on the theme of channel's getting blocked up

[mtb]

like most people, one of the things I do is problem solve in my head to keep the marbles turning
While reading dylans thread about being stuck up a creek, it re kindled old thoughts I'd had re keeping a channel clear from sand or mud
Here's my idea
consider a drinking straw if you blow through it you get a jet of concentrated air out from the other end.
I believe if it were possible to capture enough tidal flow and one got the sizes right then the tide would create the same effect as a drinking straw clearing the silt or sand because of increased flow
placed along a river or channel I think it would increase flow as the water would speed up perhaps a greater flow may help reduce flooding

so I recon if you were to lay tubes with wide openings the end the tide or current is pushing then narrow the pipes for the output end the flow would increase and the whole set up would look after it's self

wot ya fink

 

[Yacht Yogi]

I think Mr Bernoulli with his equation is going to render that impossible. If you speed up the flow then its pressure will drop and it will be shoved back where it came from by the surrounding slower but higher pressure water. So essentially the water won't accelerate down the tapering pipe because it won't be able to get out the end without slowing down and that will create a blockage. However, if you restricted the flow around an obstacle such as a rock or a boat then the it would all accelerate like a venturi (remember carburettors?). Ever seen a big ship in a narrow canal, maybe near Manchester. The banks and bottoms get scoured by the passing vessels but the vessel needs extra power to push the water out of its way.

C

 

[prv]

I think you've invented the training wall a couple of hundred years (or more?) after everyone else

Pete

 

[Blueboatman]

Some top-of-the-creek boatyards had sluice ponds.. Near low tide the pent up water would be released to scour the silt and prevent silting of the approach channel.

At Paynes Boatyard 'work parties' on LWS weekends a couple of times a year we used to shovel the mudded up slipway clear ..fueled by a bacon butty if you wus lucky..quite effective too.

 

[aslabend]

Didn't someone invent a wing, tethered to the seabed, which produced vortexes off the trailing edges that scoured silt off the seabed on the tides? Or have I been at the Snoop Dog again?

 

[sailorman]

like most people, one of the things I do is problem solve in my head to keep the marbles turning
While reading dylans thread about being stuck up a creek, it re kindled old thoughts I'd had re keeping a channel clear from sand or mud
Here's my idea
consider a drinking straw if you blow through it you get a jet of concentrated air out from the other end.
I believe if it were possible to capture enough tidal flow and one got the sizes right then the tide would create the same effect as a drinking straw clearing the silt or sand because of increased flow
placed along a river or channel I think it would increase flow as the water would speed up perhaps a greater flow may help reduce flooding

so I recon if you were to lay tubes with wide openings the end the tide or current is pushing then narrow the pipes for the output end the flow would increase and the whole set up would look after it's self

wot ya fink

Thats all very well BUT the worm huggers want to retain all the sediment within the rivers with the worms still in it

 

[JumbleDuck]

I believe if it were possible to capture enough tidal flow and one got the sizes right then the tide would create the same effect as a drinking straw clearing the silt or sand because of increased flow
placed along a river or channel I think it would increase flow as the water would speed up perhaps a greater flow may help reduce flooding

It's been done, I'm afraid. The general principle, for example, was used along the River Clyde, where a series of training walls built out from the banks confined the flow to the middle and scoured out the channel. shifting the limit of commercial navigation up stream from Port Glasgow to Glasgow itself. On a smaller scale. both Palnackie and Kingholm Quay harbours in Galloway were built where small streams emerged into the river (Urr and Nith, respectively). A sluice gate and pound kept stream water back at high tide, then released it at low tide, scouring out the mud and keeping the harbours clear. Now disused in both places, but the setup can still be seen.

 

[AndrewB]

I was always impressed by the system at Ramsgate where the inner basin held the water for sluicing the outer harbour. The sluice system was devised by John Smeaton around 1780, and it worked effectively right up to the time it was abandoned to make way for the new marina in the outer harbour two hundred years later. Since then they have had to dredge significant volumes from the harbour, particularly at the entrance, the problem being worse since the new outer-outer ferry port was built.

 

[John.edwards]

Happens naturally. The Mersey has a similar hydraulic arrangement with an inner 'basin' and a bottleneck exit, so has been a port for a long long time. The Dee was originally the roman port but got silted up because it has a simple triangular estuary

 

[dancrane]

MTB, why did you apostrophise channels ?

 

[Blueboatman]

Thats all very well BUT the worm huggers want to retain all the sediment within the rivers with the worms still in it

Mud glorious mud

I believe that the River Rother ( Rye) is no longer dredged. Being unique in being administered by The Environmental Agency, this is presumably is in line with whatever happens to be their current flavour of agenda or thinking.. Saves a few bob too



And it was never exactly a deep water port to begin with IIRC..

 

[sailorman]

Mud glorious mud

I believe that the River Rother ( Rye) is no longer dredged. Being unique in being administered by The Environmental Agency, this is presumably is in line with whatever happens to be their current flavour of agenda or thinking.. Saves a few bob too



And it was never exactly a deep water port to begin with IIRC..

Just look what happened ' Southwold after the sea walls were moved in towards the river to enable the land owner`s (& they were also the Hbr commissioners too )of the parish to grab more land to the detriment of the trading Hbr

 

[mtb]

It's been done, I'm afraid. The general principle, for example, was used along the River Clyde, where a series of training walls built out from the banks confined the flow to the middle and scoured out the channel. shifting the limit of commercial navigation up stream from Port Glasgow to Glasgow itself. On a smaller scale. both Palnackie and Kingholm Quay harbours in Galloway were built where small streams emerged into the river (Urr and Nith, respectively). A sluice gate and pound kept stream water back at high tide, then released it at low tide, scouring out the mud and keeping the harbours clear. Now disused in both places, but the setup can still be seen.

I considered tubes on the bottom because if there were sufficient flow they'd self manage. I'm conversant with the carburetter venturi theme and depression bar fitted into choke tubes, zenith introduced to increase atomisation of the fuel to get a better mixture
It isn't about re inventing some thing from 200 years ago it is for me, about considering things which could be useful
I bet some one now tells me I've spelled carburetter wrong or missed a full stop !

 

[JumbleDuck]

I considered tubes on the bottom because if there were sufficient flow they'd self manage. I'm conversant with the carburetter venturi theme and depression bar fitted into choke tubes, zenith introduced to increase atomisation of the fuel to get a better mixture

The thing about a carburettor venturi, though, is that the air doesn't have an alternative route available. It's not clear to me why tidal flow would want to go through one of your constricting tubes, certainly not in enough quantity to do something useful.

 

[dancrane]

I bet some one now tells me I've spelled carburetter wrong or missed a full stop !

Not me, boss. You've a good grasp of apostrophe use, better than many round here. But...inserting one where it ISN'T needed, is more conspicuous than omitting one where it IS.

Plurals don't need apostrophes.