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The Relief Channel is Completed
but is it up to it?

Includes updates from 2001 and 2002

Update January 2003

Over the New Year of 2002/03 the River Thames was in flood and probably reached levels closer to 1947, the time of last serious floods, than at any other time in the last 55 years. The Jubilee River took the strain, and the stretch of the Thames, from Maidenhead to Windsor, that the relief channel was designed to protect, remained only on Flood Watch with no property at risk. So the Jubilee River passed its first test with flying colours, but residents downstream were less impressed! See Aftermath. See the Floods of 2003 for a report and pictures from the Windsor area.

The following was first published in the summer of 2002

Flood Relief Scheme named The Jubilee River
Will it be up to the job?

In their Newsletter dated April 2001, The Environment Agency has published the name for the Flood Relief Scheme between Maidenhead and Windsor. It is to be known as The Jubilee River. This name was chosen following a competition and was selected from others such as Aquarius, The Garter River, The Thames Moat, Thamesis, Willow River and Baby Thames
 We still maintain that in exceptional conditions, the Jubilee River will still not prevent flooding of our valley for "once the valley is full, it is full, and you can dig as many holes as you like..." there is no doubt that lesser floods will be prevented with this and the associated flood defences that are being constructed in tandem with the new channel.
  Given very slightly different circumstances, an inundation could well have happened during the past winter for the past twelve months have been exceptionally wet. The Agency Newsletter gives details of monthly rainfall from April 2000 to March 2001 in the catchment area above Teddington Lock, the point at which the Thames becomes tidal as it flows through the London area. These figures show that in April 2000 approximately three times the average rainfall was measured (over 140mm), with May 2000 also being above average too, almost 90mm compared with an average of under 60mm.
 June, July and August allowed some respite being at or below average levels but then in September figures are up by around 65% to over 100mm. October 2000 saw almost 160mm of rain with a particularly violent rainstorm on the night of October 30th. With further substantial rain in November and early December, the figures are approaching double the averages for the period 1961-1990, the standard period for these averages to be calculated. It was at this time that the national news was beginning to report serious flood problems in parts of the country, initially in Kent. A few days later rivers in Yorkshire were beginning to overtop their banks and on a variety of occasions numerous areas around the country were severely affected, including the River Severn which drains water from the Welsh Mountains through Gloucester to the Severn Estuary. These inundations were aggravated by Spring tides, the point each month at which the gravitational effect of both the sun and the moon are working together to lift natural sea levels resulting in the highest, and lowest, tide heights of the month. Yet Windsor was spared.
 Our own observations of the river, The River in November 2000 and The River in December 2000, show that rainfall and hence periods of high water levels were concentrated in fairly definable periods, and although the weather was almost constantly overcast, at least heavy periods of rain were separated by merely 'damp' periods that allowed the water to pass through the valley and for river levels to fall once more before the next period of heavier rain leading to rising river levels once more
 The reason that we suspect that given other circumstances Windsor could have been in trouble is also reported in the Environment Agency newsletter. This is the effect of ground water on river levels and flows. Early in November 2000 experts were reporting that the likelihood was that unusually extensive flooding would occur regularly throughout the winter in susceptible areas of the UK because ground water levels were exceptionally high following the extended rain of preceding months. The ground can absorb and, in normal circumstances, retain, large volumes of water, similar to a giant sponge, only slowly releasing the water as it filters through into springs and streams. In the last year we have seen such high levels of persistent rain, that the ground is saturated and can absorb no more. Any heavy rain thereafter will flow straight off the surface and into the water courses. Continued heavy rain will certainly result in rising water levels as there is a limit to the amount of water that can 'escape' to the sea. In normal times these limits are rarely exceeded, and if they are it is for a minimal period, so the effects are rarely noticed. In 1947 a similar situation existed in that surface water could not escape fast enough and filled the Thames Valley to the point at which towns were flooded. But this was because the preceding winter had been exceptionally cold, substantial falls of snow had accumulated and when the thaw arrived, it was a sudden and accompanied by heavy rain upstream. The ground remained frozen and so the thawing snows and heavy rain, combined and the flood resulted. The Floods of 1947. Unfortunately saturated land causes the same effect.
  We are fortunate in this area that a major inundation did not occur this past winter, but ground water levels remain the highest for at least forty years. For example, Stonor Manor, Henley, is four metres (13 feet) above its previous record height in 1961. Another effect of this increased water table is the movement of sources of streams. The River Mimram in Hertfordshire is 5km (3 miles approx.) further up its valley than previously and there are a number of other examples throughout this area. Previously dry valleys now have their own streams once more and over Easter we noticed that farms along the road to Bledlow Ridge in the Chilterns, all had pumps and hoses laid out, attempting to pump out water that must have been rising, spring-like, inside their houses. The road throughout the valley had become a stream and all farm land throughout this area have puddles, ponds, and even lakes that just refuse to drain away.
 There is little that the authorities can do in such conditions except hope that this summer will be drier than usual to give the water courses and land a chance to dry out so that any future heavy rain in the coming few months can be absorbed. If this drying out fails to materialise then a repeat of the rainfall in October and November 2000 will result in higher flood levels next winter.

Other updates

October 2002. Be prepared!

from The Informer, Windsor, October 9th 2002

Windsor residents are feeling just a tad bemused by the current headings in the local papers. So what was the £100 million for? Just how effective will our new Jubilee River be? Not very it seems from this week's Press Release from the Environment Agency!
  OK, so it is a national campaign to raise awareness of the chances of flooding in the coming months following the numerous incidents of flooding around the UK in the last year or two. Windsor did not suffer then, and probably is less at risk now with the flood channel completed, but you never know!

October 2001. Scheme nears completion - "It is ready if it is needed" they say!

In their Newsletter dated October 2001, The Environment Agency has announced that despite delays caused by the extensive flooding and high water levels experienced last winter 2000/2001 work is now almost complete on the structure to provide additional control over river levels from Maidenhead through to downstream of Windsor.
Given that last year was an appalling year for many all over the country, especially Kent, Yorkshire and the Severn Valley, residents along the Thames Valley can perhaps breathe a sigh of relief as memories of 1947, now only dim and distant, may well not be repeated.
It must be said that the Environment Agency are only claiming to have 'dramatically reduced' the risk of flooding in this area, although it has been designed to prevent a repeat of the flooding that happened in 1947.
All that remains to be completed in the coming months is landscaping and the adding of final touches before next spring.
The project does not only comprise the Jubilee River. Much work has also been undertaken on raising banks and pathways which will also help, should high water levels return.
We plan to take additional photographs of the Jubilee River as time permits. In the meantime we would welcome any that you may have available, especially if you walk or cycle its length.

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