Oxford deserves a better flood scheme�Public Meeting Oxford Town Hall �17 April 2023

Community comment on Regulation 25 Consultation

Introduction �and �The Costs and Benefits of the�Oxford Flood Alleviation Scheme

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Tim O’Hara

Surveyor and North Hinksey resident

Oxford Flood Alleviation Scheme

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• Defences at Botley Road, New Hinksey & South Hinksey
• Osney Mead Defence
• Channel improvements on Seacourt Stream & under A432
• Control structure on Eastwyke Ditch
• New/raised bridges at Willow Walk, Devils Backbone, N Hinksey Causeway, Old Abingdon Road, Kennington Road
• Network Rail culvert
• Network Rail clearance of Stroud’s Bridge
• Clearance of Munday’s Bridge.
• Temporary defences at Osney Island & New Hinksey
• Bank raised at Redbridge Stream

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• … and a 5km channel

The flood channel will cause environmental damage and incur social costs because of its:

• Size: 400,000m3 (700,000 tonnes) of material excavated.
• Route: 5km. From North of Botley Rd to South of Old Abingdon Rd via Hinksey Meadow.
• 3 year (or more) construction period.
• Post construction appearance and characteristics

Proposed flood channel – central section highlighted in yellow

The channel does not provide significant extra benefit

• No channel from 200m south of Botley Road to Old Abingdon Road

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** This is 98% of 1536. 1501 divided by 1538 = 0.98 (to 2 decimal points)

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Sources: EA CPO Statement of Reasons 2023; EA App. Q (2023) to planning application

How the scheme with and without the channel will protect property

* No channel from 200m south of Botley Road to Old Abingdon Road

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Source: EA App. Q (2023) to planning application

The Importance of Flood Meadows

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Professor Kevan Martin, Thames Valley Wildflower Meadow Restoration Project

(Restorers of Christ Church Meadow and other Oxford College meadows)

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Floodplain meadows:

rare, rich and irreplaceable in our lifetime.

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Prof. Kevan AC Martin,

Thames Valley Wildflower Meadow Restoration Project

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Emma Rothero, Irina Tatarenko, David Gowing,(2020)

J. Nature Conservation

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Ben A. Woodcock, Alison W. McDonald. Richard F. Pywell (2011)

J. Applied Ecology

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Further Environmental Damage

and its ‘Mitigation’

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Jocelyn Wogan-Browne, Professor Emerita,

Osney Island resident, Oxford Flood and Environment Group member

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Hedgerows, mature tree copses and grasslands in the fields south of Hinksey Meadow

(97% of British meadows have been lost since WW2 and we are the most de-afforested country in Europe)

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This

becomes

this

Willow Walk

Environmental degradation

BEFORE OFAS

AFTER OFAS

Drone photo 4^th April 2023

(James Wynne)

Showing loss of ~1000 mature trees

(entire scheme entails felling 4000 trees)

The channel runs from Seacourt Nature Park to the Old Abingdon Rd at Kennington- 5 kms long in its full extent and up to 250 yards wide.

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Source: EA website (initially published without reference to growth time frame: corrected under pressure from public comments)

Willow Walk in

late summer now

And in future?

Social Costs

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Dr Rod Chalk, University of Oxford

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Financial cost £176M �(up from £111M in 2017)��Social cost?

OXFORD FLOOD ALLEVIATION SCHEME

Social costs:

• Loss of access to green space – welfare and amenity*
• Inconvenience
• Loss of wildlife*
• Loss of flood meadow, trees, hedgerows and natural streams*
• Dust/noise/pollution
• Traffic congestion (A34)
• Environmental degradation*

*Costs are substantial, permanent and borne by the entire community

They are NOT factored into the cost-benefit model

Positive effects of nature on mental health*

• improve your mood
• reduce feelings of stress or anger
• help you take time out and feel more relaxed
• improve your physical health
• improve your confidence and self-esteem
• help you be more active
• help you meet and get to know new people
• connect you to your local community
• reduce loneliness
• help you feel more connected to nature
• provide peer support

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*according to MIND, mentalhealth.org.uk, BUPA & RSPB

