Blackwater Silting Up

Re: Silting Up

'tis a common feature of Colliers Reach. Very dangerous for fast RIB drivers. A MMC is a Mooring Mud Circle - or perhaps it is a Mooring Mud Crater. I'll get into more trouble with the MHIC!

para basin reach by Roger Gaspar, on Flickr

Some of the crater walls can be a metre and a half - especially off Mill Beach. A RIB driver who has seen a yacht turn on the flood on its mooring might assume he could zoom inside even if the yacht further inshore has also swung...……

It is a residual feature for several years - I note the remainder of the MMC for the Una B which moved from it's mooring is still there in part ... was it 10 years ago.

Navonics of course don't show that term.....
 
Re: Silting Up

Slightly off-topic, but have you also considered the effect of the massive high pressure this last few days? Measured at 1032 hPa on Saturday near Bradwell, which is almost 20 hPa above standard and possibly affecting levels by up to 20cm.

We had a very strange time trying to get into Bradwell on Saturday night, although we draw 1.9m, usually we can get in on a rising tide after around 1.5-2hrs after LW. Tidal predictions were showing 1.96m for 6pm (which was over 2hrs past LW), yet we kept bumping the bottom on the way in (even close to the tidal pole) and grounded abeam of the first red can. Wasn't able to get into Bradwell until closer to 7pm, when theoretically there should have been 2.5m of tide. Seems we weren't the only one, there were two other yachts behind us who seemed to be having similar problems (which was reassuring as until then I was going slightly mad checking my calculations and predictions). Clearly, even taking the high pressure into account, this is an indication of something going on with silting up along the Blackwater.
 
Re: Silting Up

Bradwell Creek has been changing for several years and there is a view that the partial removal of the Baffle Wall and the opening of the sea wall further up could be contributing. Having the shallow bit by the first red can is clear evidence of a change as 8/9 years ago the shallow bit was by the second one - and the better water (albeit marginally) was in the centre of the Creek entrance as it was back in the 30's.
 
Re: Silting Up

Too far downriver to be a probable factor in silting the upper reaches, but the seawall breach in Chatterson's Creek in Tollesbury in the 1990s, AKA at the time as a Managed Retreat, has fundamentally remodelled Tollesbury Fleet.

The Fleet, or South Channel, was favoured when the marina was dug in the early 70s, but the far greater volume of water in the header tank of the seawall breach cut a gut into North Channel, and has turned South Channel into almost an ox bow lake. In the early 70s, the channel at the shram hill off Shingle Head was a good fathom deep at low water springs, but today there is virtually no water.

Therefore it would seem a reasonable hypothesis to me that a significant reduction in headwater flow could be a major factor in silting from the Fullbridge on down. Trying to sail up to the prom after this year's Maldon Regatta was frustrating, grounding three times at pretty much high water, whenever we tacked out of the surprisingly narrow gut, and the Mayfly grounded 20' shy of the visitors' pontoon. Not a spring tide, to be fair, but definitely shallower than before.
 
Re: Silting Up

Oh, yes. Back in 1988 I found that deep channel (!) on account of my Stuart Turner not going into the Creek against the wind even with the tide! Some guy was gesticulating at me to come over to the buoys and withies. Some hope.

BD. I saw Noddy dredging out the Maldon 'marina' in 2017. Impressive but he dumped the spoil immediately opposite just below the opposite bank - which makes you think where the spoil would migrate.
 
Re: Silting Up

tillergirl said:
Oh, yes. Back in 1988 I found that deep channel (!) on account of my Stuart Turner not going into the Creek against the wind even with the tide! Some guy was gesticulating at me to come over to the buoys and withies. Some hope.

BD. I saw Noddy dredging out the Maldon 'marina' in 2017. Impressive but he dumped the spoil immediately opposite just below the opposite bank - which makes you think where the spoil would migrate.
Click to expand...

That doesn't sound very compliant with EU law. Dredging in Blankenberg was held up by the law at one time, so I was told by the HM. Apparently what they used to dump offshore now has to be regarded as potentially toxic and only disposed of at authorised sites. (Nobody mention the B word, please.)
 
Re: Silting Up

tillergirl said:
Bradwell Creek has been changing for several years and there is a view that the partial removal of the Baffle Wall and the opening of the sea wall further up could be contributing. Having the shallow bit by the first red can is clear evidence of a change as 8/9 years ago the shallow bit was by the second one - and the better water (albeit marginally) was in the centre of the Creek entrance as it was back in the 30's.
Click to expand...

Are you sure that the marina staff have not raked the creek? They can only rake as far as the entrance, so that would mean some dumping there until the tide carried the surplus away.
I am told (by the staff) that they have raked it in the past. Not sure if they still do it, or admit to doing it!!.
When he was alive, Rick Cardy had a rake & used to rake a section (Mayland I think) & said that it was legal to rake as it was not deemed to be dredging. As I understand it, it disturbed the silt that was then carried out a short way by the tide.
 
Re: Silting Up

Black Diamond said:
Too far downriver to be a probable factor in silting the upper reaches, but the seawall breach in Chatterson's Creek in Tollesbury in the 1990s, AKA at the time as a Managed Retreat, has fundamentally remodelled Tollesbury Fleet.

The Fleet, or South Channel, was favoured when the marina was dug in the early 70s, but the far greater volume of water in the header tank of the seawall breach cut a gut into North Channel, and has turned South Channel into almost an ox bow lake. In the early 70s, the channel at the shram hill off Shingle Head was a good fathom deep at low water springs, but today there is virtually no water.

Therefore it would seem a reasonable hypothesis to me that a significant reduction in headwater flow could be a major factor in silting from the Fullbridge on down. Trying to sail up to the prom after this year's Maldon Regatta was frustrating, grounding three times at pretty much high water, whenever we tacked out of the surprisingly narrow gut, and the Mayfly grounded 20' shy of the visitors' pontoon. Not a spring tide, to be fair, but definitely shallower than before.
Click to expand...

I was all set for the Maldon Regatta but there wasn't enough water to sail her off the bloody mooring! Mill Beach upwards is becoming a pain, especially with a head wind.
 
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