Issued by the Ferry Hinksey Trust
Press Release
For Immediate Release
30 November 2023
NEARLY 1,000 COMPULSORY PURCHASE ORDERS COULD BE SCRAPPED BY A TWIN-PIPE & PUMP HOUSE ALTERNATIVE TO OXFORD FLOOD ALLEVIATION SCHEME (OFAS) – PUBLIC INQUIRY HEARS TODAY
NEARLY 1,000 Compulsory Purchase Orders (CPO) of land – many historic, and of environmental significance – could be scrapped if the Environment Agency (EA) adopted an alternative Twin-Pipe and Pump House proposal for Oxford’s controversial £176-million Flood Alleviation Scheme (OFAS).
In evidence submitted to a Public Inquiry into the OFAS, taking place at the King’s Centre, Osney Mead, campaigners will today (NOV 30) claim the EA has not met legal tests for CPOs, including fully considering all viable alternatives.
Jonathan Madden and Kevin Larkin, on behalf of the Ferry Hinksey Trust (FHT) the Oxford Flood and Environmental Group (OFEG) and the Hinksey and Osney Environment Group (HOEG) filed the Twin-Pipe and Pump House Scheme. one of four alternative schemes to the Inquiry, and will today be cross-examined by lawyers for the EA.
Mr Madden, who lives in Woodstock, is an exploration geophysicist, and client representative for marine engineering geophysical projects, whilst Mr Larkin is a practising architect who has designed major projects, including Heathrow Airport’s control tower.
Their alternative proposal would largely remove the need for CPOs - only temporary land disturbance will be required, with the exception of the pump house itself. The current OFAS is said to currently cost £176-million and includes creating a 5km long ‘channel’ which would run from just north of Botley Road, to south of the A423 southern bypass near Kennington, where it would re-join the River Thames. Leading independent ecologists say the dug channel would destroy 13 acres of the rich, rare species of the irreplaceable plant community of Hinksey Meadow. An estimated 4,000 mature trees and miles of hedgerows would also be lost in the West Oxford wildlife corridor and green belt.
Messrs Madden and Larkin, and the OFAS objectors - many of whom have been personally affected by past Oxford floods - do not object, in principle, to a flood alleviation scheme, but strenuously object to the EA’s failure to consider professionally designed alternatives to their CPO Scheme. They will seek to persuade the Inquiry Chairman that the EA scheme should be put on hold whilst it fully investigates visible alternatives – including the twin-pipe and pump house scheme.
Mr Madden said: "Our system has a pump house at the head-end to discharge water immediately downstream of Old Abingdon Road. A pair of parallel pipes, of 2-metre internal diameter would run from a pumping site in a small meadow at Seacourt, under the Botley Road and subsequently along the Hinksey Plain to the Old Abingdon Road.
"The system has been designed to pump at a maximum flow velocity of 7-metres/second, with a total maximum flow volume of 3.8-million cubic metres per day, for the two pipes combined. This permits controlled flow, from minimum of near zero up to maximum flow, with a rapid system response. Vitally – and in stark comparison to the EA current proposal – pumping can begin during the early stages of a flood, thereby reducing peak water levels relative to OFAS.
"Our proposal protects ancient meadow by ending the pipeline with a spillway immediately downstream of Old Abingdon Road, making it a viable and cost-efficient alternative to the OFAS’s channel/swale combination. Beyond such spillway it would ideally combine with another alternative filed with the Inquiry (Alternative A3), adding the benefit of controlled pumping in the early stages of a damaging flood to exploit water-flow capacity downstream of the city. Vitally, our system will largely remove the need for CPOs. Only temporary land disturbance will be required, with the exception of the pump house itself."
Plans which the inquiry will examine include:
- the two pipes laid side by side in a 4m-deep trench, at a nominal depth to top of pipes of 2m below ground level
- at stream intersections trench depth will be 5m, to permit uninhibited stream flow. Nominal total trench width is 8m.
- the volume of trench excavated material will be 150,000 cubic metres, with the volume of backfilled material after pipe-laying being 115,000 cubic metres, leaving only 35,000 cubic metres of spoil to be removed off site, or to be distributed over the pipeline route as a shallow bund.
- flow water energy/momentum will be dispersed at the downstream end by baffles on a wide concrete base - minimising erosion along the river bed.
- anchored pipes to the trench bottom to prevent flotational heave during wet periods, when the pipes are partially flooded or empty of water.
- the pump house and water collection pool will be sited in an excavated area in the small meadow adjacent to Seacourt Park & Ride
- anticipating loss of mains electrical power, backup diesel generator(s) would be sited on the top of the pump house
- in the event of mains electric power loss, automatic switching to generator power will take place. If one or more of the four pumps fail, the remaining operational pumps can continue moving water through. Valves on the pumphouse exit manifold can direct and limit pump-to-pipe flow as required.
Mr Madden will tell the Inquiry the alternative pump system can intervene early during flooding, and uses standard industry equipment, saving time and tax-payers money. He said: "Our system moves water volumes similar to the maximum OFAS flow rate in a controlled manner, while at the same time the natural drainage rate of the Meadows is retained: the pumped flow being additional, thereby giving a maximum total potential water drainage rate greater than that of OFAS.
"And as an improvement to the OFAS, our fast pumping can begin at an early stage of flooding, thereby ‘flattening’ the water level curve. It is also cost-efficient in terms of equipment and civil engineering. All equipment and pipes are industry standard, available ‘off the shelf’ as per usual delivery notice periods. And our entire system can be controlled remotely, with inputs from water-level sensors along the flood-control route.
He concluded: "Despite our best efforts, the Agency declined many opportunities to fully explore this pumped alternative, as well as the others put forward, and to model them all in the same way as the CPO Scheme."
The alternative pumping system has an outline cost of £22.1-million but is within the overall £70-million cost-saving proposals presented by opponents of the OFAS to the Inquiry. Following the conclusion of the Public Inquiry on December 18, the Chairman is expected to report to the Environment Secretary around March 2024, who will then rule on whether the current OFAS can proceed.
- Further details of the Twin-Pipes and Pump House scheme can be viewed at Latest News (hinkseyandosney.org)
ENDS
For further information/Interview:
Canon Chris Sugden 07808297043 csugden@ocrpl.org;
(Chair – FHT)
Jonathan Madden jonathan.madden@prussia.globalnet.co.uk
(Alternative Pumping System Designer)
Paul Eddy 07923653781 paul@pauleddy.uk;
(Public Relations Consultant to FHT)