1. Has there been any assessment of risk?
From my experience in health, water and sanitation in many low-income countries, the first rule is "Do no harm'.
Why commit to an expensive and damaging infrastructure project without at least trying and measuring the effects of the cheaper and existing alternatives? Then there might be some evidence or international best practice base for the decision which could be publicly and transparently examined.
Has there been, for instance, any serious assessment of the risks and how they might be mitigated?
What I fear is a potential future green belt land grab by the council to expand the industrial estate once the meadows are divided by the trough.
Dr Chris Vickery. North Hinksey Resident
2. Wholesale Destruction
The channel varies in width along its length, and sometimes is planned to reach 250m. width, e.g. below North Hinksey Causeway.
It will be a shallow ‘v’ shaped channel, deepening towards the First Stage channel on each side. I estimate average depth of the Second channel to be about 1 metre, but deepening to 2 metres towards the First channel.
I consider this plan as wholesale destruction of a valuable piece of green land close to the centre of Oxford. The felled trees will probably never be replaced with anything as pleasing to look at. The natural atmosphere of the area will be lost.
I am sceptical that maximum flood levels will be lowered significantly in case of heavy rain covering the upper Thames and Cherwell catchments. To give an idea of scale, one inch of rain falling over ten square miles deposits 640,000 cu.m. of water. This would fill the Second Stage Channel, assuming no outflow and one inch of rain in 24hrs, in about 15 hours. Sandford Weir can pass up to about 250 cu.m./sec at full capacity, which is in excess of any likely flow arising from heavy rain falling in the Thames/Cherwell catchment upstream of Oxford.
Problems result from constriction of the Sandford Weirs in order to protect property downstream, which results in flood water backing up above Sandford , with reduced flow rate. Everything comes to a halt, which is what happened in 2007.
Dr Jonathan Madden
3. The modelling (Appendix Q in the planning application) shows that even if the channel is built, the water beside the Hinkseys still reaches the same levels as if the channel is not built.
If the channel and all the associated structures are built, water will still pond up in the whole flood plain from the Old Abingdon Road to Botley, but the extent depends on the length of time for which the peak flooding event occurs.
History suggests that water on the Cherwell/Thames catchment area takes about 56 hours to impact Oxford. If there is just one heavy rainfall it may not do much damage. If the rainfall period lasts for a day after day this may well cause serious flooding in Osney and Botley in particular, as in Feb/March 2014.
Since 2007 there has been a little channel dredging (costing £900,000), the rebuilding pf two large culverts under the railway line below the Devils' backbone (one open, the other to be opened in flood conditions), channel works at Stroud’s Bridge and a major clearout of silt at Munday’s Bridge, though the channel there is still partially blocked. We do not know yet how much these recent works will ease the flow of water from the floodplain near South Hinksey to Sandford Lock, but they should already be having an influence.
The modelling and the archaeological investigations show that there is a ‘pinch point’ to water flow around the Old Abingdon Road. Even when new culverts are built around the ruins it will not take more than 35 cubic metres a second. That is what will cause the water to pond up beside the Hinkseys.
The value of the channel, which according to the EA is costing £83 million, is that it reduces water levels in Botley and Osney. The modelling (Appendix Q in the planning application) shows that even if the channel is built, the water beside the Hinkseys still reaches the same levels as if the channel is not built.
Thus, why not devote some of this money, instead of building the channel, to targeted measures upstream? Dr Rod Chalk has suggested, for a start, culverts at particular places from north to south under the Botley Road. My own favourite is introducing a weir where the Thames joins the Seacourt Stream to send more water down the Seacourt Stream in times of peak flow, by-passing Osney and Botley entirely. Apparently the EA excluded this four years ago, but was it given more than a cursory glance?
Dr Tim King
4. An unproven experiment
The first stage channel, about 20 m wide in the middle, continuously filled with flowing water, has the sloping sides of the second stage channel, between 40 m and 250 m wide, either side.
