Flooding

[JanetAnne]

24 minutes ago, MauriceMynah said:

This might be a stupid question/observation  but has the water level at Yarmouth yacht station changed owing to the rain? (At low water)

I cannot believe it has.

And the southern rivers still drain out efficiently. We went from flooded to normal levels in 48hrs. In fact the only way onto one of the boats was to climb on the roof which was level with the quayhead. A few days ago that same quayhead was underwater.

[JanetAnne]

2 hours ago, Vaughan said:

Classic Broads River Cruisers such as Maidie, Ladybird and Raisena - among many others - draw 4' 6" or more.  These are traditional Broads boats built before the war.

The pleasure wherry Solace ran hard aground in the lower Bure on her way to Oulton regatta a couple of years ago.  A trading wherry such as Albion would draw 7ft when loaded and nowadays, I guess she draws around 5 feet.

Sorry, but if a Norfolk wherry can no longer make passage on the main rivers without grounding in the channel, then the BA are not fulfilling their obligation to maintain "The Navigation".

The last time we bought Raisena south she ran aground/hit something passing Yarmouth yacht station. That was 2022, she didn't come south last year.

[NeilB]

The following request was posted on Facebook by Sue Hines, she's happy for it to be copied and pasted.  I've been visiting the Broads for 50 years and have lived here, on a boat, for the past 2 years so will be replying.  I hope those of you with more knowledge and experience than me will also contribute.

 

 

The following email has been received from Matthew Philpot, Chief Operating Officer & Deputy CEO, Water Management Alliance. Please contact Matthew if you feel that you have information which would be of use.

Dated 29 February 2024

Subject: Hydraulic Modelling of River Bure Dredging

All

Further to recent discussions the case of dredging on the Bure, to affect flood risk, will now be modelled by the Broadland Futures Initiative Team.

The detail of where it is considered silt accumulations are being seen and having the most effect now needs to be decided on, such that this specific modelling can be developed.

To this end we are reaching out to river users, as well as the Broads Authority, to identify those areas believed to have the greatest impact on flood risk.

Our principal interest is in the Bure and the northern rivers, but suggestions for elsewhere can also be made.

Please forward this email to anyone you feel could provide a beneficial contribution and I will collate responses for the BFI team.

Please could responses be received by the 15th of April.

Regards

Matthew Philpot CEng MICE MBA (he, him, his)
Chief Operating Officer & Deputy CEO
Water Management Alliance

m: 07884 327849
matthew@wlma.org.uk
Registered office:
Pierpoint House, 28 Horsley's Fields, Kings Lynn, Norfolk, PE30 5DD
t: 01553 819600 |
e: info@wlma.org.uk |
www.wlma.org.uk

What3Words: caring.employ.visit

WMA members: Broads Drainage Board, East Suffolk Water Management Board, King's Lynn Drainage Board, Norfolk Rivers Drainage Board, South Holland Drainage Board, Waveney, Lower Yare and Lothingland Drainage Board

In Association with: Pevensey and Cuckmere Water Level Management Board

[Mouldy]

Call me cynical - I know I am, so no offence will be taken, but this appears to be a body representing six water management boards and in association with a seventh, who are collating data, presumably to take to The Broads Authority, EA, IDB and Anglian Water.

How much evidence is required to prove that there is an issue with water levels on the Northern Broads.  The amount of red tape that needs to be unraveled before anything gets done is frankly ludicrous and at what cost?

I must just be getting old and intolerant!  No, not getting, I am old and intolerant!

[dom]

49 minutes ago, Mouldy said:

Call me cynical - I know I am, so no offence will be taken, but this appears to be a body representing six water management boards and in association with a seventh, who are collating data, presumably to take to The Broads Authority, EA, IDB and Anglian Water.

I presume this is a net effect of Duncan Baker's meeting. I'm sure it was Henry Cator who first mentioned the organisation in question. He's obviously pro dredging and suggested they could provide insight into where issues lie.

[dom]

5 hours ago, Vaughan said:

Sorry, but if a Norfolk wherry can no longer make passage on the main rivers without grounding in the channel, then the BA are not fulfilling their obligation to maintain "The Navigation".

Maybe someone should organise a wherry trip to Yarmouth for Dr.P to demonstrate the issue?

Obviously it'd be very hard to argue that dredging was being done properly when stuck fast.

[NeilB]

1 hour ago, Mouldy said:

Call me cynical - I know I am, so no offence will be taken, but this appears to be a body representing six water management boards and in association with a seventh, who are collating data, presumably to take to The Broads Authority, EA, IDB and Anglian Water.

How much evidence is required to prove that there is an issue with water levels on the Northern Broads.  The amount of red tape that needs to be unraveled before anything gets done is frankly ludicrous and at what cost?

I must just be getting old and intolerant!  No, not getting, I am old and intolerant!

