Any indication from concensus of met models for a potential flood-level surge in the English Channel , in the next few days, from my widget detailed below, prior to the pro NTSLF output, mpved sideways to this file
Belsize tide tables for Southampton
I'm researching historical extreme tides in the Solent area. I visited the Vectis Tavern to take pics and measurements of what remains of the
tide marks on the pillar
probably 17 Dec 1989 and 22 Oct 1984 and
battern part obscuring the lower one Date, probably 02 Dec 1909 (ignore this as 1989 on closer inspection)
It's reported to me by 3 different people that there used to be a mark at chest high, but no one can remember the date , probably 27 Nov
1924 or 14 Nov 1931 or even 01 Jan 1877. Anyone aware of pictures showing the inside of the Vectis Tavern before the bar was moved and
anaglypta wallpaper covered over the higher markings? (or IR camera and heat source)
Or other info concerning Cowes or IoW or Solent area dates/heights (indirectly from pics) of flooding before 1989?
Google images surprisingly shows no functions / events inside the Vectis.
Second pillar in from the High St and on that face facing the High St, inside the bar counter. The Vectis Tavern had the floor tanked , prior to the 2014 flood,
plus the town quay flood wall by then, and the flood water shown in pics
of 2014 came up thru the drains and did not reach the sea-height of the Medina.
I've recently been researching in newspaper archives for extreme marine floods around the Solent, ie Solent-wide , surge-type, not very localised
events. With depth overland of inundation as a measure of sea "storminess", less now than centuries back. Two academics have come to the
same conclusion , from a different direction and different records. The Vectis Tavern pub, Cowes, IoW used to have the levels of extreme tides
reached when it flooded the pub, marked on a pillar in the bar. With renovations in the last 10 years or so only the bottom marks can be seen
now under the counter. The present landlord let me take these pics a month ago.
It is of academic significance , because of confusion over measurement datums, what these historic tide levels were, linked to one specific site.
It's reported to me by 3 different people that there used to be a mark at chest high, but no one can remember the date , probably 27 Nov 1924
or 14 Nov 1931 or even 01 Jan 1877.
The floor of the pub has been there since 1400s (scheduled buildings register, before becoming a pub in 1700s, why you have to go down steps
into the main bar area) and this pillar since the Victorian era .
The floor is at the level of the normal astronomic tide height of spring tides. This central south region is supposed to be sinking (balancing
north rebound after the ice age) plus sea level rise would suggest more extreme marine flooding.
The 1860s 25 inch scale OS map shows the VT as not including the Town Quay half then, presumably a wall dividing then rather than a pair of
pillars , so the earliest dates noted below could not have been recorded on the pillar.
The 1909 (revised to 1989) mark is 0.64m above the floor and the 1984 0.74m and 1989 0.95m but which date is the topmost covered-over/erased one and its
height, should be about 1.2 to 1.4m off the floor.
An expanded page on this reconstructed epigraphic historic extreme tide "record" of the Solent area now on
Solent Extreme Tide Gauge
Theoretical set of marks with some heights determined from newspaper reports, so only approximate,
and offset vertically for a Cowes height.
23 Nov 1824,1.8m and 27 Nov 1703( approximate height , see "Defoe" letter and salvaged stranded ships in cargo (, contemporaneous date ie
not Julien/Gregorian adjusted) [ 150 YEAR EVENT ]
19 Jan 1804, 1.35m (reported in 1804 newspaper as highest tide for 30 years ) and 15 Nov 1840
27 Nov 1924, 1.25m [80 YEAR EVENT ]
14 Nov 1931, 1.2m ? (Wootton IoW report to 4 inches above 1877 level, but may not relate so well to Cowes and Soton levels as also a Yarmouth ref to being less than Boxing Day 1913 = printing error for 1912 or 1915?. So perhaps down-rate this to half way between 1.2m and 0.9m for Cowes-Soton longitude. Or more likely like the Eling Tide Mill record, in that the maximum height recorded is not the marine surge level reached , but the necessarily lower level in the impounded side of the mill )
01 Jan 1877, 1.1m (Mr John White newspaper quote of Cowes tide-height reference and 1818 one. 1 foot 4in above the 1916 flood on Coopers Arms epigraphic 1877 record of 2 foot 7 inches above the pub floor level)
04 Mar 1818 , 1.05m
20 Dec 1983, 1.02m likely height at the corresponding unseen black paint level mark, covered by the support batten of the Vectis Tavern bar
counter, only 1983 year numbers fully showing June 2015 .
17 Dec 1989, 0.95m (actual mark, VT landlord comment in local press)
27 Nov 1954, 0.95m [ 30 YEAR EVENT ]
25 Dec 1912, 0.9m (Capt Samuel Leigh report, 4 inches below 1877 level, in Newport. Coopers Arms , Northam, 19 inches above floor level); and 29 Dec 1951 (From Macmillan report in the Echo as being 7 inches below the "official " record high tide of 27 Nov 1924 of 16ft 9in at Town Quay (probably actually 26 Nov and 0.4m higher as the tide gauge broke like the Dover one that day, see below, but 16ft 9in figure used here)
26 Dec 1999, 0.85m and 10 Mar 2008 and 14 Feb 2014 (Cowes tide level peak of 5.35m but officially 2.734m ODN =3.24m Cd,reported in 2821-IW, but CHC half-hourly record of 14/02/2014 23:30 5.24m ,14/02/2014 23:00 5.35m ,
14/02/2014 22:30 5.26m, Town Quay wall rebuilt about 2000 nearly breached ,just wave peaks over-topping, the recent "flood level" in the Vectis Tavern is what got through the sandbagging, reported by landlord in 21 Feb 2014 County Press as 2 foot deep by 11pm having started coming in at 10:30, so extra entry here below at inferred no quay wall blocking of ) and 25 Dec 1912 [ 5 YEAR EVENT ? ]
03 Nov 2013 0.8m and 16 Dec 1910 (provisional as not researched in local press yet)
(14 Feb 2014, 0.77m Vectis Tavern , if like the 1980s marks and before the Town Quay sea wall was built , the potential level in the pub)
23 Oct 1940, 0.75m Southampton Docks tide plot
05 Nov 1916, 0.75m (Coopers Arms reference to 3 inches below 1912 mark in
one Echo report and 19 inches above floor level in 1918 report and 1 foot below the 1877 mark)
22 Oct 1984, 0.74m (actual mark, VT landlord comment in local press)
15 Jan 1918 , 0.65m (Coopers arms reference 5 inches below 1912 mark) and
04 Jan 2018, (0.65m for St Denys, 0.56m VTS) [Incidently my widget, first validation run for elevated tide with large surge residual since Valentines Day 2014 , did better than NTSLF, for the highest tide since 2014.
For Pompey and so something similar for Soton, NTSLF on the last run output before actuality
had surge of 0.32m, very messy plot, 0.50m surge at Pompey in actuality.
If I ran their show, I'd place one timing yellow circle per high tide on the 0.0 height axis and make sure the black trace was laid down first, if its not possible to lay down each colour as first run first, latest run last.
While at it sort out the most unprofessional clock on the tide gauge presentation, time increments that go 21:30, 21:45, 21:60, 22:15, been like that since they started.
I had 0.54m as last Soton prediction of surge on the 4.8m , 12:13 tide of 04 Jan. VTS tidegauge peaked at 5.31m at 12:05 and PRH vernier just touched 5.4m at 12:03 ]
08 Oct 1960, 0.62m Southampton Town Quay (Hampshire River Board report as 16 ft 0in (16ft 9in VTS equates to 5.6m, so 16ft = 5.37m in VTS terms)
02 Dec 1909 , not determined
17 Oct 2012, 0.6m , 4.9m predicted tide, 5.35m at VTS
22 Oct 1909, 0.55m and 10 Jan 1993
05 Dec 2006, 0.45m , 4.7m predicted tide with 0.5m surge at VTS 5.2m tide
12 Jan 1978, 0.45m
0.3m equivalent height of water emerging from the drain at Priory Road Hard, St Denys, Southampton, for comparison assuming 0.2m difference in Cd terms between Soton and Cowes in elevated water conditions..
0.0m floor level of the Vectis Tavern, July 2018 I make 4.55m (Cowes 2018 Cd terms) not much higher than astronomic height of mean spring tides in Cowes, 4.2m (cD). I was talking to resident of Cowes who was playing in a band in the noughties, 2005 or 2008 perhaps, when a surge came in the Vectis Tavern. Unfortunately I forgot to ask if he had any pics as even out of focus , they might include the original tide markings on the pilllar, before the counter was built out around it. They carried on playing through the rising flood water. His recollection of the VT around that time is of a high level drinks shelf around all 4 sides of the pillar , with a 45 degree
bracket under each side. This pic from another pub and lower level shows the sort of thing , a generic name for them anyone? Googling gets nowhere , a pub landlord commented that it may be H&S reason for the high level
ones not to be seen these days. High enough to be above most people's shoulder level , so not barged into .
He remembered the 2005? or 2008? noughties sometime, the level it got to was not marked on the pillar but was above the 1980s marks and below a mark from the 1940s. He remembered 1940s because in quizzes in the pub , the landlord would often cover over the flood marks and one of the questions in the quiz was what was the date of the topmost mark? (see 1949 below)
Anyway if that shelf was , say, 1.5m high and the topmost 1980s
marked flood level is 1.02m off the floor , then he drew out a view of what he rembered and
the noughties height would be about 1.2m and the 1940s one about 1.3m
off the floor. It could have been a rainfall only event though, too much rain falling on Cowes and too few exits to the sea along Cowes High St.
16 July 2018 UKHO predicted second tide of 4.3m at Cowes time 16:19 . Using the 1968 recorded OS bench mark and 4.15m OSD height at the hard near Market Hill on the other side of the High St, near the low-level arched window.
Going by DEFRA/EA report FD2319/TR and combined SLR
and isostatic rebound effect on Portsmouth tide gauge of -1.45 +/-0.6mm/yr for Cowes. The earliest I could find ODN/Cd conversion of 2.59 (as used in 2018) is in EA 2001 tide tables, what with the new Cowes breakwater surely needs updating.
Portsmouth -1.45mm per year back from 2001 to 1968 .
Using BM 4.15m , the under-edge of the course of new-build black brick on the north side of the hard, Abney levelled to 1.47m below that BM, so
5.27m Cd 2018. The BM ,9.93ft 1968 OSD at the hard opposite Sun Hill,
as High St spot-height there was 9ft, perhaps repaving is higher and covered the mark, the brick on the corner there looks old , I did not think to
check very low down, but not seen July 2018.
Took a much closer look Monday 13 August 2018 and one brick of that
BenchMark survives in situ, the 2 adjascent bricks have been replaced (marked green Xs), but
enough of the left fluke and central fluke survive to reconstuct the full
benchmark, green and blue lines, in x and y and most importantly here the z sense.
The Abney level monopod midpoint is only 14.5m from the benchmark
and the corner of the SWA building with its own quay wall.
So Sun Hill slip/High St Benchmark is 9.93ft OSD or 3.03m.
Abney eyeline relative to the cutmark 4.29m and the level of the SWA quay is 1.78m below that, so 2.51m OSD , +/- 0.01 or so , no better than that,
maybe only +/- 0.02m (needd repeating with a verified gyro-stabilised laser
level for mm accuracy). So any newspaper reference to the sea reaching the
High St at the Sun Hill slip ,means the water level was higher than 3.03m-0.49m or 2.54m OSD assuming present day road level.
www Cowes tidegauge for time 15:12 was 4.56m . Making a bund of
kelp laying on the slip and with a piece of clear plastic tube set in a small
frame of Dexion as a stilling well, the level of the tide at that time was -0.72m
from that SWA quay top. So tide at that time and place was 1.79m OSD ,
so the conversion for OSD to CD I determined to be 2.77m (cf with the
official figure of still 2.59m).
For the Market Hill slip , with longer Abney gauge sighting run , the
less convenient intermediate level of the underside of the
modern black brick line was 1.47m OSD, BM 4.15m , at 15:30 13 Aug 2018
4.58m www Cowes tidegauge and stilling-level level of the sea was -0.91m
from the black brick line, so OSD to CD conversion of 2.71m
but the Sun Hill measurement is probably more accurate.
For the Town Quay www 4.58m at 15:20 and -0.94m
from the Town Quay top surface near the crane, so quay top of
5.52m Cd and applying the 2.77m conversion then 2.75m OSD.
( disagreeing with when I did this a few years ago coming to 5.30m for the quay wall top, whatever that means as 2014 Valentine's Day flood would have fully overtopped the quay wall if only 5.3m ). Perhaps a gyre setup between Town Quay
and the Yacht Haven tide gauge or overall level change due to the breakwater.
( The following text retained but since updated from 13 Aug data explaining the Valentines Night anomaly
Ignoring that, and using the water between Market Hill hard and quay as
manometer, and assuming the levels were the same at 5 minute time differences of taking measurements. 4.15-1.47m = 2.68m black brick level,
water level = 2.68-1.02m = 1.66m, Quay top level = 1.66 + 1.06m = 2.72m OSD , so 2018 Cowes Cd level of 2.72 + 2.59m = 5.31m Cd . As 2.59m OSD->Cd
has been in use since at least 2001 and using the Pompey 1.45mm/yr ,
perhaps a conversion of 5.33 or 5.35m is valid but still does not explain the
Valentine's observation 2014 of reported 5.35m tide of just the peaks of
the waves slopping over the quay wall. )
Using OSD data and Abney levelling to the pavement level at the corner of the Vectis Tavern at Town Quay/High St junction to be 2.19m OSD if the quay is 2.75m OSD and via the 1968 OSD benchmark 1968 height of 3.51m on the wall of Hurst ironmongers near the bench, going by that route , the Vectis corner I make 2.31m OSD .
Taking the simple average , then that pavement level at the Vectis Tavern level as 2.25m or 4.84m Cd with 2.59m OSD to Cd conversion or 5.02m with 2.77m
OSD to CD conversion.
Q=quay wall top, L=lamp-post,S=mid-position Abney level monopod point, X=Vectis pavement level, B= Benchmark at topmost rail of the seat height on Hurst ironmonger's wall half covered in layers of paint.
Then 0.09m up the cement bund to the door threshold and then down 2 steps for 0.36m down to the vectis floor level.
I'll go with 4.82m - 0.27m= 4.55m (Cd Cowes 2018) Vectis floor level until I find an OS referenced height for the top of the Town Quay wall. Mean High Water springs for Cowes 4.2m, so no wonder the "tide" came up through the Vesctis floorboards quite regularly at spring tides , before they tanked/sealed the floor (do such treatments "blow-up" in an extreme flood situation and static hydraulic pressure, ?).
While measuring tide heights around time 16:19 , I measured the depth below the grill, of the trap water level in the Fountain Yard one-way exit road nearest, road drain to the Crane, no rain as drought around then:-
3:42pm -0.346m
4:10 -0.334m
4:17 -0.365m
4:43 -0.393m
Readings of the drain level 13 August
15:12 -0.25m (www tide 4.56m)
15:18 -0.26m 4.58m tide
15:36, -0.29m 4.51m tide
While monitoring this drain level there was some high frequency
disturbance to the level, SWA pump activity or trapped air or wave action on
flap valves and "water-hammer" , so the drain level would have been a bit higher without pumps cutting in .
Didn't think to survey the level to the drain grill but looks within 0.1m or so of directly following the tide height (the foot of the nearby lamp-post at paviour level is 4.85m if the Vectis corner is 4.85m, so grill could be about 0.1m lower, and Cd level of drain water at 16:10 4.75m-0.334m = 4.42m). www CHC tide gauge at 15:54 4.41m and monitoring the tide pole viewable from the Red Jet pontoon over a minute or so around 16:05 read about average of 4.36m.
The following needs some expert advice on, and input from the cowes Commissioners would be useful.
Event for event, for surge events rather than normal tide height difference, about +0.2m in VTS terms for corresponding to Southampton, the ideal stilling well, inside a building. See 04 Jan 2018 for 12:00 readings of elevated water levels cross-correlation VTS and Cowes
VTS 5.30 and Cowes 5.19m , so in the absence of Cowes Harbour Commission data for 2005,2008,2014 surges offset of only 0.11m may be more valid.
So far hangs together
quite well to +/-0.2m or so using newspaper reports of flood heights relative to previous and cross-referred events along with reported depths of
water in specified streets and reference to terms like knee-high as a measure of depth. Impassable on foot I take to be thigh high or higher going by asking numerous people , what their take on the term would be.
By June 2015, the green wallpaper has been removed from the Vectis Tavern. Just emulsion paint is covering the , at least one, flood markings
on the pillar.
(pics with folding 1m ruler)
Daily counter top cloth-cleaning has worn the emulsion paint off the 1983 marking, above the previously known 1909/1989?,1984 and 1989 ones under
the counter. The counter top surface is 1.05m above floor level, so the 1983 black line would be about 1.0m.
So why is the original Flood Level caption is so high about 1.7m off the ground, not uncovered recently, as it was found under the wallpaper.
Enough of the 0 , E and C showing before 1983, to be fairly confident this was the
date part of the mark for the flood event of 20 Dec 1983.
October 2015 Anne let me explore under the paint between the 1983
mark at counter level and the Flood Levels legend. Centred on the 9 of 1983 , I masked off a strip 11.5 to 13.5 inches from the left side of the column. Slowly washed back the top layer of emulsion in that masked off area and saw no black paint marks. Then went deeper down the middle , to the pinkish layer and then black appearing but it must have
been the original sealing coat of mock stove-enamelling or whatever,
they used over plaster in the Victorian/Edwardian era to give a hard
base layer. So no sign of any additional marks seen.
As any flooding that is reported in the local press , to have flooded
Cowes High St, would have flooded the Vectis , prior to sealing the floor, would have entered the pub. So likes of 1960 and 1924 floods
are not recorded there, unless a different marking system to the existing
stencilled ones, was used, or sited elsewhere in the pub.
She let me unscrew the piece of boarding obscuring the lowest mark.
Now I'm not so sure it is Dec 1909, is it another mark for Dec 1989,
it would explain the similar stencil size. Shows part of the wide black bar. Close comparison of the 2 images, 1989 one is upper one.
I now think the lower image shows the turning in for the
central crossing of an "8". In both cases the top of the curve of the C is higher than the top of the 9 curves. So perhaps all marks were made
during the 1980s under one landlord.
Hampshire Advertiser, 03 Jan, 1877.
19ft 8 in or 3ft 8in higher than our usually highest normal spring tides
and 59 years previously , 2 inches lower than this one.
So far I have more faith in the 1877 reported statements of Mr John White of Cowes than local wrongly ascribed datums "official" historic
extreme tide records , which place the tide height reached in the 1924 flooding as being the same as 1999 flooding , when there is something like a 0.4m
difference, and no mention of the 0.1m higher tide in 1989 , just because their tide guage was out of action then .
As he or his family must have had daily contact with tide and ground level for more than 59 years he was probably the "John White of Cowes"
who built "specialised lifeboats " at Cowes and founded in 1805 what became John Samuel White shipyard of Cowes. A lot of JS Whites records ended up at the Beckford Rd , Cowes Library, whether this tide record probably not, not at the Newport Record Office anyway.
Also Beken photographs of flooding , PV98 catalogued as 1899 date
has the wrong clothing for that time and no blurring of the rowers in the boat in the High St outside the National Provincial Bank, probably
1920s to 1930s and another with Morris J van maybe 50s is undated totally, PV117 dated 1920, number 42734 of 1960 and other
flooding pics in their catalogue of Medina Rd, sea front etc 42733,PV102,PV71,PV99/100/101, PV56,PV71.
Useful tabulation of flooding events recorded in the Times on
http://dro.dur.ac.uk/1072/1/1072.pdf
Echo 27 Nov, 1924 and Hampshire Advertiser 29 Nov 1924.
For anyone who thinks the 1924 tide height was the same as 1999, or Valentine's Day 2014, you need a goodly amount of flood water to cause
domestic furniture to float around, stop people leaving upper stories of houses and no reports of houses in Adelaide Road , St Denys, flooding
in living local memory. The Southampton Times (weekly) of 29 Nov 1924
referring to the flooding in Adelaide and Priory Roads "Small articles of furniture were washed into the streets and indoors domestic utensils were floating about". In 1920 there was more houses in Priory Rd, where the
community centre is now. As these houses were below late 20C road level, there is an argument that they could have been the ones flooded. Firstly the floor level of those houses was about the original house part of this building, of the behind-the-bar floor level in the Junction pub, still observable in 21C.
Secondly I spoke to a now deceased one-time resident 1960s and through all 1970s who lived in one of those now demolished houses. They never had the Itchen creeping up the rear gardens, in his time there, ie the 1976 flooding elsewhere .
The works only about a century late. (Northam not just protected by raising the banks but also uprating Imperial Rd pumping station and instituting the Lower York St pumping house in Northam)
I dropped in Southampton Archives and the "Fundamental " Fundamental Bench Mark, shown elsewhere on this page.
From 1868 Series 1 252 scale map, only to 1 decimal place placed on maps, height of bench mark then 75.6 ft, FBM at the then OS
headquarters ,at the red line ,still in
this position and green line to the printed height .
Later height on the brass plaque screwed over the original bench mark
'92
74.35 ft (no one has tried unscrewing these screws, perhaps because of the notice saying damage to this is a
criminal offence).
Then the Penna Liverpool - Newlyn height difference of about .02m
from analysing the colouring, gives the error picked up in newspaper reports as 0.40 +/-0.02m until OS reveals a 2 places of decimals First
Geodetic Levelling height for this bench mark .
http://www.cage.curtin.edu.au/~will/GJI_ODN_slope.pdf
I find it very disturbing that this error in the record is not stated anywhere that I've found. I can only assume
the same error applies to other ports around the UK as it is independent of Southampton using their own
local PLWD datum, as that is stated in the contemporaneous record as being 7.48 ft below the then Newlyn
datum. So the1924 flood was 6.0m +/-0.02m , not the 5.6m recorded in the official tide-height history of Southampton,
see
www.estuary-guide.net/pdfs/southampton_water_case_study.pdf
They would not have been using the Second Geodetic Levelling height in 1924.
Unfortunately I was plain wrong as to the reason behind the down-playing of the 1924 flood event. On the maps it looks like the same origin for the geodetic surveys, at the gates of the OS headquarters London Rd/ Avenue.
But the fundamental FBM was not there for the first geodetic survey.
Going to the original survey report , in the Cope Collection
of Soton uni, the origin was a carved BM on the wall of the guard block at the entrance to the OS. Perhaps still there under later rendering but about 15 foot from the "tomb" FBM, very close inspection of the maps shows that also.
The tomb FBM emerged somewhere between the 1934 map and the 1948 map.
For a difference beteen 1GL and 2GL, comparing the map heights
on different maps, then one such pairing is 13.0 (1GL decimal foot) and
12.35 (2GL decimal inch) so 0.65ft +/- 0.05ft, unfortunately I've
not seen any early, 1GL, decimal inch resolution levels for anywhere in Soton.
The more interesting reason for the down-playing of the 1924 event is described lower down in the 1924 section.
No reason to believe the situation of wrongly recorded flood histories does not apply to other ports and historic
tides.
The first site I've seen, emerged 2015, where they would have usually used the
erroneous 1924 Southampton data with impunity, but have excluded that and all Soton data
Surge Watch
With the getout clauses
, "A particular issue with older events are consistency issues with the vertical datum used at that time, in relation to modern datums. These are
reasons we chose to leave this type of addition to a subsequent stage. " and
"These tide gauges are operated for example by port authorities (such as at Southampton where a new digitised record has been extended back
to 1935). However, because they do not form part of the National Network, such data can be of lower quality and require extensive and time-consuming quality control measures. That is the main reason we did not include this data at this stage."
This erroneous 1924 "data" has been the incorporated into
the computation of erroneous flood event return periods in multi-million pound flood prevention schemes. Their specious 1000 year return period height not even reaching the true 1924 level of flooding locally. A number of theses also using this erroneous data.
Southampton Archives image,
, as "SC/E/6/24/156" is indexed as flooding in Clarence St,
Northam. From another image showing what is called New Liberal
Club, Northam, shows the club
and a shop , and general house forms that match , behind the cart in that image, and then
from street directories it is probably housing blocks, shop and Evan's Liberal Club, 6-8 Belvedere Terrace,
Northam. Two boys in sunday best and Eton Collars, girl moved head quarter of a turn in exposure, no ripples in the water, 10 foot away poor
focus, and people hanging out of each upstairs window on the right.
Was the interest because no one had seen a camera before and the date was much earlier, say 1877?. Gas lighting been in southampton since
1829, same lamps were shown in a dated 1921 picture of that area. The archivists have suggested dates of 1900 or 1910.
Then from OS street spot heights and this FGL-SGL OS correction of 0.4m , the flooding was to 6.0m +/-0.3m , the errror range because OS
maps of the time only gave integre spot heights in feet.
If the cart in the Belvidere Terrace pic , viewing the original sepia postcard in Southampton Central Library, shows the name CHaMberS
and larger letters below fishmonGEr (discernable placed as large letters here, although brushes and pans on it) then John Chambers was at
number 10, 1897 to 1900, maybe a bit longer but not a continuous set of Kellys. As postcards like this were produced by professional
photogtraphers , there was a commercial photographer AG Butler, 25 Northam Rd at that time. So now 2.5 of 3 different pointers to
the historic datum correction for Southampton being 0.4m, if
not 1924 then another , unknown date, of similar flooding extreme height.
Another image,in fact two, out there of the Cooper' Arms Clarence St, William St, shows only about a 5.6m flood , Boxing day 1912.
of 25 December 1912 , quote from the Echo
"Priory Road the unusual sight was witnessed of a small boat ferrying stranded pedestrians to and fro like a gondola in Venice"
Some additional miscellanea
Benchmark found in 2017 on the south side of Redbridge Bridge, earlier called Red Bridge, over the third arch
, 30m, from the Romsey railway track.
The benchmark about in line with the left edge of that pic, above the road surface. The cut under the railway is presumably a hangover from when the building behind was a transhipment warehouse , loading/unloading cargo from seagoing ships , over to canal barges to/from Romsey etc.
When VTS read 4.23m at HW of a 4.3m tide, top of parapet 3.62m from the water and benchmark 0.58 below
the parapet. There is a modern Cd referenced tide pillar on the causeway
bridge, reading 4.26m , 5 minutes later when VTS read 4.22m.
So height of benchmark above Cd 4.26 + 3.62 - 0.58 = 7.30m
First Geodetic Levelling Lyndhurst to
Southampton, levelling point on Redbridge Bridge was a "bolt"
not a "mark" cutmark, so probably not on the 1GL.
From 1909 map recorded height 15.7 ft (decimal ft) + 2.72m (Cd to OSD)= 7.51m +/-0.015m
From 1952 map , OS National Grid First Edition , re-levelled on Newlyn Datum 1941 and 1946
15.04 ft (decimal inch resolution) + 2.72m (Cd to OSD conversion) = 7.30m +/-0.0015m.
So difference between 1GL and 2GL for that spot 0.21m +/-0.015m, taking the same Newlyn - Soton, Cd to OSD conversion, which implies 2.52m instead of 2.72m conversion factor for old records based on 1GL.