This second stage channel is only occupied at peak flood time. This is an experiment; has not been tried before in the UK. Weedy species will colonise, but they will be Indian (Himalayan) balsam, and unpalatable hybrid sedges. In view of the lack of maintenance by the EA recently, which has created many of the flooding problems can we expect them to maintain the secondary channel so that water continues to flow along it?
The formation of a new channel will empty the old ones (Hinksey, much of Bulstake and Seacourt Streams) creating anaerobic swamps and killing all the fish and wildlife characteristic of a healthy channel. This must be set against any eventual gain of wildlife.
It is fake news for the EA to claim that the destruction of up to 4,000 trees, with its effects on bats, birds, insects, bryophytes, lichens, and so on will produce a net increase in wildlife. It takes 60-80 years to create the full biodiversity of a newly created habitat from scratch (references can be provided), and that goes for freshwater, swamps and woodland as well as MG4 flood meadows.
No previous example
The EA have been forced to use the TVERC ‘biodiversity calculator’ which is based on area of potential habitat rather than species richness or diversity. There has been no case in the UK of a flood meadow being created from ordinary grassland (e.g.MG5), because it requires the purchase of land which is occasionally flooded, and the expensive annual regime of an annual hay cut followed by aftermath grazing.
Hinksey Meadow has been a flood meadow for 1000 years and is so much more diverse than Iffley Meads SSSI (BBOWT). There are 199 ha of MG4a vegetation left in Britain and 7 ha is on that site, which the channel and its construction is due to devastate; the drying out caused by this channel may well put paid to the rest. By suggesting that it can be replaced elsewhere at a stoke, the EA either displays considerable ignorance or a cynical disregard for biodiversity and the public.
Dr Tim King
5. Precious land, precious water: why the present Flood Alleviation Scheme fails to deliver a solution
We should not allow subterfuge and alacrity for finding a ‘solution’ to one problem to approve hastily a crude, crass and disruptive plan. Time, money and cross-discipline creative energy needs to be invested by Oxford which is a home to heritage, research and innovation, to come up with a superior plan to conserve water that will confront the complex challenges of the future without changing forever the places that we should be cherishing and conserving.
Limited public debate
At first it seems extraordinary that there has been relatively little discussion about a scheme - estimated at costing the vast sum of £120 million - that will cause an unprecedented level of disturbance and environmental change in one of the most beautiful parts of Oxford.
Why has public debate and interest in the scheme has been at a rather low level? In part, I am sure that this is because so few people have become aware of how dramatic and extensive the ‘environmental re-engineering’ will be. The official material that came through my letter box was, to be polite, understated. If I had not heard, by word of mouth, about the nature of the plans I would bet that I’d still be in the dark about it all. Whilst there were opportunities to see and discuss the plans, I did not get the feeling that this grand scheme was being given the sort of profile that such a huge investment would normally receive. Inevitably, one begins to wonder to why this might be the case.
Could it be that the plans would not withstand closer scrutiny? Casually one might concede that a changing climate will necessitate improving the flood protection by such radical methods. However, the problem is much more complex. To anticipate future pressures generated by man-made changes not only on the floodplain but also surrounding areas will be extremely difficult.
Twenty years from now, will everyone look back and bitterly regret allowing a vast and expensive ditch to be ploughed through a swathe of previously protected countryside? I am sure that this will be the case. We need to ensure that the present scheme is not approved. We must not allow other options that are more in keeping with the environment, represent sustainable development and preserve precious natural resources to be cast aside.
This scheme conflicts with other regional needs. Whilst it intends to move water out of the Oxford floodplain, simultaneously in Oxfordshire there is a considerable debate over planning a water reservoir to meet with projected requirements. Not only have water shortages been headline-making this summer but high profile claims have been made that climate change will exacerbate water shortages in the future which raise the possibility of insufficient supplies to meet consumer demands.
