Our 10th Annual Public Meeting

We held our 10th Annual Public Meeting two days ago. Attendance was less than last year but then we have not had a flood for longer! However we still had a respectable attendance.

Jon Mansbridge and Penny Burt from the Environment Agency kindly updated us on the (good) progress of the Oxford Flood Alleviation Scheme, with the planning application due to go live in the first half of May. Jon summarised the scheme so far and what we can expect next. Penny dealt with the environmental aspects – the aim being to preserve as much of what is there already as possible and to enhance in other ways. The area is rich in habitat and wildlife so there is an excellent base to build from.

City Councillor Colin Cook was made our Flood Star for 2018, and was presented by Liz Sawyer with the now traditional bottle of Chateau OFA.

Simon Collings spoke about the Seacourt P&R extension application, now approved, and which we have spent so very many hours opposing over the past year and more. In particular, Simon set out our concerns over groundwater flooding both on and off site, which have not, in our view, been at all adequately addressed in the planning process. A meeting with City Council officers and consultants has since (today, 27 April) taken place to discuss our concerns in detail.

Nick Hills spoke about maintaining community preparedness for flooding.

The evening finished with a talk from Graham Brogden, of insurers Aviva, on how insurers are now paying much more attention to ensuring that post-flooding repairs are done in a way that will leave the property more resilient than before, rather than just replacing like for like. We’ve been advocating this for years so it’s good to see the insurance industry working in this common-sense way.

Many thanks to our speakers, and to those who came for their support.

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Representatives of OFA will be meeting with City Council officers and their consultants this afternoon to discuss our continuing serious concerns over the (now approved) Seacourt P&R extension. Cllr Colin Cook will also be there as will a representative for Layla Moran MP who is unable to attend in person: both strongly opposed the application.

There’s an article in today’s Oxford Mail

http://www.oxfordmail.co.uk/news/16188420.Flood_hit_Seacourt_Park_and_Ride_site_would_have_been___39_closed_for_three_weeks__39__this_year/

 

 

Seacourt P&R: Planning Review Committee meeting

Oxford City Council’s Planning Review Committee met last night to reconsider the application to extend Seacourt park and ride. This had previously been approved by West Area Planning Committee but a review had been requested by concerned councillors.

The review committee confirmed the previous decision.

There is a report in the Oxford Mail.

We believe this decision is a huge mistake and we are disturbed by aspects of the decision-making process.

There is no lack of parking spaces here, nor overall. Should it ever be needed, better usage of existing parking could easily be achieved by live signage on the ring road. We have collected online data and visited the site over the very busy pre and post Christmas periods – the existing car park has never once been full. Opening of the new Westgate has not caused problems and many people clearly choose to drive into the city rather then use park and ride.

The cost is huge, £4.1 million is already budgeted. And there are many other urgent calls on the public purse. People are homeless and sleeping on the streets just a mile away.

The site floods from groundwater – an aspect that has received scant attention, despite our highlighting it repeatedly. Because of groundwater flooding there will be a net loss of floodplain if this development goes ahead. The site will also flood when the rivers flood. This will make it expensive to pump out, maintain and repair.

The decision is undoubtedly contrary to national planning guidance (NPPF) which is there to protect the floodplain and Green Belt. A previous extremely similar application on the site was the subject of a Planning Enquiry in 1998 and refused by the Secretary of State in 1999. Since 2007 the guidance has been strengthened following the Pitt Report on the Oxford and nation-wide flooding in 2007.

It is possible that the present application will be Called-in by the present Secretary of State for Communities and Local Government, Sajid Javid:  we have requested, jointly with Layla Moran MP, that this should happen. If the application is Called-in a Public Enquiry will follow. The reason for our request is that a decision to develop a car park in the floodplain sets a serious national precedent. Building in the floodplain is deplorable, except in the most exceptional cases – which this most certainly is not.

If the extension does eventually go ahead it is not impossible that the Council will in time come to regret it – as construction costs rise, maintenance is expensive due to recurrent flooding (exacerbated by climate change) and occupancy is low. But that will be no comfort  – much better it should never happen in the first place.

 

Risk of local property flooding

From the Planning Officer’s report to the West Area Planning Committee, December 2017:

“9.149. During the consultation process, reference has been made to the suggestion within the Factual and Interpretive Ground Investigation Report that the proposed drainage strategy will require the use of lime stabilisation to avoid damage to the paving within the car park expansion from changes to the clay layer below ground and that this needs to be given further consideration as part of any drainage proposals for the site. The concerns raised are that lime treatment is likely to have an impact on the permeability of soils below the car park, and therefore needs to be appropriately considered. 