A cutmark benchmark still exists on the current road bridge over the Test at Redbridge, on the north parapet , a pillar section 10m east of the extended line of the Anchor pub front facade.
More surviving benchmarks all OSD in St Denys,
Ex methodist church, not the old Ivy Rd side with the Edwin Jones
http://www.diverse.4mg.com/church_BM.jpg
foundation stone. The PR side , replacing the earlier BM as 1950/60s
looking brickwork and modern BM plate number G2702 (skill of OS bench mark carving had gone by then) , 3.67m, 1994 map.
Next 2 on 1994 maps but not seen as private houses
130 PR, 3.62m
90PR 3.47m
Priory Rd Railway bridge 3.28m , with 20cm marked ruler and chalk marks
http://www.diverse.4mg.com/rail_BM.jpg
(the 7.61m on the other side probably
disappeared with some obviously recent brickwork)
Junk shop , corner St Denys Rd, and in Priory Rd, 4.06m
http://www.diverse.4mg.com/junk_BM.jpg
Spot heights along PR , only to .1m, PR next top railway track 3.7m,
Adelaide Rd junction 3.0m, Ivy Rd 3.0m, Eastfield Rd 3.7m, Priory Ave 3.7m.
Kent Rd , lowest point near railway bridge 1.5m .
On the Whitworth Cres side of the Bitterns Rark Hotel, plate marked
OS BM G2701.
Near the Town Quay ,historic BM map recorded height data changes
Winkle St BM 15.3ft=4.66m on 1860s map, 14.58ft =4.44m on 1948 map and presumably rounded to 4.4m on the 1993 map.
Opposite Town Quay (maison dieu church?) BM 14.7ft 1860s, 14.09ft 1948 and 1933.
God's House tower BM 13.84ft = 4.22 1948, 4.10m 1993
Very old surviving levelling benchmark Russell Place , opposite where RJ Mitchell lived at number 2 , Portswood. Its lost the plate with the height value under the "ft in", shows the crown of King George (1st) and the military broad arrow that later became the bench symbol.
http://diverse.4mg.com/BM_GR.jpg
Before OS HQ moved to Soton
Looking at early tide tables, big gaps.
The 1930s tables just refer to above or below the datum with no extra qualification
1930 highest predicted for that year was 15.1ft on 15 Jan
and lowest of -1.0ft 23 Sep
Only highest of the year looked for, in these later ones
1933 , 14.5ft 8 aug and 05 sep
1948 14.8ft 04 oct
1949 , 14.8ft 22,23 oct ,24 sep, 17 march
Echo of the time only gives the approx times of daily HWs , not predicted heights
Found a useful resource at the Winchester Record Office
record W/K1/56/1
from 01 jan 1905 to end of 1935 someone's weather station log for Winchester, respected enough to have his summaries placed in the
Hampshire Chronicle. Height unknown and calibration etc unknown
wind/temp min and max/rainfal/barometer at 9am and percolation gauge readings
barometer data for days with less than 28.8 inches at 0900
so for eg 24 S xx below read 1924 wind south 28.xx inches
10 dec 08 e 79
2 dec 09 sw 75
3 dec 09 s 64
21 dec 09 s 85
23 jan 10 sw 69
9 dec 10 s 80
22 to 24 feb 14 s,sw 51,93,24 (sic)
14 to 15 dec 14 se,s 77,74
2 jan 15 s 75
13 to 14 feb 15 s,se 81,77
28 mar 16 s 75
18 to 19 nov 16, ne,sw 71,55
12 dec16 n 79
23 dec 16 s 79
28 aug 17, sw 77
no wind direction from now on
8 mar 22 68
30 dec 24 75
8 jan 24 70
27 feb 25 82
20 to 22 dec 25 61,63,64
19, 20 nov 26 81,51
25 mar 27 78
22 dec 27 77
1 feb 30 70
12 oct 30 26.69 inches (sic) day before 29.75, after 29.95 , nothing in remarks
31 dec 30 78
12 mar 34 74
17 mar 34 77
15 dec 34 63
22 feb 35 74
25 feb 35 61
27 dec 35 80
Chronicle of marine flooding around the Solent area. Must be more as tends to be via backwards referals to previous floodings in the
newspapers
A cautionary tale of meddling with the sea and an inundation of 08 March 1630,
from Oglander Memoirs 1595 - 1648,
[At Brading Haven, Isle of Wight]
" Sir Hugh Myddelton before he sowlde tryed all kindes of
experiments in itt ; he sowed wheate, barley, oates, cab-
badge seed, and last of all, rape seed, which proved ye
beste, but all ye others came to nowghte. The greate
inconvenience wase, in itt ye seae browght so mutch
sand and ooaze and seaeweed that choaked up the pas-
sage of ye fresch to go owt; insomutch that I am of
opynion that if ye seae had not broake in, Sir Bevis
coold hardlie haue kept itt ; for ther woold haue been
no current for the fresch to go owt; for ye easterne
tydes browght so mutch sand that ye fresch wase not
of fforce to drive itt awaie, so that in tyme itt woold
have lain to ye seae, or else ye fresch woold haue
drowned ye whoole countery. In my opynion itt is
not good medling with a hauen soe neare ye mayne
ocean. The countery (I meane ye comon people) wase
verie mutch agaynst the inninge of itt, as owte of theyr
slender capacitie thinkynge by a little fyshinge and
fowlinge there woold accrue moore benefit then by pas-
turage; but this I am sure of, it caused aftor the fyrst
three yeres, a greate deale moore healthe in these partes
then wase evor before ; and another thing is remarkable
that wheras wee thowght itt woold have improved
owre marishes, certainlye they weare the woorse for itt,
and rotted sheep whych before had fatted theyre. The
cawse of ye laste breache wase by reason of a wet tyme
when the hauen was ful of fresch, and then a high
springe tyde, when boath the waters met underneathe
in the loose sand. On ye 8th of March, 1630 [Old Calendar], one
Andrewe Eipley, that wase putt in to looke to Bradinge
Haven by Sir Bevis Thelwell, came in poste to my
howse in Nuport, to informe mee that ye seae had made
a breache in ye sayde hauen neare to ye easternmost e
ende.
I demaunded of him what ye chardge myght be
to stop it owte, he told mee he thowght abowght 40
shilhnges, wherupon I bid him goe thither and get
woorkmen agaynst ye nexte daye morninge and some
cartes, and I woold paye them theyr wages; but ye
seae ye nexte daye came soe forciblie in that there wase
noe medling with it, and Ripley went up presentlie to
London to Sir Bevis Thelwell himselfe, to have him
come downe and take soome further cowrse ; but within
four dayes aftor the seae had wone soe mutch on ye
hauen, and made ye breache soe wide and deepe, that
on ye 15th of March when I came thither to see itt, I
knewe not well what to judge of itt, for wheras at ye
fyrst 5 woold have stoped it owt, no we I thinke 200
will not doe itt, and what will be ye evente of itt tyme
will tell. Sir Bevis on ye newes of this breache came
into owre Island on ye 17th of March, 1630, and
browght with him a letter from my Lorde Conwaye to
mee and Sir Edward Dennys, desieringe us to cawse my
Ladie Woorseley 1 on behalfe of her sonn, to make up
ye breache whych had hapened in her grownd throwgh
theyr neglecte. "
There then followed a Jarndyce v. Jarndyce lawyering situation costing many thousands of pounds in the 1600s , still in the courts 5 years later.
Brading Haven remained submerged till reclaimed 240 years later
1703
Could anyone hazard a flood-level "VTS height" from the data provided by letters to Daniel Defoe. I assume the ships run ashore were full
sea-going cargo vessels of 1703 and because it was from the SW would have gone ashore between Itchen Ferry and Bitterne, before the
railway came through but similar ground and height to the present day Weston Shore. There is no records such as port tax books etc for that time, earlier and later yes, lost in that flooding?. What is known is that
the cargo trade with Soton at that time was mainly with the Channel
Islands , so perhaps smaller cargo vessels than full ocean-going ships.
So far , from Ships of North Cornwall, John Bartlett, for ships
recorded for customs purposes of the 36 ships he listed covering the year 1703 going into Cornish ports, the average tonnage was 25 tons.
from OCR'd Oz version, worth reading
https://ebooks.adelaide.edu.au/d/defoe/daniel/storm/complete.html
"Southampton, February the 17th, 1704. Sir, Yours I have received, in which you desire me to give you an account of what remarkable
damage the late violent storm hath done at this place; in answer, we had most of the ships in our river, and those that laid off from our keys
blown ashoar, some partly torn to wrecks, and three or four blown so far on shoar with the violence of the wind, that the owners have been at
the charges of unlading them, and dig large channels for the Spring Tides to float them off, and with much a do have got them off, it being on
atops sand or mud, had but little damage; we had, God be praised, no body drowned, tho some narrowly escape't: as to our town it being most
part old building, we have sufferd much, few or no houses have escapet: several stacks of chimneys blown down, other houses most part
untiled: several people bruisd, but none killd: abundance of trees round about us, especially in the New Forest, blown down; others with
their limbs of a great bigness torn: it being what we had, most material. I rest. Sir, your humble Servant,
Geo. Powell."
The early barometric record
I make the minimum to be a not remarkable 965mBar for Burnley,
Lancashire. The Toricelli barometer had been around for only a few
decades but even so Vernier scaled models being used in 1703, Halley presumably Fellow of the RS, and of comet fame. Adding dots and
asssuming the inch record only recorded when it passed through integre inches
TOWNELEY UPMINSTER.
Day. Hour. Height of Mercury. Day. Hour. Height of Mercury.
Nov. 25 7 28.98 Nov 25 8 29.50
3 .64 12 .39
9½ .61 9 .14
26 7 .80 26 8 .33
3 .70 12 .28
9½ .47 9 .10
12½ 28.72
27 7 .50 27 7½ .82
3 .81 12 29.31
9½ .95 9 .42
28 7 29.34 28 8 .65
3 .62 12 .88
9 .84 9 30.07
29 7 .88 29 8 .25
(28.47 in of Hg = 964.0 mBar, presumably non sea-level adjusted value)
Soton Archives , checked the council minutes for 1703 plus first half of 1704, but no ref to the great storm or payments for repairs.
The accounts book for disbursements , St Mary Extra church (on Peartree Green)
( I forgot to transcribe the amount, probably involved much the same water meadows , later used by the Portsmouth spur railway, between Itchen Ferry and Bitterne that the two cargo-laden ships in Daniel Defoe's book, were grounded on)
28 Nov 1734 (so probably flooding a bit before that day)
"gave two men and theyre familys for loss by the sea coming in upon theyre land and drownd theyre cattle"
21 jan 1804
E and W Cowes ,houses and shops, with 3 to 4 foot of water
Highest in living memory
19 Jan ,1804 highest for 30 years, then Portsmouth
flooded 28 Jan, 1804
18 nov 1808
Broad St , Southsea , shops with 30 inches of water
Portsmouth 9 inches more than ever remembered
Friday, into Point St, nearly to Point Gates, on the Parade
to the kerb stones of the pavement
04 mar 1818
"near hurricane"
houses washed away in Portsmouth .
Mess-room of Haslar Barracks flooded
The Platform, Southampton, partly washed away
22 and 23 November night and morning,1824 storm and floods, small part of the coverage in the Hampshire Chronicle of the time. I assume tunnels for freshes we would call culverts
these days.
http://www.diverse.4mg.com/floods_1824.jpg
The full surge was the Tuesday before this publication date of the Southampton Herald of 29 November 1824.
"The much agitated state of the barometers , at this time, added not a little fear of the inhabitants" but no barometer readings unfortunately.
There is some more weather related info for the preceeding days.
1824 event I seem to have uncovered data that corroborates the newspaper report of 6 foot above normal astronomic spring high tide level.
Previous academic reporting of 5 foot of water in Poole town but lacking for this area.
Something like 2.6m above normal spring tide for Chichester.
That the sea broke through at Catches Corner to the Fort,Sandown IoW, and flooded in to Newchurch and Brading, making Bembridge to
Yaverland an island. That seawater taking days to drain away down the East Yar. Sometime I will find a representative ground height for
Newchurch, I'm assuming Google maps and Earth are as useless as they ever were for that purpose, despite quoting z-axis to mm .
Old Portsmouth High St, flooded up to Oyster St.
As 4 at least events in the last 310 years are of >=1924 I place that 6.0m level as an 80 year event.
Then 1703 and 1824 levels of about 6.5m VTS/cD can probably assigned the status of 150 year events.
Nov 15 1840 ,
The times
Friday morning, Portsmouth,lower part of the town flooded to 5 or 6 ft, people were seen in the upper rooms soliciting aid...
In Southampton, the change in the weather began to manifest
itself about 11vo'clock and increased in intensity to 12 o'clock, when the tide having risen a foot above high water mark, though the time for
high water was not till 2:30 ... being 4 foot above the usual level .. . the roads were impassable except to vehicles.
Bursledon on the road the water was up to the horses backs.
Stokes Bay , a shepherd having got to the highest point of the field ... was drowned without it being possible to give assistance.
Hampshire Advertiser (21 Nov 1840), the Southampton and Weymouth stage coach, 3 inside and 5 outside passengers, at Redbridge Causeway.
Stopped by the tide which reached nearly 5 feet over the roadway, and fallen timberwork. Passenger Mr Furmedge of Dorchester held the
heads of the lead horses for 3/4 hour with water up to his arm-pits while the timberwork was extracted from wheels and harness.
More a novella than a newspaper report, from the days when we
got proper floods (see also 1821 a very similar event much the same area)
The extended flat run of the Redbridge Causeway, spot height on old OS maps, was 10 ft, the same
as the then spot height for Adelaide Rd / Priory Rd Junction.
I don't know how much of that quoted 5 foot / arm-pit height
related to wave action , but imagine that amount of water
descending on the road outside the Junction Pub.
Lymington , "Capt J. Symonds, RN had four feet of water in his dining room" . From his will as John Symons, RN pensioner,HRO 5M62/22 , page
875, died 13 Sept 1885. Freehold dwelling Alexandra Cottage, Bath Rd, Lymington.
Bequest of his yacht "The Annie" to wife Jane Symons.
In 1891 census Alexandra Cottage is 105 Bath Rd.
This 4 feet of water may have been when he was residendent at Keyhaven.
Flood related material from Milford on Sea Record Society, August 1920
itself edited down by Dr V D Harris, from source material that then 100 years ago was in the
possession of Sir Ralph Payne-Gallwey.
Journal of colonel Peter Hawker and his connection with Keyhaven.
In 1821 ... long spell of terrible weather, about 30 days rain . Terrific
hurricane which took place on the 28th Dec ... The tide is so tremendous
that the breakers literally rage and foam against the houses (of Keyhaven) ...
the whole population here are driven to their attics ... No communication from
house ot house except by boats ... lasted more or less for 3 or
4 days , but was never as bad as the first day.
(Aside From HC for Thursday 27 Dec 1821) ... overnight, the mercury sank to
28.5 inches during the hurricane, on Sunday it sank to 28.2inches ...
The tide yesterday (28 Dec ?) was very high, the sea defences between
Sothsea Castle and Lump's Fort were all washed down and the sea
breaking in. Lump's Fort, Stoneham's mill, Marmion Place and all the
lands (upwards of 300 acres) and houses in that neighbourhood were
completely inundated. ... others retired to the upper parts of their premises.
A small cottage in Marine Row was washed down. ...
Southampton, about noon 28 Dec. an extraordinary high tide, the wind
blowing very hard at S and S.W. ... The tide was so very high as to
overflow a great part of the Quay, and its force so very powerful that
many large stones of immense size have been washed from their
situation.
______
(back to Keyhaven)Then 15 November an awful breach had been made in the sea bank and
let in an average tide.
______
18 november a hurricane more terrific than the 13th with rains, floods
and darkness. ... Captain Symonds who lived in the house called Harewood near by, but was ill in bed at the time, had the tide in his rooms four feet
deep before he could save his furniture from saturating.
(contemporaneous geography from that MRS booklet - First house is Fisher's Mead next to Keyhaven Cottage
of Col Hawker. Harewood's is mentioned in a Lymington handbook , with map, of 1841. Also called Harewood Cottage and near Aubrey House.)
____
Another gale with rain and indeed a hurricane in January 1847 and there would have been another flood had not Mrs Whitby ,on the colonel's
entreaties, raised her banks 15 inches.
______
Church vestries 4 Jan 1825 , to consider the rebuilding of the
poor house which had been swept away in November [sic] (or December) 1824
during a severe gale and flood.
Dec 26 1860, The Times , shipping casualties
Destruction of Ryde Pier by ships blown through it.
From Northam School, Peel St, Southampton daily log book printed in Victorian Logs by E W Gadd ( school and its yard still there, so levels surveyable. Unfortunately none of the 15 benchmarks in Northam survive to the present. I think building plans for the school and later rebuilding etc are in the archives, but I did not think at the time to call them up, may have recorded an OS referenced level as one BM was on the Peel St side, built over by a recent disabled ramp construction )
1866,1869 and 1875 refs below
30 Jan 1866
"Few present - very wet - yard nearly flooded
01 Feb 1866
"Yard flooded - very wet"
29 Jan 1869
" A very few at prayers this morning in consequence of the streets
being flooded"
"wind was at hurricane strength " , "extraordinary high spring tides",
"furniture floating about in their residences, compelling them to remain in their bedrooms"
(There is one week's gap in the record with no explanation , presumably much flooding)
Next entry
06 Feb 1869
"few present - very wet - yard nearly flooded",
"in some houses the water reached to the third or fourth step and to the
tops of the fireplaces"
10 Nov 1875 ( an allusion to flooding, I forgot to transcribe)
From Hampshire Advertiser of 13 Nov 1875
Weather records made at OS office Soton, lat 50'54'50' , long 1'24'0 at 78ft barometer corrected for temp and height 10 Nov 9am 28.806 inches.
"High Tide . On wednesday there was an unusually high tide
, Totton the water flowed up the road to the Red Lion Inn (HRO 79A01/H2/2/1 for hi res pic (Whitbread/Brickwood Estates album) as in 1997 had a benchmark at the front 3.57m OSD, Commercial road spot-height outside 3.0m, 4.79m BM at the railway footbridge , very neat one directly under the wall mounted post-box set in the station building and 3.0m spotheight in Station Rd and now gone 10.45m (=3.19m) BM on the then police station?/142 Commercial Rd )making its way into the old established and well known hostelry and even over the cross roads making its way into the shop of Mr Drew, the butcher opposite the Red Lion.
Thumbnail pic http://www.diverse.4mg.com/red_lion_totton.jpg
The Causeway was covered for some time and the houses at the Totton end
of it suffered considerably , among threm the police station, where a considerable quantity had to be bailed out ... At Testwood and Eling the tide flowed into the mills and did considerable damage. A high tide on Wednesday was quite unexpected ,and it was not anticipated there would be one until Monday after the full moon and consequently spring tides, and therefore the usual precautions were not taken (so no awareness of surges coming along the English Channel ).
Taking "making its way into" as meaning an inch over the door threshold , taking one string of laid brick plus mortar to be 0.08m .
Plus taking the average of 8 benchmark heights above their respective local ground levels , in terms of layers of brick and mortar, in 3 areas of IoW
and Hamphire, 5.5 layers,5,8.5,3.5,4.5,9.5,6.6 and 5.5 giving an average of height above local ground level of something like 6 bricks and mortar.
The HRO pic of the Red Lion , Totton from 1970s/80s unfortunately had a
car parked in front of where the benchmark was. The resolution on the
original positive photographic print was enough to show individual bricks
and maybe benchmark if unobscured. With 3.57m benchmark height , unless or until a better pic turns up , I make a best estimate for that flood height of about 3.4m OSD
or 6.1m Cd. As the benchmark must be for practical chisselling and surveying
purposes more than 3.5 bricks above car park level and the sill height of the window was 10 bricks above car park level, the bounded error must be about +/- 2 brick courses or 3.4m +/-0.15m OSD. The 3.0m road crown spot height of Commercial Rd near the Red Lion and its car-park slope is also consistent with about 3.4m flood height. There was some rebuilding of the Red Lion last century but the floor level should have stayed the same.
Yarmouth High Tide ... wednesday morning ... washing over the quay ...
testimony of oldest inhabitants, the highest known for the 34 years.
Printed ed 13 Nov, Tides for Soton for the ensuing week, mornings and add 25 minutes for post noon tides, spring tides rise 18 feet , neap tides 8 feet and highest spring tides 2 days after full moon or change of moon
Sun 10:57
Mon 11:37
Tu 12:00
We 12:40
Thu 1:34
Fr 2:28
Sat 3:32
Cowes. Tuesday night it rained here in torrents, and on Wednesday morning the tide rose much higher than had been
known for many years, inundating all the low parts of the town,
and the sewers,being full of water, were unable to discharge the
torrent that into the town from the hills at the rear, consequently
a great many houses at the Point and the High Street were inundated.
... Down at the Green and round by the Royal Yacht Squadron Castle the scene was very striking, parts which we have been accustomed
to see uncovered by water even at our highest tides, being entirely
submerged and the road by the shore from the Castle to Egypt
was impassable in many places, it being as much as 18 inches deep,
and washing water over the turf on the Green and around the seats
in the most de?ast manner. ... One of the most serious things was the very short time in which the tide came up the last three feet.
A gentleman who observed it has informed us that he, at 7 in the morning, on looking seaward from the rear of his premises,
saw that the tide was very high for a neap tide, and measuring from the
top of his quay found there were 2 feet for it to rise before it could be
over the wall. Not thinking for an instant it would rise
to that extent, and left that portion of his premises, and was
extremely surprised in rather less than half-an-hour to be
called, as the tide had made its way over the quay, and very
energetic measures had to be taken to keep it out of his
dwelling-house, at the door of which it was one foot high
by 8 o'clock, consequently the water rose about thre
foot during the last hour. ...
(17 Nov edition) Weymouth. At high tide some parts of the quay were inundated.
... at the West Quay the water was higher than it had been for 32 years ... At Northam it was about as it was 7 years ago"
01 jan 1877
(nothing found for 01 Jan 1872 in the local papers of the time, see Coopers' Arms, misreading of 40 yearold 7 for 2 ?)
highest for 30 years
Michael Southgate book Old Totton, 5 feet of water at Totton Causeway
Northam Chapel (church) flooded to 2.5 feet
Ransom's Terrace 3 foot high to the window sills
Peel St, Northam, water 6 stairs high in a house
Eling bridge up to the side rails of the bridge
Lymington Bath Rd , residents evacuated by boat
Newport IoW 1 foot higher than any tide in 25 years
Yarmouth quay flooded
Flooded houses in Portsmouth
Cowes "clay-up" phrase mentioned, tide 19 foot 8 inches , 3 foot 8 inches higher than normal spring tide. 59 years previously an extreme tide
that was 2 inches lower than this one
23 January 1890 (not researched yet in local papers)
Cutting perhaps from Hampshire Chronicle, railway to Hayling Island washed away. Low lying parts of Fareham and Lymington inundated. Cowes "the tide rose several feet higher than usual, and inundated low parts of the town"
Guernsey wind 60 to 73mph recorded.
From Digital Times 18 inches to 3 foot deep in the lower part of Christchurch town and the Wick - Christchurch ferry across the Stour had to cross "meadows covered deeply with water"
12 December 1893
Hampshire Advertiser of 13 December 1893 quotes concerning the "hurricane" and flooding around Southampton the day before.
"Such waves as were witnessed yesterday have never before been seen in Southampton river. They were not the short choppy sort we have been accustomed to
see in rough conditions but long rolling waves such as are to be met in mid-ocean. "
"At high tide about 1 o'clock in the afternoon the water rose 12ft or 14 ft
higher than the previous tide had done. "
04 Sep 1903
A reference in a book on Pompey, to flooding in Southsea.
Nothing found in the Echo , other than a large circus tent was blown away by a "cyclone".
Incidently at that time the Echo carried predicted Soton (first) High Water times and heights in terms of depth at Empress Dock , so of the order 33 to 36 feet.
Hampshire Chronicle only had reports of gale damage.
26-27 oct 1909
4 foot deep Waterloo Rd Lymington
High St , Cowes , knee deep
East Cowes near "Mr Robertons " was knee deep.
Ryde railway tunnel IoW 10 to 12 feet of water depth.
Eling bridge under water and houses flooded
16 Dec 1910
In Digital Times as use of boats in the Cowes streets "several feet of water"
in Cowes High Street, Bosham flooded, SW gale of 75mph maximum at Dover
Echo 16 Dec, Western Esplanade and Western Shore impassable morning high tide. A steam boat sunk
12 Dec 1912
(see Echo report of the Coopers' Arms floodmarks)
Nothing found of flooding in the Echo on 12 Dec but 13 Dec had a report of ship wreckage
washing up on the IoW
26 dec 1912
Boxing Day, 1912,highest tide for a quarter of a century "The Echo"
2 foot of water in houses of Rudmore Portsmouth
highest tide for 40 years
Southampton, highest for 1/4 century, older people saying longer.
Southampton West (Central) Station trains axle deep in water.
Cowes, 2 feet in shops, 150 yards
Crown Inn , E Cowes 4 feet and 5 feet in the kitchen
The Dec part of the 1912 Lymington newspaper microfilm was next to unreadable, Colinwood for that , but maybe the same microfilm source.
Captain Samuel Leigh , Newport, stated that the flooding New Years Day 36 years ago (1877) was 4 inches higher than this thursday.
3 ft higher than normal for Newport.
3ft in the deepest part of Cowes High St, swamping houses in Medina Rd, Bridge Rd, Mary St, Langley Rd, Brunswick Rd.
In E Cowes , knee deep in York Ave
26 Dec 1915
not researched yet
05 November 1916
11 nov 1916,date reported of
Southampton "northern" = Northam flooded , tide abnormally high.
Cowes streets flooded, stopped pedestrian traffic
9am on Sunday barometer 28.60 inches (968.4mB non-sea-level? )at Winchester
Minimum at Ryde, IoW, 28.7 inches
The Echo, 06 Nov 1916
"As is usually the case under similar circumstances opinions differed as to whether or not the watery visitation was the worst the locality had
endured. Most people declared emphatically that it was; but this was refuted by the evidence of the lines painted on the panelled walls of the
passage of the Coopers' Arms, at the corner of William Street and Millbank Street near the waterside, marking the high-water mark of previous
floods. Two broad black lines mark the point reached by the invading water on January 1st 1872 (misreading of 1877 , correctly transcribed in the 1916 reportage of these tidemarks) , the worst flood , according
to this record, within the memory of living man, and that of Boxing Day four years ago, while a good 3 inches below the latter a neatly-drawn
chalk line indicates the limit reached by the rising tide yesterday. "
( So same broad black lines as in the Vectis curiously. Half a chance this
record may still survive. The passage went from the front bar at Millbank St parallel to William St to the toilets. The interior wall went with all
the walls of the then 3 bars. As a broken mirror is known to
still be fixed on the wall under the current stud wall so may have
the original panelling/wainscotting under complete with tidemarks).
Report of the water reaching Northam rd , entering a paper-shop ,134 and a corn dealers next door, 136 Northam Rd, facing St Augustines
Church, about 20 to 25m north of the Kent Street junction with Northam Rd.
