Brayman
Well-Known Member
Re: The Benson Shoals (Picture)
Looks about right to me.
I did my Actief bit last year I remember.
Looks about right to me.
I did my Actief bit last year I remember.
The EA Survey
- Thread starter boatone
- Start date
Steve Clayton
Well-Known Member
Re: The Benson Shoals (Picture)
I'd like to know when the lock gates were last changed - mid 90's maybe?
My theory: the upper sluice gates are now lower/closer to the river bed. As they are opened then the current draw has the effect of pulling some of the sediment towards the lock. The mainstream flow/eddy just outside the lock cut adds to this pull but reduces within the lock cut to the point when the overall pull is reduced and sediment is deposited and the buildup starts.
As water enters the lock and starts to cover the sluice openings then this too will have a lessening effect on the current draw above the lock gates.
I'd like to know when the lock gates were last changed - mid 90's maybe?
My theory: the upper sluice gates are now lower/closer to the river bed. As they are opened then the current draw has the effect of pulling some of the sediment towards the lock. The mainstream flow/eddy just outside the lock cut adds to this pull but reduces within the lock cut to the point when the overall pull is reduced and sediment is deposited and the buildup starts.
As water enters the lock and starts to cover the sluice openings then this too will have a lessening effect on the current draw above the lock gates.
Chris_d
Well-Known Member
Re: The Benson Shoals (Picture)
I think you maybe right about the flow through the lock, this may affect the build up of the shoal above the lock. I personaly would put it down to the reduction in operations and through traffic. It would be interesting to see the data for traffic flow through Benson from the 80's, 90's, 00's, only my unreliable anecdotal evidence but I would say there has been a significant reduction.
I think you maybe right about the flow through the lock, this may affect the build up of the shoal above the lock. I personaly would put it down to the reduction in operations and through traffic. It would be interesting to see the data for traffic flow through Benson from the 80's, 90's, 00's, only my unreliable anecdotal evidence but I would say there has been a significant reduction.
apollo
...
Re: The Benson Shoals (Picture)
Same as everywhere else then.
I was absolutely stunned to see not one but TWO different dredgers on the reach from Bray down to Boveney this weekend. One by Monkey Island, one down by Oakley Court.
I wonder if the flood relief is causing the main river to silt up there?
Same as everywhere else then.
I was absolutely stunned to see not one but TWO different dredgers on the reach from Bray down to Boveney this weekend. One by Monkey Island, one down by Oakley Court.
I wonder if the flood relief is causing the main river to silt up there?
byron
RIP
Re: The Benson Shoals (Picture)
[ QUOTE ]
I'd like to know when the lock gates were last changed - mid 90's maybe?
[/ QUOTE ]
VERY interesting observation and one that carries a lot of weight in my view.
[ QUOTE ]
I'd like to know when the lock gates were last changed - mid 90's maybe?
[/ QUOTE ]
VERY interesting observation and one that carries a lot of weight in my view.
Andrew_Fanner
Well-Known Member
Re: The Benson Shoals (Picture)
Speaking of slow gate changes, Sunbury's "spare" has had the top gates off since December now. Seems a bit slow even for a spare. I noted a workboat in the lock on Saturday, said boat looked like an Envag one in terms of colourscheme etc but had no Envag logo or name, just a big yellow "F" on it. I'll drag the picture in this evening if time permits.
I assume that's a contractor's vessel, so EA have stopped doing the work themselves I guess.
Speaking of slow gate changes, Sunbury's "spare" has had the top gates off since December now. Seems a bit slow even for a spare. I noted a workboat in the lock on Saturday, said boat looked like an Envag one in terms of colourscheme etc but had no Envag logo or name, just a big yellow "F" on it. I'll drag the picture in this evening if time permits.
I assume that's a contractor's vessel, so EA have stopped doing the work themselves I guess.