The applicant has confirmed that the surface water drainage strategy has been designed as a tanked system which assumes no infiltration below the attenuation layer, with all storm water discharge from the site via a controlled outfall into Seacourt Stream. An impermeable membrane is included within the construction to prevent water saturating the clay. The underlying clay is of a low permeability whether lime stabilisation is employed or not, and it is envisaged that the attenuation will operate effectively in either scenario.” [emphasis added]

There is no mention in the Application of tanking, nor of an impermeable membrane. We have therefore not known of this till very recently and had no opportunity to comment. While there is little or no detail, the idea that the car park may be separated from the underlying groundwater table, as this implies, raises an extremely serious question. That is, where will the displaced groundwater go? This is a lot of water over such a large area. It is likely that it will cause a significant rise in groundwater levels around this low-lying site. This could cause (new) groundwater flooding within houses (and gardens) nearby. No decision should be taken until the details of  what is planned are made clear, appropriate calculations and modelling done, and presented as part of a further revised Flood Risk Assessment.

[By the same token, when it rains, water will be trapped within the tanking , draining only slowly – more pumping needed?]

OFA symposium on natural flood management techniques : Summary Report

OFA symposium on natural flood management techniques : Summary Report
26 March 2015, Oxford, in collaboration with the Environmental Change Institute, University of Oxford

Could techniques such as planting trees and creating more wetlands in the upper Thames help to reduce flood risk in Oxford? This was the question we asked a number of experts to address at a symposium attended by around 60 people – a mix of academics, local residents and officials from local councils and the Environment Agency – on 26 March 2015.

Professor Mike Acreman, a rivers and wetlands expert from the Centre for Ecology and Hydrology at Wallingford, gave an overview of what science today can tell us. Prof. Acreman started by pointing out that fluvial flooding is natural, with benefits to the environment. We cannot stop it happening. He said that in theory tree cover should help to reduce runoff, through ‘canopy intervention’ and’ improved soil infiltration’ but the scientific data on this are weak. A study at Pontbren, in the Brecon Beacons, showed that soil infiltration was increased by hedges and trees. Restoration of mires on Exmoor has also shown some benefit in improved water retention. But the volumes involved are small compared to the total volume of water involved in a flood event. Foresting small areas of a catchment might bring localised benefits, but would have no measurable effect at the level of the wider catchment. To impact the whole catchment change to the landscape would be required on a massive scale, and even then this would have very limited impact in a major flood: soil can only retain so much water. During a period of prolonged rainfall the ground becomes saturated, as happened in late 2013 in the Thames catchment. Any additional rainfall simply drains into the river system. He also explained that interventions which have local benefits may have unintended consequences downstream. Flooding has temporal as well as spatial scale effects, and delaying the peak from a tributary can result in it being superimposed on the peak in the main river, rather than arriving before it, so increasing the overall peak level. Prof. Acreman argued that we need a mix of conventional engineering approaches, and enhancement of natural processes, to effectively manage risks.

Lydia Burgess-Gamble, a research scientist with the Environment Agency, talked about the work the agency is doing on natural flood-management (NFM) techniques. She explained that since the Pitt Report on the 2007 floods the EA has been engaged in more work of this kind and a small number of schemes have been established, with positive early results. These are small, localised interventions such as the 30 attenuation ponds (10,000 m3 of storage) built on 10 km2 of farmland around the village of Belford in Northumberland. In Pickering in North Yorkshire conventional flood defences have been supplemented by woody dams and tree planting by the Forestry Commission. Here the aim is to reduce flood risk from 25% a year to 4% by arresting flow in a ‘flashy’ beck which runs through the town. In the Thames valley there has been work including leaky dams slowing runoff into the Evenlode at Honeydale Farm. Flooding in Stockton-on-Tees is being tackled through building 40 storage ponds in locations identified through modelling. This scheme is at the initial stages of implementation. The EA plans more of these projects, creating ‘opportunity maps’ and working with natural processes where there is potential to achieve ‘healthy catchments’. ‘Catchment laboratories’ (including data collation and workshops) are proposed, building on ‘green engineering’, but there remain many knowledge gaps and the full impact of these types of interventions will not be understood for some time. Lydia said NFM was one tool only.

Derek Holliday of the CLA, which represents farmers and other landowners who together manage 70% of the land in England, described the major shift which has occurred in the last 10–15 years away from subsidies for crop production towards payment for ‘ecosystem services’. He argued that even bigger shifts need to happen but this requires a clear policy framework – farmers need to make spot decisions between land management options, and his members say they tend not to have the necessary information to favour flood-friendly options. They also worry about the `reversibility’ of these options, policies being changed. Without a clear framework, landowners will not make the investments which change would require.

With the fourth speaker, Nathalie Schaller from the Environmental Change Institute at the University of Oxford, we changed tack slightly and looked at climate change and its likely implications. After each extreme weather event the public wants to know if ‘climate change’ was a contributing factor – but limited research has so far been done. Nathalie presented the results of a study of the degree to which human-generated greenhouse gases increased the likelihood of the Jan/Feb 2014 floods in the UK: this type of approach is known as ‘event attribution’. A large number of computer simulations were run for different scenarios to try to separate out anthropogenic carbon from underlying climate variation. The study found that human activity had on average increased the risk of the 2014 floods happening by 40%. The implication of this for the future is that extreme weather events are likely to be more common.