Special relief deliveries of coal to dry out the houses.
Also reported as occuring at neap tides
High Neap Tides. Although they were neap tides yesterday they were very high, higher than has been experienced for many years. This was
especially so with the evening tide between 6 and 7 o'clock. It is estimated that it was several
feet higher on the western side of town than the usual "neaps"
and was notable for the time it lasted, it being quite 3 hours before the water showed any sign of receeding along Western Esplanade. (In general Soton neap times are centred on about time 06:00 or 18:00 and springs around 12:00 or 00:00 times).
The 1916 flood reached 134 and 136 Northam Rd. Old pictures, before the 1960s Northam clearance perhaps late 1950s going by the billboard, in the archives show those shop floors being at pavement level. As the Echo
specifically refers to flooding only on that side of Northam Rd, not the church side, I assume the water did not reach the crown of the road.
Generally pavement level is much the same as the crown of a made-up road
these days but untarmaced 1916?. That OS 10 foot spot height was the the same as the Priory Rd /Adelaide Rd of that early map series. But as spot heights were +/- 6 inches, could be 1 foot different to the Adelaide/Priory Rd spot height I suppose.
So about 5.7m +/-0.3m in current VTS terms. The road spot height a bit down-slope of the Coopers' Arms was 7 ft or about 4.8m Cd.
From Southampton Council minutes, the flood relief comittee set up after that flood stated 700 properties , just in Northam, were flooded and
supplied 40 tons of coal and 4 tons of wood to dry them out.
Lymington seriously flooded at 7:20 am time of high tide, water 3 or 4 feet deep in Mill Lane and Waterloo. Huge stacks of railway sleepers in
the station yard were carried up to the level crossing. Portsmouth several feet of water in some streets.
In Lymington
I'm amazed no one was killed in Lymington 1916, just some minor injuries. 2 broad-sheet columns.
The bridge acted as a dam to the incoming surge with the second tide at 8.30am, the first tide at 6.30am had inundated initially. At the Free
Masons Arms at the bridge the water burst through from the front to the back of the building and scoured a trench 2 foot deep outside "as
clean as if it had been excavated".
Maybe possible to find which house this following is ,from Kellys/census etc, perhaps still survives.
Bath Rd, Mr F ?oolford (first letter illegible) had 4 foot 8in in his lower rooms. 1918 Electoral Roll, William Woodford , Bath Rd no number, with
Amy Gertrude Woodford.
Another building , next to the "Pumping Station" all the lower rooms filled with water and a "tidemark" on hte outside , 10 foot above ground
level.
6 horses at the Waterloo Depot were standing in 4 foot of water.
As well as saying in the (Lymington) Chronicle, it was similar character floods to the ones of Oct 1909, 1912 and 1877 also says Nov 15 1840
and Dec 26 1860 , so 2 more early dates to research.
IoW Observer. Reached Simeon St, Ryde
County Press. 3 ft water Bridge Rd, Yarmouth.
1916 not as high as Boxing Day 1912.
"time of dead neap tide" did not expect flooding. Sunday morning,
2 ft at the deepest of W Cowes High St. Floating furniture.
Freshwater Gasworks manager, Mr W. J. Ford in his house , the
water rose to within inches of the ceiling.
2014 OS map shows Kent St/Northam Rd road height as 2.7m+/-0.15m
and Adelaide Rd/Priory Rd as 3m +/-0.15m. At the end of Princes St , between the EMR scrap metal works and Southampton Dry Stack is the old Northam Point hard. The road height near there is 3.0m and old railway track to the hard (continues to the bit of track still visible under Northam Bridge). On a 4.84m (VTS) tide I surveyed the most landward brick pillar , base level to be 0.51m above that , and the base of the
remaining traffic bollard near the railway track , to be 0.61m above that tide level. The railtrack rises 4.4mm per m towards Mount Pleasant over 23m , so 0.1m rise there. So in VTS terms, 5.55m +/-0.1m by me and 5.75m +/-0.15m (OS obfuscation). Millbank is then lower than that local "high point" at the road junction just outside the yacht
stack yard. Northam area would seem not that protected from 5.6m tides, certainly not any 6m one.
Followup on the Northam situation and the flood of 700 houses , 05 Nov 1916 .
Luckily the Imperial Rd CEO (Combined Emergency Outflow) is more reliable than the VTS tide-gauge. It is the small, low-down!?! Southern Water building behind the Old Farmhouse pub.
Half a square metre area (as partially blocked with rubble) Itchen outfall under SilvaFrame yard on the Itchen , so probably .45m diameter pipe from that pump and under at least 3m head of water to cope with as well.
A 3 year snapshot of public data on p37, station 27 of
https://www.cefas.co.uk/media/52803/southampton-water-sanitary-survey-report-review-2015-2009-report.pdf
degree of event severity ("bubble" diameter), rough date +/-4 days from scaling the graphic
6, 05 Oct 2010
6, 25 Oct 2010
4, 29 Oct
19, 06 Nov (*)
6, 02 Dec
11, 05 Jan 2011
17, 09 Jan
14, 10 Feb
5 , 20 Feb
10 , 13 Dec (**)
14, 21 Dec (***)
8, 02 Jan 2012
6 , 04 Jul 2012
Probably includes tide blocking of Northam and Bevois Valley storm drains by normal tides and severe rainstorms.
(*) probably the .5m surge on the 11:40 4.7m tide of 08 Nov 2010
(**) maybe 4.86m tide on 16 Dec 2011
(***) maybe 4.84m tide on 25 Dec
A wind/wave assisted tide of 5.35m is enough to have unimpeded access to the low laying part of Northam streets. The owner of the chandlers at Shamrock Quay saw the water go over the yacht yard ground and just start to go down the drain in William St on 27 Oct 2012.
That and presumably other points of ingress, coped with by the CEO pump then and the other 5.6m tide events.
With an Abney level for the Coalporters end and around 136 Northam Rd, and using the long-run level along Northam Rd benchmark heights from the maps. None of the 15 or so Benchmarks around Northam have survived but 3 of the buildings along Northam Rd have survived but with the marks rendered or thick painted over. Assuming the carved marks were the same original 2 foot from the then pavement and also assuming the pavements have all been built up by the same amount.
The landing steps at Coalporters Rowing Club, from measurement at high tide and VTS gauge , gives a Cd height of 5.13m.
The shop at 138 Northam Rd was 1 step higher and not flooded.
So height of the 1916 flood >5.23m < 5.4m Cd
Going by the OS map road spot heights then less than 5.4m , or if tarmacked by then , less than about 5.55m.
A laser-level survey repeating that levelling would be a good idea as a lot of assumptions otherwise.
October 2018 was passing the Prince of Wales with bright sun, but glancing oblique to the brick surface and saw the remains of the benchmark that had eluded me before. One brick of it is seriously spalled due to frost damage and road salt , leaving the horizontal bar on one brick and just the lower end cuts of the
left and central barbs and parts of the depths of the lower grooves,
someone had filled the top bar with motar. About 200m from this BM and the now BT cover in the pavement adjascent to where the 138 Northam Rd shop used to be and GPO cover in the pavement of the 1950s archive pic.
Cannot be sure the level of that cover was not raised with the Northam rebuild,
nor no knowledge of what level of water went into the shops in 1916. But Abney levelling the BT cover to the pub BM, over the reduced survey distance of 200m, ie more confidence. 1967 OS height of that BM 11.05ft = 3.37m plus 2.72 conversion gives 5.52m Cd for the 1916 flood.
From the separate Echo reports of the flood marks in the Coopers of 1916 and 1918, 1877 flood was 2ft 7 in off the floor level, 1912 1ft 7in, 1916 1ft 4 in and
1918 1ft 2in off the floor. So in Cd terms and until someone can laser-level to the River Itchen or perhaps dGPS to the Prince of Wales BM as a local spacial and temporally close reference , taking 1916 Abney'd flood level of 5.52m
the Copper's Arms floor level 5.12m , 1877 flood level 5.91m Cd, 1912 5.6m, 1916 was 5.52m and 1918 was 5.48m.
Assuming the 7ft spot height of the 1965 OS map is exact at its position in
William St, and allowing 0.05m of a tarmac resurfacing since 1965, and
Abney levelling , gives Coopers Arms floor level of 4.96m Cd, then +/-0.15m
for OS spot height uncertainty (OS spot heights at road junctions are
always integre, so must be +/-6inch uncertainty there , but elsewhere? going by the 1912 and 1917 spot height surveys the other OS spot heights are also rounded up or down wherever they occur along roads rather than at junctions) .
The road crown 30m nearer the Coopers Arms is 6 inches lower than
the OS 7 ft spot and 8ft spot heights in bits of Millbank Street away from the Coopers, whatever that means.
I discovered a load of material in Soton Council Archives on the aftermath of the 1912 flood and the 1917 plans for Northam after the 1916 flood. Plank barrages in numerous places around Northam, didn't materialise as they managed to get all the Itchen boatyards to raise their yard levels, plus the new pumping houses. SC/EN4/12/81 , SC/EN4/12/79 , SC/EN4/12/78 ,
http://diverse.4mg.com/northam_1912_r.jpg ,
http://diverse.4mg.com/northam_1917_r.jpg ,
In the corner of the 1912 plan , dated 26th Dec 1912 the day after the flooding, someone went around surveying the lowest roads in Northam , with spot heights to 1/100 ft resolution and surveying heights reached at various places around Soton.
Surviving office building pics superimposed, not to scale.
By 1917 they'd decided to up from 11ft to 12ft as the protection level.
The 1912 and the 1917 plans would be using the 1Geodetic Levelling OS Datum , 0.65 ft locally higher than 2GL datum.
Western Shore power station was where Toys r Us, Coach Station and Geothermal plant is located now. The baths were Western Esplanade, Corporation Wharf at Albert Rd and the sewage farm is now Kent Rd Sewage works. Fay & Coy were in William St Northam , where the Coopers arms pub is. From the later Echo report of the Coopers flood mark for 1912 of 1ft 7in =1.58ft gives a Coopers floor level of 8.94ft ,taking the average reading between the sewage works and Albert Rd heights rather than the suspiciously low (inside a near wateright room? ) of the Northam reading .
In 2GL OS datum terms this is 8.29ft = 2.53m OD or 5.27m Cd (2018),
giving the 1877 (2ft 7in)floodmark a height of 6.06m Cd (2018)
For the second route , Abney levelling the short diagonal
from this Bowrring office across William St to the Coopers
and the 1917 plans. Unfortunately the details are only representative not scaled fully, as presumably from roadside sketching , not origianl building plans. Note one of the pyramidal topped brick pillars survives at the gate. Using the 12ft level, at the window sills , and optically levelling gives a Coopers floor level of 5.41m.
Using the 8.90 Office floor level, at the bottom of the door as the visual correspondence to the present, gives a Coopers floor level of 5.20m Cd (2018) and 1877 flood level of 5.99m Cd (2018).
As the relevant crown of the road between Bowering's Office and the Coopers was 7.97 +/-0.01ft 1GL , yes that accurate like the 1912 survey assuming the council surveyor had done his sums right. If the 8.90 door-bottom floor level is correct then only 3/4 inch of tarmac between 1917 and 2018 for that road spot, or 9 inches if the 12 ft level at the window sills was correct. Either could be correct I suppose, all the HGV lorries compressing the ground using that road since 1917 plus a few inches of tarmac or concreting because industrial estate plus tarmac.
The third route, via the just surviving Prince of Wales pub benchmark of height 11.0ft and the Echo info at the Coopers and invading a shop at 138 Northam Rd ,Abney levelled to the telephone duct cover outside, gave Cooper's Arms floor level 5.12m .
Looks like the Coopers arms floor level is about 5.2m Cd and the 1877 flood level about 6.0m Cd ,and from the reported floodmarks, 1912
5.68m Cd, 1916 5.6m Cd and 1918 5.56m Cd.
As it stands then, the 5.6m 2008 and 2014 floods could have inundated Northam , if those pumps failed. What level of flood tide >5.6m would overwhelm the Southern Water Imperial Rd pump?
Update December 2018, I levels surveyed from the benchmark of the
Prince of Wales to the floor level of the Coopers with a Tokyo optics Sokkisha B2 professional auto level that someone gave me for my researches . The original specifications of this was +/-1mm in 1km
surprisingly. Checking it against the rotary laser-levelled line at the Priory Rd hard , over a span of 54m (2x 27m) 1mm difference in heights.
Not possible to take a reading when a fast train is bouncing the sleepers 150m away, above one of the soggy-bottoms or wet-bed parts of the track through St Denys where underground streams disrupt the ballast, the cross-hairs bounce about 5mm in the x32 scope.
Not so far checked against 230m span along the River Itchen at high tide yet as requires a decent portable stilling well to setup the marks and >4.3m tide and meteorologically quiet. The following is readings taken to 1mm
and the confidence should be to +/-1cm for the floor level of the Coopers' Arms.
Prince of Wales benchmark 3.368m OSD of 1967. Level at lamppost near
Norman and Kenilworth Houses 4.039m eye-level and tripod position at the bend of Northam Rd, 44m and 60m spans. With tripod on the raised bed at the bins area of Mauretania House, eye-level of 4.325m between the lamppost and gate upright on Millbank St
between Clyde House and Forth House, tying back the shrubbery in the sight line near there, spans 102 and 113m .
With tripod on Millbank St and eye-level of 3.561 between the gate post and the Coopers equal spans. Relative to 3.368m of the Prince Of Wales OS benchmark I make the level of the floor of the Coppers' Arms to be 2.337m OSD (1967) or 5.077m Cd (2018) with a (until a calibration check) confidence of +/-1cm , so 5.08m. December 2018 after calibration of the auto level against Cemetery Lake on Southampton Common and a pair of benchmarks in
Priory Rd, St Denys as the relative heights don't seem to have changed over 100 years since the original carving , a correction for the floor level
of the Coopers as being 11mm higher, so 2.348m OSD (1967) or 5.088m Cd (2018).
So the historic marine flood levels , from the Echo reported Coopers' Arms tidemarks are 1877 5.87m, 1912 5.57m, 1916 5.49m , 1918 5.44m.
Assuming parity of the surge component in surge conditions , between Cowes and Southampton and the 1877 John White reported observation that the Cowes level in 1818 was 2 inches less than the 1877 flood, makes the 1818
height 5.82m. So in the last 200 years 3 flood events with evidenced height higher than Valentines Day 2014, being in 1818, 1877 and 1924 , plus at least one in the 1980s or 1990s, probably 1983.
15 Jan 1918
The best "epigraphic " record to date , of Soton marine flooding.
Another date to explore with other local newspapers, the tuesday 15 Jan 1918, of that echo report on 17 Jan 1918. 65 tons of coal distributed to Northam residents by Soton Council , 50 tons previously for the 1916 floods.
The most likely reason, along with Imperial Rd CEO, that Northam did not have serious flooding problems , since 1918, despite higher surge situations.
The Lower York Street and Lower William St pumping stations. In the Soton council minutes, at the same time the Imperial Rd site was uprated to electric power ( original pumps were worn out and needed a "strong man" to get them going ) they instituted a pumping plant in Northam , that is probably still there, in the unsigned building (just SSE transformer notices) . Quote for pumps, pump-house and outfall 21,594 GBP (July 1920).
Mention of requiring a 5 ton travelling crane, shown on the 1933 map, building and crane not on the 1910 OS map. That building/plot and ones at Shamrock quay are the only survivors from earlier times. The Lower William St facility,
http://www.diverse.4mg.com/lower_william_pumps.jpg
tacked onto the back of Camper Nicholson, with Southern Water sign on it. The warning of explosive vapour inside suggests that one is DC
powered from a large battery bank, like telephone exchanges, when the mains fails. Going by the delapidated state of the external woodwork, I wonder how often the batteries are deep-cycled or replaced and general maintainence
of the pumps etc.
When runnng ,it was so loud that people at the Camper Nicholson yard complained (Jan 1923). The pumps under the road, sometimes heard these days, are just to keep surface water from the Oyster Quay/Millstone point yard. Bottom pic shows the Lower York St 300kW or so transformer and the black panels are where the entry doors also function as large area air intake filters, presumably for cooling the motor/s and so not submersed for water cooling.
Using modern day pump data, 5 ton weight would give you one 150KW water pump capable of clearing 1000 cubic metres of water an hour , up 10m.
Maybe more capacity than that, for 3m or so head , but a long horizontal run out to a Millstone point outlet though. Perhaps 2 such pumps or 3x 100Kw, with stepped cut-in points.
The giant "Dutch pumps" that cleared the Somerset levels a few years back, each had 7 times that capacity. No pump noises heard when I took the pics of the pumping station with a 4.5m tide.
27 nov 1924.
Meteorology of the passage of the storm described in the third pane of text on 28 November, gust of 72mph at Petersfield.
From the Times newspaper, so low res pics placed here, lowest labelled isobars, 4mB spacing, for 6pm 25 Nov 992mB, 26 Nov 980mb and ,
27 nov 980mB. Understanding the meteorology of this 1924
storm I would have thought was the most significant analysis of
all the storms in the last 100 years but because it was falsely
classified as only a "5.6m (VTS) " flood , not explored as deeply
as it should have been, to know what to look for in the way
of extreme flooding, other than surge timing coincident with high tides.
6pm synoptic of 23 November had the low of 994mB 100 miles
south of Iceland and then 6pm 24 Nov, 990mB 50miles NW
of Stornoway. So the worst storm of the last century in flooding
terms for central south coast came from the north, looping around Ireland and into the west English Channel.
Southampton West (now Central) station flooded to 3 foot depth, to
just short of the tunnel
Soton Floating bridges at street height both sides, lapping the
bases of the lamp-posts each side.
Portsmouth Sally Port, houses with floating furniture .
"... coal carts were commissioned to take children home and at the
sea end of Broad Street the water reached up to the horses' girth.
Men in waders assisted pedestrians by carrying them over the flooded
areain White Hart Rd. " (Notes :for the same series of OS maps that
show Priory Rd / Adelaide Rd junction spot height as 10 ft and so
the lowest point of Priory Rd as 8 ft, so +/-6 inches. And plural horses' girth which
are 2 ft 6 inch or more above ground . Then if strictly, as that paper
reports, then the sea end
data , which is higher than the minimum at East St, gives a floodwater depth of about 6.35m in VTS terms. End of Broad St spot height 9ft
and East St junction of 8 ft.
Benefit of the doubt as the horses would have had to
pass through the deep part of Broad St to get to the seaward end but the paper referring to the minimum road height as the sea end , at East st,
then 6.05m or so in VTS terms. If the horses were up to their
girths at the seaward end then at East St they would be near enough swimming and the coal carts of kids would be floating as well I should think.
The spot height at Broad St and White Hart Rd is 10 foot ,
but no spot heights given along White Hart Rd.
3 to 4 foot of water at Emsworth on the Portsmouth-Chichester road
Cowes High st impassable, almost to the seats of the parade, west Wight isolated, Yar Road waist deep.
Hythe thursday morning , 4 foot at high tide, invading many houses
Scores of rats in Northam
{The local bod with remembered picture of pub flooding , is not the Junction but the Bridge Inn. Remembered as 1933 dated on the picture,
hanging in the public bar of the Bridge. Pic showed the landlord in the flooded cellar, Itchen rose to Priory Rd pavement level at the elevated
height of the pub and entered the barrel delivery hatch in the pavement, but no flooding in the Bridge bars. [see 1953 "coverack or Lynton/Lynmouth" rainfall event, this flooding could have been due to housing in Priory Rd impounding flash-flood rainfall off Portswood high ground causing this high level of flooding]
The pic of drinkers in a flooded Junction maybe this pic via Chinese whispers or another picture}. Anothe rold resident who was sometimes cellar man for the Bridge Inn said Itchen water often invaded the cellar on a normal spring tide. I only noticed in 2018 that the power points around the bars are raised above the dado atop the wainscot panelling. I originally thought to protect
the heritage panelling but later realised a now redundant grill
for hot air heating was knocked thru the wainscoting and also the
room dividers were crudely sawn thru in the 1970s.
It was possible mains electricity would have come to the Junction Inn
within local memory of floodings of 1909,1912,1916,1918 and 1924
so deliberately initially at high level. The mains comes in at the
lounge door up to ceiling level for the meter. None of the
wainscot panels loose in 2018 to see if there was a tidemark
still existing in the plaster from historic floods, as distinct to
ragged dirty mark of fireman's hose water of the recent fire.
It is entitrely possible the wainscots in there were deliberately
introduced to avoid having to strip plaster and replaster from
repeated flood events in the early 1900s.
In 1924 the pilot of the Mauretania taking the ship out of Southampton took the ship out too fast knowing the effect it would have on flooding
to Cowes from prop wash, at a time of an elevated tide. From www resource 1 of the 15 or so sailings from Soton was on 27th November. If
there was a transcript of the "trial" of that pilot, there may be more technical info on height of tide and the effect on Cowes. The commisioner's
wont talk to me about the case, not even confirm what date of the offence. The case is still in the minds of local pilots as a warning for turning
large ships , sending propwash towards Cowes
when turning around the Bramble. Eventually found a report in
Portsmouth Evening News 14/2/1925 and the incident occured on october28, 1924, so no connection with 27 Nov 1924 flooding.
Quoting 5.6m for 1924 as far as I'm concerned it is all GIGO. Repeating GIGO is still GIGO . Cherrypicking? , don't use early
tide record data because they know there is elevation problems
with it and then pluck the 1924 data from that historic data, just because it is repeated each year in the local tide tables, well
divorced from its original context and the then datum used.
1930 and 1930 Southampton docks Tide tables had no mention of the 1924
flood event. It was present in the 1948 tables as "High Water , November 27th 1924 ,rose to 16feet 9inches above datum (P.L.W.D)" , so emerged mysteriously sometime between 1933 and 1948.
I've not even seen how they got to 5.6m
So I'll give it here, it is too simplistic.
I can only go back to 1948 Southampton Harbour Board tide tables.
They state the tide reached 16 ft 9ins above PLWD on 27 Nov 1924.
Elsewhere it states PLWD is 7.48 ft below Newlyn datum
So 16.75 - 7.48 = 9.27 ft = 2.825 m relative to Newlyn
Add the current OSD/cD conversion of 2.74m
and you get 5.565m
rounded to 5.6m
Totally ignoring how they determined Soton heights relative to Newlyn.
I can only assume they brought in a surveyor who surveyed back to a convenient bench mark at the bottom of town, that then height related to
FBM 1 in London Rd via OS maps of the time.
So the Town Quay tide gauge data would have its elevation determined via the FGL and still be the datum used in 1924 reference height.
Ignoring the second tide gauge, perhaps the Empress Dock one. The current VTS tide gauge would be surveyed and height referenced
ultimately back to the SGL that was in use from 1930s onwards.
Adjustment for changing from FGL to SGL , 0.4m
An odd graphical plot of FGL SGL adjustments
http://www.trigtools.co.uk/data/AbstractMap_0003.PNG
I wonder why not the actual changed values , like southampton London Rd FGL of 75.6 (from first series map) and SGL 74.35 ft on the FBM
itself, so -1.25 ft. Somewhere off the -0.75 ft "contour" on that plot,
probably to do with least squares plotting of the contours.
Interesting historical background stuff on there
http://www.trigtools.co.uk/data/2GLMain.htm
There was a piece on local TV concerning the history of Gun Wharf Key, Portsmouth. Some brickwork was shown withg carved dates on
it but no info relating to it. Thinking it may be flood markings, I went over there. No, Kilroy was here type graffiti, dates and intitials and the
1924 graffiti one 1.6m off ground level. This was on the Old Infirmary building near Vulcan house and Nelson Gate. Interesting to see the present
levels around the shopping arcades etc, compared to the height
of the ground level for the Old Customs House. Ther emay be an
OS benchmark on the landward side of that building.
low res pics at Beken of Cowes of flooding
http://www.diverse.4mg.com/beken.jpg
Concerning the above consecutive 5 dates of
04 Sep 1903
27 oct 1909
26 dec 1912
05 nov 1916
27 nov 1924
there is a common factor between them, not knowingly repeated
as far as the precipitating meteorology and extreme flooding, ie >5.6m Cd locally.
For the last 25 years or so I've monitored the meteorology that
can lead to local flooding, central south coast.
In that time I don't remember a depression that has come from the north , round Ireland and then the English Channel.
We just don't seem to get the serious flooding that occured about 100 years ago.
Synoptics in the Reanalysis
http://www.wetterzentrale.de/topkarten/fsreaeur.html
and plugging in those 5 dates and the days preceeding.
were depressions that came from the north, skirted west of Ireland and hand-brake turned into the Channel.
A low res version of 23 to 29 Nov 1924, to get inside platform file size limit
Anyone aware of any reason for so many storm systems of that track but of that era, perhaps rarely repeated since ? It would seem that for our area the worst-case scenario is a storm from the north, charges the North Sea with excess water (inverse barometer effect), and a surge through the Dover Straits and then summing with a surge from the same ,or different, storm affecting the west of the English Channel, then the presumably chance event of that summing combining around high tide and spring-tides as well for maximum inundation.
One person much more expert than me hypothesised as an explanation,
"Such a track would require a strong NW'ly jet. Such a strong jet
requires deep cold air to the NE and warm air to the SW, with global
warming and sea ice melt cold plunges ain't what they used to be (sub
510DAM even in November). Hence synoptics are different nowadays, hence different weathers. "
and another expert analysis of those unrepeated? storm tracks of a hundred years ago.
"you sound to be describing a polar low coming south in the cold sector of a larger depression and then altering course ("hand break turn") and deepening (possibly explosively) when it meets the trailing cold front region of the larger depression. Such things happen. I'm not an expert on very high latitude meteorology (everything changes there because the low temperatures cut down the role of latent heat, which is normally dominant, and sensible heat and radiative balance become relatively more important). However the obvious climate change is the decrease in sea ice extent over much of the year with very significant implications for all the surface energy exchanges. At a first guess one might have thought the result would be an intensification of polar lows but if they depend on baroclinicity ,then maybe the frequency will indeed be reduced.
The 1924 coverup
The underlying black image is from a reprint from the Feb 1949 edition of Dock and Harbour Authority, in Soton Uni Cope Collection . Tidal Features of Southampton Water by Lt Cdr D H Macmillan, Hydrographic Surveyor to Southampton Harbour Board. Whether he or a predecesor decided he did not want to be part of a conspiracy, there is an easily overlooked, very subtle clue in this image. Unfortunately it is a compilation of a number of Soton charts depicting unusual tidal events, so a bit cluttered and maximum file-size of 250Kbyte for these hosting platforms.
The one of interest ,labelled 27 Nov 1924 is associated with my overlaid red and yellow curves. A very precise draughtsman's hand has hand-written the date legends and also the very precisely drawn arrows to different levels such as PLWD. The tip of the arrow precisely to the line, also to the lowest recorded level. But look at the 1924 curve, it stops short of the trace top, this is where the cover-up starts. I should also point out that the time scale at the top and bottom is wrong relating to the 1924 event at least.
The centre time is not noon but midnight , confirmed in the newspaper coverage.
