On a tidal river, so little wave perterbation and no higher abnormally
high tide line since. An untouched piece of sloping bankside covered by
a thick layer of decayed oak tree leaf litter at least 50 years deposit
as above the nurdle depositions.
What could have been floating on a river 100 years ago to make a
recognisable extreme tide strand line.?
Cork and charcoal and wood natural or human wrked, is about all I can
think off, coal, coke, bakelite , celuloid, rubber of sort of human
origin are too dense to float in water.
Would bits of oak twig survive in some sort of recognisable state under
100 years of decayed leaves?
Loads of stuff floatble for strand lines in the last 50 yers, nurdles,
crisp packets, polyptop rope etc

--
Global sea level rise to 2100 from curve-fitted existing altimetry data
<http://diverse.4mg.com/slr.htm>

N_Cook <diverse@tcp.co.uk> wrote:
> On a tidal river, so little wave perterbation and no higher abnormally
> high tide line since. An untouched piece of sloping bankside covered by
> a thick layer of decayed oak tree leaf litter at least 50 years deposit
> as above the nurdle depositions.
> What could have been floating on a river 100 years ago to make a
> recognisable extreme tide strand line.?

Oil? Used for lubrication if not propulsion and likely they weren't too
careful about it getting into the water.

Was it the kind of river to have shipping?

Also runoff from industrial processes like gas works, tanneries, etc that
would end up in the river.

> Would bits of oak twig survive in some sort of recognisable state under
> 100 years of decayed leaves?

In suitable anoxic conditions, quite possibly. Black organic deposits are
often formed anoxically (see coal, peat bogs, etc).

> Loads of stuff floatble for strand lines in the last 50 yers, nurdles,
> crisp packets, polyptop rope etc

They'll be coal in a few hundred million years...

Theo

On 06/08/2023 21:50, Theo wrote:
> N_Cook <diverse@tcp.co.uk> wrote:
>> On a tidal river, so little wave perterbation and no higher abnormally
>> high tide line since. An untouched piece of sloping bankside covered by
>> a thick layer of decayed oak tree leaf litter at least 50 years deposit
>> as above the nurdle depositions.
>> What could have been floating on a river 100 years ago to make a
>> recognisable extreme tide strand line.?
>
> Oil? Used for lubrication if not propulsion and likely they weren't too
> careful about it getting into the water.
>
> Was it the kind of river to have shipping?
>
> Also runoff from industrial processes like gas works, tanneries, etc that
> would end up in the river.
>
>> Would bits of oak twig survive in some sort of recognisable state under
>> 100 years of decayed leaves?
>
> In suitable anoxic conditions, quite possibly. Black organic deposits are
> often formed anoxically (see coal, peat bogs, etc).
>
>> Loads of stuff floatble for strand lines in the last 50 yers, nurdles,
>> crisp packets, polyptop rope etc
>
> They'll be coal in a few hundred million years...
>
> Theo
>

International shipping used the river at the time.
Going by the recently demolished gasworks site, I've no idea what the
ground contamination was, but after rain , some of the ground had a
vibrant sort of electric purple colour, impressive but disturbing.
I suppose bits of tarry stuff might show up from the then sloppy
bunkering of vessels. Also someone suggested that around then they used
wads of coconut hairy-fibre brown covering waste material, much as
bubble wrap is used today, to protect fragile items in transit.

--
Global sea level rise to 2100 from curve-fitted existing altimetry data
<http://diverse.4mg.com/slr.htm>

So, are you asking this for any specific reason? Layering of sediments and
the like has always occurred, indeed there are some satellites that have
ways of sensing fast changes in this sort of data, as it will point to some
change maybe over 100 years or so, not the sort that takes thousands of
years.
Brian

--

--:
This newsgroup posting comes to you directly from...
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Blind user, so no pictures please
Note this Signature is meaningless.!
"N_Cook" <diverse@tcp.co.uk> wrote in message
news:uap09l$2fcik$1@dont-email.me...
> On a tidal river, so little wave perterbation and no higher abnormally
> high tide line since. An untouched piece of sloping bankside covered by a
> thick layer of decayed oak tree leaf litter at least 50 years deposit as
> above the nurdle depositions.
> What could have been floating on a river 100 years ago to make a
> recognisable extreme tide strand line.?
> Cork and charcoal and wood natural or human wrked, is about all I can
> think off, coal, coke, bakelite , celuloid, rubber of sort of human origin
> are too dense to float in water.
> Would bits of oak twig survive in some sort of recognisable state under
> 100 years of decayed leaves?
> Loads of stuff floatble for strand lines in the last 50 yers, nurdles,
> crisp packets, polyptop rope etc
>
>
> --
> Global sea level rise to 2100 from curve-fitted existing altimetry data
> <http://diverse.4mg.com/slr.htm>