Short Sighted Failure
It seems short-sighted to design and implement, at great expense, a ditch to move precious water away from Oxford. It seems common sense to ensure that water is conserved and employ various means to prevent excess water from moving into the floodplain in the first instance. A feasible plan is needed to conserve water for later use when it is plentiful and would otherwise cause flooding. Oxford is home to much internationally significant research and innovation. Its inability to deliver a state-of-the-art plan that will solve these closely connected problems with minimal environmental impacts would be a spectacular failure and a wasted opportunity.
The need to have joined-up approaches to water management will only become more important in the future. In recent years there has been a considerable amount of development in the Botley and Cumnor areas. This is increasing the pressure on the immediate area of floodplain due to water run-off from buildings and other structures whilst extra residents and businesses add to the demand for fresh water supplies.
On the horizon, more dramatic developments and many new houses are planned for the local area. Building almost from scratch a drainage channel across the floodplain seems a blunt, unsophisticated device. Is it possible to factor in all the potential effects of man-made environmental change to guarantee that the £120 million scheme can even solve the flooding problem alone? Surely it is better to stall such huge costs and determine if a more robust, creative and wide-ranging answer to local needs can be forthcoming?
The claims by the Environment Agency that large-scale re-engineering of the local landscape and ecology will, in time, increase biodiversity seems specious. Where is the evidence to support this? It has taken considerable conservation efforts to expand the Oxford population of just one species - the endangered creeping marshwort (Apium repens) - into a protected area in a location that will be impacted by the scheme. Does the Environment Agency genuinely believe that actions such as cutting down hundreds of mature trees, bulldozing through old hedgerows and carving a huge ditch into ancient flood meadows to modify local hydrology will not generate a long-term decrease in the biodiversity?
Evidence indicates that the Environment Agency is not sufficiently prepared for the aftermath of the grand-scale disturbances to the area. The proposed radical changes to the environment will benefit invasive, non-native species. These will thrive and spread after the scheme has been instigated, often excluding native species. Their potential effect on the operation and effectiveness of the channel itself has not been given adequate attention. Control - let alone eradication - of invasive species across such a swathe of land is highly problematic. The planning submission appears to have no convincing long-term plan to deal with invasive species across the developed area – this is a serious oversight in planning for the future.
In particular, Hinksey Meadow represents a biodiverse habitat that was once far more abundant but is now vanishingly rare. How can a channel of this kind be inflicted on this precious protected area? Oxford has an international reputation for heritage and conservation yet seems prepared to sacrifice an important area for development as a drainage system. With increasingly fragmented natural habitats, conservation of this corridor of land in an urban setting should be a priority.
We should not allow subterfuge and alacrity for finding a ‘solution’ to one problem to approve hastily a crude, crass and disruptive plan. Time, money and cross-discipline creative energy needs to be invested to come up with a superior plan that will confront the complex challenges of the future without changing forever the places that we should be cherishing and conserving.
Dr. Robert Grant-Downton
6. On trying to get those in power to change their minds
Wherever we look, the most obvious trappings of power and competence involve appearing to be in control and appearing to be right. However illusory these appearances may be, maintenance of the illusion is accorded very high priority by governments, institutions, and our own personal psyches. Instead of associating competence with a well-manicured record of correct decisions, we need to view it as the ability to fail creatively and to learn from the experience.
B.F.Johnston and W.C Clark. Redesigning Rural Development, (John Hopkins University Press 1982) p.240
7. Plants grow in clogged drains in the Botley Road
I am constantly looking at the waterways between Osney Island and Seacourt Tower. I’ve been here 40 years and only once have I seen anyone doing any clearing. Numerous drains along the Botley Road are so clogged with soil that plants are growing out of them.
I feel incandescent at the obfuscation from the council with every complaint. The council think trees, as does GWR, are a plant in the way, something to be maimed so it dies, and then they can chop it down.
An Osney Resident