If the main flood event had been during the day , they would not have allowed the
recorder to continue faithfully recording , but displaced downwards by a fixed amount, they would have stopped the whole mechanism, clock and pen-trace (see a modern day near equivalent failure 13 November 2019 , qv).
The flood event started about 23:00 on 26 Nov 1924, not the apparent record showing it having seemingly peaked at 10:50am and newspaper record "reached its height soon after midnight". As there is no "nipple" distortion repeated, lower down, on the following displaced midday tide trace,ie not engaging the limit stop again, the amount of slip must be no more than 2.7 inches or 2.7 feet.
Portsmouth had the midday tide of 27 Nov 1924 as their extreme tide, as the peak surge of the previous cycle, that so severely affected Soton, had passed Portsmouth before its corresponding midnight high tide . The 5 foot residual at low water, Soton 26 Nov 1924, was not due to a west-going surge ,like the "Canvey" 1953 low water surge, as no record on the Dover tide-gauge record ,unless there was some sort of secondary low in the eastern English Channel on 26 Nov 1924. This 5 foot surge , by the time it got to Dover at about their 26/27 midnight high tide , may have been what did for their tide gauge and the last 23:00 normal reading of 26 Nov 1924.
Since finding that Macmillan article with the multiple plots from Soton tide gauge,
a librarian at the NOC library found a cleaner , more rectilinear plot of the
same data, used in the updated plot lower down with the clutter of the other plots removed except the
minimum of the lowest plot, pointing out the significance of different treatments of the
legend arrows . MacMillan D H (1958) ,
The Southampton Tidal Model, Journal of RICS Nov issue, reprinted
in Tide p112, London C R Books ltd, 1966, OPJ MAC in NOC library catalogue.
Because of the biblical blind faith about this Soton flooding event being around noon , the time-stamp ,date and text highlighted by red asterisk of the Echo later the same day.
" The Almanzora (15,550 tons) ... shortly after 4am the liner broke from
her moorings at berth 22-23 in the Empress Dock and (? one word) about
swinging on her stern ropes which had not parted. ...
The Almanzora commencing to swing through an arc of 100 degress
towards the City of Marseilles .... The Almonzzora had the full force of the
gale blowing against her starboard side and the bow ropes 15 in number
were the first to give way ...
The fury of the gale showed no signs of abating as the morning
progressed and there was another thrill with regard to the liner Almanzora
just before 11am. On this occasion the iron bollard which
is set firmly in the quay was snapped off by the strain imposed by the
liner, which was then taking the full force of the gale. "
Returning to 26/27 Nov 1924 the synoptic chart on NOAA historic Reanalysis, does not agree with the available contemporaneous meteorology, ie 975mB isobar at Lands End is not possible. My amendment is included, but needs a meteorologist to nail down a better idea of the situation between Portland and Soton that afternoon and night. The coloured squares are my wind interpretations, and red isobars are 2mB spacing.
Blue hashing means remove the NOAA and yellow is altered NOAA 5mB spaced isobars. The pane I've added is for 21Z on 26 Nov, data shifted by linear interpolation for MetO 0100 readings to 0000 times etc of NOAA plots
But agrees with the following data
Portland Bill barograph "drop showing a fall and rise of 9mb within the 5 hours ending 5h on the 27th Nov 1924"(Met Office monthly report)
http://diverse.4mg.com/1924_nov_26+27_winds_r2.jpg
http://diverse.4mg.com/1924_nov_26+27_850HPa_r2.jpg
Daily Weather Report, chief forecaster 26 Nov 1924
"A depression covering a large area is stationary off the southwest of Ireland but secondaries are likely to form and maintain southerly winds "
(NB: Beware trip-hazard , as the heading info is in a train of indistinct footnotes on different pages, the column headed change of pressure in the last 3 hours, is in units of half millibars)
26-18Z 26-22Z 27-01Z
Scilly 980.5mB 979 978.5
Falmouth 980.2 978 977.7
Portland 984.3 981 976.7
Calshot 986.9 984 983.4
Dungeness 991.3 989 990.2
Guernsey 983.3 - -
Times Newspaper, 28 Nov 1924
gust of 72mph at Petersfield
Using my widgets for windstress to surge( stands up reasonably well against NTSLF+reality ), but is only for the large scale , not the small scale like a Portland to Soton localised deep depression.
The main surge that night , was due to wind from the south, a lesser version of the Great Storm of 1987 (about 1.2m surge at Newhaven , Soton something similar going by the mayem of floated and loosed boats moored in the Itchen , that should have been safely in the mud as lowest of neap tides and nearer low water than high. More usefully recent data from these minor south/SSW surge events
http://www.ntslf.org/data/realtime?port=Portsmouth&from=20161120&span=4
http://www.ntslf.org/data/realtime?port=Portsmouth&from=20160328&span=4
and the more numerous WSW wind induced surge data for the surges of 27 Nov 1924.
Using the NOAA SLP plots and info from the 850HPa 6-hourly plots
as they stand I now get the main surge as being much as when the tide-gauge mechanism slipped. The extra , from the localised meteorology , needs a proper meteorologist to fathom out.
For the next low water I make the mechanism slip to be the metric version of 0.77m . I suspect a pro meteorologist modifying those NOAA plots for sea level and 850HPa winds, for the period over midnight 26-27 Nov, for south Hampshire/Sussex would look halfway towards the 1987 images of the Great Storm, scaled back from 104mph Herstmonceaux gusts to 72mph Petersfield gusts.
For the next high water 0.71m , so taking the the slip , not quite the average but for convenience, to be 2.5 feet or 2ft 6inches lower recorded water depth.
Repeat of my earlier amended Macmillan plot of the Soton tidegauge record
26-27 Nov 1924, time-shifted 12 hours. Horizontal orange line , minimum level to agree with
newspaper reports, the next high tide at Soton with 2.5 inches of slippage
is lower than the endstop height and enough height to continue on to Portsmouth to give the flooding recorded there. Orange curve is conjectured , only a good shape, no othe reveidence for it, otherwise undefined
during the slippage. So amended tide height must be at least
1.33ft or 0.4m from newspaper reports and probably no more than 1.8ft or 0.55m higher than the official recorded height.
Blue is the original pen trace displaced upwards 2.5 inches, curved orange line at the
top has no evidence for its character as undefined in the slippage time-frame, just looks sort of right continuation of curve at flood and ebb.
Adding 2.5 inches to the actual pen trace at 23:00 would be too high in the sense of implying a very skewed rapid rise in water level after 22:30 instead of smooth continuation of curve, some slack or friction in the undefined slippage period perhaps.
Green dots are hour and feet graph alignment points of the red curve, for
transparent copying with scaling on to the tide-gauge plot .
Red curve is a close-fit harmonics generated "Southampton" tide curve , a perfect fit would pass thru the purple points in the small purple circles, of the Easytide data.
Assuming the admiralty easy tide retrofit data is valid, although from spot
checks of other historic contemporaneous data only the low water times and heights
have good agreement.
It looks as though the earlier Cary Porter gauges used a spooling mechanism , with fusee compensator (the cone and weight on the pulley axis under the mainframe), using what is generically called perforated tape and sprocket pulleys, presumably bronze or phosphor-bronze and studs or balls on the data transfer pulley, (wide pulleys on this image).
http://trigtools.co.uk/data/2GL_AutoTG.JPG
avoids silt and grime transfering onto the measurement frame pulleys , if a simple counterweight returned to the stilling well, is used.
Easy to have a slippage there, with limit-stopped geartrain, looping up of the suspension tape/ribbon, disengaging sprockets, then an integral number of sprocket gaps slip of the tape, leaving no obvious sign of slippage until the next verification check.
Attention now turned to the surge over low tide of 26 Nov 1924 when it all started, was there enough wind in the
English Channel to still have 2 foot residual of water at Soton, late evening on the 26th.
I suspect yes, but needs some more expert advice about the validity of introducing the
white isobar at 987mB in the below plot. Comparing the metO Daily Weather Report data (DWR_1924_11.pdf) on the 26 Nov and a
somewhat similar, wind from S or SSW and surges 27-28 March 2016.
Low Water 19:40 27 Mar, 1.0m, O type flood tide curve fitting
+4 2.5m 23:40 residual=2.86-2.5= 0.36m
+4.5 2.6 r3.3-2.6 = 0.7m
+5 3.1 3.83-3.1= 0.73m
+5.5 3.6 4.65-3.6= 1.05m
+6 4.1 5.16-4.1= 1.06m ,02:40
+6.5 4.3 5.27- 4.3= 0.97m
LW 07:50 28 mar, 0.9m ebb O tide
-3.5hr 04:20 4.2, r= 4.83- 4.2 = 0.63m
-3 4.1, r=4.95- 4.1= 0.85m
-2.5 3.8, r=5.0 - 3.8 = 1.2m
-2 3.3, r=4.76- 3.3= 1.46m
-1.5 2.5, r= 3.72- 2.5 = 1.22m
-1,1.8, r= 2.73- 1.8 = 0.93m
-0.5, 1.1, r = 1.66- 1.1 = 0.56m
So a 4 foot surge , but by then the windstress was from the west.
Residuals between EZ tide times and harmonic generated tide-curve
and the still working Soton tide gauge pm 26 Nov 1924
Noon 1.1ft,
1pm 2.0ft,
2pm 3.5,
3 pm 5.0,
4pm 5.0,
heavy skewing starts
5pm 2.0,
6pm 0.4, (probably my misplacement of the timing and character of the YFS)
7pm 2.0,
8pm 2.4,
9pm 0.8 , (again probably YFS misplacement of my tidal curve)
10pm 1.8 ft
A more rigorous selection of harmonics would probably tidy up the
disparity around YFS and about a 2ft residual for the late afternoon and
early evening and again for the next flood tide.
1924 26 Nov pm ,peak surge Soton 15:30 hr, so 8 hours between the 2 southerly quarter surges, one flood duration.
2016 , 3 hours between SSW and wsw, could be an ebbtide duration in some future surge event.
Sufficiently different from NOAA Reanalysis plots, but as I've not seen any historical
French data, I've assumed the straight line between Brest and Paris has the correct
isobar pressures , assuming they were available to NOAA, then the 6 hour data from DWR
pdf and -3hour change values in units of half mbar. Yellow text is isobars minus leading 9 and wind direction
and red is my isobar reconstruction. For the start of the surge in both cases 1924 and 2016,
the isobar spacing in the Gulf of St Malo to Guernsey was much the same.
I've not yet found a modern example of a minor secondary Low, for winds comparison, other than a too
weak one on 05 May 2015 ,
south of Portland tracking towards IoW.
9pm, 73kph St Brieuc, 205degree
10pm ,83kph, centre on Guernsey, 215deg, 4 hours before Soton surge
11pm, 88kph, Cherbourg,215deg
midnight, 88kph, mid channel, 225deg
1am, 88kph, south of IoW, 210deg
2am, 78, solent,210deg
Lower plots is GFS 2016 comparison with same 2mB isobar spacing but
changed absolute pressures and timing shifted to compare with 1924.
Now what should have come first, the lead up over 25/26 November.
No direct significance I suppose but pm of 25 Nov, force 4 winds in the SE quadrant. Then the next day , most of it is consistent force 5 winds from the SE quarter. An unusual sustained wind direction, I can only find something representative recently with GFS so isobar and isotach data, in the way of the southern end of a passing trough on 10 Dec 2017.
Between 03:00 and 08:30 before the wind,at VTS 20 to 25Knots, changes from ESE quarter and air pressure drops, surge for those hours .2 to .6m, then later surge is
from winds from the west. Tide letter Flood H and Ebb J to K , similar
air pressure to 1924.
10 Dec 2017, Pompey 04:00 to 08:00, surge .35m to .48m
Lymington 03:00 to 06;00 , .2m to .5m
On the wider scale into the channel, for those hours in the wind source direction, 36 to 41 knots. On 25 Nov , force 5 , so about 19 knots, so a background surge for the SE wind, of 2 foot or 0.6m is quite possible.
The 2 foot of water on the 1924 tidegauge time-shifted plot at noon of the 26
Nov and at YFS and beyond into the evening before the late evening surge comes in. Just leaves the 5 foot surge around low water in the mid afternoon.
So 2 foot of that accounted for, leaving 3 foot or 0.9m for the surge
from the SSW, from St Brieuc/St Malo. The 2mB isobar spacing, of 35.4km of the "straight" wind coming from France, early pm of the 26 Nov 1924 and simple geostrophy
giving about 140kph wind in the Gulf of St Malo to Cherbourg. Assuming the secondary low I've inserted is valid , with the 987mB isobar. Not knowing how to handle the tight geometry, small radius of curvature , have scaled the MetO record of the Guernsey
force 6, 43kph anemometer reading within its 2mB part of the plot, to the other similar curvey isobars and spacings giving 33kph wind towards IoW. Also from geostrophy I make the windstrength ,radius of curvature about 32km, for the curvey sections, so 21% of what it would be with same spacing but straight, giving 27kph wind to IoW.
Assuming that wind regime carries on muchly unchanged towards IoW and using my SSW widget, gives a surge of 1.1m so well over the required 0.6m on top. If the spacing of the isobars in the St Malo area was just 10% wider, then that surge component drops to 0.84m and 25% wider the surge drops to
0.58m .
This all requires a proper meteorologist+oceonographer and more data from the time, from France or Dorset, Hants or IoW weather reports perhaps.
Yes there was still elevated water levels for the noon tide time, worse for Pompey that time, as the previous short-duration peak tide over-night had passed Pompey well after their high tide time.
Not the Southampton official recorded value of 16.75 inches or 16 ft 9.5 inches , they could not agree on the fudged value, over the actual topmost recorded height, it would seem; but something more like 18ft. From the pic on (century of Newlyn pdf) of a Cary Porter tide gauge the ink delivery arm is pretty robust and direct, not a long springy carrier. I've never seen a "nipple" like form to the top of a surge event trace , historic or recent. Until I see a good image of such recorders, this is my assessment. To avoid the stylus/ink delivery tube going over the edge of the cylinder as rimless, a limit stop in the top-wire mechanism. The 0.2 inch is recoverable,so the small hump in the plot, but as some point in that initial forcing (between 14 and 14.2 inches/ft), a set-screw bushed cog in the drive chain slipped 1.5 to 2 inches (1.5 to 2 ft) or wire slip, so falsely recorded the maximum tide height and following tide cycle as too low.
Sometime after 1903 (Soton Dock Board yearly records) they must have changed the original 14 inch drum or custom paper+gearing change to read
18 inches, set to +16 ,-2 inches , wrt PLWD, going by the Macmillan article , page 7 (Honfleur and LeHavre double high water comparison) by 1928 looks as though Soton recorder was 18 inches set as +16/-2 inches or 16/-2 ft wrt zero and page 3 by 1948 chart recorder was 21 inches set as +17/ -4 inches about zero. The following relates to the then Newlyn tide gauge, probably 24 inches, and if end stop allowances were the same, the drum of the Soton one may have been 21 inches.
Source material , pics on
http://eprints.nottingham.ac.uk/33859/1/resubmitted_pdf%20%28Green%20Version%29.pdf
and
http://www.tandfonline.com/doi/pdf/10.1080/01490419.2015.1121175
Brass drum 24 inches wide, from scaling handle dimensions, 2 inch parcel tape and vanishing point scaling of assumed A4 sheet of paper nearer the camera.
Paper 23 inches wide including margins
Heavy rulings at 1 yard/3 foot spacings, so not the same torn paper as remaining chart selotaped to that drum , to be photographed later in colour.
Hours marking around centre of drum at about MSL of 11.5 inches
and at .25 inches on left of the paper edge and .75 inches from right
End stops on the wire giving limit of pen tracings as 2.5 ft and 21.5ft, to avoid pen carrier hitting the paper clamps, before going farther and falling off the drum edge . Also protects the clock mechanism as well. But why the paper clamps could not have been fixed to the drum ends is a mystery. Also a mystery
why the ink carrier had to be so chunky close to the paper, requiring loss of use of 1.5 inches of paper at either end. I could see there being a specified number of quarter turns to that top clamp, so there is a specified stick-slip fail-safe "clutch" at that point. Shame a calibration/maintainance manual does not survive. These endstops could slightly ride up the pulley at either end and give the nipple trace. Balance of probability for the permanent offset, after an endstop/wire-pulley jam, in the gear train would be slip under the fingertight knurled clamp to the wire on the pen carrier, rather than grub screws on gear bushes somewhere.
Note "float band" suspension to the stilling well float, does that mean
it was wound around the large plain pulley, not using a counterbalance weight . So requiring thickness of the band taken into account with the gear ratio so something slightly larger than 12:1 ratio. If the band was quite thick , then in jam situation , on the recorder section, instead of looping upwards, it may have introduced quite a torque to the float band drum and so forcing the top clamp action , far more than the balance weight difference.
Same size weight carrier cans under the table but presumably more weight in the can at the clock drive end than the other , to give enough force to
make sure the float band winds around its drum reliably, but low enough to retain close to neutral load/lightening to the float.
Perhaps insufficient return force ,in wintertime, for the 1918 note in the Soton Dock board minutes about a requirement to heat the room that housed the tide-gauge and encase the gauge , as eratic ink flow problems specifically mentioned and "other reasons" perhaps being this along with stiffening of lubricant with lower temperatures.
120 teeth on large cog, about 56 on the driving cog, unfortunately cannot see the actual diameter of the recorder wire drum as hidden by its flange.
Taking flange diameter then gear ratio of about 9.3 but must be greater than that. Works out to be a 1.5 inch diameter drum to carry the
traverse wire, for 12:1 ratio.
http://www.bidstonobservatory.org.uk/wp-content/uploads/2016/08/gauges-fig2a-800x1024.png shows a simplified version of the presumed arrangement, no intermediary gear and no mention of number of turns of the pen wire over the drum or whether fixed anchor or shiftable if loss of counterpoise weight.
Instead of the wire being anchored to that drum, perhaps just a turn or 2 and relying on capstan friction drive / Eytelwein forces. If that was the case I'd expect to see a pair of alignment paint marks with a line across , where the 2 cogs mesh at half the chart height, as an
easy routine check for any slippage. It looks to me , with the paper overlap etc, the drum rotates counterclockwise wrt to the clock face. The top of the tide being at the gear train end. So with an extreme high tide, the end stop
at that end would jam at the small brass pulley, and overcome the
capstan friction and back torque of relatively small balance weights, and 2 inches of slip. For multifilament steel wire over brass, for one turn , ratio of forces is about 2 to 1 , for 2 turns about 5 to 1, coefficient of friction about 0.12, Eytelwein's formula. For anticlockwise drum, the problem end , ie jammed endstop giving much easier slip would be the clock end. Perhaps the last pictured graph paper , the selotaped one, was placed the wrong way round wrt overlap, that would explain the catching and ripping of the paper.
So if the steel wire was wrapped around the 1.5 inch drum the other way , and recording drum rotating clockwise , then the easy-to-slip end would be the high tide end at the gear train end of the recording drum.
That way round would also make sense for normal use, ie viewing the recent past trace towards the operator , rather than on the rear of the instrument.
Perhaps the steel-looking triangular structure to the rear of the gear train, was for braking the pulley with the float band attached, for changing paper sheets. If the wire was anchored into the 1.5 inch cylinder, then there would be about 6 turns permanently on the drum, but the tails shifting axially quite a bit, so
account would have to be allowed for ,ie the use of a fusee double-cone form to compensate (possible to compensate for float-band diameter change on the main pulley by a cone form added here and the change gear ratio,by change of diameter here, along with paper scaling change and stay with a 14 inch main drum). Plus more likelihood of the windings upsetting and jamming if more than two and varying take-off angles.
The pic on this site ,
http://trigtools.co.uk/data/2GL_AutoTG.JPG , of a Cary Porter tide gauge, shows a different arrangement of balancing the float suspension, or removed on dissassembly of the Newlyn one. It shows wide drum for taking up the
suspension band of about 1.25 inches wide, I like the fusee drum for its weight, to offset the
different weight of support band at float top and bottom , due to the length of steel band. Whether compensation for marine growth and corrossion of the
float, unknown. Like cine film sprocket hole drive system or more like Baudot paper tape, before writing data.
I see no sign the band was pierced or half-balls on the main suspension drum (balls set half into drilled holes), so another place it was possible to jump. Even if there were detend balls , the band could ride up , disengage and then re-engage in a different position, due to the then unbalanced action of the counterbalance weight and fusee. If perforations every inch say, then jumping an integral number of inches is possible.
Further work is required on the 2inch/2 ft or whatever amendment fit, some skewing, so the yellow curve agrees with the newspaper record "reached its height soon after midnight". So the white curve is the likely tidal plot, if the tide gauge had not malfunctioned, with 18 foot maximum tide height reached at just past midnight. From the float diameter of 2.6ft and the "flying-saucer" geometry of two spherical cap segment volumes. And if the recorder wire tensioning cans had a maximum of about 2.9Kg of lead in them , from the dimensions in the pics. From the capstan back-torque via the 1 to 12 gearing, then a maximum of about 32 Kg could depress the float about 4 inches , bending the float band instead, until the wire on the 1.5 inch drum slipped. Perhaps the after-thought-looking steel-looking triangle structure at the rear of the gearing is a restraint to stop the float band falling of its top pulley in such circumstances. There seems to be no secondary pulley to take a counterweight to the float , or a return path through the base of the recorder , so perhaps the float-band is wrapped around that large wide pulley. Unknown forces involved but looks as though the slippage occured at 23:00 leading to an overshoot of slip to about 2 inches in the wire and 0.8 inches from 0.8foot of looped float band. The end-stop was now
away from the pulley and the pen carriage could drift back as the half-hour linear trace , as reduced forces
on the carriage now, less than normal, until about 23:30. Then the remaining bit of slack taken up between 23:00 and 00:05 or so, slope change, when normal service could resume but with 2 inches/2 foot of permanent , until reset, slip in the mechanism and 2in/2ft of under-recording of the next tide cycle.
So for the white plot corresponding to the recorder plot 23:00 after the main slippage) to 23:30 slope -0.8, 23:30 to 00:05 slope -2.1 and -2.3 00:05 to 01:30 increases to slope -2.3 before the inflexion corresponding to the second high water .
The only consideration in 1903 was for legal purposes , if a ship grounded at high water, they had a record of what the tide height was, no
requirement to record low waters. So they went for the lowest quote which was for a 14 inch drum , so 14 foot tide span, ie barely enough to fully cover
a mean spring tide at Soton, even if they could use the full width of the paper.
Newlyn and Dover also had Cary Porter tide gauge recorders in 1924, the Dover recorder also crapped out that time. No Dover public record from 23:00 26 Nov 1924 for the next few weeks while it was repaired/recalibrated I'm assuming. They also had a ship careering around untethered in the port at that time, just like Soton that time.
Fitting red harmonic curve to purple Easytide tide datapoints for Dover 26 Nov 1924, blue historic tide gauge hourly data up to 23:00 crap-out and green as hour and metre marks.
I did not bother improving the harmonics fit and improving my skew fit of the low tides by about half an hour, as this plot was enough to show nothing untoward from the North Sea was destined for Southampton on 26 Nov or the early hours of 27 Nov 1924, to account for the tide gauge apparent anomaly, nullified by my yellow Soton tide-gauge amended plot.
These days VTS just lets the trace flatline or "no data" in surge event crap-outs.
Looks as though the centre of that 1949 compilation plot, for the 1924 event , was midnight , not noon, the label "noon" should read "noon or midnight according to context".
The peak of the tide was the early hours of 27 Nov 1924, so the previous tide cycle, not around noon.
The 18:30 timestamped publication of the Echo newspaper Thursday 27 1924
" The storm reached its height soon after midnight, and continued in unabated violence until day was dawning. To most people sleep was impossible ..."
The low before 2014 Valentines Day flood was also 3 foot above predicted , but the timing was spot on. Something produced heavy skewing of the LW preceeding the midnight surge at HW 1924.
I could not get a thin line trace off the UKHO Easytide site, so fitted 11 of Doodsons 23 Soton harmonic components to the Easytide text data.
My red harmonics curve is not perfect, the purple blocks are the Easytide LW/HW datapoints. Checked OS 1859 Soton tide records and 1930 Soton tide table predictions against Easytide . LW timings were spot on
for 1859 and 1930 but LW heights and HW heights and timings are probably
no better than scaling from the full/new moontide cycle.
Green points are 1 hour marks and 0 to 17 foot marks to align both grids before hovering and locking down , with 16.75ft representing a current 5.6m VTS height, and LW timings of either side of minight , rather than noon 27 Nov.
Yellow is "corrected" pen trace , moved up 2 inches/2 foot.
Purple dots in purple diamonds are the EZ datapoints
Even so, the LW around the time of the Portland Bill barograph drop
showing "a fall and rise of 9mb within the 5 hours ending 5h on the 27th"(Met Office monthly report), does not look enough. The apparent pen trace makes no sense at all for then or the later HW wrt the reanalysis met situation.
No evidence of tide-gauge recorder drop out in the time-sense, the unskewed LW timings are now consistent . The Y-trace error could be simple grub-screw of a bushed pulley, slipping on a spindle rather than bent stylus arm or designed-in slip clutch in the Y-drive system. Would then only be discovered when the later readings did not reflect general awareness of the tide levels or routine mean-sea-level cross-checks via the dipping "electrode" and sea contact in the stilling well, separate from the float.
Easy tide data for Soton then
Wed 26 Nov 1924
HW LW HW HW LW HW
00:20 03:34 09:52 12:47 15:58 22:31
4.3 m 0.7 m 4.9 m 4.5 m 0.5 m 4.9 m
14.1ft 2.3ft 16.1ft 14.8ft 1.6ft 16.1ft
Thu 27 Nov 1924
HW LW HW HW LW HW
00:43 04:19 10:53 12:34 16:42 23:14
4.5 m 0.5 m 5.0 m 4.6 m 0.4 m 4.9 m
14.8ft 1.6ft 16.4 15.1ft 1.3ft 16.1ft
metres converted to ft , not tide gauge feet.
11 of 23 Doodson harmonics for Soton, fitted to the Easytide 12 historic tide datapoints for 26+27 Nov 1924 , with an R^2 value of 0.9992.
The Echo of 25 Nov 1924 showed the times of Soton tides for 26 nov as 8:57am and 9:18pm and 26 Echo for 27 Nov as 9:41am and 10:4? pm (? unreadable digit) , [incidently 01 Dec 1924 Echo for tide times for 02 Dec , 1:20am and 1:33pm displaced timewise the other way wrt the present day UKHO tide times, problems with predicted tide times were noted in the minutes of the Dock Board around that time, also silting problems of the tide-gauge stilling well, the bottoming out leading to wrongly predicted tide tables ]
With a bit more harmonics fitting , should be able to tidy up the Young Flood Stand that is not quite the right timing to match the tide gauge record + 2 inch offset, yellow and red curves 0800 to 1000 27 Nov, or perhaps a bit more than 2 inches of slip
The 16:00 predicted LW delayed 1.25 hours, the "reconstructed" HW delayed 1 hour, rather than the nipple of 0.25 hour delay.
For my convenience I used a sine sum of harmonics with a positive phase component, for the normal cos version and negative lags, simply remove Pi/2 from each of the phase angles below. Similarly to time shift for a different t=0 origin and each sin(wt+b) component, simply add or subtract to the phase component of each harmonic , (w angular velocity)*(time shift in hours) and subtract redundant multiple 2*Pi .