On 07/08/2023 09:28, Brian Gaff wrote:
> So, are you asking this for any specific reason? Layering of sediments and
> the like has always occurred, indeed there are some satellites that have
> ways of sensing fast changes in this sort of data, as it will point to some
> change maybe over 100 years or so, not the sort that takes thousands of
> years.
> Brian
>

Although tide gauges have been around for at least 100 years, if the
records survive , the datums/calibration procedures tend not to survive
as gauging sites tend to move around different sites in a port.
It would be nice to have another way , other than newspaper accounts, of
the levels of extreme tides in earlier decades.
So by nurdle counts, "best before" dates on crisp packets,etc its been
possible to correlate recent high tides with the known records
In local chart datum terms
at 4.95m a strand line for 4.90m tide 23 April 2023 (would have been
obliterated last week due to a 5.14m tide 02 Aug 2023)
and going up slope
5.16m a strand line for 5.22m tide of 21 Aug 2020
5.55m a strand line for 5.60m tide of 14 Aug 2012
5.76m a strand line for 17/18 Dec 1989 that has no official recording,
just living memory and newspapers etc would suggest about 4.75m.
Then Nov 26 1924 there was , from the meteorology and newspaper records
a tide of about 6.0m , but in the records as 5.6m as that was the height
before the pen trace of the clockwork tide gauge recorder hit the
traverse end stop , but that fact not recorded in the record, just the
uppermost normally functioning trace.
A lot of reliance is placed on coastal flood resilience civil
engineering etc on the statistical analysis giving return periods of
extreme floods. If the most extreme ones are unknown/questionable its
GIGO, (economically useful) underplaying extreme tide levels

--
Global sea level rise to 2100 from curve-fitted existing altimetry data
<http://diverse.4mg.com/slr.htm>

On Monday, 7 August 2023 at 10:00:13 UTC+1, N_Cook wrote:
> On 07/08/2023 09:28, Brian Gaff wrote:
> > So, are you asking this for any specific reason? Layering of sediments and
> > the like has always occurred, indeed there are some satellites that have
> > ways of sensing fast changes in this sort of data, as it will point to some
> > change maybe over 100 years or so, not the sort that takes thousands of
> > years.
> > Brian
> >
> Although tide gauges have been around for at least 100 years, if the
> records survive , the datums/calibration procedures tend not to survive
> as gauging sites tend to move around different sites in a port.
> It would be nice to have another way , other than newspaper accounts, of
> the levels of extreme tides in earlier decades.
> So by nurdle counts, "best before" dates on crisp packets,etc its been
> possible to correlate recent high tides with the known records
> In local chart datum terms
> at 4.95m a strand line for 4.90m tide 23 April 2023 (would have been
> obliterated last week due to a 5.14m tide 02 Aug 2023)
> and going up slope
> 5.16m a strand line for 5.22m tide of 21 Aug 2020
> 5.55m a strand line for 5.60m tide of 14 Aug 2012
> 5.76m a strand line for 17/18 Dec 1989 that has no official recording,
> just living memory and newspapers etc would suggest about 4.75m.
> Then Nov 26 1924 there was , from the meteorology and newspaper records
> a tide of about 6.0m , but in the records as 5.6m as that was the height
> before the pen trace of the clockwork tide gauge recorder hit the
> traverse end stop , but that fact not recorded in the record, just the
> uppermost normally functioning trace.
> A lot of reliance is placed on coastal flood resilience civil
> engineering etc on the statistical analysis giving return periods of
> extreme floods. If the most extreme ones are unknown/questionable its
> GIGO, (economically useful) underplaying extreme tide levels

Roman fish farming tanks in the mediterranian were set very accurately
relative to sea level because they used waves washing over ramps to
provide circulation of water and this only worked properly when the ramps
were at just the right level relative to the sea.
Original work on this was done by Nick Fleming. There is a lot of literature
on this subject now.
John

> --
> Global sea level rise to 2100 from curve-fitted existing altimetry data
> <http://diverse.4mg.com/slr.htm>

