Saturday, 13 April 2013

Saturday 13 April 2013 GOBA Mooring R.Wissey

Today’s cruising has been very short, just 30 minutes from Denver Sluice complex to the GOBA moorings on the River Wissey in the rain.

What was a great deal more interesting was our conducted tour of the full Denver Sluice complex arranged by Peter Webb of the Gt Ouse branch of IWA and lead by Dan Pollard of the EA.

The first port of call for our visit was the lock which happened to coincide with a Narrowboat locking out and a cruiser coming in. Dan talked of the history of this structure and how it has changed over the years including the large barge lock known as “Big Eye”.

From here we walked round to The Head Sluice or A.G.Wright Sluice that lets water out into the relief channel and down to Tail Sluice at Kings Lynn. This arrangement can pass about 150 million litres of water per second when fully open.

Next port of call was the” Hands Off Channel”, this is a much smaller metered channel with and automatic level control at the top end and metered volume adjustable sluices at the outflow end.

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Automatic level control

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Metered adjustable Sluice

The purpose of this is to ensure there is always a minimum flow of water down the relief channel to keep the water fresh. In parallel with this is a normal lock to allow boats to navigate the relief channel.

By the exit of the lock there is yet another channel coming in with its own sluice, called the Impounding Sluice, this is the Cut Off Channel and runs round collecting flood waters from higher up the Wissey, Brandon Creek and Lark to bring them direct to the relief Channel without them having to flow through the Ouse.
This channel serves a second purpose exporting water to Suffolk and Essex water via a large pipeline that connects in half way along its length.
There is a final sluice, the Diversion Sluice, again quite small that connects between the Ely Ouse and the Cut Off channel just above the Impounding sluice which can feed water into the Cut Off channel when water is required by Suffolk and Essex water but there is no flow coming in from the heads of the rivers of under the Impounding sluice from the relief channel.Denver 2

Many thanks to Peter Well of the Gt. Ouse IWA and Dan Pollard of the EA.

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