The time origin for the following is 00:00 26 Nov 1924 to avoid big number Julian day hours, amplitudes in metres
MSL 3.036m
amplitudes and phases (sine and positive phases form)
M2
+(1.3594 * sin(0.505868049 * x + 2.727388038 ))+
S2
(0.4066 * sin(0.523598775 * x + 1.485351304 )) +
N2
(0.27798 * sin(0.496366918 * x + 2.417776917 ))+
k1
(0.0875 * sin(0.26251617 * x - 0.664718536 ))+
O1
(0.03414 * sin(0.243351878 * x +1.02520388 )) +
M4
(0.279475* sin(1.011736098 * x +1.643132654))+
2MS6
( 0.0948963* sin(1.029466825 * x +1.82214 ))+
2SM6
(0.1856 * sin(1.535334877 * x - 0.556910409 ))+
M6
(0.1753 * sin(1.517604149 * x -0.536804469 )) +
2MN6
(0.064 * sin(1.527105283 * x -0.681902743 ))+
MN4
(0.07498 * sin(1.002234979 * x + 1.699629457 ))
Image of a Cary Porter on
http://www.tandfonline.com/doi/pdf/10.1080/01490419.2015.1121175
Largest pulley takes the wire from the stilling well , then called the trunk.
I make the gear ratio about 25:1 and scaling the asssumed A4 sheet of paper to vanishing point, 2 inch packing tape and 2 handles in the image , probably a 24 inch version at Newlyn. 18 inch version at Soton in 1924.
12 hour rolling-mean analysis of the Newlyn hourly record and fitting 6 harmonics to the Easytide spot data , there seems to have been 2 very similar surges , near successive high tides, so more evidence that the Soton gauge had a 1.5 or 2 inch (1.5 or 2ft) slippage of the pen recorder gear-train, not just the Reanalysis met-data suggesting an error. As both shown LW and next HW are below predicted tide curve 27 Nov 1924.
The following is gobbldigook to me, anyone know what it means, a pic , a manual or something exists of a Cary Porter gauge ?
http://vocab.nerc.ac.uk/collection/L22/current/TOOL0622/
Neither the Science museum nor any technical museums in the UK seem to have an example, looking in the UK listing of conserved scientific apparatus .
Soton and Newlyn 1924 tide-gauge hourly records subjected to 12-hour rolling mean analysis to check on residuals as well as tide curve fit to the tide gauge data (avoids requiring predicted tide times and also picks up a good
idea of the residuals if not coincident with high or low tides).
Using 2014 Valentine's day data for scaling the rolling mean residual up to 2014 reality, then at 16.5 hr 26 Nov 1924, taking MSL for tide-gauge year of 1924= 3.083m, then surge of 0.68m. Likewise rolling mean analysis gives .65m surge at 03.5hr 27 Nov 1924, for the followup surge. There being no
reason for that surge , when reaching Soton, to have attenuated down to
negative, ie below predicted, nor the residual for the intervening low tide being below predicted.
The Newlyn record with a 6 harmonic fit for the EasyTide data .
Wed 26 Nov 1924
HW LW HW LW
03:47 10:31 16:08 22:55
5.7 m 0.8 m 5.8 m 0.7 m
Thu 27 Nov 1924
HW LW HW LW
04:33 11:18 16:54 23:41
5.9 m 0.7 m 5.9 m 0.6 m
About 0.3m residual at Newlyn LW would not become -0.1m for Soton LW
A life-long resident in Keyhaven with a flood mark on her sitting room chimney, 1.3m off the floor. Not the lowest house in Keyhaven, and a bit higher than The Gun pub.
House built 1887, (future) father's family moved in early years of 1900s, and same family living there continuously for about 100 years. As a teenager he experienced the flood and told his children the story. The flood forced them upstairs for the night. Daylight hours , the next day , the house was still flooded. They had to stay upstairs most of the next day, he swam through the sitting room to the kitchen , to rescue the floating bread-bin, for the family to eat something. Flood line not dated, but father was too young for 1916 and 1918 ones and 1931 height is probably mininterpretation of IoW newspaper record of Wootton , as a tide mill , probably like Eling tide-marks , on the "wrong" landward side of the mill. Leaves only 1924 when he was a teenager, and the extended elevated water characteristic of 26-27 Nov 1924 agrees also,
the low water was still at night time.
Abney gauge levelled to the relatively
nearby surviving benchmark on what was " The Old Stores",Keyhaven , Grid reference SZ 3041 9157 and modern datum level of 1.91m OSD.
That benchmark not on 1939 OS map LXXXVIII . 10 and 06, but the Quay and Salt Grass benchmarks agree in levelled height 5.75ft and 5.42ft and to within 3 to 6mm with the data on the http://bench-marks.org.uk/ site.
The Saltgrass benchmark is still there close to the marshes, I'll Abney level between it and a high tide sometime , in the curved brick wall of the rising drive into the Stables area of Saltgrass. Carved intp a .5x.5 m white stone, but carving is being lost to errosion of the stone. Cannot be sure of the
integrity of the stone placement, the wall is in a poor state and may have
been dismantled and rebuilt at some time.
From Milford Record Series June 1929, 05 Nov 1914 Penington Sea Wall
breached ,occupants of cottages at Keyhaven Quay removed by boat and 1925 + 1926 more Keyhaven flooding , no mention of 1924.
The Keyhaven 1924 flood height comes out at 2.68m OSD and taking the modern CD/OSD Lymington conversion of 1.95m , and UKHO Easytide (modern CD?) high tide Lymington height of 26 Nov 1924 of 3.1m at 22:19 gives a surge of 1.53m.
Going by UKHO Hurst Point tide comparisons , Keyhaven may have something like 0.2m lower springs tide heights than Lymington, so perhaps a maximum residual more like 1.73m locally there.
UKHO has the Lymington high tide of 27 Nov 1924 0.2m higher than the previous night's tide , and of course much smaller tide range than Soton. With the new sea wall at Keyhaven , the same problem now ,like at Lymington, of tide-blocking of any water off the land on the land side of these walls. 2014 Valentines night, sea height got to 3 or 6 inches of overtopping the Keyhaven sea wall (2 local reports to me), but trapped rain+river? water the other side rose to about 1.4m OSD at Keyhaven. The original sea wall , for 1924, was probably the height of the now concreted over bolt benchmark at Keyhaven, in the wall top face and level of 1.75m OSD.
Height of new extended height of wall not found on www, but Lymington to the top of the large flood gates at the hard of the quay, measured 1.4m over a 3.05m tide. At keyhaven measured about 1.65m over a 2.7m tide at Hurst Point so probably the same 4.45m over Cd. The increased height to the
Keyhaven Sea wall made 1992/1993.
Again, that surge figure and the subsequent elevated levels of water on 27 Nov 1924 is inconsistent with the apparent 1949 article with the Soton tide gauge plot , but consistent with a tide-gauge mechansim-slippage revised plot of that event. So far nothing found in the local paper for that time. On the day of printing , 27 Nov 1924 , but paper would be put to bed the day before, ironically a report
that the quay wall at Keyhaven had a breach and would be more liable to flood.
The next week a report by a visitor surprised to see hatchlings boxed up
on the kitchen table of Vidle Van farmhouse , to be taken upstairs along
with furniture for an anticipated flood later, but visitor did not stay.
In comparison the 1916 report of Keyhaven flooding stated, Mr Durnford,
dairyman ,had his premises surrounded by water, which does not sound like 4 foot.
January 2023 revisited the 1924 flood after a request to
MetO Exeter library/archive and the archivist kindly scanned in
the 6-hourly plots for 26&27 Nov 1924 not in the online DWR pdfs.
Also the daily log books of Calshot , Shambles light ship and Sovereign light ship of those days. The plots also had
cuttings from the Times of the time placed on the sheet.
Tide gauge slippage more likely about 1.5 feet rather than
the earlier reckoning of 2.5ft
MacMillan D H (1958) ,
The Southampton Tidal Model, Journal of RICS Nov issue, reprinted
in Tide p112, London C R Books ltd, 1966, OPJ MAC in the local NOC
library catalogue. Instead of deleting the other plots , this time I've highlighted the relevant one with red blocks.
He overlaid them all to occur over one nominal day.
For this one of that spaghetti, 27 Nov 1924
was the day of mayem in the docks when a 16,000 ton ship was loose in
the docks propelled by force 9 wind. It looks like the damage started
with the earlier very high tide about 23:00 26 Nov , straining the
mooring warps and partially lifting a bollard out of the quayside,
fully wrenched out later the next morning along with the the remaining
warps breaking.
The revised times in pink under the residual plot.
The docks board of the time only bought a self-recording tide gauge
for legal rasons. If a ship grounded near low tide, so they could show
the lack of water was meteorological rather than lack of dredging.
Hence selcted range of -5 to +16.5 feet
So only the height reached before hitting the spring prior to and then endstop of the plotter
drum ("breaking" it) went into the official record.
From local press reports and 3 data points,
1/ houses in Adelaide Road were flooded
2/ furniture floating in the houses flooded in Priory Rd
3/ 3 foot of water in the lowest road adjascent to the R Itchen.
Still Millbank St, Northam , though few people realise how low
The Coopers/Joshua Tree/Browns pub still is, as after WW2 all the
commercial yards boarding the river agreed to raise their ground levels,
and more pumps installed in Lower York St etc.
That level is my horizontal blue line above the archived plot, about
0.4m above the 5.6m official record.
The tide gauge was a Cary Porter with the connection between float and
12:1 reduction gear of the plotter was perforated phosphor-bronze strip.
The relevant pulley a foot in diameter, 2 inches wide with studs or
balls about 1/4 diameter and about 2 inches separation to make
calibrated engagement with the strip.
Best compromise of thickness of the band having to make a quarter turn
around the pulley and strip strength .
As a safety mechanism , if the plotter traverse hit the high end-stop,
the perforated band would loop up and disengage from the studded
pulley. The pulley would stay in place due to the counterweight and
fusee compensator for the changing weight of suspended
phosphor-bronze band. Until the tide dropped and band re-engaged with the pulley, displaced by some amount of the looping and perhaps another 2 inches of sliding over the studs before engaging.
The rest is the meteorlogy and effect on the sea compatible with what
would seem to have been about 1.5 feet of slippage minus 2 inches, of
extra sea height beyond the arrowed "breakage" point.
The green plot is Belsize tide curve for those 2 days , without the
century of sea level rise component. I've not found the conversion between
Empress Dock sill height below Port Low Water Datum , so
the main tide points positioned shifted vertically relative to the
Mean Tide Level on that plot and time shifted 15 minutes to agree with
the plotter timings. The green curve shape I've taken from the
1924 curve shape rather than Belsize.
The blue line is the displaced pen trace elevated by 1.5ft slippage
and the residual plotted above as the distance separating
green curve and the pen trace and potential reconstituted follow-on blue trace.
The surge amounts are taken from VTS and ntslf records with similar
winds. The main HT flooding surge at 23:00 would have been from S wind
from France to Portland Force 9 to Force 11 recorded on the Shambles Light
Ship, anchored south of Portland that evening, carried with the tide
pulse and little wind at Soton then.
The surge at low tide 26 Nov was from
the east , with Force 9 recorded at Le Havre and Lympne in Kent.
Belsize 26 Nov 1924
time metres
low 3h46m 0.61
high 10h10m 4.7
high 12h2m 4.58
low 16h10m 0.49
high 22h31m 4.61
day 27
time metres
high 0h30m 4.42
low 4h31m 0.41
high 10h54m 4.8
high 12h46m 4.63
low 16h53m 0.32
high 23h17m 4.71
Southampton Advertiser weekly 1924
soton tide predictions HT1 only
times GMT and heights above the sill
of the Empress Dock (new moon 26 Nov 5:16pm)
22 Nov 1924 // 6:29,37ft 4in//6:49,37ft 0in
23 Nov// 7:04,38ft 5in//7:45,37ft 11in
24 Nov// 8:11,39ft 1in//8:34,38ft 10in
25 Nov// 8:57,39ft 9in//9:18,39ft 5in
26 Nov// 9:41,40ft 0in//10:04,39ft 6in
27 Nov// 10:23,39ft 11in// 10:48,39ft 9in
28 Nov// 11:09,39ft 10in//11:35,39ft 5in
29 Nov// 11:56,39ft 4in// ---
Meteorology mainly from the Calshot daily record.
26Nov representative spot surge heights, interpolating other times
13h ESE f5
23/10/2022 VTS example
surge= .38m= 1.25ft
15hr E'S f6
11/02/2021 (VTS)
surge= .4m= 1.3ft
16hr SSE f7 locally
and if f9 from Le Havre to England
surge of 4ft
18hr SE 5
29/10/2022
surge 1.5ft
21h ESE f5, much as earlier
1.5ft
22.75 hr
1 foot Inverse Barometer , f9-11 wind surge from S of Portland
on tide pulse 2.0 foot, 0.5ft SE'S locally, 0.5ft hangover from
afternoon giving surge of 4 ft
"Rough sea, waves ?clashing/sloshing/crashing?
over break water and
spray reaching office
windows, very high tide
wind force 7 gusting at
times over 40mph from SE by S "
local wind and barometer on their own, well short of
requirement for the reported flooding.
Modern time comparison for surges induced by S aspect wind from St
Brieuc coast to Portland.
28 Mar 2016
20 Nov 2016
and middle of 07 Dec 2021 with highest sustained at St Brieuc S F6 and
highest at Portland S F7 rising to S F8 at Soton 14:00.
GFS gave F8 mid channel, Channel Light Vessel highest sustained was F8.
According to which tide curve you use , the surge in the Solent area
2021 was between 0.6 and 0.95m
For 1924 the wind along the continuation tide pulse from Portland
dropped to SE F5, but much more wind south of Portland.
At 1800 26 Nov 1924 , 5 hours before HT here, F9 at Nantes, France and
F6 at Rennes,
moving round the low so mid evening that F9 patch became SE to S, F9 to
F11 over water, experienced by the Shambles light ship 5 miles SSE
of Portland,
presumably only recetly seen in the Eng Channel in 1987 Great Storm,
Channel Light Vessel highest on Valentines day 2014 was F9.
27 Nov 1924
01h SSE f8
07/12/2021 (as VTS)
surge 1.9ft
07h SSW f8
13/02/2022 (VTS)
surge = 1.2ft
09h SSW f9
14/01/2020
surge = 3.0ft,
13h SW f7
14/01/2023
surge = 1.15ft
01/02 dec 1924
Bath Rd, Lyminton flooded
Cowes High St impassable
Soton West station (renamed Central) 3 foot of water up to just short of the tunnel
Floating bridges at street height both sides and water lapping the lamposts
Not as high as Boxing day 1912
27 dec 1924
2 foot of water at Soton West station
Rose well over Eling Causeway, needed waders to cross, receeded after 1 hour . Tide came over Main Rd at Rumridge Totton
20 July 1929
No local marine flooding, but another example of Portswood high-ground "monsoon" rain run-off to Bevois Valley.
background to 2011 meteotsunami
Nothing obviously out of place in the 1-hourly Newlyn tide-gauge plot of that time.
For Hampshire, nothing found in the Hampshire Chronicle and the Echo unfortunately only stated
"tidal waves of considerable extent" Southampton,IoW and New Forest coasts around the time of the local storm which claimed 3 lives in Southampton (lightning) and the New Forest.
RAF Worthy Down reported temp fall from 83 to 65F in 12 minutes.
1.38 inches of rain at Brokenhurst in 2 hours.
0.81 inches during the storm over Southampton, produced 2 ft of flooding at Holts yard (now Aldi site interestingly shop floor level
about 2 foot above Empress Rd level) Empress Rd, run-off from Portswood high ground, not necessarily anything to do with high tide tide-blocking , just too much rain-water to go down drains etc.
Probably relevant report of a boy who had to be revived , nearly drowned.
At Botley on the R Hamble , he was caught by an extremely strong outgoing current in the river.
Nothing stands out to me, in the MetO DWR pdf of July 1929 relevant to this.
From the Times newspaper report of the 20 July 1929 meteotsunami
FOLKESTONE - The wave at Folkestone was estimated to be 12ft in height as it rushed along the beach and into the harbour. No fewer than eight of these waves entered the harbour ,which was empty of water at the time. ...
200 yards to the full length of the inner harbour.
A 16 year-old youth ...fishing on the breakwater ...
was caught by the wave ... His body has not been recovered. ... A small boat with two men in it was lifted up on the rocks at East Cliff and left high and dry.
The town during the whirl-wind was almost in darkness, but not a drop of rain fell, and there was no thunder and lightning.
Hastings. - A 20ft wave swept into Hastings .. Mrs ...
was drowned when the boat in which she was a passenger capsized.
Isle of Wight. - On the east side of the Isle of Wight a bank of sand swept along the sea front with considerable force. Many boats were overturned on Sandown beach and hundreds of visitors quickly sought temporary shelter from the wind storm.
Worthing. - ... After a brilliantly fine afternoon, with the sea dead calm , a heavy mist appeared to seawards between 5 and 6 o'clock. This was followed by a black cloud, very high, and about three or four miles in length , accompanied by a terrific gale of wind. The sea was churned up into a wave quite 6ft high , which came sweeping towards the shore at an alarming pace. It extended as far as the eye could see, and within five minutes the sea had risen from low to half full tide. ...
May be a low water effect, impossible or much reduced severity at high tides.
From an expert
"Its possible such (meteotsunami) events are more likely at low tide in that at least some of the descriptions sound like a bore. If at low tide there are extended mud or sand flats then a wave train in deeper water might transform into a single bore (aka hydraulic jump). At high tide the wave train would remain as a series of waves going up and down, or breaking against, the harbour wall. Hence at low tide the energy would be concentrated into a single event with more destructive capability.
At places where there is an extensive beach at low tide, as the tide comes in, you sometimes see small bores or more rarely solitary waves, forming and propagating across the beach. Ive often seen this at Saunton Sands in N Devon. Only about 1 ft high but no reason they couldnt be larger depending on the excitation."
12 Jan 1930
83mph Worthy Down. 13 Jan Echo parts of the road flooded to Messrs Whites, Yacht and Engineering works, Itchen .
Vehicle storage building associated with the Woolston side of the Floating Bridge flooded
10/11 nov 1931
Terminus Terrace, Soton 1 foot deep to front steps
Yar Bridge under 6 inches of water, not as high as the previous Tuesday flood. Bridge Rd , Yarmouth, 8 inches.
Less than Boxing Day 1913 , W Wight became an Island.
Shanklin highest tide for 15 years
Newport 18 inches more than usual spring tides
Portsmouth worse on 10 nov. Highest tide for 20 years, 2 ft 6 in in Broad St. Curious absence of wind at midnight extremely high tide.
Tide 16 foot 3 in, 2 foot higher than predicted
Western IoW seperated from the East section
Cowes worst since 1912 with 3 foot in the High St, Shooter's Hill
to Midland Bank
Hamble 2 foot above normal HT
Boxing day 1915 reached nearly the same height
Sloop Inn , Wootton flooded and Wooton Mill of L J Souter flooded
to 2 feet, which was 4 inches higher than in 1877 (beware mill probably on the impounded side of the barrier, so not reflecting the marine surge situation - see Eling Tide mill "record")
23 Oct 1940
From the 1949 Lt Cdr D H Macmillan book (qv), on Soton Tides. Reported as reaching , in then terms, 16.1ft which probably
translates to metres and current Cd datum of a 5.5m tide
23 Oct 1949
Possibly the Vectis Tavern flood event, as quiz question (qv) unknown date in the 40s, high tides but perhaps tide-blocking and excessive rainfall on Cowes high ground, confined by the shops of the high St.
Pressure of excessive rainfall runoff, lifted manhole covers around Southampton.
1.15 inches of rain over the weekend, bring ing to 6.45in the total for Oct up to 9am 24 Oct.
High tides too, predicted height 14ft 8in exceeded by several inches
30 July 1951 not researched yet. 62mm of rain in 45 minutes in Cowes (Philip Eden book) could be just a rainfall flood event and source of the Vectis Tavern flood level question.
28 Dec 1951
From the Echo the next day, from D H Macmillan
"1HW rose to over 16 feet at 10:30pm and was 16ft 2 in at 10:51 instead of 13ft 3in
as predicted. The high levels remained with little recession until 1am when they had fallen only to about 14ft 8 in and at 2am the level was still up to 12ft 8in - that predicted to 12:46am."
The Marsh at Hythe was flooded to a depth of about 18 inches.
2 foot of floodwater in Woodmill Lane, Southampton.
02 Feb 1953
included as local effect of "Canvey Island " but surge was mid tide locally . Soton Hydrographic surveyor stated LW was 3 foot over predicted
and previous HW was 1ft 6 in higher than predicted
31 Oct/ 01 nov 1953
Purely a rainfall event, like the Coverack , Corwall event 2017, no marine involvement.
Adelaide rd flooded as well as Priory Rd. Tropical extreme rainfall presumably giving the reverse of usual, ie the housing blocking the otherwise natural run off to the Itchen , high ground Portswood+Highfield+common rainfall not going down the road drains, flooding into
St Denys and Empress Rd areas along with our own heavy rain. The Priory Rd floodwall would not help in a repeat of that situation (climate-change increased possibility),and recent build up of ground at the hard car park makes the landward flooding likelihood worse.
Probably the event ,so far pub mythology, different people have seen pictures of the Junction pub flooded and the cellar of the then Bridge Inn , flooded Priory Rd to the pavement level outside the highish point of Priory Rd ,via the beer delivery hatch in the pavement also photographed .
The route for this Portswood run-off was probably across the original Dukes Rd and into the then dip at the west end of the Horseshoe Bridge and into Empress Rd and across the railway into PR.
I think I see why Portswood Rd "monsoon" rainwater goes along Spring Crescent rather than down Bevois Hill, because it looks as though there is a small incline between there and the top of the hill.
Then Lawn Rd , then much as before, I should think.
Ptrobably going across Thomas Lewis , depite being higher now
. Then down the new access rd to the station, Drummond Rd and then across the railway into PR, rather than over the patch of ground they seem to be taking years to build an office block on, and over the railway.
Preliminary determinations , awaiting a >=5.3m tide or sustained >= 20mm/hr rainfall.
Looks like with current dilapidation of sewers foul and storm, even a 5.3m tide would not raise the level in the deep .45m main sewer to the top of the pipe.
Looks like 45mm of rainfall in the previous hour would be required to bring the sewer level up to 5.1m VTS height. There is a footpath of sorts between the
railway line and Thomas Lewis , to walk along , rather than the edge of the
urban freeway, to visibly check how many lift pumps are working.
After 2 of the 2017 severe rainfall events , I only saw 2 of the 3 large lift pumps working.
The 1953 event would not have been a tide-blocking example, purely a "Coverack" type event. Assuming 9am-9am meteorological days 2.82 inches of rain in one day, weak neap tide ,tide letter C, low water 00:14 on sunday 01 Nov 1953, preceeding the 3am phone call from Kent Rd because of flooded houses.
I'm aware of the extreme rainfall route down Avenue Road etc from the Common and general Portswood high ground, down Spring Cres into Lawn Rd and Empress rd and across the railway into Priory Rd at the Junction Pub, the flow I witnessed not strong enough to float parked or moving cars but probably enough speed and height to knock over someone. There is an unculverted underground stream that causes endless problems (bouncing rails requiring speed restrictions) to the shifting of underlaying ballast of the main London rail route, the route of that is about under the level crossing.
Whether that is a route for high level rain events and up-welling , I don't know.
From Soton Council minutes earlier in 1953, up to 1897 there was a stream from the common that fed into the Itchen around 316 to 330 Priory Rd, assumed unculverted and just filled in, again unknown whether another severe rainfall route.
The ground at the one-time Ferryman site , off Priory Rd (north) and southwards was reclaimed/raised-up prior to 1953 .
There was another such event IIRC 1920s came across in the Echo archives but as not marine related , no details taken.
A more localised near repeat of such an event , early hours of 08 February 2016, for Kent Rd, short heavy downpour, but nothing sustained. The pumps at the seawage works stopped, presusmably an automatic cut out , to protect their electrical equiplment , when there is local fooding. A large amount of rain, well beyond the capacity of the road drains, swept down Wellbeck/Portswood Rd, under Kent Rd railway bridge. Flooding the local houses, and because no one-way valves in their toilet pans, water coming out of the overloaded local sewer system. I've heard the recording of the "conversation" with the emergency call-out engineer who had to manually reset the trip. A similar event occured sometime about 28 Feb and 28 March 2016 . Perhaps more a problem with the pump control in the sewage works, rather than excessive rain as such. One of those overnight 2016 rainfall floods caused flooding of an upstairs room, Kent Rd. Such was the torrent from the Wellbeck side, it bounced off the abuttment to the road bridge ,off the abuttment to the rail bridge, reflecting off the slope of the front garden and flowing into the ,despite Febuary, open window upstairs.
04 dec 1953
Lymington Bath Rd flooded a third time, also Bridge Rd and Waterloo Rd
26/27 nov 1954
Car in 4 foot flooding at Seaweed Hut, Weston Shore, Soton
Lymington flooded, Christchurch worst for 30 years
Bath Rd , Lymington, 5 foot of water
Bournemouth hotels flooded
Hurn airport gust of 72mph
Bath road ,lyminton, to wellington boot height
Eling over the bridge but passable, water to the door of the Anchor Inn
Weston Lane, Soton , 1 foot deep, Mersey Cottage 11:30 reached house but not to inside level (Only Elsie and Florinda cottages survive from 1880 in that area )
2 weeks previously flooded at high tide at Woodmill
Cowes High St, Shooters Hill to the Pontoon
29 July 1956
No marine flooding reported in the Echo, but 74mph gust at Soton Airport
Week of 17 October 1959 (not researched yet)
08 oct 1960
Hampshire River Board 11 annual report in 1961 and minutes of meeting
28 Oct 1960 [HRO H/CL5/1/64/1 ] At Soton docks 2ft 8in above predicted giving 16ft 0in, 08 Oct 1960 . Peak Bartley Water discharge did not coincide with
peak tide. 2 foot of fluvial water in a Rushington Rd bungalow. 9.94 inch of rain in first 9 days of Oct ,
287% of average. Houses flooded Rumbridge St and a factory near
Brokenford Lane. Kinross bungalows flooded to depth of 4ft 3in on 11 Aug 1960 and to 5ft 0in on 09 Oct 1960.
MetO DWR for 07/08 Oct 1960
low 986mB , W of Brest 0Z 08 Oct 1960
low 983. S of Lizard, 06Z
low 986, between Start and portland, 12Z
low 983mB Bristol Channel 18Z
Winds degrees, knots , 0Z, 06Z, 12Z, 18Z 08 Oct 1960
Scilly ,160, 16k : 340, 22k : 290, 14k : 190, 20k
Plymouth , 100, 8k : 70, 30k : 330, 9k : 24, 25k
Hurn , null : 150, 12k : 130, 18k : 220, 13k
Thorney Island , null : 150, 6k : 170 . 18k : 190, 20 k
newspaper reportage
White Swan Mansbridge flooded
Belgrave Rd flooded
Buses diverted from flooded Weston Shore
Hythe shopping centre flooded on 2 tides in 24 hours, sandbags ok for the
first but not the second early sunday morning and many shops and houses flooded
Cowes High st flooded, "1 foot exceptional high tide", 2 foot at
greatest Shooters Hill to the Post Office
W Cowes ferry booking office under 4 inches of water
The Times 10 Oct "In Belgrave Rd, where firemen were pumping for many hours ( through Saturday night and much of Sunday ) ... the road is near the river Itchen and high tide coincided with heavy rainfall"
The Echo 10 Oct. Weston Shore "Bus services to Netley were diverted because of the water on the road at Weston Shore.
