of the Section 130 duty. Such interference could be deemed
to amount to a public nuisance and therefore, there was a possibility
that the Council could not properly support the scheme.
- In view of this,
legal advice was sought from David Holgate QC on a joint instruction
with Northamptonshire County Council. Mr Holgate confirmed that such
a scheme would be incompatible with the highway authority’s duties under
Section 130 if the increase in the extent and duration of the flooding
was not "reasonable". As to whether the increase is reasonable in a
particular case is dependent on a number of factors, including whether
or not objection to the scheme – by preventing its implementation -
would result in flooding of other lengths of highway in locations where
it could be more damaging than the temporary flooding of the A361 in
the manner proposed.
- To enable the
highway authorities to decide whether or not the increase in extent
and duration would be "reasonable" officers requested and obtained information
from the EA to enable them to understand in sufficient detail the likely
frequency, extent and duration of the flooding of the A361 and the benefits
the scheme would bring to other roads in Banbury. Having analysed the
information provided by the EA officers have concluded that on balance
the increase in extent and duration, taking into account the existing
impact of the natural flooding on the A361, footpath/cycle route and
surrounding highway and transport network, and the benefits brought
about by the scheme, is not unreasonable and therefore would not amount
to a public nuisance.
- In light of this,
your officers’ view is that the scheme can be supported in principle.
However, the details of the scheme and how it will be managed give rise
to a number of issues that currently remain outstanding.
- The CPO as currently
drafted is not sufficiently clear as to what rights the EA are seeking
to acquire. Counsel advised that the County Council should maintain
its objection to the CPO until such time as those rights have been clarified.
The EA have since confirmed that they are seeking easements to flood
the highway as and when necessary; County Council officers have responded
that, subject to certain conditions, the Council would be able to give
limited easement in this respect as far as they control the land as
highway authority. To withdraw the objection, the easements/rights must
be clearly documented in a separate agreement with the EA.
- As far as your
officers are aware, no similar scheme has been undertaken by the EA
in this precise manner in any other part of the country. Therefore,
potential liability to third parties is very much an "unknown". In view
of this, Counsel has advised that Oxfordshire County Council should
not withdraw its objection to the CPO without obtaining indemnity from
the EA to protect the County Council against potential third party claims
arising as a result of the scheme whatsoever. We are currently waiting
to hear from the EA whether it will agree to give this indemnity.
- If the EA are
not able to give such an indemnity, Counsel has advised that the highway
authorities should maintain their objection. In this event, the CPO
procedure will continue with Oxfordshire and Northamptonshire County
Councils as objectors, and a decision will be made by the Secretary
of State as confirming authority. If that decision is to confirm the
CPO the Order will still be subject to special parliamentary procedure
before it could take effect.
- Essentially, the
purpose of the parliamentary procedure is to resolve the incompatibility
of the powers. In circumstances where a decision of the Council would
be in breach of its statutory duty and/or not in the interests of highway
users, such a decision is taken by a "third party" – thereby not being
a decision attributable to the Council and therefore, not a decision
for which the Council could be held to account.
- It is important
to note that there is a distinct difference between the County Council
acting in its capacity as highway authority and reacting to naturally
occurring flood events and how it might react to planned flood events.
Management of this scheme is therefore crucial and the Council’s liability
to the public will be affected by the way the scheme is managed.
- In a natural flood
situation, the County Council can only reasonably be expected to react
as and when a flood is brought to its attention and must then do all
that is reasonably necessary in those circumstances. Where a planned
flood event takes place there must be an adequate procedure in place
to ensure that the Council has advance warning that a flood is going
to occur and that all necessary diversions and other measures are in
place. A satisfactory management agreement will therefore need to be
reached and a protocol drawn up to protect its interests as highway
authority prior to any objection being withdrawn.
- The increase in
flooding will have a physical impact on the highway. The EA have acknowledged
that the increase in the physical wear and tear/maintenance required
as a result of the increase in depth and duration of the flooding needs
to be addressed. Commuted maintenance sums and any other costs arising
as a result of the scheme will be required to ensure that the Council
can carry out its maintenance duties under Section 41 of the Highways
Act 1980. The above-mentioned indemnity will need to extend to potential
claims against the Council for claims arising from damage caused to
the highway.
- Permanent works
would be required to provide a new access from the A361 to service the
proposed flood control structures and to construct the flood embankment
over the footpath/cycle route along the former A361. A Section 278 Agreement
would be required to permit the EA to carry out these works.
Financial
Implications
- As already stated
there would be some direct financial consequences to the County Council
should the scheme be implemented and those costs would need to be quantified
so that they could be recovered from the Environment Agency. For example
there would inevitably be some damage to the fabric of the carriageway,
through prolonged saturation leading to an increase in the ongoing cost
of maintenance. Diversion signing would be required and there would
be an initial cost for its provision and an ongoing maintenance cost.
There would also be a staff cost in setting up and maintaining the diversion
route in the event of a flood warning.
RECOMMENDATION
- The Cabinet
is RECOMMENDED to accept the Environment Agency’s Banbury flood alleviation
proposal on the basis set out in the report and agree the withdrawal
of the County Council’s objection, subject to the following conditions
being met to the satisfaction of the Director for Environment &
Economy and the Solicitor to the Council:
- the documentation
in a separate agreement of any rights to be granted to the Environment
Agency by the Council;
- the agreement
of a management protocol for early warning of flood events and for
establishing and removing of diversions;
- agreement
by the Environment Agency to reimburse the Council’s reasonable costs
incurred as a direct consequence of the proposed scheme;
- the granting
of a full indemnity to the Council by the Environment Agency.
STEVE
HOWELL
Head of Transport
PETER CLARK
Solicitor to
the Council
Background
papers: Environment Agency Banbury flood alleviation proposal
Contact
Officer:
Brian Fell, tel (01865) 815083
Christina Daniels,
tel (01865) 815383
December
2005
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