Scheme to reduce flooding in Oxford will NOT put downstream at greater risk 

An independent review of the Oxford Flood Alleviation Scheme, commissioned by Vale of White Horse District Council, has confirmed that the proposed flood alleviation scheme will have no impact on communities downstream in the Vale or South Oxfordshire.
The Oxford Flood Alleviation Scheme will be approximately three miles long and will run from the north of Botley Road to re-join the River Thames near Kennington.  The scheme will reduce the risk of flooding from the River Thames to all homes and businesses in Oxford, as well as to services and major transport routes into the city, particularly around Botley and Abingdon Road.  This will help avoid a repeat of the disruption and damage caused by floods in 2007, 2012 and 2013/14.
Communities downstream were concerned that the Oxford scheme would increase their flood risk.
In 2016 the Environment Agency produced technical modelling using sophisticated computer programmes which showed that the scheme would not change flood risk of communities downstream. As with all Environment Agency modelling this was independently checked.
In 2017, due to local concerns, Vale of White Horse District Council commissioned independent expert, Water Resource Associates, to further review the work carried out by the Environment Agency.
This independent review confirms that the Oxford Flood Alleviation Scheme will not put communities downstream at any greater risk of flooding. To read the full Water Resource Associates’ review visit whitehorsedc.gov.uk/OFAS.
Cllr Matthew Barber, Leader of Vale of White Horse District Council, said: “This is very positive news.  Although we have always been supportive of the Oxford scheme it was important for us to listen and respond to our residents’ concerns.  We’re pleased that the independent review findings confirm the Environment Agency’s modelling, providing much needed reassurance for downstream communities that they won’t be impacted by the new scheme.
“We know communities by the River Thames will always have concerns over flooding and we will continue to work with them and Environment Agency on feasible and appropriate flood prevention projects, such as the St Helen’s Mill scheme in Abingdon.”
Dr Harvey Rodda from Water Resource Associates said: “After receiving all of the documentation from the Environment Agency and their consultants working on the OFAS we were pleased that a thorough investigation on the potential downstream impacts had taken place and the results showed there would be a negligible impact of flooding on the areas along the downstream reach of the River Thames from Sandford to Mapledurham.”
Jo Larmour, Project Director at the Environment Agency said: “The Oxford Flood Alleviation Scheme will have a positive impact on people and communities outside of Oxford. The scheme will reduce disruption to roads and the railway during flooding, a relief to those who commute into Oxford or travel on surrounding transport links. This will also benefit the approximately 7 million people who visit Oxford every year.”
Advertisements

Thoughts on OFAS

Why do we need a flood scheme at all?

We have had five major floods since 2000 and climate change will make things worse (indeed there is evidence from Oxford University that it already has). Oxford residents, and the economic well-being of the City, will suffer badly if something is not done. While the scheme will cause disruption during its construction it is imperative that Oxford is protected.

But what about downstream, won’t they be worse off?

All the detailed computer modelling for the Scheme (and we have recently heard on the grapevine that a totally independent consultancy has confirmed this ) says that flooding will not be made worse downstream. We know that comparisons are made with the Jubilee River – this scheme is nothing like that. Indeed OFAS is actually increasing the capacity of the floodplain, which together with bunding and rerouting of flow will reduce flood risk to many hundreds of properties.

Is it a concrete channel?

No, it isn’t. What it is is a much more naturalistic 2-stage channel, used around the world for flood relief.

How will the environment be affected?

While there will, regrettably, be some environmental losses, we are pressing hard – collaborating with the Environment Agency, and with support from others, particularly the Freshwater Habitats Trust – for environmental enhancements as part of the scheme. While one cannot compare one environmental loss directly with another environmental gain we believe the positives will be considerable.

Maintenance.

It’s so important that there is a plan now for the very long-term maintenance of the Scheme. In our experience over the last 10 years  “if maintenance can be neglected it probably will be”. There are some honourable exceptions and we certainly have we have no criticism whatever of the local EA maintenance team, who achieve a huge amount with very limited resources. Others do nothing or very little unless goaded and embarrassed into action. This Scheme, being “natural” will deteriorate quickly if not proactively maintained. The initial intent was to plan maintenance for 10 years: that is simply not good enough for such an expensive and important project. We have proposed that maintenance be planned for in perpetuity by setting up a responsible, funded, local body, maybe as a charitable trust (or similar).

A Green group

thinks that Oxford could and should be protected by very different means – while they are short on specifics, their main idea seems to be that planting enough trees upstream in the Cotswolds would solve Oxford’s problems. It wouldn’t. Expert opinion at our 2015 Symposium of Natural Flood Management (NFM)  made that very clear. Even afforesting the whole of the Cotswolds (not that that would ever happen) would not do the job. Oxford is simply too far downstream for that. That’s not to say that NFM can’t work in smaller catchments, nor that it might not make a contribution.

Flooding land upstream?

The Environment Agency’s Oxford Flood Risk Management Strategy (OFRMS) suggests this may be needed one day if climate change makes things sufficiently bad. Involving as it would temporary flooding large areas of farmland and other land it is never likely to be easy to implement.