"45ft craft and a cabin cruiser carried away from moorings in the Itchen"
Parts of Hythe High Street were flooded twice in 24 hours. "In each case the cause was apparently a high tide which held back the water excaping from higher ground. "Traders stood by in the early hours of Sunday morning for the second high tide. This brought severe flooding , which broke into a score of business premises.
Rainfall equals 1955 record.
"for the second time in 8 days flooding occured in the low-lying parts of Cowes ... caused by heavy rainfall which coincided with an exceptionally high tide which was whipped up by a strong southerly wind " Cowes High St flooding from the Sun Slip to the foot of Shooter's Hill. The ticket office at
No damage reported in Newport which suffered most from floods the week before.
24 Oct 1961
This is one of 4 high resolution pics ,not on the public shelves, of Hythe public library.
http://diverse.4mg.com/hythe24oct1961.jpg
Abney levelling from the benchmark on the rear of Lloyds, 2.95m OSD and scaling by the building dimensions, I make the height of that flood
2.61m OSD or about 5.31m Cd.
http://www.diverse.4mg.com/belgrave1961.jpg ,
From the Echo of 25 Oct 1961, gales and rain.
Unfortunately the pic of long gone housing,128 houses, in Belgrave Rd, Portswood like the 700 houses of Northam flooded in 1916, were demolished in the 1960s .
Belgrave Rd , because of the railway embankment , is in a rain collector basin if blocked or tide-blocked drains and so no use for marine flood heights.
But the Echo recorded the info that the sea level reached 1ft 9in more than predicted at 16 ft 2inches wrt PLWD ( = 5.42m Cd).
Not so different to my "photogrametric" level of 5.31m Cd from the Hythe Library pic, despite being across the water.
03 Oct 1967
58knots gust at Calshot,48 knot gust at Soton Weather Centre
04 Oct 1967
Hythe, The Marsh and High St "several inches" of water
Cowes Medina Rd, Red Funnel Terminal and High St flooded
02 Nov 1967
In the Echo, Lymington flooded 18 inches at the quay up to Quay St,
caused by a very high spring tide and a SW gale (force9 at the needles from another article, another article was about a flying saucer or rather a 30x60foot flying cross at Woodmill).
http://diverse.4mg.com/lymington02nov1967.gif
20 Dec 1968
From the Echo , Hythe. "Continual rain and winds and a very high tide caused
flooding in Hythe this morning" .
http://diverse.4mg.com/hythe21dec1968_r.jpg
(Banks at 17,19,21 The Marsh , mock-tudor Building on left at St John's St junction was Wilts and Dorset bank in early 1900s)
The benchmark to the rear of the bank looks suspicious as the brickwork
looks too recent and recessed mortar lines. Assuming it is the original benchmark at 2.95m OSD, Abney levelling to the front of the building I make the flood water level in that pic about 2.41m OSD, window dimensions and posistions are different now to that pic.
"6 to 9 inches deep in The Marsh". "Cars for sale in a showroom near the pier
stood in about 3 inches of water". "High tide was at 11:47 this morning and
there is another high tide tonight at 12:28 am.
I've seen reports that the seawall that was built/built up to protect Hythe centre is showing leakage, but requires >5m tide to check this.
The construction is concrete block seaward , brick landward with reinforced concrete at the core. Hopefully there is deep cantilevered subterranean
footings to counteract something adrift with a lot of mass and 3 foot
of draught acting as a battering ram against this wall, but it looks as though it was simply built on the existing rock wall. I've seen somewhere the
design brief , if not for the Priory Rd ,St Denys (Belsize) flood wall then a similar floodwall. The horizontal reinfoced concrete footing has to
survive the mass of a car doing 30mph and aquaplaning (driving deliberately
fast through a flood) and hitting such a wall, hence the apparent overengineering beyond just resisting static hydraulic pressure.
16 August 2018 with VTS measuring 4.47m at 14:50, sea level -1.52m
from the top of the brick and block seawall at Admirals Way, so about 6.0m Cd.
Lymington , same Echo. "At high tide the water reached the top of the steps
and the entrance to the saloon bar of the Ship Hotel".
21 Dec, 1968, The Echo. "early afternoon ... a few inches higher than yesterday's lunchtime floods". "A high tide 3 foot higher than normal
was the main cause of the flooding"
In 23 Dec 1968 Echo pic of Netley Abbey end of Weston Parade flooding on 21 Dec.
http://diverse.4mg.com/weston21dec1968_r.jpg
Overlaying a masque of the salient features of that pic over an
image taken on 2018 ,
http://diverse.4mg.com/weston+masque.jpg ,
I was hoping it was possible to see 50 years of developement of the oak trees , to scale and line up, but no. Standing on that low wall , as the original photographer would have done, and multiple points along the wall.
Shown is the best match ,when scaled, for the block W at the chamfered end of the wall,
C curves on both sides of the road at Abbey Hill, the edge of the road
at the then railings and the V of the flood line to the crown of the road.
Levelled at high tide to find the level approx rhat shown in the
1968 image , to the end of the kerb-stones, before the hedge starts, to
kerb top as too busy a road to stand at the crown to survey.
Meteorologically quiet, 22 Feb 2019, with tide peak at VTS of 4.73m ,
measured that level to +0.64, so about 5.37m for 1968.
While its still there, for anyone surveying at Weston, a benchmark (2.90m OSD of 1972 map) on Weston Shore in 2018 at the shelterless "shelter"
near the kids play park. The wall is covered in moss/lichen so had to
chalk over the moss or it would not photo. 1/2+1/2m folding rule for scale.
http://diverse.4mg.com/weston_BM.jpg
Also 21 dec "A 16 ft spring tide caused flooding in the Southampton
area on Saturday, the tide itself rose to nearly 15 ft and strong winds whipped
it still higher." "At high tide on Saturday , the road outside Beaulieu Abbey
was blocked for an hour until the tide passed". Bench mark apparently
still at the rear of Lloyds Bank, The Marsh, Hythe 2018 but looks suspicious as
recessed mortar , the benchmark at the pier is original, cast bracket type ,
on the sea wall in sea-ward of the ticket office numbered CSBM S1219
11 Feb 1974
HW 1:34am and 1:49pm
954mB low 50miles NW of Hebrides and secondary low of about 962mB 300 miles WSW of Cornwall 1am synoptic
No Soton floating bridges 5:30 to 8:15 am and around 2pm
72 knots at Soton Airport in am
Weston Parade, knee deep
Hythe Ferry , 1pm, could not moor at Town Quay ,
stated due to excessively high tide, had to return to Hythe
18 inches of water at Hamble Foreshore
Forton Rd , Gosport rose to doorstep level and Mason's newsagents
would have been flooded but sandbagged.
Stokes Bay Rd closed
1976 14 October
The Times 16 Oct Oil tanker Bohlen sunk off Brittany also the Freeland sank there, 227,000 ton Andros Antares ran aground off Le Havre
The Echo 15 Oct, Needles Coastgaurd reported gusts to 80 knots
" The swollen Beaulieu river lapped almost to Lord Montagu's front door as the river overflowed and flooded Abbey Gate in the centre of the village."
(Will have to see if there are nearby surviving bench marks there and Abney level to a high tide sometime)
Probably when this pic was taken , Flood Weston Shore 1976.jpg
http://www.dailyecho.co.uk/resources/images/2870411.jpg?type=articleLandscape ,
Council minutes, Empress Rd flooded sunday 9 may 1976, other days in 1976 with presumably rain flooding 20 July, 26 Aug, 22,24,26,27,28,29 Sep and 01Oct.
11/12 jan 1978
North Sea surge higher than 1953 Canvey Island event
82mph gust at London Weather Centre
Main coast road at Sandgate A259, Folkestone flooded and closed
13 Dec 1981
The Echo of 14 Dec , "giant tidal wave swept up the Channel".
Weston Shore. "cottages were flooded with up to 4 foot of water when
high winds and thawing snow created a freak tidal wave. "
http://diverse.4mg.com/beaulieu13dec1981_r.jpg
"police had to wade waist high in freezing muddy water"
"a mammoth spring tide caused floods described 'as the worst in living memory' on the Isle of Wight"
20/21 December 1983
May 2015, the green wallpaper has been removed, at some point, from the Vectis Tavern. Just emulsion paint is covering the , at least one, flood
markings on the pillar.
Daily counter top cloth-cleaning has worn the emulsion paint off the 1983 marking, above the previously known 1909,1984 and 1989 ones under
the counter. The counter top surface is 1.05m above floor level, so the 1983 black line would be about 1.0m. The "Flood Levels"
legend at about 1.7m off the floor is original , emerged like that
from under the wallpaper.
Likely 20 or 21 Dec 1983, part of the C of Dec is probably showing.
Reported in the Echo "reached a high of 15 feet" , whatever that means. 4.4m high water predicted in the 1983 "blue book" for that midnight
tide. Those tide tables had been metricated for many years. Another tide gauge somewhere in 1983? And also from the Echo
the storm caused "two gaping holes in the protective banks" of some
unspecified part of the Test or Itchen.
Using the Vectis tide-mark of 1.02m off the floor and floor level to be
4.55m (qv) and assuming parity of the surge component of tide heights of
Cowes and Soton , makes that tide 5.82m at Southampton.
Lymington Times, 1983 , 2 sentences only and refers to 1 foot of water
at Lymington Town Quay. At Christchurch, highest tide for 4 years,
higher by 2 inches than any in those 4 years.
In Newport,IoW, Quay Arts Centre had 6 inches of water over the floor.
E Cowes premises flooded in Ferry Rd, Castle St, York Ave,
Link Rd, Well Rd. Phoenix Brewery Company yard , water was to
seat level in vehicles.
24 nov 1984
Bosham and Bognor flooded
17/18 Dec 1989
Lee on Solent up to 70mph
Lymington flooding worse than the 1954 flooding
Cowes, 4 days High st flooded, 4000 sandbags, Vectis Tavern flooded 8
times in that period. Cowes, Carvel Lane to The Fountain Hotel
Newport Planning dept car park, cars 1 foot deep
in floodwater
Lee-on Solent, 70mph gust
Lymington , previous worse was in 1954 , but worse this time,
Bath rd 5 foot of water, Harbour Master records lost in the flood
as stored on the grounf floor.
10 Jan 1993 , from The Echo of 11 jan
At Weston Shore, waders were not enough, worst for 15 years.
Spice of Life pub in Gosport, drinkers rescued by RNLI rubber dinghy, worst at 13:30, Old Portsmouth roads 1 foot deep.
If no 3 , Bemister's Lane , Gosport then spot height 11 ft (25" map)
Red Funnel ferry needed a tug to dock at Town Quay
Met report concerning an equal record of 916mB recorded near the Faroes overnight
Trying to date this minor flood pic
http://www.panoramio.com/photo/33546674
Must be before 24 August 1988 as Guinness Book of Records records the largest street party in the world a week or so before Thomas Lewis
Way opened.
Pic shows the housing in the original Dukes Rd the other side of the , never made, "level crossing" at the rear of the Junction. All went for the
bypass. Old Dukes Rd , that lined up with Priory Rd, was still there in 1981.
So perhaps 22 Oct 1984
Probably later , after the housing was demolished but before the Waterloo arms was demolished, this roof scape i nthat pic
http://theendofthepub.tumblr.com/
and before that office block was built at the Horshoe Bridge/A335 corner.
Bridge Glass was trading in Priory Rd, 1999 but not 2000
Payne Builders moved 1996 into then new 236 Empress Rd ,the large block , now NHS use, corner of Horseshoe Bridge and Thomas Lewis
Way, so before 1996.
Waterloo Arms fire late 1992 and demolished 1994, I don't think the fire was so bad as for the roof or chimneys to collapse or be pulled down
for safety reasons, so before that.
So after 1988 and before 1994 ,so could still be 1989 or 1993 flood.
The camera was opposite no 72 Priory Rd (from shop wall and the Junction windows alignment) and the flood line at crown of the road on the
line joining the telephone pole to Ainsley's house.
Assuming that was at maximum of the flood then a lot less than the 1989 or even 2008 flood, could anyone put an equivalent VTS height to that
position in Priory Rd?.
So my money would be on 10 Jan 1993 flood.
One further line of research. I assume somewhere in the council is local traffic regulations repository. That image shows a lorry ban sign on the
shop wall. That ban came in because the Horseshoe Bridge weight carrying limit was lowered , while still open to traffic, and before it was
closed to all traffic because of rat-run and kerb-walking reasons.
shows , side on, the front of the shop absorbed into Belsize, used to have Cadbury's painted advert on the wall. Belsize still in phone listing of
1995 so no relevance to dating, just a bit of local history
I'll declare to be 10 Jan 1993 and "VTS" height of 5.3m until/unless other info emerges.
Of all the strange places, Soton traffic reg info from Balfour Beaty
" The Prohibition Of HGVs over 7.5T except for Loading was introduced in 1982 under the following order:
The City of Southampton (St Denys Area) (Prohibition of Commercial Vehicles) Order 1982
The Prohibition of Motor Vehicles except Emergency vehicles was introduced in 1997 under the following order.
The City of Southampton (Dukes Road) (Prohibition of Driving) Traffic Regulation Order 1997"
1999
Monday 27 Dec 1999 when there was 4 foot of water in Waterloo
Rd, Lymington , Fulmar Rd , Hythe and half submerged cars at Hurst Spit car park,
mid day , Selsey and Pevensey sea defences breached,
predicted pressure was 992mB and tides of 4.5 and 4.3m. Associated with
a bad storm in N France, nothing untoward
predicted by the French Met service, 107mph wind and 31 people
killed in N France, just a low over Poland, their equivalent
of Oct 1987 English storm.
2005
See my graff.htm "Southampton Graffiti " file whereever it may be these days, archive.org pehaps, also 2008 and other local flooding info
2008
http://www.diverse.4mg.com/10mar2008_hard3-1.jpg
wonky camera, viewed from the still dry ground aroud the tree
, as the water came over the hard before evacuating from that area.
Cowes 2.638m ODN 10/03/2008
I level-surveyed from the 1969 23.68ft OSD benchmark=9.958m Cd on the large upstream pillar on the Bitterne side of Cobden Brisge. Via vertical Rabone Chesterman surveying tape and a tripod site in Riverside Park.
Incidently the worst benchmark ever in all likelihood, chisselled into acid-etched green granite aggregate concrete.
Sighting and measuring inaccuracy about +/-5mm , unfortunately 1 pixel of the 2008 image from Riverside Park is about 4cm.
For the top edge of the 7th flute down I have 6.883m Cd
and top edge of the 8th flute down 6.422m , so interval of 0.461m and ratioing the corresponding image points I get 5.707 +/-0.04m Cd for the height of the Itchen when that pic was taken. 12:04:01 on 10 March 2008 according to the metadata in the picture file.
Ryde
2.909 ODN 17/10/2012
2014
Cowes tide gauge readings half-hourly
14/02/2014 23:30 5.24m
14/02/2014 23:00 5.35m
14/02/2014 22:30 5.26m
For the www pic taken from a second floor window opposite the Vectis, the Vectis window actually measured is 1.26m top to bottom, so simple ratioing with no foreshortening compensation, I make the water level in that pic 4.85 + 0.12m = 4.97m Cd (Cowes 2018). Going by the landlord quote of 2 foot in the pub, then 4.55m +0.6m so 5.15m, perhaps the average of 5.06m is reasonable figure.
Yarmouth ODN 2.146 m
Ryde 3.060m ODN
Using my first pic I took 14 Feb 2014, 1 manhole (MH)covered in water, one exposed, I surveyed the local level that night as 5.622m +/-1cm Cd wrt the 6.0m nail, so Cd (2.74m one). Gs are the 2 lines of grey paviors set in the orange. That bit of road not been dug up since 2014. But I was a bit late, it was past peak when I took the pic and the peak was probably something like the level of that manhole cover that I surveyed.
VTS had a peak of 5.58m in the current archive and contemporaneous record, where did the 5.60m figure come from? I cant find any contemporaneous record in my files, of 5.60, were they using 2.76 Cd-OSD not 2.74m in 2014 ?
2016
For the record 28/03/2016 02:00 read 5.31m at VTS on a 4.3m tide,
the peak residual ,from "tide letter" processing was at 01:20 and 1.27m so
higher residual/surge than 2014 Valentine's day
2018 04 Jan highest since 2014
http://www.diverse.4mg.com/2018jan04_flood_rx.jpg
If no rain water around, and Itchen level less than about 5.5m (over the hard and round the houses) then the level in the road , is likely less than the Itchen.
Top pic was at 12:06
Peak on the vernier gauge was 5.40m Cd at 12:03 .
Peak on the temporary tide gauge 5.23m. The 6m mark level , connecting the OS benchmark G2702 level, via laser level on the PR church hall and the 5.00m vernier point with VTS at Dock Head (from average of numerous pairings).
Vernier tide-gauge at the Priory Rd hard, the 5.0m VTS/Cd point is the vertical fixing post ,4 bays down of the railings on the downstream side. Then 0.1m
up or down from the 5.0m point is 1.41m horizontal distance along the fence, either side of the 5.0m pillar.
No seepage of Itchen water seen the other side of those double gate flood-gate.
VTS peak at 12:05 was 5.31m
Middle pic is the tide heights , if veiwed vertically down at the stantion mounts of the railings. Requires clearing a gutter in the leaf-litter, nurdles and anti-fould scrapings and a bit of mental maths for tenths of bay railing readings.
No pump noises heard at the 3 sites that protect Northam
with tide height about 5.1 to 5.2m so without a load of rain coincident with an elevated tide, still no knowledge of when those pumps cut in.
No obvious intrusion , via non-closed outlet flap valves seen.
About a foot of water at the low point of the river path at Mount Pleasant Industrial Estate, the boardwalk was above Itchen level still.
Re: EA Woolston gauge cross-correlation, but would take a lot of instances to rule out gyre effects etc.
At 11:30 Woolston read 2.206, so + 2.74 = 4.946m Cd
VTS read 5.03m
PRH vernier about 5.04m , inferred backwards from reading at 11:40
At 12:00
Woolston read 2.518 OSD -> 5.258m
VTS 5.30
PRH Vernier 5.39m
Cowes 5.19m
High levels on previous days, highest was 03 Jan 2018 5.28m at 1130 St Denys,
vts gauge read 5.1m at 1105.
**********
Some dates to research , gales reported at Hythe, may not involve marine flooding though.
Dec 12 1893
Jan 02 1899
Nov 17 1916
Feb 09 1949
Dec 08 1954 To deck level of Hythe Pier, more than 1 foot of water
in The Marsh , reflooding to a lesser extent on the evening tide (Book:
Hythe Pier and Ferry a History p94)
Jan 26 1967 "18 inches in depth covered the High St, Prospect Place and The Marsh (Pier and Ferry book p94, qv)
Feb 20 1967 close-run flood, rain stopped before high tide, so no flooding
Feb 27 1967
Nov 14 1977 ,several inches of floodwater
*******
Here's an interesting example of precise flooding data from a newspaper
report that is so specific it could hardly be erroneous, no reported flooding affect to Solent area
13 Dec 1942, Soton echo of 24 Dec 1942
Reported at the time as a percolation flood at Chessil Bank.
A Post Office pillar box on Victoria Square , Chiswell, just an inch or 2 of the top showing above the water and letters floating out of the slot.
Also saying that gale was the worst since 1824
[
http://www.estuary-guide.net/pdfs/historical_trend_analysis.pdf
... Datum or projection corrections
Chart depths (z-values) can be referenced to several different datums, for example Ordnance Datum Newlyn (ODN), Chart Datum (CD) or a
local datum. A simple correction is required to ensure each successive dataset datum is consistent, commonly ODN. The referenced datum level
is often related to tide levels (e.g. chart datum is approximately the level of lowest astronomical tide at a particular location). These tide levels
will obviously vary over time, according to a number of timescales, such as long term relative sea level rise and the nodal tidal cycle.
Importantly, principal chart datums have changed: prior to 1921 the standard datum was derived from measurements taken at Liverpool
between 1840 and 1860. In subsequent years, large errors were found in the levelling for different parts of the country. At Harwich the error
was as much as 0.55m (Doodson and Warburg, 1941). ]
Interesting aside , tsunami/extreme meteorological marine effect?
In Hampshire Chronicle of 30 jan ,1804 reporting events at Falmouth the thursday night before publication.
"The hurrricane was preceded by an uncommon agitation in the sea, which seemed to indicate an extraordinary concussion of nature. The
water
in Falmouth harbour about three hours before , rose suddenly to the height of seven or eight feet perpendicular, recoiled and rose again three
successive times in the course of a few minutes; in the same manner it is remembered to have done at the time of the earthquake that destroyed
old Lisbon. "
Many houses blown down and ships foundered, the storm "exceeding any within the memory of man"
1989 flooding Priory Rd
http://www.diverse.4mg.com/priory_rd_flooding1.jpg
http://www.diverse.4mg.com/priory_rd_flooding2.jpg
17 Dec 1989.
94 to 102 Priory Rd, sometime between easter 1988 and easter 1990 (from boat ownership of the time). The sea wall in that area was rebuilt
after that flood but hopefully some feature in those images remains to this day. The original photographs still exist but higher res scans not
available for a month or so.
pic of the tidal epigraphic record pillar in Eling Tide Mill, ballpoint markings, not carved, so not clear, with overlaid red text I've added for clarity.
http://www.diverse.4mg.com/Eling_Tide_Mill2.jpg
Heights from floor ,
.435m Dec '99 [5.635m Cd agrees with VTS/ABP ] ,
.42m Mar '08 [5.62m Cd agrees with VTS/ABP],
.30m Dec '89 [ 5.5m Cd Vectis Tavern has 5.65m Cd ],
.28m possible line, no date seen [5.48m Cd],
.24m ditto [5.44m Cd] ,
.21m ditto [ 5.41m Cd],
.09m Dec '92 [5.29m ] .
Valentines Day 2014 reported to me as about 0.02m above the floor [5.22m Cd, VTS 5.6m Cd],
just above the floor level . The 2014 flood event was a very fast rising surge, so no chance for restricted supply to the mill pond/Bartley Water level, to rise in sympathy, so about 0.4m lower than VTS, recording some indeterminate level between millpond and Southampton Water maximum height, dependent on the free flow from wheel pit out of the building above hurst floor height into the millpond . For floods relatively higher on the Southampton Water side , rather than landward pond side, presumably means a Southampton Water height was equal or higher than those marks. Of course the height in Bartley Water could be higher than Southampton Water due to rainwater in the New Forest , see 1960, a bit upstream was 5 foot higher than at the causeway. From the miller in April 2018, a few weeks after the mill fully re-opened, the hurst floor level is 5.2m Cd , so added to the wrt floor heights above, and a few inches of water above floor level on 04 Jan 2018, no updated mark then and the existing ones seriously faded, so this pic and my original higher resolution pic are probably the only record of those marks . A nice boardwalk walk is now open around the Bartley Water area, well worth walking . Also of note in that area, at the start of the walk, near the mill, the local electricity transformer has no special protection from local flood water.
VTS the same, Dec 99 and Feb 14, 2014 but .4m difference on this pillar
And also '89 0.13m lower than '99 , compared to Vectis Tavern , Cowes 0.1m higher for 89 compared to 99
Probably quite a simple explanation the tide record disparity
https://www.flickr.com/photos/pikerslanefarm/4790370610/
The mill must get flooded from the non-seaward side, but as the inflow to the millpond is restricted, the level reached in the mill may never
reach the sea-level, if the surge is up and down quickly
The Eling tide mill Chessell make tide guage has been data linked to the EA for many years by phone line, whether they store it , relaease it ,
unknown. I can find no internet reference to this data. Also of interest relating to Eling and more generally. From a local who one time lived in 67 Downs Park Ave, Eling , in his time called Springfield Rd. Building an extension
or conservatory requiring planning permission and there must be some
database linkage to EA or SWA. Anyway someone came out from the
EA or SWA to check on a water-level mark on the wall of that property.
It should still be there as its a "protected" mark as it records the height that flooding from Bartley Water reached in 1960 whan there was an excessive amount of rain in the New Forest, probably not related to any marine flooding, perhaps just a normal high tide causing a degree of tide-bloccking. So somewhere internal to EA or SWA there must be some searchable resource of
flood marks and heights, presumably a database now, and presumably would
include tidal water floods as well.
So if the thickness and weight of the outflow flaps around St Denys is now greater and now requires say .3m landward-side differential static
head of water to open them now, that makes sense. Update 2018, the rubber is the wrong formulation or hardened or expanded or something , but the flap at the public hard never closes these days.
Priory Rd hard EA tide gauge in October 2014
http://www.diverse.4mg.com/ph_tide_gauge.jpg
assorted pics of Cowes during undated floods held
at Newport Record Office, some appearing in
the County Press so dateable, last one is of Lyminton
http://www.diverse.4mg.com/talk2r.jpg
http://www.diverse.4mg.com/talk3r.jpg
http://www.diverse.4mg.com/talk4r.jpg
I've been researching the point at which it is hazardous to life by keeping static flood-water out of houses/ false sense of security. The "Belsize "
consulting engineer quoted a figure that I did not commit to memory, but less than the 3 foot I would have intuitively thought. BRE data on
this is locked behind a paywall. So a cross-ref to USA data
**********
http://www.leedsbeckett.ac.uk/as/cebe/projects/flood/flood_resilience.pdf
...
During the 1980s, the USACE (US
Army Corp of Engineers) conducted a series of tests on the structural resistance of brick
facing walls and concrete block walls to hydrostatic loads (USACE 1988). A small range of wall
configurations were tested. The results showed complete failure of the walls at flood depths of
around 2ft (0.61m) for both brick and concrete block walls. Significant deflections of the walls
began to occur at around 1ft to 1.5ft (0.3m to 0.45m). A test wall with simulated roof restraints
withstood slightly higher loads. A picture of one of the test walls is shown in Figure 7.
(picture shows depths quoted are to the bottom of footings , not ground level, but no upper story/cross bracing as of the testing outlined below)
...
b) Whilst the test walls failed at flood water depths of around 2.4ft (0.73m), this improved to around 3ft
(0.91m) for tests on full scale dwellings due to the additional strength provided by the composite
action of the walls and roof. Wall failure is potentially very sudden and catastrophic.