Apparently modelling was already planned for later this year, at the flood meeting Duncan Baker suggested this was a priority and should be done sooner rather than later.  I suspect the email is an attempt to show they have listened to everyone.

I also suspect the modelling will show that none or very little dredging is required.....  Lets just hope I'm also being cynical....

[dom]

12 minutes ago, NeilB said:

I also suspect the modelling will show that none or very little dredging is required..... 

I still don't understand how no-one is questioning whether the already scheduled Bure mouth BA dredging might be a factor in the current situation.

https://www.broads-authority.gov.uk/__data/assets/pdf_file/0021/490071/UPDATE-NTM-07-2023-Dredging-works-on-the-Lower-Bure.pdf

I'm sure the original document was more specific and they seem to have changed the way the area in question is highlighted, making it much more vague. I can't help but wonder though if the minute they do this, it'll be like removing a plug and vast quantities of water can suddenly move, quite possibly taking a load of silt with it.

I've suggested elsewhere that the delay might be funding - but it could also be that they're afraid to do it before things dry out, in case it suddenly shows their culpability in upstream flooding.

 

[PaulN]

On 25/02/2024 at 13:24, NeilB said:

If you not aware of the 1953 floods there's plenty of info online but Wussernames post gives a good idea, in Norfolk alone exactly 100 people died.  My great aunt was rescued from the roof of her Sea Palling bungalow by the lifeboat in 1953, which she recalled frequently! 

I don't know if anyone who read the minutes and attended the meeting picked up on this - "on the 21 st/22nd December we had one of the biggest surges we have seen on the Broads. We have been incredibly fortunate that it came on a low tide. There was a surge of over 1.5m to 2m in some places and that is what pushed all the up. This meant that the three top-end gauges on the rivers and they recorded their maximum heights all through this period on that time. Not only that but they were the highest heights recorded this century"

What's not shown in the minutes but can be heard in the recording, is the chap from the EA saying "Had this occurred on a high tide we'd be looking at a 1953 situation".........

 

Whatever the causes are, this is going to happen again so the authorities need to be planning for this eventuality. 

I am fed up with hearing comparisons with the 1953 floods as an excuse, particularly from the EA to justify what is happening now, rather than the lack of dredging. People advocating this in my opinion are just grabbing a flood event out of our history, without bothering to find out what caused it.

I live on Canvey Island where the floods are well documented as 58 people lost their lives in 1953. Last year the local BBC radio station broadcast details of these events all day, with various interviews, on the 70th anniversary.

The 1953 floods were not caused by prolonged rainfall and the rivers being unable to cope with the run-off from surrounding fields. It was caused by an exceptional tidal surge from the sea. The prevailing south westerly winds were high, driving water across the atlantic to the north of Scotland, the winds on the north sea then went northerly and storm force, coinciding with high water on a big spring tide. An exceptional low pressure over the North Sea allowed sea levels to rise well above the spring tide predictions, as a tidal surge drove down the East Coast inundating the sea defences.

What we have now is the rivers not flowing away fast enough into the North Sea to cope with the additional run-off from the land. 

In the last few years when moored on the River Bure, I have witnessed many times the tide turning at Low Water much later than predictions due to water still trying to escape from the upper reaches. Also when approaching Great Yarmouth to cross Breydon Water at low water, my echo sounder which is set to read depth under the boat has got close to zero, which can only be down to lack of dredging.

In my opinion, if the water depth gets very shallow, the water will slow down and deposit more silt and hence the trapped water will spread out on the upper reaches. The shallow hump acts as a damn, similar to a weir on a canal.

So in future, before am EA representative opens their mouth to justify the lack of dredging, I consider they should check their facts. 

[BrundallNavy]

Just been looking at the Potter Bridge heights over the last 7 days .  Max height was 5'6" and minimum was 4'9". Something needs to be done as even day boats will pass at these heights let alone Martha's motor boats. 

[grendel]

it appears some people are having issues seeing this thread, as you will see its still here.

[Hylander]

50 minutes ago, grendel said:

it appears some people are having issues seeing this thread, as you will see its still here.

Crumbs I thought I was the only one up at this ungodly hour.

[grendel]

got to get an hour in the hot tub with a coffee before starting work in 15 minutes, its a daily routine that allows me to clear my thoughts ready for a day of work.

[BroadAmbition]

Jamie Campbell has just recently written an interesting article, he kindly gave me the ok to post it in here:-

 

Broad Sheet has just landed on the doorstep. The front page is BA propaganda on dredging and flooding - with predictably round shoulders. I'm sure that we are all aware that the whole river system has been subject to structural alterations for centuries. 

