Will a channel be the answer to flooding? + Video

Banbury Cake: David Ramsbottom, flood management director, and Andy Tagg, flood group manager, look over a large testing tanks. Picture: OX64559 David Fleming Buy this photo » David Ramsbottom, flood management director, and Andy Tagg, flood group manager, look over a large testing tanks. Picture: OX64559 David Fleming

UNFORTUNATELY forecasters predict climate change will cause more rain and more flooding in the future.

With two severe floods within two years, Oxfordshire is bearing the brunt of that reality.

Flooding earlier this month claimed two lives, destroyed homes and businesses, and shut two of Oxford’s main roads for several days.

In its wake, experts are asking again: how do you solve the problem of flooding in Oxford?

More than 3,600 homes and businesses in Oxford lie in floodplains.

And just 12 miles away from the city lies the headquarters of a global research and testing company which counts flood defence within its specialisms.

HR Wallingford was initially a government organisation, but now claims the Government and the Environment Agency (EA) as its clients.

The head of flood management for HR Wallingford, David Ramsbottom, is convinced a £125m scheme could be the answer.

He worked with the EA in 2009 creating an Oxfordshire strategy for flooding.

They came up with plans for a flood diversion channel running west of Oxford starting north of Botley Road and ending at Sandford Lock in Kennington.

The 2m deep by 30m wide earth and gravel channel was christened the Western Conveyance Channel.

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But although in a public consultation of 2009, the EA stated, “work could start by 2013”, the scheme was shelved because of the estimated £160m cost.

Mr Ramsbottom said: “The Thames at Oxford divides into lots of channels so there are lots of routes into which the water could flow.

“But we created a computerised model of the complicated system in Oxford to try and predict where the water would go and it looked like it would work.

“My personal view is the new river channel would be the best thing to have, but it is expensive.”

He explained building a flood wall to try to defend parts of the city would simply not work because the ground under Oxford is very permeable and so water would just seep beneath.

Banbury Cake:

  • Flooding at Bullstake Close in the Botley Road area of Oxford on January 10

The EA also looked into lowering the floodplains by removing one metre of top soil, but that plan was ruled out.

Since 2009 the EA has reworked the project so it would cost £125m, rather than £160m, but the funds are still out of reach.

Environment Agency spokeswoman Cheryl Walmsley said: “We would expect to be able to bid for £40m from the Government under the partnership funding approach, once the rest has been secured from third party contributions.

However, this next phase does not yet meet the economic criteria needed for work to start.

“We have already delivered the first phases of the Oxford strategy and we have spent £2.5m on a range of measures, such as the temporary defences, to reduce the risk to properties from lower level flooding.”

Defences including putting up temporary barriers at Osney Island proved a success in the floods.

It is the smaller flood defence systems which the head of HR Wallingford’s flood group Andy Tagg backs as the solution to the problem.

He said: “Clearly we need to think very clearly about just allowing rivers to flood in their natural floodplains. Building big defences to channel the water down really isn’t the answer because it just passes the problem on.

“We need to let the river flood naturally along its whole length.

“Smaller flood defence systems for houses is the best way forward.”

Included in this are barriers for doors, toilet bungs to stop flooded water coming up through the sewerage system, and new floodproof UPVC doors.

Mr Tagg has also advised the Government on how to build new homes to better standards of flood resistance.

This included using waterproof insulation, waterproof paints, and moving electrics a metre higher.

He added: “These kinds of devices have become a lot more popular.

“The estimates are about 300,000 homes in the UK will need these kinds of devices in 25 years, and it costs about £30,000 to put right a flooded house.”

A PLACE WHERE THE EXPERTS STUDY WATER MANAGEMENT

HR Wallingford was originally a government organisation formed in 1947 called the Hydraulic Research Station.

It moved from London in 1951 to set up base in Howbery Business Park at Crowmarsh Gifford, Wallingford.

In 1982 it was the second organisation to be privatised by Margaret Thatcher. It was renamed HR Wallingford in 1991.

In 2003 it built the biggest test centre in the UK for flood testing and research.

HR Wallingford is an international hydraulics organisation which acts as a consultancy and research company. It has offices in Houston, New York, Dubai, Mumbai, Shanghai, Kuala Lumpur, Perth, and Brisbane, but its headquarters are in Wallingford.

It deals with coasts, shipping, climate change, drought, energy and flooding.

Flood and water management is one of its five departments.

Banbury Cake:

  • A mocked-up living room with flood defences at the research station

Its biggest clients include the Government and the Environment Agency.

The company employs about 290 people, with 25 people working specifically in the “flood group”.

The floods group covers extreme flooding, flood defences, forecasting, the environment and risk analysis.

It has tested about 20 flood defence systems since 2010.

The tests are done either through a computerised model, or in its 11,200m test centre called the Froude Modelling Hall.

CASE STUDY - JUBILEE RIVER FLOOD ALLEVIATION SCHEME, WINDSOR

  • The Jubilee River was built in the 1990s at a cost of approximately £110million as a flood alleviation scheme similar to what was planned for Oxford.
  • It opened in 2002 to reduce the risk of flooding to more than 3,000 homes in Cookham, Maidenhead, Windsor and Eton.
  • It is 7 and 1/4 miles long and 50-metres wide.
  • It diverts river water from the Thames upstream of Maidenhead, and runs parallel and to the north of the river before rejoining the Thames downstream of Windsor at Datchet.
  • During flooding, water is diverted from the Thames into the Jubilee River, reducing water levels through Maidenhead, Windsor and Eton.