***************
So an 80 year event , like the 1924 flooding should be allowed to enter buildings. There should be no attempt to resist it unless the occupants
are outside the premises, then it potentially becomes a litigation exercise with house insurers. (see astronomical Milankovitch cycles or
Dansquaard- Oescher millenium scale cycles for possible reasons why flooding events may have been more severe a hundred and more years ago,
considering sealevel rise should make things worse these days, all
else being the same )
The local sub-transformers (along the railway line , North Rd and at PR rail bridge) should trip out when salt water reaches the company fuse
of the first house to be seriously flooded, for each transformer. And of course mains eectricity powered sump and pumps will fail.
As no one sems to have found what the SSE protocols are for pre-emptive area protective isolation, to protect their infrastructure and avoid
house occupants being electrocuted and consequential litigation. The trigger level must be higher than 5.8m (VTS/Cd) as SSE would have had at
least 6 hours notice of what was then going to be a 5.8m flood on 2014 Valentine's day.
Just done some vital missing research.
1970s bent-wood dining chair standing in for Edwardian one.
0.82m high , top of seat 0.44m . Dining chair was not properly floating until .52m depth. When it started floating it was anchored by the rear
legs until .52m depth . Starts to sort of float at .42m , fully floating .52m. Chair weighed 2.7Kg
So someone rushing around rescuing stuff , creating waves, then perhaps about .35m before what I'd call furniture was floating.
Wooden hearth surround, wooden newspaper rack and coal skuttle with coal in it would be floating before that, but I would not call that
furniture.
No low slung wooden easy chair to try that.
From a local resident , the 2m high or so concrete sea defence wall south of low lying Alton Grove and Beachway , Portchester,
was constructed in the 1980s.
Well Rd, East Cowes flood protection measure, June 2015, not concerned
about 4x4 being loaded up with them feloniously.
An aside on erroneous? misinterpratation of instrumentation
and a report of a barometric correlation of tide height difference
at St Denys compared to VTS ie slope in the Itchen.
If their tide gauge was placed in a tank of static water would they show barometric variation of the reading? Gauge was pressure type
so indirectly measuring the height of water above it, requiring a second
atmospheric pressure gauge to offset that component and
no mention of compensation for change in salinity/density of the water over spring/neap or high/low tide cycles.
Years ago establishing what readings at VTS meant for St Denys at tops of tides.
4 bays of railings down from the top of Priory Rd hard corresponded to
5.0m at VTS and 0.13m per bay of railings above or below that.
And also for when the open outfall at the hard made an ideal stilling well, the height at VTS for water coming out of PR drain and also height
relative to the bench mark under the railway bridge (non-flood walkway side, nearer the bungalow rather than mid bridge for some odd reason).
I wasn't looking for any miscorrelation relating to atmospheric pressure but did not notice anything untoward, to my measurement accuracy ,
on the hard , of half a railing <>0.06m
So at this stage I'll go for instrumentation anomaly rather than real effect of barometric variation of St Denys heights wrt to VTS.
EA gauge at PR hard needs 2.76m adding to it for VTS height
I thought I'd better check my hygrometer out the other way.
Dissolved 35gm of kitchen salt in 1 litre and it read 1028 sp gr
Water sampler consisting of a plastic litre milk container with a lump
of iron slung under it , so will sink with the container full of air.
A piece of cord tied to it and a second cord with a bung on it.
Let the bunged empty container sink and then pull the bung out.
Samples over a range of first high water tide heights.
For extended peaks at VTS only the latest time noted here, daytime around first high water tides only. PR height is from my tide gauge of
4th down railing is 5.0m and 0.13m up or down from that per railing.
EA height is the wooden mark + 2.76m
"date","vts ht","vts time","atmospheric pressure mb","PR height","PR time","EA height","sp gr","water temp","comment"
"08-12-14","4.47","11:50","1019","4.51","11:51","4.49","","","PR reading taken after VTS peak of 4.53 at 11.35 "
"09-12-14","4.36","12:25","1026","4.40","12:25","4.39","1021","8"," extended VTS peak - PR peak"
"10-12-14","4.95","13:00","1017","4.93","13:01","4.96","1023","8","PR peak"
"11-12-14","4.45","13:50","1011","4.48","13:54","4.49","1022","9"," earlier peak missed, extended vts of 4.47 at 13.45 - an earlier PR
wave assisted drift line peak of 4.52m"
"12-12-14","4.12","14:30","997.5","4.08","14:35","4.09","1011","9","VTS peak of 4.27 at 14:05 - no earlier peak PR drift line seen "
"13-12-14","4.03","15:20","1012.5","4.00","15:13","4.04","1021","8","PR peak - extended VTS peak - 1021(sic)"
"14-12-14","3.85","15:55","1010","3.80","16:08","3.84","1014","7","PR peak"
In the above , I've assumed that there is no differential land movement
across the width of Southampton over the last few centuries. There are
substantial underlying layers of clay and even peat in the geology under
Southampton. It is quite possible for differential shrinkage or
expansion of these layers, requires specialised geological input.
http://www.southampton.ac.uk/~imw/Fawley-Power-Station-geology.htm
Human made artefacts found near enough under the NOC, who would have thought geology could change so fast . Perhaps 200 years is enough time to show relative differences in Soton heights only 1km apart.
2015, the new tall flood wall at the double gate on the odds side of Priory Rd, 0.80m below the black coping stone level.
This marks 6.0m ( VTS ) level , laser-levelled across from the "vernier" tide gauge on the Priory Rd hard, peak level that corresponds to VTS 5.0m (4 bays of railings down from the car park end )peak of tide , regardless of any time difference of the peaks, in benign meteorological conditions and +/-0.13m per bay of the railings along the hard.
Also levelled across from the G2702 flush bracket OS benchmark, 3.67m OSD on 1994 map, of the church in Priory Rd and that flood-wall height represents 6.055m converted to Cd/VTS ( 2018 conversion of 2.74m), 3.315m OSD.
For 1990s conversion factor of 2.72 then represents 6.035m, so for
1972 and last surveyed in 1948 ,last levelling survey maybe earlier, probably within 1 inch by two completely different routes.
So pretty good agreement , 1 to 2 inches difference, considering the potential errors, or the tides at St Denys are routinely .055m higher than VTS.
Taking a representative accuracy of a 1200m
range laser-level to be +/-0.5mm per 10m. Split range for levelling at the hard as 20m, range for the church levelling 75m.
VTS is 4.2km from the hard, rough concrete to the hard surface.
Not known whether 2.74m is the true conversion of Cd to OSD for Dock Head, let alone St Denys or 3.67m recorded by OS in 1994 is still applicable today.
Taking the flush bracket level as the ledge over the tip of the arrow rather than the equivalent to the traditional mid point of the horizontal bar of a chisselled benchmark, as per ( https://slideplayer.com/slide/14056516/ )
The 5.0m (VTS) point , 4 bays in downstream side,on the hard is about +/-0.02m over 20 to 30 readings in calm weather, different barometer readings made no observable difference.
0.355m laser-level height difference between "-0.80m" wall level and higher benchmark, so
3.67m
-0.355m
=3.315m OSD nail height
+2.74 conversion
=6.055m Cd/VTS
Followup to negative surge observation , on my page
http://www.diverse.4mg.com/graff.htm
Antisurge for 19-20 Nov 2002 passed east to west along the channel. Deep low that passed over the top of the North Sea preceeding.
No NTSLF surge predictor then, so negative passage even more difficult to extract.
30 Dec 2015 the day a flood surge disappeared.
An antisurge travelling east to west along the English Channel. From the residuals of the morning high tides of
+0.5m at Newlyn, +0.49m at Castletownbere (Eire, NB 2.48m conversion between Marine Institute and tide-gauge readings, for offset to Chart Datum at Malin Head) and +0.42m at Le Conquet (France) and SW wind 25 to 30 knots in the channel I would have predicted about +0.7m surge for Portsmouth and Southampton high tides around 14:00 of 30 Dec.
Its a pity surge waves in reality going one way are not coloured red and the other going the other way, green and antisurges coloured yellow.
So trying to extract one from the other plus astronomic tides and even local effects is always going to be debateable.
But I'd say the negative surge affecting Portsmouth afternoon of 30 Dec 2015 has an origin at the top of the North Sea.
From the various NTSLF port surge plots
Wick peak negative, approximate timing 00:00 morning of 30 Dec, nominal amount -0.1m
Aberdeen 01:30, -0.2m
North Shields 05:00, -0.8m
Whitby 05:30 , -0.9m
Boygrift, Lincolnshire 06:30 , -1.4m
Cromer 07:00, -1.7m
Felixstowe 11:30 or later (near their high tide), -1.4m
Sheerness 13:00, -2.0m
Dover 13:00, -1.2m
Newhaven 13:30, -0.3m
Portsmouth 16:30, -0.2m
North to south to east progress.
Any normal surge passing east through Dover, the degree at Portsmouth is about half the value at Dover, same for antisurge?
So perhaps -0.6m at Portsmouth high tide , cancelling the +0.7m or so surge from the west.
I can only assume Storm Frank passage to the west and north of Scotland, removed a lot of water out of the top of the North Sea to set that antisurge into train.
Unfortunately no NTSLF surge prediction for Lerwick. I would suggest that the Lerwick residual at their high tide of only 0.2m with passage of Low Frank was not as big as I would have thought, passing 300 miles distant.
NTSLF predicted this antisurge well in advance so not due to submarine landslip or tsunami event.
Nothing seen appropriate to the North Sea antisurge seen on the Stornoway surge plot.
Whatever the source mechanism of that antisurge , the NTSLF bigdata machine was spot on for Pompey, 0.0m in actuality
From that Pompey plot and estimating for Southampton pretty good agreement , first high water was about +0.2m and second -0.3 wrt predicted astronomic heights.
Other possible instances, at least highly anomalous at Sheerness,
I've not looked at wetterzentral/Digital Times for the met charts of these dates yet.
From BODC data disc for Sheerness station 1990 to 2002.
1997/02/19 22.00 to 0830 next day with maximum antisurge of -2.26m
1990/12/25 17.00 -2m
1999/12/24 09:15:00 -1.9m
2002/10/27 12:00:00 -1.8m
Disparity between VTS and UKHO tide tables in 2016, resolved
Looking at VTS archives 29 Jan 2016,
it looks as though Soton is going through a period of triple high tides per tide cycle.
13:41 (UKHO), 13:56(VTS), and at 16:16 for 29/01/2016 . So VTS and UKHO were both technically correct, depending on how you define first high water. Both have their source of data at the admiralty so should be the same.
They are all 3 likely maxima of the cosine summations to 2 decimal places, with peaks surprisingly in reality showing up on the tide gauge at those times. Surprising as 20kn wind around , although NTSLF pompey and Bournemouth, and lymington gauges were showing close to zero residuals for the first 2 high tide times and neutral 1012mB air pressure.
So VTS was going for the highest of the 2 "first " tides and UKHO going for the earliest.
Then only 4 fields available in HTML presentation pages, into which 6 blocks of data was trying to be fitted, must be giving the "typos".
It looks as there are many months in 2016 where this 3 high tides per tide cycle are occuring.
Exploring cross-connection between local storm-drains and foul-water drains in the area.
So at extreme floods , and sea-water entering the foul-water system via the ground level air-balancing hoppers below roof-run off down-pipes.
The following refers to the manhole MH in Ivy Rd , in the pdf report of the URS report , July 2014 , of flood risk interactions, lidar derived heights, sewer CCTV report etc in St Denys.
The worst situation so-far (as only been aware of it since 2016) relating to sea-water level increase in the 450mm pipe was late 2016 and 210mm.
One resident is using a builder's inflatable bladder, rugby-ball -like, lift inspection cover and fit. Otherwise a test-bung tethered so it cannot migrate into the system, or permanently fit a one-way backflow preventor in the sewer pipe.
For 1 in 600 fall in 450mm pipe in Ivy Rd. I make the 200mm of water level in MH2701 ( OS SU43142701) to be 3.23m in VTS/Cd terms and so the drain cover outside 23 Ivy Rd to be 5.92m (VTS) which looks about right compared to cover of MH2601 at Ivy and Priory junction of 5.71m in VTS terms. The lidar survey gives the
gutter height at No 5 Ivy Rd to be 5.70m Cd.
for 13 Dec 2016
time, height, manhole water level in VTS terms, VTS tide height
9:26, .200m,3.23m,4.77m
10:03, .210,3.24,4.78
10:31, .205,3.235,4.68
11:05, .200,3.23,4.70
12:01, .210,3.24,4.71
12:52,. 190,3.21,4.36
13:55 , .190,3.21,2.90
15:04, .135 ,3.165,1.10
for 14 Dec (tide height from public hard vernier gauge as no VTS)
10.38,.175m,3.205,4.83m
For 15 Dec
11.23,.205,3.235,4.97
12:01,.215,3.245,4.76
12:34,.21,3.24,4.72
Priory Rd lowest drain north side, water level was -.155m down from grill top
at 11:39 and -0.4m down at 12:23
For 28 Nov
22:25,.14,3.17,3.97
So more than a 4.5m tide before Itchen water input exceeds sewage works pumping, at MH2701 monitoring before 0.9km pipe run, with only one pump going presumably. Agrees with the waterfall noise , at the higher level from Ivy Rd ingress, only becomes apparent at that sort of tide height . No sign of anything like 5.2m tide for rest of 2016, to check for effect of higher tides .
With the current dilapidation level of the sewer system, looks like "cloudburst" rainwater ingress is more significant.
Effect of rain morning of 22 March 2017 on foul-water sewer.
3.2m tide was irrelevant to this , rainwater only. Noisiest I've ever heard the manhole in Ivy Rd, in full pelt of presumably Ivy Rd house-roof run-off , dropping through the lamp-hole into the deep sewer.
Sewage works has bays for 5 Archimedean screw lift pumps, one is empty, so 4 pumps maximum.
I assume more than 1 archimedian lift pump was working, as at 08:54 measured only 40mm in the deep 450mm sewer, despite a lot of earlier rain
09:28 depth 275 mm
09:47 280mm
So sewer pipe more than half full. What that means for high tides > 4.7m or so , plus heavy rain, to be determined .
From my own rain gauge
08:50 to 09:16, 1.6mm or 3.7mm/hr
09:35 to 09:48 1.4mm or 6.5mm/hr
Park Walk, Soton weather station 5.1mm rain, 07:45 to 10:00
19 July 2017 19:09 , at the height of the deluge , I measured 0.77m of
water in the Ivy Rd manhole, so a foot above the area main .45m sewer
pipe diameter.
The radar pixel for St Denys showed 25mm/hour for then , local St Denys www raingauge >= 120mm/hour then.
16.5mm rain in that intense downpour, 3.6 minutes of 120mm/hr , at limit of raingauge resolution for these bits of data. Then averaging out the rest as 64 minutes of 11.2mm/hr but can be ignored as it was the initial cloud burst that filled the manhole . So just 3 times that duration or 10 minutes , for the sewer level to get to 5.1m (Cd/VTS level).
28mm of rain in 68 minutes
I did not know until this next reading , that the peak sewer level locally
might come 5 minutes or so later, ie this one may have been higher than .77m and so less than 10 minutes projected up to a sewage flood, coming through domestic toilet pans.
Air in the pipe system can mean sewage emerges from the pans before the levels in the sewers have equalised,
18 Aug 2017, 4mm of
rain 180mm/hr peak according to St Denys gauge.
It was still rising about 5min after locally it had stopped .
16:23 , .10m
16:26, .14m
16:28, .18m
16:32, .26m
16:37, .25m
Residential road of slope about 1 in 120 gutter flow below kerb top, but lower down at a slope between that and level, the rainwater in the gutter was flowing over the pavement, say 1 in 300 slope.
So rose to more than half the diameter of the .45m diameter deep
sewer in 9minutes, or rise of .16m in 9 minutes .
So 12 minutes of 180mm/hr rain or 36 minutes of 60mm/hr then the local sewer system level would be to 5.1m in VTS terms ie gutter level of Priory Rd at the hard.
A realistic rainfall profile would be something like 20 minutes of 60mm/hr, then 10 minutes of 120mm/hr and finally 5 minutes of 180mm/hr.
From 08 Sep 2017 and fairly constant heavyish rain averaging out at 4.3mm per hour for 1.3 hours, the sewer depth did not increase. So for maintaining the level in the sewer system , between intense cloudbursts , would require greater than 4.5mm/hr, more exact figure not yet known.
Whether the rainfall flooding situation is more or less likely than 1953 unknown, just due to the local topography. In 1953 there was shop/housing where it is now a car park at the hard, but in recent times the level of the
ground at that car park has been built up to the <>5.5m Cd level of the top
of the hard. So height there been upped from about 5.2m to 5.5m.
From the near miss 29 May 2018, a more genearl assesment of cloudburst rain , leading to sewerage invasion of low lying houses in the area.
I was in town at the start of the heavy rain about midday . I got off the bus , and passed Kingsbury Rd/Empress Rd road-centre sewer manhole about 12:15 and 6 inch fountains of overcharge water. About 1 inch above the cover air-balance holes at Empress Rd/ Dukes Rd/New spur road to Horseshoe Bridge. Massive turbulence in the river near the "Belsize" pontoons and boats from the storm-drain system from Newtown/Common?
No, mid 2018 I discovered the plan of the sewer system of the catchement to
Portswood/Saltmead sewage works. Catchement is not Newtown or Bevois valley (presumably that goes to Millbrook or Woolston via a route near/under the Itchen/Test, like the Riverside Park under-Itchen pipeline ) but St Denys, Portswood, Highfield, Basset, Swaythling, Bitterne, Thornhill ,Midanbury, out to and including West End.
http://www.diverse.4mg.com/portswood_sewers.jpg
Passing manhole MH2701 in Ivy Rd about 12:25 absolute silence over it and
I could see the full manhole-width water surface, as above the lamphole level and presumably above the level of the top of the 300mm pipe from Priory Rd.
I've never heard silence from it even middle of the night. Grabbed my measuring apparatus and at 12:29 measured 1.34m of water depth above the low level sewer from Newtown area.
I doubt the peak level was that much higher, but with that measurement implies it rose to 0.71m below gutter level in Priory Rd. 12:49 manhole level had dropped to 0.82m.
Useful input from a hydraulics engineer, I was not aware of:- "A concrete pipe (most 18 inch pipes these days are concrete) will carry less water when it is full that it does when only three-quarters full. This is due to the friction exerted on the full circumference of water in the pipe in contact with the pipe wall itself. At three-quarters full, less water is in contact with the pipe, and the top of the water experiences virtually no friction from the air above it. That is why flood waters rise so quickly, but take a lot longer to drain away."
I'll levels-survey Empress Rd sometime as I was probably passing there about the peak flow time, due to the delay in the sewer from town compared to bus.
As this is the highest I've measured in that manhole, probably mainly due to roof-runoff Newtown area rather than local component.
Rainfall analysis
Newport IoW, max rain rate 13mm/hr 08:30 today 29 May 2018
Gosport max rain rate 60mm/hr 07:50
Hythe max rate at 12:14 7.2mm hr, total 3.9mm today, midnight to 15:00
Southampton central park 35 minutes of 13mm/hr followed by 6 minutes of 93mm/hr
Local rain gauge 5.8mm in 23 minutes as 15mm/hr then 11.7mm in 23 minutes at 30mm/hr and buried in there something less than 4 minutes at 120mm/hr.
22 mar 2017, y=0.28 26min of 3.7mm/hr + 13 min of 6.5mm/hr, reading taken 9:47
18 july 2017, y=0.77, 3min of 120mm/hr (drain reading taken 19:09 only 2 or 3minutes of the monsoon rain, before 8min of 80mm/hr + 32 min of 21mm/hr, possible under-recording of the rain gauge at the start, perhaps more like 240mm/hr for a couple of minutes)
18 Aug 2017, y=0.26, 10 min of 5.1mm/hr + 1min 180mm/hr, reading 16:32
29 May 2018, y=1.34 , 23 min of 15mm/hr + 23min of 30mm/hr , reading at 12:29, rainstorm ended locally St Denys 12:14, similar time for Empress Rd.
28 June 2021 about 17:35 to 17:50,about 1 min 0f 152mm/hr and 14 min of 20mm/hr, manhole observed 17:55 after the peak, plenty of noise because lower level was not coming up the lamphole.
40mm of rain in 4 hours 12 July 2021.
Fuzzy rain-rate intensity data, along with the sloping gutter level.
In 2017 houses 50m distant, were hard to pick out, yesterday was less intense at its peak and they were still visible. Previous time of water level rising above the lamphole , the gutter level of rainwater of Ivy Rd was up to pavement level, ie close to crown of the road level. This time about half way up the kerb, slope of Ivy Rd is 1 in 146, for some idea of the rain-rate.
For continuous rain intensity,for local high-level sewer level to reach Priory Road gutter level of 5.1m CD, rain only , ignoring any cross-connect with the Itchen on a high spring tide or surge situation. Very rough formula as it uses the St Denys met station data but the levels in the sewer system under St Denys take roof run-off rainwater from old houses in the very large area Portswood, Bassett out to Chilworth, Swaythling, half of Bitterne and out to West End.
Formula updated Sep 2019 to include data from 08 Feb 2016 00:50 to 00:58
(sewerage coming out of toilet-pans in the houses of low lying part of Kent Rd )
and the two intense rain events of Sep 2019.
Tell-tale toilet paper on the 5.09m (Cd) foot rung of the manhole (so some unknown level greater than that), after URS CCTV survey of March 2014 and pics in their report, showed clean steps.
And also 18minutes of 3mm/hr,6 mins of 85mm/hr ,1.41m depth in the manhole 10 July 2018,
13:58, 0.22m
14:00, 1.41m
14:02, 1.35m
14:04, 0.58m
14:06 , 0.41m
rough and ready revised formula for the water in the manhole
in Cd/VTS height terms
y=3.2+ 0.00277*t*r^0.93
giving for the 5.1m Cd level and the gutter level of the low point in PR.
For the period of maximum rainfall rate, ignoring any lesser rainfall periods in the same event.
t= 2min duration, r= 530mm/min rainfall
t=3min , r= 340mm/min
t=5min,r= 200
t=10 min,r= 95
t=20 min, r=45
t=40 min,r= 20
t=1 hour, r= 14 but possibly not, like the observation that
for a long period of 5mm/hr rain rate, no observed rise of sewer level, lower limit yet to be determined.
This is assuming that the emerging water from the drains in Empress Rd , I saw on 29 May ,goes to the deep sewer under Priory Rd and then into Ivy, I've not seen system plans of the pipe-runs there.
The drain between Spacagna and Hampshire Glassware is about the same line (about 5 degrees out) the southern sewer parallel to that bit of Priory Rd and 2 large access drain covers at the horse-shoe bridge road junction with the Empress Rd extension , on the URS plan at the Adelaide/Priory junction drain, as distinct from the one angled 20 or so degrees to it.
Unfortunately there seems not to be any large resolution map with either spot levels for Empress Rd or any benchmarks ever being there.
But the one on the north pillar , under the buddlea (Railtrack maintainence lack of), on the Horseshoe Bridge, had a height of 31.49 ft OSD in 1948. A crown-of-road spot height for Earls Rd/Bevois Valley Rd junction in 1973 was 5.2m OSD.
My attempt at levelling , 8 legs down from the bridge to HGL drain, as bends,corner and vegetation impinging and 2 legs from there to outside Hampshire Electroplating, nearest Imperial Rd of the 3 drain covers there and 2 legs to Earls Rd junction.
The inch or so of water I saw coming out of the HGL cover was not bubbles , but only dribbles finding its way through small cracks as otherwise all vents are blocked with road silt. So that water could well have been road surface water in the rim area being expelled by a build up of air pressure inside, as quite a bit higher level than the cover with 3 x 6 inch continuous fountains of water coming out, at the electroplating firm.
levels, 1948 the same as 1972, other than feet to metres.
Bench Mark ,Horseshoe bridge 9.60m
Earls Rd 5.2m ( possible recent road layout increased the level , but that only increases the level determination below )
Electroplating corner Kingsbury/Empress Rd 2.48m OSD (5.22m CD).
Spacagna/HGL corner from Abney levelling up from Kingsbury giving 2.48m +2.26m (Cd 7.48m ) and levelling down from the bridge benchmark gives 3.82m (Cd 6.56m).
So loads of error there, 0.92m difference. Taking the 2 leg levelling (likely more accurate) from Earls Rd to Empress drain cover as 5.22m Cd and water level as 5.37m Cd.
When I measured the Ivy Rd level at 12:29 as 1.34m , the next reading about 20 seconds later was 1cm down and the next reading another cm down, so the level had been an unknown amount and timing, higher.
1.34m translates to 4.37m Cd.
With all the decades of lorries bouncing along Empress rd, there could well be a broken/displaced sewer below causing a constriction, causing increased level under Empress Rd . Until some more accurate levels surveying, it is possible the peak level in Ivy Rd was quite a bit
higher than 4.37m , as much as 4.9m , only .2m below Priory Rd gutter level.
But the processed data above, I've only used the known Ivy Rd data of 29 May .
Rainfall only event 7am 24 Sept 2019.
Minor flooding in Kent Rd today, one of the Kent Rd residents recorded video of water coming out of the local manholes.
As it did not get to the "explosive" stage when no air is left in the lower sewer and hydraulic pressure can rapidly buid up , no eruptions from toilet pans, just coming out fairly leisurely at ground level outdoors. From pic of manhole mh2701 it locally reached 4.7m Cd level below Ivy Rd, comparing before and after pics.
That Kent Rd manhole not yet levels-surveyed yet but wrt the railway bridge benchmark of 6.22ft = 4.6m Cd, 4 bricks above lowest road level and local lay of the land, looks reasonable agreement.
From the local met station rain gauge I make it equivalent to 18 minutes of 40mm/hr over the relevant period , breaking it down to something like 6 minutes of 80mm/hr and 12 minutes of 20mm/hr.
Rainfall event 17:30 27 Sep 2019
Direct comparison of the torrent to normal appearance of this chokepoint manhole.
Roughly from spread of LED bulb reflections into areas not usually possible to reflect,the level then was about 0.15m below the bottom of the manhole (so deep level sewer level/pressure of 4.0m Cd) and water level in the manhole about 0.15m above benching of the manhole , although a foot higher, as seperated by the "eye" of the cascade ,not contributing to or affected by the deep sewer level.
I made it about 3 minutes of 180mm/hr off the local raingauge.
How a 3-way spiralling occurs with 2 inputs , one output in a square chamber is beyond me. Previous such torrent pic showed the same 3way interlaced swirl. Piece of toilet tissue still caught on a foot-rail as a tell-tale from the previous higher rainfall event.
Apalling state of the sewer in Ivy Rd, presumably the hydraulic pressure of groundwater and ground heave has destroyed the fairing between 150 to 225 mm pipe junction, for both sewage contamination of groundwater and extra groundwater entering the sewage system in rainfall events. Gravel in the pics at the manholes Eastfield Rd/PR and South Rd/PR mangoles evidences similar elsewhere. 100% silt at Adelaide Rd/Pr presumably covers similar gravel there.
So expect the road to collapse at some time about 10m south from the manhole near the happy-clappy church in Ivy Rd
Storm Pierrick 08 April 2024
The local peak about midnight was 5.61m compared to Woolston of 4.7m.
Perhaps as the normal HT1 local height is higher than Woolston conjectured due to the moon pulling the water up the Itchen , but yesterday coming in early the moon breaking its travel up the Itchen.