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Temporary loss of access

Willow walk has been closed for 3 months forcing a 2-mile diversion on a busy trunk road for pedestrian and cyclists and causing massive inconvenience for commuters local residents and school children

Access to the flood plain will (now) be severely restricted for 5 years

Permanent loss of access

Pity the residents of South Hinksey

Works compound and material storage

Works compound and material storage

South

Hinksey

Village

Trees felled

Access haulage road 20m wide (2 bus lengths)

Haulage Road

Haulage Road

Haulage Road

Haulage Road

A34 national trunk road at South Hinksey

Inadequate South Hinksey slip road is just 90m

• 111 HGV movements/day at this junction

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• 40 mph speed restriction must be applied

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• A34 is frequently at a standstill under normal circumstances

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• Delays will spill on to ring road & M40

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• Disruption in addition to the massive disruption already planned by the closure of Botley Rd

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HOEG�Pumped Pipeline

Seacourt

to

A423 Bypass

East side of Railway

Kevin Larkin (Architect)

Jonathan Madden

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Triple level plan and profile drawings of pump house.

Vehicular access to pump house from car park.

1. Top: Utilities – diesel electric standby generator; switch gear; fuel tanks.

Spillway diameter: 100m

Major axis: 40m

Minor axis: 20m

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ii) Penstock level: flood water intake into axial flow pumps.

iii) Axial flow pump room. Sub-ground level. Four pump output converged into two pipes.

Profile of spillway into penstock and pumping system. Spillway protected with grilles to control debris ingress.

Outlet of 2 x 2m diameter GRP pipes, on shallow gradient to ca. 2.5m depth.

Flood level

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Grassed area surrounding utilities housing

Pylon anchors with ‘H’ girders reinforce concrete surround and spillway.

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X-sections showing buried pipeline in trench to scale parallel to the Electric Road. (Measurements in mm)

• Plan view of Pumping Station, adjacent to Seacourt Stream

• Section through Pumping Station, illustrating Axial Flow pumps and three-level design

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Advantages of Pumped Pipeline System

• Uses well understood techniques and designs, common for water management and fluid transport in general
• Moves water volumes equivalent to and greater than OFAS channel. Design is for 44cumets/sec.
• Pumping can begin at an early stage of flooding, thereby ‘flattening’ the water level curve. Lowest level of inlet spillway connects to Seacourt Stream at 56m AOD.
• Cost-efficient in terms of equipment and civil engineering
• Very low volume of spoil removal off-site reduces heavy vehicle movements on local and main roads
• Reinstatement of existing landscape eliminates need for annual maintenance costs

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Pumped Scheme: Approximate Costings:

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Costings: cont’d

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How the scheme design can be improved based on the present planning consultation under Regulation 25 ��Brian Durham�New Hinksey Resident�Archaeologist to Oxford City Council (retired)

In August last year the planning authority requested that the application be `supplemented with additional information which is directly relevant to reaching a reasonable conclusion’.

The applicant (Environment Agency) has responded.

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Reg 25 para 5.2 Channel improvements on Seacourt Stream please provide confirmation these have been applied to Scenario A2

• The applicant has provided the `confirmation’, but in doing so has made no effort to explain the extreme difference values at the four nodes in question (red boxes).
• These values would make the alternatives A1 and A2 appear to perform worse for Botley Road and Osney.
• The communities need the Peer Reviewer to examine the source of these extreme values.

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Better Flood Scheme Public Meeting 2023

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17/04/2023

Reg 25 para 5.1 Willow Walk New Bridge #N/A values please provide the missing water levels or full explanation

The applicant has ignored the request for missing levels at what is ecologically the most sensitive location next to MG4 grassland.

The communities need the Peer Reviewer to ask why the engineers were not able manually to infill these gaps in their model output?

Better Flood Scheme Public Meeting 2023

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17/04/2023

Reg 25 para 5.3 Please provide the reason for not applying locally-lowered beds in modelling proposed bridges

• The applicant responds - In the no-channel scenarios the bed level at these locations is set at the surrounding field levels as localised lowering will provide no hydraulic benefit and will silt up to the surrounding field levels over time
• We need the Peer Reviewer to remind the applicant that:
• they used `lowered beds’ themselves in the 2018 scheme
• They are here predicting what the model will do, when they were not prepared to do that at Willow Walk New Bridge (above)
• And to ask how this exercise helps compare the performance of alternatives?

