Interclubs 2008 - or not! :-(
A few point-and-click pics taken of the flooding that is expected to get worse! It was over the channel walls earlier and another 20+ cumecs are expected before the weekend that the Interclubs were going to be held! See you all in 2009!
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Addendum January 2011
These notes are added following the issue of a study that was commisioned to establish what would happen if the hippos were left in the channel when the river flooded. Based upon my images
and observations here, the results can be seen as a matter of fact.
The staff gauge in the main river just above the sluice gate at the top of the channel was reading 23.980.
I have added 6 images from February 2009. These show 4 images of Newnham sluice and two of the Cardington Channel - one from above the bridge and one from below showing the stilling basin. The image from above the bridge shows the river level approximately 300mm under the bridge soffit ie lower than the level when the September 2008 images were taken (200mm). Whilst the levels were a little different, it is possible to see the effect that the hippos and boards have in the flooded channel because, in February 2009 the channel had no hippos nor boards in place and in September 2008 both of these were in situ.
It seems that the resultant difference can clearly be seen by the river level at the stilling basin and in the channel itself. When considering the following, it must be kept in mind that the level of the main river was around 100mm lower in Feb 2009. Both the stilling basin and the channel level can be seen to be noticably closer to the top of the concrete surrounding structure in September 2008.
Whilst the difference in water level in the stilling basin is maybe 100mm to 150mm where the channel begins, the water in the channel is around 350mm lower at the beginning of the channel.
But the September 2008 level drops noticably as we look at the picture halfway down the channel. Given that the water discharging from the end of the channel is essentially spilling over the
boards into a lower level of water with only the centre section of the channel discharging horizontally into the water below, there is minimal resistance from the rising water below the channel. It can therefore be concluded that the hippos in the channel and boards at each end are directly responsible for the increase in water level but only within the channel itself. There is no evidence to suggest that water levels upsteam or downstream of the channel are affected.
In the event that the river level at the entrance to the stilling basin increases by 200mm, at which level the flow will be obstructed by the footbridge itself, the river will spill over the concrete surrounding structure in the stilling basin irrespective of any hippos or boards being in place. The level in the channel is likely to spill over the concrete surrounding structure in the region of the upper area but will clearly succeed in discharging all of the flow that is able to be channelled into it with the restriction being the footbridge. The only factor that will cause the level of the channel to increase will then be obstructions further downstream causing the lower water level to rise, creating hydraulic backpressure against the flow. The channel will then break its banks for the entire length of the channel irrespective of their being any hippos or boards in situ.
The conclusion is that the installation of the hippos and boards at either end of the channel have no effect upon the capability of the channel to discharge flood water entering the stilling basin and no greater flooding is caused above the channel, within it or below it. Accordingly, I see no reason why the hippos and boards cannot be left in the channel to allow increased use of the facility as a slalom training venue. It is drastically underused at present due to the significant set-up time required to install and remove hippos and boards.
Read More*************************************
Addendum January 2011
These notes are added following the issue of a study that was commisioned to establish what would happen if the hippos were left in the channel when the river flooded. Based upon my images
and observations here, the results can be seen as a matter of fact.
The staff gauge in the main river just above the sluice gate at the top of the channel was reading 23.980.
I have added 6 images from February 2009. These show 4 images of Newnham sluice and two of the Cardington Channel - one from above the bridge and one from below showing the stilling basin. The image from above the bridge shows the river level approximately 300mm under the bridge soffit ie lower than the level when the September 2008 images were taken (200mm). Whilst the levels were a little different, it is possible to see the effect that the hippos and boards have in the flooded channel because, in February 2009 the channel had no hippos nor boards in place and in September 2008 both of these were in situ.
It seems that the resultant difference can clearly be seen by the river level at the stilling basin and in the channel itself. When considering the following, it must be kept in mind that the level of the main river was around 100mm lower in Feb 2009. Both the stilling basin and the channel level can be seen to be noticably closer to the top of the concrete surrounding structure in September 2008.
Whilst the difference in water level in the stilling basin is maybe 100mm to 150mm where the channel begins, the water in the channel is around 350mm lower at the beginning of the channel.
But the September 2008 level drops noticably as we look at the picture halfway down the channel. Given that the water discharging from the end of the channel is essentially spilling over the
boards into a lower level of water with only the centre section of the channel discharging horizontally into the water below, there is minimal resistance from the rising water below the channel. It can therefore be concluded that the hippos in the channel and boards at each end are directly responsible for the increase in water level but only within the channel itself. There is no evidence to suggest that water levels upsteam or downstream of the channel are affected.
In the event that the river level at the entrance to the stilling basin increases by 200mm, at which level the flow will be obstructed by the footbridge itself, the river will spill over the concrete surrounding structure in the stilling basin irrespective of any hippos or boards being in place. The level in the channel is likely to spill over the concrete surrounding structure in the region of the upper area but will clearly succeed in discharging all of the flow that is able to be channelled into it with the restriction being the footbridge. The only factor that will cause the level of the channel to increase will then be obstructions further downstream causing the lower water level to rise, creating hydraulic backpressure against the flow. The channel will then break its banks for the entire length of the channel irrespective of their being any hippos or boards in situ.
The conclusion is that the installation of the hippos and boards at either end of the channel have no effect upon the capability of the channel to discharge flood water entering the stilling basin and no greater flooding is caused above the channel, within it or below it. Accordingly, I see no reason why the hippos and boards cannot be left in the channel to allow increased use of the facility as a slalom training venue. It is drastically underused at present due to the significant set-up time required to install and remove hippos and boards.