On 07/08/2023 12:44, John Walliker wrote:
> On Monday, 7 August 2023 at 10:00:13 UTC+1, N_Cook wrote:
>> On 07/08/2023 09:28, Brian Gaff wrote:
>>> So, are you asking this for any specific reason? Layering of sediments and
>>> the like has always occurred, indeed there are some satellites that have
>>> ways of sensing fast changes in this sort of data, as it will point to some
>>> change maybe over 100 years or so, not the sort that takes thousands of
>>> years.
>>> Brian
>>>
>> Although tide gauges have been around for at least 100 years, if the
>> records survive , the datums/calibration procedures tend not to survive
>> as gauging sites tend to move around different sites in a port.
>> It would be nice to have another way , other than newspaper accounts, of
>> the levels of extreme tides in earlier decades.
>> So by nurdle counts, "best before" dates on crisp packets,etc its been
>> possible to correlate recent high tides with the known records
>> In local chart datum terms
>> at 4.95m a strand line for 4.90m tide 23 April 2023 (would have been
>> obliterated last week due to a 5.14m tide 02 Aug 2023)
>> and going up slope
>> 5.16m a strand line for 5.22m tide of 21 Aug 2020
>> 5.55m a strand line for 5.60m tide of 14 Aug 2012
>> 5.76m a strand line for 17/18 Dec 1989 that has no official recording,
>> just living memory and newspapers etc would suggest about 4.75m.
>> Then Nov 26 1924 there was , from the meteorology and newspaper records
>> a tide of about 6.0m , but in the records as 5.6m as that was the height
>> before the pen trace of the clockwork tide gauge recorder hit the
>> traverse end stop , but that fact not recorded in the record, just the
>> uppermost normally functioning trace.
>> A lot of reliance is placed on coastal flood resilience civil
>> engineering etc on the statistical analysis giving return periods of
>> extreme floods. If the most extreme ones are unknown/questionable its
>> GIGO, (economically useful) underplaying extreme tide levels
>
> Roman fish farming tanks in the mediterranian were set very accurately
> relative to sea level because they used waves washing over ramps to
> provide circulation of water and this only worked properly when the ramps
> were at just the right level relative to the sea.
> Original work on this was done by Nick Fleming. There is a lot of literature
> on this subject now.
> John
>
>> --
>> Global sea level rise to 2100 from curve-fitted existing altimetry data
>> <http://diverse.4mg.com/slr.htm>

[ correction
5.76m a strand line for 17/18 Dec 1989 that has no official recording,
just living memory and newspapers etc would suggest about 5.75m. ]

This may be what NOC prof Ivan Haigh was telling me about proxy records
for tidal records in the Med, a couple of months ago ,but did not go
into detail.

I liked the example shown on a TV prog last month relating to IIRC about
1m rise in tide levels in Venice since the renaissance.
One of those classical top-notch painters used a camera obscura to
draught out images of buildings before painting.
So any architectural details were spot on, in scale, including the slime
line around the base of buildings which bears witness precisely to
normal high tides. The same slime line on the same existing buildings in
venice , but now much higher up, by a measurable amount.
Then "jacking up" Venice by hydraulically injecting water slowly under
Venice over years. Apparently this was successively done somewhere in
USA 80 years ago or so, because oil extraction had lowered the town so
much, it was flooding.

--
Global sea level rise to 2100 from curve-fitted existing altimetry data
<http://diverse.4mg.com/slr.htm>

On 07/08/2023 09:59, N_Cook wrote:

> Although tide gauges have been around for at least 100 years, if the
> records survive , the datums/calibration procedures tend not to survive
> as gauging sites tend to move around different sites in a port.

If its a river or and area with moving sand banks then water levels over
a decade may be very variable due solely to silting or dredging. The
height of a tide may also be influenced by the amount of water flowing
down a river when te tide is coming in.

--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

On 07/08/2023 13:55, N_Cook wrote:
> This may be what NOC prof Ivan Haigh was telling me about proxy records
> for tidal records in the Med, a couple of months ago ,but did not go
> into detail.
I think you are mistaken, Venice is not being submerged by rising sea
levels, it ins sinking into the swamp it was built on

>
> I liked the example shown on a TV prog last month relating to IIRC about
> 1m rise in tide levels in Venice since the renaissance.
> One of those classical top-notch painters used a camera obscura to
> draught out images of buildings before painting.
> So any architectural details were spot on, in scale, including the slime
> line around the base of buildings which bears witness precisely to
> normal high tides. The same slime line on the same existing buildings in
> venice , but now much higher up, by a measurable amount.
> Then "jacking up" Venice by hydraulically injecting water slowly under
> Venice over years. Apparently this was successively done somewhere in
> USA 80 years ago or so, because oil extraction had lowered the town so
> much, it was flooding.

That is the thing to do. give the building proper underpinning so they
dont sink
sea levels have been rising at ~ 3mm a year for the last 5000 year+ and
are not changing rates.

--
In todays liberal progressive conflict-free education system, everyone
gets full Marx.

On 07/08/2023 16:12, The Natural Philosopher wrote:
> On 07/08/2023 13:55, N_Cook wrote:
>> This may be what NOC prof Ivan Haigh was telling me about proxy
>> records for tidal records in the Med, a couple of months ago ,but did
>> not go into detail.
> I think you are mistaken, Venice is not being submerged by rising sea
> levels, it ins sinking into the swamp it was built on
>
There's another minor point - there's F all tide in the Med.
>

<snip>

Andy