We might like to bear in mind that the Waveney didn't always join the sea at Lowestoft and Lykeling Fleet was straightened to produce Oulton Dyke (sections of the old Fleet are still visible) I have some figures for the amount of 'fall' of the River Waveney. Surveys report a fall of 20m between Hoxne and Beccles, a distance of 25 miles. The fall between Hoxne and Great Yarmouth is recorded as 24.25m. We therefore have a drop of 4.25m in the 25 miles of navigable waterway between Beccles and Great Yarmouth. The 'fall', without allowing for tidal effect is only .17m in every mile. Six inches of silting in a mile can take away the natural flow of the waterway entirely, at which point it becomes purely a tidal inlet and there is a notable reduction in effective draining of the hinterland. 

I don't know the level of fall on the north rivers and for the point of this discussion, I'm not interested in salt incursion. I'm sure we are all fairly familiar with the range of alterations made to the course of the various north rivers within that system - but I'll list them anyway.

Like every other Broad, the River Ant didn't flow through Barton Broad, (the turbaries would have flooded). The Ant was re-routed to flow through Barton, presumably to create a fishery. The old course of the Ant re-joins the current river around Crome's broad. The Ant used to flow into the Hundred dyke (near St Benets) and then joined the Thurne at Coldharbour. The combined rivers then flowed in the opposite direction, along Sock Drain and out to sea near Horsey. This was the mouth of the river that was reopened by the 1953 floods. When rivers are persuaded to flow in the opposite direction, there really cannot be much fall involved.

The monks of St Benets cut through their own causeway (leading from the Abbey to St John's Chapel or Hospice in Ted Brewster's garden) and re-routed the Ant a short distance into the Bure. They also straightened the river past their dock (the old course through South Walsham marsh is still just about visible). The Bure then flowed into the sea to the north of Great Yarmouth at Grubb's Haven or Cockle Water (roundabout the Greyhound stadium). The Yare once reached the sea just south of Corton - the peninsula has been continuously shortened in an attempt to produce a tenable harbour for Great Yarmouth. In short, the entire navigation has been b&ggered about for centuries. 

I wonder if we are all not trying to be too clever. Water is lazy - it only flows downhill. On an impervious and level surface, it'll just sit there - which may well now be what happening on the Thurne.  Stokesby to YYS is nine miles and it would be interesting to know the drop per mile on these reaches. Certainly dredging the lower Bure would help water escape the system - but its got to want to get itself down there too. A natural gradient may be required in addition to a tidal gradient.  Thought for the day. 

[BroadAmbition]

JA - And the southern rivers still drain out efficiently. We went from flooded to normal levels in 48hrs. In fact the only way onto one of the boats was to climb on the roof which was level with the quayhead. A few days ago that same quayhead was underwater.

 

What a giveaway.

By now most forumites and agencies will be acknowledging even if only to themselves that the lower Bure is badly silted up.  I'd love to know how those same agencies would answer JA's post above.

How is it that the southern rivers can drain out excessive rainwater in 48 x Hrs back to normality?

How is it that the southern rivers are not suffering excessive salt incursions?

How is it that the northern broads can't seem to drain out / clear the excessive rainwater?

Hmmm - Let me see - Has Breydon and the Yare from Haven bridge got the same amount of silting and shallow river depths like the lower Bure has?

No doubt time for yet another long expensive study with nerds and computer models to back up their theory that there is no need for dredging and that it won't do any good

Griff

[NeilB]

Jamie mentions the level of fall on the norther rivers, this was mentioned at the flood meeting as per the extract below.

Henry Cator added that the fall between Potter Heigham and Great Yarmouth 0.7m over 15 miles which gives you a fall of one in 42,000. There is no way that one in 42,000 is going to keep itself clear. It is going to suffer from sedimentation and build-up of sediment. This will affect the ability to carry water. There are certain hot spots and low spots that need dredging and one of those is the yacht station at Great Yarmouth.

[Hylander]

Lovely to see the river levels going down.

 

[Broads01]

Almost as if you could fit a canoe under the bridge 😄

[Hylander]

Not certain if this has been raised here before but it did strike me that 'Louise' the facilities boat must have an awful job getting under the bridge.    It must be a worry for properties without main drainage.

 

http://www.broads.org.uk/wiki2018/index.php?title=Boat_Details&BoatId=1079&BoatHistory=1110

[grendel]

I have read somewhere recently that this is indeed the case- it was a report on the affect the flooding has had on local businesses- and also mentioned Martham boats and phoenix fleet amongst others.

[Hylander]

oh dear bit off if you cannot have your holding tank emptied for over 3 months.   Also they do refuse collections.

[Bikertov]

15 hours ago, Broads01 said:

Almost as if you could fit a canoe under the bridge 😄

But not a Stand Up Paddle Board ...

[bucket]

6' 8" clearance under Wroxham bridge first thing today! It has dropped by a foot since last Friday. 

Still a bit to go but isn't it amazing what one dryish week can do?

 

[BroadAmbition]

6ft 8” ?

Happy days, can breeze  ‘B.A’  through at that

Still not a prayer at PHB though 

Griff

[Lulu]

Just gone past at 9.00am approaching Ludham