Banbury Cake:

  • The Jubilee River flood alleviation scheme just north of the Thames carries flood water past the towns of Windsor and Eton close to the M4 at Slough
  • More than 1,000 homes in the Maidenhead and Windsor area were protected from flooding by the scheme in 2003. But communities downstream of the scheme, in Datchet and Old Windsor complained the scheme worsened the flooding.
  • In 2004 an independent review concluded it did not. Also during the 2003 floods the channel was damaged and needed expensive repair work.
  • Technical director for flood management of HR Wallingford, David Ramsbottom, said: “The concept worked, but at the first major flood there was some bad damage done to the actual river which cost about £2.5m to repair. So it is a proven concept, it will work.”

Comments (5)

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5:45pm Wed 22 Jan 14

AlanAudio says...

Obviously something needs to be done to protect homes and businesses in Oxford, but won't a relief channel simply speed up the water on it's way to towns further downstream and make things even worse for them ?

The countryside around Oxford is a flood plain and when that land is temporarily flooded, it holds water that would otherwise cause problems both locally and elsewhere. We need to be looking at ways of making the flood plains do a better job of soaking up excess water, rather than simply sending it off downstream.

It's no good looking at one location in isolation, we need to consider the entire route of our rivers and all of the countryside and townscapes near to them.
Obviously something needs to be done to protect homes and businesses in Oxford, but won't a relief channel simply speed up the water on it's way to towns further downstream and make things even worse for them ? The countryside around Oxford is a flood plain and when that land is temporarily flooded, it holds water that would otherwise cause problems both locally and elsewhere. We need to be looking at ways of making the flood plains do a better job of soaking up excess water, rather than simply sending it off downstream. It's no good looking at one location in isolation, we need to consider the entire route of our rivers and all of the countryside and townscapes near to them. AlanAudio

7:14pm Wed 22 Jan 14

Englishman says...

We need to stop building on flood plains. Simple really.
We need to stop building on flood plains. Simple really. Englishman

2:27am Thu 23 Jan 14

Sophia says...

Englishman wrote:
We need to stop building on flood plains. Simple really.
No, it isnt.

Long term the main cause of increased flooding is not building on he floodplain but climate change, with heavier, more sustained downpours

And to the extent that building on the plain is a problem, not building more would not deal with what has already been built.

A 'bypass', vastly expensive, simply ensures Abingdon and Reading flood more quickly and for longer

The answer is a combination of small scale preventive schemes, flood proofing of individual houses, keeping watercourses clear and perhaps deepening floodable areas of countryside away from homes to take water out of the river at peak flood. In fact, more of what has already been done and which has proved successful to date.
[quote][p][bold]Englishman[/bold] wrote: We need to stop building on flood plains. Simple really.[/p][/quote]No, it isnt. Long term the main cause of increased flooding is not building on he floodplain but climate change, with heavier, more sustained downpours And to the extent that building on the plain is a problem, not building more would not deal with what has already been built. A 'bypass', vastly expensive, simply ensures Abingdon and Reading flood more quickly and for longer The answer is a combination of small scale preventive schemes, flood proofing of individual houses, keeping watercourses clear and perhaps deepening floodable areas of countryside away from homes to take water out of the river at peak flood. In fact, more of what has already been done and which has proved successful to date. Sophia

10:03am Thu 23 Jan 14

Yellowlines says...

It's more simple than you think. Dredge the Seacourt stream which bypasses Oxford and comes out above the lock at Sandford and then force the environment agency to start dredging again. If the river is deeper and wider it can carry the extra water. If work is done from Sanford downstream then it should be ok. If farmers kept their river banks free from fallen trees this would help greatly.
It's more simple than you think. Dredge the Seacourt stream which bypasses Oxford and comes out above the lock at Sandford and then force the environment agency to start dredging again. If the river is deeper and wider it can carry the extra water. If work is done from Sanford downstream then it should be ok. If farmers kept their river banks free from fallen trees this would help greatly. Yellowlines

12:19pm Thu 23 Jan 14

Patrick, Devon says...

Yellowlines wrote:
It's more simple than you think. Dredge the Seacourt stream which bypasses Oxford and comes out above the lock at Sandford and then force the environment agency to start dredging again. If the river is deeper and wider it can carry the extra water. If work is done from Sanford downstream then it should be ok. If farmers kept their river banks free from fallen trees this would help greatly.
All that does is speed up the flow downsrteam and cause more floods there. Its the capacity of the floodplain and the capacity of the surrounding land to hold the water that counts. Natural wetlands serve such purpose, but modern agriculture has drained many, which means that rivers rise very quickly when it rains, and fall very quickly when it doesnt. Hence we have a flood/drought cycle. The simple answer is to understand how this works in nature, and amend our land use practise accordingly.

In urban areas, the paving over of gardens to provide car parking is also contributing to the flood/drought problem.
[quote][p][bold]Yellowlines[/bold] wrote: It's more simple than you think. Dredge the Seacourt stream which bypasses Oxford and comes out above the lock at Sandford and then force the environment agency to start dredging again. If the river is deeper and wider it can carry the extra water. If work is done from Sanford downstream then it should be ok. If farmers kept their river banks free from fallen trees this would help greatly.[/p][/quote]All that does is speed up the flow downsrteam and cause more floods there. Its the capacity of the floodplain and the capacity of the surrounding land to hold the water that counts. Natural wetlands serve such purpose, but modern agriculture has drained many, which means that rivers rise very quickly when it rains, and fall very quickly when it doesnt. Hence we have a flood/drought cycle. The simple answer is to understand how this works in nature, and amend our land use practise accordingly. In urban areas, the paving over of gardens to provide car parking is also contributing to the flood/drought problem. Patrick, Devon

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