Following the presentations there was discussion, with the presenters responding to points from the audience. The conversation ranged across many issues and it is not possible to capture all the points made. The overall conclusion was that natural flood-management techniques can bring benefits in smaller catchments, especially in lower-order flooding events. Isolated projects in the upper Thames would, however, have no measurable impact on Oxford with its large catchment (about 2,500 km2 upstream). A complete re-landscaping of the Thames catchment might, if it could be achieved, reduce flood peaks by 10–15%. Achieving the transformations in land-use necessary to deliver this benefit would require radical new legislation and/or a new culture, taking ‘around 40 years’ to implement. As a means of addressing flood risk in the city ‘natural’ methods would not replace the proposed flood relief  scheme for Oxford and Abingdon, but might help prolong its life expectancy.

An interesting point of detail concerned the role of insurance companies which in theory should have an interest in funding flood-risk reduction measures for land, but which are not incentivised to make such investments.

There was also some discussion of groundwater, which is a major contributor to flooding in Oxford, over and above fluvial flooding. There appeared to be little which could be done to reduce groundwater at a macro level directly. Lowering surface water levels tends to lead in due course to lower groundwater levels.

There is potential scope for natural flood management techniques to benefit small communities, depending on the local catchment characteristics. There is still much to understand about what does and doesn’t work, and in what context, but the Environment Agency and others are establishing more schemes and are keen to implement projects in the Thames catchment if suitable sites can be identified.

These links download pdfs of this Summary Report, and of three of the speakers’ presentations:

OFA Symposium 2015, NFM and Oxford, Summary Report + links

Presentation by Mike Acreman

Presentation by Lydia Burgess-Gamble

Presentation by Nathalie Schaller.

OFA Annual Public Meeting, 2011

Our fourth Annual Public Meeting was held on 16 November 2011

We were delighted to welcome, as last year, Andrew Smith MP, County and City Councillor Susanna Pressel and City Councillor Colin Cook. A representative attended on behalf of Nicola Blackwood MP. Apologies were received from County Councillor Rodney Rose and City Councillor Oscar Van Nooijen. Last, but by no means least, about 75 members of the public came, an excellent attendance more than four years after the last flood.

The meeting began with the award of the sole OFA Flood Star of 2011 to Paul Kirkley. Paul works as an engineer for Oxford City. His professional skills, commitment, and cooperative way of working have been instrumental in turning ideas into practical flood relief projects which will help many residents escape the miseries of flooding.

2011 APM Paul Kirkley, Flood Star
Nick Hills presents Paul Kirkley (left) with the OFA Flood Star award

A review of the year included:
Nick Hills on the several measures now in place to protect Earl and Duke Streets, including the completion this year of the road hump at the north end of Earl Street (to be supplemented by a barrier on top during a flood) and a new route for flood water down Lamarsh Road, through Kingerlee’s land to the open meadows to the south. Nick also described the new flood culverts under Willow Walk installed this summer by the Environment Agency and originally suggested by OFA.

Andy Webber told us about the survey which he undertook of Castle Mill Stream. Following this survey the Environment Agency has cleared trees and debris from the channel at the northern end. We now await clearance under badly silted-up railway bridges, removal of sunken boats and a review of the operation of various weirs and sluices.

Paul Kirkley spoke about a possible scheme to reduce risk for residents on the east side of Duke Street, which in the process would further reduce risk for the whole Duke and Earl Street area.

Brian Durham gave an account of the problems of getting flood insurance and how a ‘DIY’ community flood risk assessment might help.

John Mastroddi told the meeting about developments at Munday’s bridge in Kennington, crucial to the drainage of the whole western flood plain. We have been campaigning about this for over four years. It now seems very likely that major improvements will be made here by Thames Water in the spring of 2012.

Richard Thurston spoke about Osney Island. Thames Water has added telemetry to the West Street Pumping station – so if their surface water pump fails, their control centre will receive immediate notification. The City Council’s scheme for property level flood protection in Bridge Street, Doyley Road and South Street (for which the funding is in place) is welcome news and should reassure many Islanders; finally, Thames Water has provided costs for the extension to the surface water drainage scheme (‘sump and pipe’) to relieve South Street and Bridge Street, but there is no funding as yet.

David Macdonald, local resident and senior hydrogeologist with the British Geological Survey, has been studying groundwater in our area for some years. He told us of a project he is leading which, if it is funded, will see Oxford have the UK’s first groundwater warning scheme, available to residents via the internet. OFA is supporting the application for funding of the scheme.

Peter Rawcliffe outlined the new central government funding arrangements for flood-related works. We discovered about three months ago that the Environment Agency had not applied for any money for Oxford under this new scheme. This came as a bombshell: so to remedy this appalling situation we have submitted suggestions to the EA for them to assess (this entails computer modelling) and then to apply the funding formula which tells one how much funding would be available. Proposals that score highly enough will be put forward for consideration by DEFRA’s Thames Regional Flood and Coastal Committee. Proposals have to be in by the summer and the EA is working to that target. We hope to be able to let you know preliminary results soon.

2011 APM Andrew Smith MP

Andrew Smith, MP for Oxford East (above), kindly thanked OFA for their hard work and success, and offered his continuing support.