Low Flow in Teddington

[SnowCat]

Teddington Reach - Low Flow Warning.

Is this to slow the rowers down, Tedders?

Guess, it's nearly time for the mudlarks again?

 

[teddington_lock]

Not sure what that is about , probably someone has hit the wrong button !

3 rads open at Tedders as of 0600 this morning , so doubt there is low flow.

Give the lock a buzz and enquire , I'm not back until tonight.

 

[SnowCat]

So not a massive treacle spillage then?

Ah well, perhaps someone was bored with all the yellow boards

 

[teddington_lock]

Just spoke with them , no 'low flow' warnings , so I've changed it.

Thanks for pointing it out.

 

[Brayman]

When would we ever expect to get a Low Flow warning, and is it perhaps, really only relevant to Teddington?

 

[stuartbaggs]

And why exactly is it something to be warned of?

Are there any other strange warnings that can be displayed on the conditions page?

 

[teddington_lock]

No , low flow is the only oddity

It is in place mainly for the summer months , should we ever have any.

As you know , part of the EA drought plan for the thames is to limit locks to once every fifteen minutes or so in times of severe drought , I suspect that the 'low flow' warning would be used in this instance. Probably triggered by when one of the flow measures along the river hits a predetermined number of cumecs ?

Peculiarly the low flow warning might not really apply to Tedders as we have the lower thames operating agreement in place where XYZ cumecs has to pass over our weir each day. It can be altered by consultation temporarily , but I believe it can never drop below 400 million litres per day.

 

[Brayman]

Thanks Howard

 

[Richard Shead]

What about draw off ?

 

[chuckaduck]

What about draw off ?

I was thinking the same ... isnt the annual draw off at this time of year, ony didnt mention it as it seemed obvious !!!

 

[stuartbaggs]

Tomorrow

http://www.pla.co.uk/display_fixedpage.cfm/id/2695

 

[My She]

Totally ignorant here - what is the annual draw off?? I'm guessing to top up reservoirs??

 

[Mirror Painter]

http://www.thamesdiscovery.org/events/thames-draw-off-walk

I think I'd like to go to this ^ . Have asked the wife what's in the diary.

 

[Richard Shead]

Totally ignorant here - what is the annual draw off?? I'm guessing to top up reservoirs??

When they leave the gates open at Richmond and let the tide right out.

 

[Mirror Painter]

MyShe

http://www.pla.co.uk/display_fixedpage.cfm/id/2695

Had to look it up this morning

 

[Richard Shead]

Some pix

Eel Pie and Marble Hill Park

 

[TrueBlue]

......
Peculiarly the low flow warning might not really apply to Tedders as we have the lower thames operating agreement in place where XYZ cumecs has to pass over our weir each day. It can be altered by consultation temporarily , but I believe it can never drop below 400 million litres per day.

I have always hesitated to ask -
Why is there a statutory / contractual obligation to pass a certain amount of water downstream. After all it gets flushed downstream to join all the flotsam and jetsam that washes back and forth in that nasty tidal bit?

I could understand some obligation in olden days when there were mills upstream (after all that's why a number of the weirs and hence locks were constructed in the first place). A similar arrangement for Thames water to abstract "our" nice clean water is understandable.

BUT AFAIK there is no abstraction below Tedders.

Does anyone know if similar agreements are in place on other rivers?

 

[teddington_lock]

AFAIK it's to keep a certain amount of water flowing through London in order to stop it stagnating in the capital.

In theory , if there was no flow , then the tide would just push the same bit of stagnant water back and forth . If that bit of stagnant water was full of sewage after a big emergency discharge from mogden for example , then you have the potential for disease

 

[My She]

http://www.thamesdiscovery.org/events/thames-draw-off-walk

I think I'd like to go to this ^ . Have asked the wife what's in the diary.

Thanks, Moxon, that's interesting

 

[TrueBlue]

AFAIK it's to keep a certain amount of water flowing through London in order to stop it stagnating in the capital.

In theory , if there was no flow , then the tide would just push the same bit of stagnant water back and forth . If that bit of stagnant water was full of sewage after a big emergency discharge from mogden for example , then you have the potential for disease

Thanks, T_L; seems logical. I suppose somebody, somewhere did some calculations on how much volume was required to keep "the big stink" at bay.

OTOH, I idly wondered if it was a hangover from earlier times when the MWB might have abstracted water - for example the (now disused) reservoirs at Barnes and others a bit further up.