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Better Flood Scheme Public Meeting 2023

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17/04/2023

Reg 25 para 5.10.2 Need for single-bridge design at Old Abingdon Road

On 16 February 2021 the applicant’s consulting engineer described the single offline bridge option as a `more elegant solution’, and HOEG asked to see County Highways view of this option.

The communities can reasonably ask for that response to be made available in the planning process

• Biggest flow obstruction in Scheme,
• backs up water into South Hinksey and New Hinksey.
• Proposed bridging starts to obstruct flood water in a 2-year return period.
• Avoidable by raising the proposed decks less that 1m (shown green) to let the flood flow through.
• Even better, a single new bridge constructed on open ground saves three years in construction

Better Flood Scheme Public Meeting 2023

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17/04/2023

Proposed bridging at Old Abingdon Road (red) and

flood-friendly, traffic-friendly alternative (green)

Reg 25 para 5.10.3 Need for protection of the railway at Kendall Copse East

• The Scheme directs flood water towards a 550m-long stretch of railway line.
• This is relevant because:
• National rail infrastructure
• Oxford’s economy depends on railway servicing of the BMW Mini Plant
• Oxford will use this line for passenger service to Cowley Station;
• The alternative is to take the water under the railway (image opposite). A viaduct can logically be constructed one track at a time because of an extra track.
• The communities can reasonably ask for the planning process to include a statement from a Network Rail chartered engineer that the present design has no avoidable risk for the railway.

Better Flood Scheme Public Meeting 2023

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17/04/2023

Reg 25 para 5.10.4 Need for formal floodplain compensation analysis

Scheme has not provided a floodplain compensation analysis (FCA). For example:

• At New Hinksey the scheme is putting an earth bank round 10 hectares of floodplain, sacrificing 100,000 cubic metres of flood storage.
• Without this, the east floodplain would gain an extra 5% alleviation effect.
• Function of bank could be achieved with a low masonry wall along Abingdon Road back of footway

The communities can reasonably ask for the Peer Reviewer to assess the extent to which this embanking degrades performance of the scheme

Better Flood Scheme Public Meeting 2023

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17/04/2023

Floodplain compensation analysis provided by City Council for Seacourt Park and Ride extension

Applicant’s response to peer review

• `Based on the hardware available at the time [2018] the run times for 2D grids smaller than 10m were prohibitive.
• …. attempts [to reduce run time on a GPI machine] were unsuccessful and resulted in unreliable performance of the model.
• Considerable time was spent unsuccessfully trying to determine the reasons for this, including discussions with the TUFLOW support service.’

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Modelling domains

The Environment Agency is on record that the proposed meadowland channel design has never been tried on this scale.

The communities can reasonably ask for the Peer Reviewer to assess whether the applicant’s response on their modelling (opposite) justifies the experimental design of the meadowland channels, given the scale of ecological and landscape damage we have heard.

Better Flood Scheme Public Meeting 2023

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17/04/2023

Reg 25 para 6.2 Please simulate a higher resolution or multi-domain set up

Is this good enough to expect our cooperation?

1. Given the evidence of under-resourced and `unsuccessful‘ modelling, HOEG has forewarned Oxfordshire County Council’s flood officer of gaps in the Regulation 25 responses.
2. The communities can reasonably ask for the Peer Reviewer to provide a expert opinion on: the even-handedness of the comparison process; the reliability of the modelling; and any degrading of floodplain storage, also written statements from County Highways and Network Rail on the remainder.
3. HOEG has drafted such a letter that will go out before the deadline of midnight tonight, adding any thoughts from this meeting, thereby formally alerting the planning authority to expect further comment from yourselves.

Better Flood Scheme Public Meeting 2023

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17/04/2023

NEXT STEPS�How to comment�

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Patricia Murphy, author and TV Producer/Director, 

Oxford Flood and Environment Group

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NEXT STEPS

How to comment

The planning process

WE ARE HERE

WHAT YOU CAN DO

Compulsory Order Process -

Making our voices heard� the power of numbers �

Effective Comments and Objections

• State clearly whether you support 85% of the measures but want the Channel from Botley Rd to Old Abingdon Road scrapped
• DO NOT COPY AND PASTE!
• Just a few lines is acceptable
• You can say you support the questions raised by HOEG and OFEG to the Regulation 25 letter.
• Where you can find inspiration eg. objection on www.oxfordfloodandenvironmentgroup.com
• https://hinkseyandosney.org

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Economic, impact, errors and omissions

• The EA has admitted that the flood scheme is untested on this scale, that the 2018 flow modelling was limited by available computing power, and their attempts to remedy this have been unsuccessful. 
• Failing to create sufficient openings in man-made obstructions – the design would create flood backup as a result of obstruction by the proposed bridge decks at old Abingdon Road and by omission of a modern viaduct at the railway in Kennington.
• - Modelling errors according to independent hydrologists and engineers not addressed in recent consultation. There is no evidence that the peer reviewers understood the issues around sensitivity tests. Nor have there been tests for impact of bunds and defences.
• The EA has failed to model the economic impact or have a fair comparison process of not having a channel. Despite the fact that the channel provides under 3% of benefits to just 25 extra properties and is the most expensive aspect of the scheme
• EA need to demonstrate that the channel is not a risk to the railway and that the twin bridges design in optimal
• Failure to review the safety of the lowered floodplain in the light of unsuccessful modelling by applicant
• democratic deficit - inadequate public consultation
• Waste of money and resources that could be used for a better flood scheme
• Better Alternatives Available not properly considered – eg pump
• Unacceptable impacts on traffic on the A34, including a 40mph speed restriction
• uncertainty about the effectiveness of a temporary bridge at Kennington

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HOEG will be asking the planning authority for:

Objections – Environmental

• Biodiversity loss – a minus 1% loss of over 2,000 trees and miles of hedgerow with mitigation offsite not yet secured.
• �- Loss of irreplaceable Hinksey Meadow and Kennington Pit Local Wildlife
• �- Loss of access for at least 5 years and loss of public land long-term ��- Assault on greenbelt – loss of 133 acres and 250 acres of farmland. Breaks several National Planning and Policy Framework directives and fails to demonstrate “exceptional circumstances in light of new requirements about protecting green belt.
• Not future proof – will not keep up with climate change
• Harm to people’s health, particularly in South Hinksey, from pollution, noise, vibration, dust and air
• does not follow the ‘mitigation hierarchy’ of first avoiding impacts (e.g. no channel through Hinksey Meadow), then mitigating (narrower channel) and then compensating (trying to create new sites).

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• A ‘no channel’ option would avoid most of the OFAS impacts.

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INFORMATION SOURCES

• https://hinkseyandosney.org

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• https://www.oxfordfloodandenvironmentgroup.com
• https://consult.environment-agency.gov.uk/thames/oxfordscheme/
• https://www.onlyoneoxford.org/save-hinksey-meadow

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• Insta – Hinksey_Meadows

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• https://www.facebook.com/profile.php?id=100090583792185

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How To Comment�

• Matthew.Case@Oxfordshire.gov.uk
• https://myeplanning.oxfordshire.gov.uk/Planning/Display/MW.0027/22#undefined

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• MP  layla.moran.mp@parliament.uk
•  anneliese.dodds.casework@parliament.uk

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Councillors https://mycouncil.oxfordshire.gov.uk/mgMemberIndex.aspx?VW=TABLE&PIC=1&bcr=1

https://mycouncil.oxford.gov.uk/mgCommitteeMailingList.aspx?ID=0

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• Petition https://www.change.org/SaveHinkseyMeadow
• Therese Coffey if you support a public inquiry  therese.coffey.mp@parliament.uk

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• “Wildflower meadows are a unique and irreplaceable part of our cultural heritage, no less than Stonehenge and the Rollright Stones.

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• But floodplain meadows also play a vital and complex role in our 21st century society, and not least in mitigating floods. Their loss is of national and international significance.”

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• Catriona Bass of the Thames Valley Wildflower Meadow
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What will be Oxford’s gift to our green King?

DON’T LET THIS SUMMER BE THE LAST FOR HINKSEY MEADOW AND THE WILDLIFE CORRIDOR