The water in the Adelaide Rd drain was rising at just the same rate as the water in the gutter, meeting at the grill.
In 220 years of local flood reports, the St Agabus day/ named Storm Pierrick was the first instance in the summer months of April to September, perhaps another feature of climate change.
The wartime , so not newspaper reported , almost mythical flooding in July was probably a rainfall not marine, local only flood, of Cowes High St.
Left pic below of Cowes High St about midnight 08/09 Apr 2024.
The lowest level is at the Town Quay and Vectis Tavern hidden from this right Streetview pic in the recess behind the run of buildings on the right.
Flooding came up the drains, depite sandbags, pubs and shops flooded .
Pic taken at corner of the High St and Carvel Lane about 10m from the OS Benchmark on Hurst ironmongers. In OSD terms peak level of 2.64m at Cowes midnight 08/09 Apr on the EA tidegauge.
Various benchmarks & spot-heights
1965 Horseshoe Bridge 31.45ft,Bevois Hill /Lawn Rd spot 58ft, Spring Crescent /Lawn BM 48.74, dip in original Dukes Rd to Horseshoe spot 26ft
1948 Rail Bridge, PR 10.77ft and 11.00ft BM, 23 Adelaide rd BM 10.83ft,
90 PR 11.44ft, 130 PR 11.90ft, Cobden Br (near now built on priory foundations and bus stop , 8 bricks up and about 5m from midbridge end of the brick wall) 20.43 ft BM, SW corner of 358PR 18.54ft on north wall so veiwable from 360 PR side ,there in Jul7 2018 at some point
in the past someone has decided to make a feature of it by filling the cutmarks with mortar, so contrasting to brick,
S corner of 233 PR 19.26ft (brick rebuilt?/new vent obliterating? not seen in 2018), SE corner of Conservative Club SDR 19.45ft BM (rendered over? not seen 2018),
NE corner 207 PR (present still in 2018 viewable from the pavement 9 bricks up) 16.15 ftBM, Kent Rd Rail Bridge NW corner 6.22ft (1948) OSD, still there June 2018 4 bricks up from the present road surface and 2 bricks in of the main load-bearing wall rather than revetment/abutment wall, so the dip under the rail bridge is 4.35m (2018) Cd near enough agreeing with the LIDAR survey,
opposite side of road to 114 Kent Rd 9.84 , SW corner of 326 Portswood Rd ,19.18ft . 2018 Bracket BM on the Bitterne Park Hotel and 37.08ft BM on the
return wall of 32 Manor Farm Rd, Bitterne Triangle.
With the argument there may be a slope in the surface of the River Itchen at high or low tides, due to Correolis Effect. I don't believe it was a real effect, more badly/non calibrated temporary bubble tide gauges .
But could there be locally a slope in the land as distinct from generally GIA sinking south Hampsire.
From BODC data for Lerwick , between 1957 and 1999
mean sea level has only risen 30 mm relative to the rising land there.
But for Portsmouth between 1962 and 2002 then sea level
relative to presumably sinking Portsmouth , 170mm rise. Assuming no
change in sea currents to affect these readings or 136mm for 32 years.
So for a notional neutral port (none available in the long-term BODC record),
rise of (30+136)/2=83mm in 3.2 decades= 2.6mm/yr, much as the global sea level rise over that period. IOW area is sinking at the
rate of about 1.7mm per year due to recovery from
the last ice age.
Basically no measurable tilt in 50 years along Priory Rd from St Denys Rd to the rail bridge. Just 4mm in it, via Sokkisha B2 calibrated to 4mm per 100m, but as the benchmark on Priory Rd rail bridge and corner shop with St Denys Rd only stated to +/-1 cm on 1:1250 OS maps, no observed tipping in 50 years
since 1969 map. What about the perpendicular direction.
Looking from a bus I noticed one I thought had vanished , on Cobden Bridge, so line perpendicular to Priory Rd.
http://diverse.4mg.com/cobden_BM.jpg
The one on the brickwall St Denys side is normal but the one on the upstream Bitterne side concrete pillar, with built-in seat, is little more than the horizontal groove and that carved in the acid-etched concrete, to expose the blue-grey aggregate for effect, very slight traces of the broad arrow/ bench leg grooves.
Benchmark heights 20.42ft and 23.68ft, 153m +/-1m from 1:1250 1969 OS map and 153.3m apart by surveying tape.
Well beyond centi-foot and levelling measurement error , offset of 0.111m over 50 years.
Unfortunately , as evidenced by the 3 degree lean of the un-buttressed brickwall holding the benchmark, with the new flats behind, probably just shows subsidence of the bridge approach road and wall, near the steps down to the rowing club footpath.
Update 16 June 2018.
It sounds like the local sewer pipe dilapidations (on the URS CCTV survey) and cross-connect between normal spring high tide Itchen water, via the always open to the road gutter/gully storm-drain system, into the local high-level sewer has returned. The 29 May midday storm water must have flushed through or dislodged the gravel/silt build up that the previous cloudburst had formed, with the then outcome of stopping the cross-over. Assuming someone wasn't emptying a bath at 13:30 at the time, there was a lot of noise coming from the Ivy Rd manhole at 4.7m first high water, not so loud for the 4.6m second high water at 16:00.
Extreme rainfal near realtime predition,using
https://neige.meteociel.fr/satellite/latest-ir-color.gif
and its archives.
https://www.meteociel.fr/observations-meteo/satellite.php?mode=infrarouge-colorise
Probably due to the oblique view from geostationary position to 50 degree N of the UK, for very high cloud tops the pixel for Soton is displaced about 20 miles east and 5 miles north, ie over about Petersfield in that image.
Plenty of pink and white representing the highest cloud tops on the recent false-colour IR imagery.
Rummaging around on EUMETSAT & NWCSAF www pages I found no applicable
colour scale. From an amateur metman the missing colour scale probably
represents a negative scale of temperature . Meteociel reducing 24
colour bins to 8 and geographic morphing from geostationary satellite
view to easier "over-head" view, and deliberately dropping any confusing
to the general public, back-to-front scale.
So my rough scaling in cloud altitude terms
white (cumulo nimbus?) 16 to 18km
pink (ditto ?) 14 to 16
purple 12 to 14
red 10 to 12
orange 8 to 10
yellow 6 to 8
green 4 to 6
light blue 2 to 4
dark blue 0 to 2km
From their archives "pink" over Antwerp 4 to 5pm CET and "white" over
central Holland 7 to 8 pm CET 18 June 2021 for the first extreme storm
system I looked at like this. Areas of pink and white mean alarm bells
then and a week ago over mid Europe.
That false colour IR imagery site gave "red" cloud for a long duration passing over London 25 July, for its flooding.
On 24 July it gave one 1/4 hourly image of one small splodge of white,18:30 CET, about 20 miles ENE of Dinant for its flooding, otherwise a lot of pink.
Inconsequential rain for St Denys early am 27 July 2021, came from "green" cloud in that ir imagery.
Sewage contaminated flooding of Salisbury Rd, Cosham on the local news, came from about 3/4 hour of "yellow" contained within the greater green area of that cloud system.
I dropped into Salisbury Rd, Cosham 05 Aug 2021 and got talking to someone who took some of the 3am pics of their flooding. These days its about 4 times a year that sort of flooding. Their choke point is a sharp bend in the sewer (plus roof run-off) turning off Salisbury Rd into Hilary Avenue, breaking out at the sewer manhole there and gutter gully access drains. Water coming from Park Lane, Magdala Rd and the splendidly named twittern the Groke , then down the 100 yards of Salisbury road to
the low point at the Knowlesly+Lonsdale end. Enough depth of water to float a few parked cars.
Been happening for historic times. Also similarly someone with a van , down the road, parks it across the road, as its a rat run, if during the day and some warning of flooding. A neighbour had bought a rain gauge for monitoring and also put an elbow on the roof downspout pipe, so all his rainwater is diverted into hardy garden shrubbery, no one else having done this locally. Talking to plumbers , builders and their suppliers there does not seem to be an off-shelf-product, like rain water butt diverter kits, for diverting extreme rainfal from roof run-off downspout/downpipes away from sewer ingress. In Cosham they know now how to measure the depth in the sewer, with laser tape measure and also take pics with a basic compact camera, torch in one vent hole, fixed-focus camera angled ino the other. Also said about the Meteociel.fr IR images for maybe advance warning.
According to the IR imagery, somewhere in the Portsmouth-Chichester area had "pink" cloud tops about 6pm 07 Aug 2021,no sferics, I've not seen any reports of flooding though.
Early 09 Aug 2021 , for us 15mm of rain in an hour, peak rainrate of 66mm/hr then 1.5 hour later lesser peak, "red" cloud pixels for Gosport for much the same system and "orange" an hour later overall making sewage contaminated flooding in Cambridge Road/Grange Crescent and Leesland Road, Gosport . "a blockage near Anns Hill Cemetery caused the mayhem" so could randomly happen at the lowest points of anywhere there is a sewage pipe system allowing roof run-off.
But a few days later the landlady of the Junction Tavern, Leesland road in an interview said it was due to "a long standing problem".
So perhaps someone is trying to blame it on wet wipes or such, not a built-in chokepoint like in Cosham and potentially here, both having 2 pipe runs feeding into a manhole , with a different third direction of outflow.
I went for a wander around the area, intending to have a pint at the pub and a chat with the landlady , but it was closed due to flooding.
Another associated area that was flooded that time was Brockhurst Rd/Cambridge Rd, such that at 6am it was only just possible to get to the Royal Mail depot, water nearly reaching the bus shelter on the Gosport going side of the road. 33 DK Dollys Allsorts also closed due to flooding to a few inches over the shop floor. Recently some sort of flooding in that area about 4 times a year, the levels of 09 Aug about every 2 or 3 years, been much the same for the 40 years of one old resident. None of the manhole covers in the area have air-balance vents, so no chance of finding the sewer depth or flow direction.
One connecting theme , otherwise a bit of a coincidence is the close association with railway track, but I don't see a connection.
St Denys, Cosham , Gosport tracks removed but prominent embankment in place re-used as cycleway/footpath.
Also Winchester flooding in 2020 Cranworth Rd, Winchester right next to the railway.
For rainfall flooding near realtime predicting , it seems it requires looking at the false colour IR plots and lightning strikes nearby.
Going "abroad" as usual and delving into the archives of meteociel.fr and blitzortung for lightning archives.
Winchester flooding (2021 published Winchester-S19-finalreport.pdf with onlt half a sentence in 35Mbyte mentioning roof run-off into combined sewers)
27 Aug 2020 , 15:40 to 16:00 GMT ,orange in green cloud, 50 strikes approx 5 miles radius
again Winchester 24 July 2021 02:20 to 05:50 GMT
orange , and also red in orange cloud, about 500 strikes in 3 rounds over 3.5 hours
Cosham 27 July 2021 01:40 to 02:10 GMT
yellow in green, about 45 strikes
Gosport 09 August 2021 05:00 to 05:10 GMT
orange, about 10 strikes
Where such as "red in orange" means orange over the spot about 20 miles ENE of point of concern and red elsewhere in that say county-wide orange cloud system
My contribution to relieving the local sewer system from extreme rainfall
Tapping the downpipe during heavy rain and overflowing gutter, did not sound hollow and making a small hole in it,water jetting out. So decided to make a mod. To unblock that downpipe would be a workup anyway as continuous 18 foot long run to the gutter and I'd have probably sawn across it and find or make a breakable union in the join for next time.
Original pipe 2.5 inches and mod is 2 pieces of 1.75 inch pipe.
Both are the same angle , camera angle distorts it. Angled 45 degrees upward and away from the wall towards hardy shrub and concrete path.
Cut the 1.75 inch pipe at 45 degrees. Marked and then chain drilled elliptical holes , end-snips tidying up the cut. The outlet pipes hot-melt glued in place. Copper wire is in case birds think its a nesting box. So far I've seen the lower pipe only in action but only enough flow to arc about 2 inches .
For anyone else making a on-the-fly rain gauge out of a roof downpipe, for run-off from pland area of 29 sq m of roof , needs >40mm/hr before an arc of water emerges out of the lower port.
That cross of copper wire, bird-blocker, soon traps moss, so perhaps flap valves required. In area terms , 50 off 1.75 inch pipes to one 12 inch pipe and probably more than 50 houses in Ivy Rd
I already knew the drain cover was blocked so any low level flow vertically into that area is no problem, when little rainfall.
I suppose if the pipe had not been blocked I'd cut off a 3inch piece of polythene pipe, bend in the middle , tie a piece of cord to it in case it opens up wrongly, push upside down V fashion down the lower port, push a carrier bag cut into pieces no larger than 3 inches (to avoid sewer blocking if dislodged) in the lower port and some gravel in the top , then try a bucket of water poured in, to check it was blocked.
I've fixed a 1.5m haberdashers tape measure horizontally to my improvised rain-rate gauge , so with a watch and a torch if at night I should be able to do some sort of cross calibration with the local www Davis weather station , 150 metres away. If this works then maybe a sensitive water gauge fitted to the pipe so I can remotely monitor without going outside.
Walking under Kent Rd rail bridge I was wondering , when the next heavy cloudburst river runs through , how much damage will be done by those road-block heavy box planters that will float at speed into the parked cars of Kent Rd as well as flooding damage.
Enclosed is a low-res version of my reconstruction of "rivers " that emerge or get enhanced in 30year say cloudbursts , on 1938 map.
Red 50 foot contour just about visible in the lo-res image
Off the common , down Spring Crescent , name is significant as the underlying river/spring is culverted under Lawn Rd you can hear thru the manhole even the driest of summers.
The next one still there , but would back-up at the Lawn Rd culvert.
Next one goes down the footpath , past the Dolphin to the station,
where it always floods as the Thomas Lewis road foundations/drains intecepted the subterrainian "river". Some water would go to the railway level crossing area and the rest to the Junction area with the other 2 flood branches.
Welbeck Avenue may derive from Well Beck before all the housing and wants to flow to the Kent Rd area. With some help from a resident of Grosvenor Close, the river that
goes through the university grounds goes underground at Shaftsbury Ave,
and goes overground in extreme rain between Richmond and Donnington gardens,
behind the north of Grosvenor Close to 21/23 Arnold Rd then into Portswood Rd and
some going along the cutway and out at 473 Portswood Rd.
The most northerly one is the beck between Broadlands and Sirdar roads that passes the WW2 army pill-box and "The Brook" pub is presumably named after that brook .
Exploring St Denys underworld
The Victorian cavern running under Eastfield that presumably very few people know about.
The URS CCTV sewer survey (keywords itchentides,URS,CCTV,pdf) does show one end in the image of MH3702
but as no additional lighting or exposure for the bottom of the manhole and
image forshortening its not obvious and not referred to in the text of the report.
That end , PR and Eastfield Rd and the other end junction of
South Rd and Eastfield both have full vented covers so able to
photograph and measure the interiors, but the route of the
cavern , not direct under Eastfield but right-angled via
PR/South Rd junction. Track of this cavern may well
go within half a metre of the foundations of the
new build 3 story house at that corner, knowingly?.
Chamber is about 0.6m wide and 1.8m high to perhaps stoop-walking height
at South Rd of about 1.5m and 100m long.
This is an overflow chamber designed for Victorian rainfall
and sensibilities as far as overflow into the Itchen catering for
part of St Denys extreme rainfall. "Solids" tend to settle out and relatively clean water at the top , where the overflow outlets are.
In the 1970s much the same idea at the sewage works 2m diameter 450m long cavern along the rail line to the university boat club.
Dimensions with 1970s sensibilities and for much larger city , well 1/3 of city, out to Bassett and West End .
As its not usually a running sewer , the frog-up 3/4 brick-batts instead of sloping curved benching are for grip of sewermen's boots.
The 8 inch pipe marked red X is the outlet pipe , URS shows another one,
no sewer gunk staining as outlets not inlets.
No ref on the URS plan , so may output to the storm drain system or to the river. If the latter presumably destroyed on demolishing
and rebuilding beyond 152 PR.
Strong stench of sewage smell of the last PR flood emerging upwards from the storm
drains, nearly to the crown of the road
of 5.25m 13:00 tide 21 Aug 2020, as no rain then.
OS road spot height at PR/Eastfield of 3.7m OSD (6.44m Cd) and laser tape-measuring
and a bit of geometry makes the outlets centred at 5.68m Cd.
The water level is 3.04m below road level so 3.40m Cd .
Compared to the URS pictured permanent water level at the hard
area of PR is less 3.8m Cd which
is the dry height of the base of the first URS manhole
not containing foul water at Adelaide/Priory junction , these are likely at the same water level and provide a simple way of monitoring that level that threatens to
invade the lowest houses in extreme or sustained heavy rainfall,
just requires a simple laser tape measure.
With no rain around and high tide checks tide of 4.3m at 10:45 15
Nov 2021 3.05m below road and down to 3.93m below road at 11:15 16 Nov
with 4.4m tide ,so nothing suggesting R Itchen in normal flood
at least infiltrates that drain system.
The rubble layer in the South Rd image is 2.58m below road level, looks like a bodge-up piece of plywood there to dislodge sometime and just the right size to block an 8inch pipe when it floats off into the system.
For the record, as not covered by the URS report.
The other fully vented manhole covers in St Denys
PR/Pettinger, perhaps defunct, seems to be rubble filled to 1.15m below road level
PR/ North Rd water 3.63m below road
PR/Priory Ave water 3.93m below road
Kent Rd at rail bridge water 0.80m below road
Adelaide Rd near St Denys Rd water 3.80m below road
*******************
Just in case its of any help to anyone. I expected there to be some much simplified cut-down application/widget for determining surge levels but nothing found. I could not even find the speed of the tide over shelving areas of the channel approaches, deep ocean yes, and English Channel of course about 6 hours between Newlyn and Southampton. So far the follwing has only been validated against .5m or so surges 02 and 03 Feb 2017 and Storm Brian 21 Oct 2017. For "hurricane" ophelia 16 Oct 2017 over-predicted by 30% even on the 18Z GFS data of 15 Oct, presumably because the core went across my sampling line rather than with it and the extreme-most first sampling point was right on the track and a projected wind speed of 135kph and zero relative angle at that point.
So the x0.66 scaling factor becomes x0.5 , for storm track more north of north-east heading.
Interestingly , the GFS model a few days in advance of those surges , then using my widget, gave a "300 year" surge of 1.9m , it did not transfer to
reality though, GFS 06:00 run of 29 Jan 2017 and next 12 hours.
I always thought such an extreme surge would stand out by being 940mB or isobars so skewed as to be almost unresolvable, but its mainly down to position and track over land and coupling with the jet stream.
http://www.diverse.4mg.com/virtual_1.9m_surge.jpg
This widget only
having the 2008 and 2014 5.6m Soton tide surges to work with as the GFS archives only go back to cover those dates.
Speed of tide over channel approaches, best fit , came out to be 2.2 times
the speed in the channel.
I originally used a geostrophic curve fit to work off the synoptic charts, not perfect curve-fit , like the wind-stress one but if any use to anyone the
relevant basic code
' pixel spacing to wind conversion
' this conversion is only for Meteociel.fr synoptic charts
' chart outputs at 00:00,06:00, 12:00, 18:00 hours and 26 degree line end
' adjusted to HT at Soton
' with appropriate curve fit
wind = 146.47*(entry2^(-0.31637))
wind2 = 0.1*(int(10*wind + 0.5))
' cos'd wind for component along 26 degree line
coswind= wind*cos(result*pi*2/360)
The later version using the isotach plots , 1 hourly outputs available for
GFS on meteociel out to 120 hours.
So met model data such as
http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=252&mode=14
using freeware graphics package IrfanView v4.33 to turn the UK 26 degrees
and overlay this line into a long box, left hand end co-ordinate 410pixels for Europe plots and extreme left (ie off the turned plot) for high res hourly plots
of France
http://www.diverse.4mg.com/line2.jpg
ending at the Isle of Wight for picking off wind strength and direction
relative to the 26 degree line
freeware JustBasic v1.01
The Basic wind-stress to surge code for west to east English Channel surge (no comments about its sloppiness please)
' This program ask for an angle and "colour" of wind on GFS 10m "vent moyen" plots, in kph
' there are no error traps for erroneous inputs, so cancel and repeat
'
dim array1( 7 , 6)
pi = 3.141592654
for j= 0 to 6
input "Please enter an angle for point "; j ; " =" ; entry
result = entry
print result
input "Please enter kph wind for point"; j ; " =" ; entry2
result2 = entry2
print result2
print
print
wind = result2
wind2 = 0.1*(int(10*wind + 0.5))
' cos'd wind for component along 26 degree line
coswind= wind*cos(result*pi*2/360)
' wind to stress
' using Geernaert 1987, North Sea roughness coefficients
' and appropriate curve fit
stress1= -0.0117 + 0.001035*coswind - 0.000017212*coswind^2 + 3.0092598*(10^-7)*coswind^3
array1(j,0) = result
array1(j,1)=result2
array1(j,2)=wind2
coswind= 0.1*(int(10*coswind + 0.5))
array1(j,4)=coswind
stress1= 0.001*(int(1000*stress1 + 0.005))
array1(j,5)=stress1
next j
print "point","angle", "wind kph","coswind kph", "stress"
for k=0 to 6
print k,array1(k,0),array1(k,2),array1(k,4),array1(k,5)
next k
' sum of averages along channel approaches, assuming 2.2x 60kph tide speed in the channel
newlyn=2.2*(0.5*array1(0,5)+array1(1,5)+array1(2,5) + .5*array1(3,5))
' sum of averages along English channel
soton=0.5*array1(3,5)+array1(4,5)+array1(5,5) + .5*array1(6,5)
print "Wind Stress constituents"
' need to multiply by a factor to give surge amplitude
print "Newlyn", "Soton"
print newlyn;"u", soton;"u"
print
print "x 0.66 to give stress surge component in m and add to inverse barometer for each of Newlyn and Soton, or x0.5 if storm track is
north of north-east and sampling point is right on the most extreme wind"
*******************
In case of any use to anyone. Lymington tide gauge records analysed
for surges .5m or higher. Like VTS, a number of such events may be missing due to short term failed gauges .
Surges recorded at Lymington, calendar years start 2010 to end 2016, from
http://www.channelcoast.org/data_management/real_time_data/charts/?chart=87&tab=tides&start=&end=&disp_option=
21-11-2016 15:30' 3.2, 0.5m
19-11-2016 23:30' 2.73, 0.51
28-03-2016 01:50' 3.74, 0.9
09-03-2016 02:30' 1.06, 0.65
13-02-2016 05:30' 2.03, 0.53
09-02-2016 11:00' 3.45, 0.5
08-02-2016 14:10' 2.14, 0.66
06-02-2016 14:10' 1.03, 0.65
02-02-2017 19:40' 1.34, 0.68
patches of corrupted data
19-11-2015 18:00 3.21, 0.6
17-11-2015 01:20 3.34, 0.63
29-03-2015 12:40 2.01, 0.51
lot of corrupted data nov ,dec
14-02-2014 22:50 4.24, 1.29
11-02-2014 09:20 3.32, 0.58
08-02-2014 17:30 3.12, 0.6
06-02-2014 15:20 3.22, 0.52
05-02-2014 01:50 3.74, 0.85
01-02-2014 17:30 0.62, 0.51
31-01-2014 16:30 0.67, 0.52
26-01-2014 07:20 3.23, 0.53
06-01-2014 20:00 1.31, 0.72
04-01-2014 12:10 3.62, 0.5
03-01-2014 05:10 0.98, 0.59
01-01-2014 15:50 1.14, 0.77
31-12-2013 10:10 3.69, 0.64
30-12-2013 10:21 3.39, 0.5
27-12-2013 04:40 3.29, 0.66
25-12-2013 03:10 3.28, 0.54
23-12-2013 15:50 3.49, 0.71
06-12-2013 02:50 3.86, 0.67
04-11-2013 01:10 3.69, 0.78
03-11-2013 21:50 3.68, 0.65
28-10-2013 05:30 3.6, 0.86
04-02-2013 04:40 3.31, 0.51
31-01-2013 06:40 1.16, 0.54
29-01-2013 17:40 1.06, 0.56
14-12-2012 10:30 3.71, 0.54
04-11-2012 09:10 2.37, 0.55
18-10-2012 05:30 0.83, 0.59
17-10-2012 05:00 0.96, 0.78
08-06-2012 00:30, 3.5 0.56
26-04-2012 01:10 3.61, 0.78
18-04-2012 08:30 3.27, 0.6
16-12-2011 07:40 1.63, 0.64
14-12-2011 18:10 1.27, 0.52
12-12-2011 23:30 3.5, 0.7
16-12-2010 20:20 3.09, 0.54
12-11-2010 15:10 3.35, 0.62
08-11-2010 05:00 1.13, 0.56
27-02-2010 09:10 3.49, 0.55
25-02-2010 20:20 3.27, 0.51
23-02-2010 05:00 3.13, 0.53
I doubt any conclusions can be drawn other than apparent peak of surges in 2013-2014 and very few in april to september.
May well have other instances, as much obviously corrupted data I've not determined, logged and checked against VTS .
residuals at max or min of elevation, not necessarily high or low astronomical tide times.
there were many other >0.5m residuals but not recorded here as <.5m at associated max or min , even if short by just 0.01m.
ignore ' and , which are added field separators
Extended surge covering multiple low and high tides, just 1 surge recorded here, unless an intervening max or min residual was less than .2m
**********
Global Sea Level Rise , that was in this section now on ,
http://diverse.4mg.com/slr.htm
*********
Pagham harbour event on the local news , some observations.
Whatever it was, was surely not due to the channel surge of that day as barely 0.2m on the English Channel tide gauges and NOC surge predictor/monitor and virtually no wind ( 10mph or so wind from SE , in Chimet archives etc).
Has any hydrographer or oceanographer nailed down the cause of it?
Some sort of eddy-effect and heaping associated with the strong spring tide stream going around Selsey Bill? . But if that was the case why has it not happened in the previous 31 years, ie giving a flood event worse than 10 Mar 2008 and 14 Feb 2014 channel storm surges.
(31 year ref on http://paghambeach.blogspot.co.uk/ )
Unlikely a meteotsunami as not summertime.
Perhaps that eddy effect in conjuction with apparently relatively recently emerged local spit to the harbour ?
From Prof Philip Wilson of Soton Uni, it could have been a soliton, initiated by a ship wake or two ship wakes travelling into shallow waters. Whether that could explain the duration of the 30 second or so video image I saw, I don't know.
***********
In case it is useful to anyone testing surge models of the UK, etc.
There was a GFS model run 06:00 of 29 Jan 2017 that , if it had come to reality for the mid afternoon tide of 04 Feb 2017, would have given something like a 1.9m surge for Soton/Portsmouth.
Even on the relatively low astronomical tide, would have meant a foot more than Valentine's Day 2014 locally.
The cyclogenesis? feature in the isotach plots was in just the right/wrong track and timing. In reality that storm went over France and on 03 Feb rather than 04 Feb. I somehow thought a major channel surge would be with a 940mB low, long fetch over a large bit of Atlantic, or standout by the low having so packed isobars as to be almost unresolvable, not a short patch of intense wind near enough sync'd with the tide.
In the end, for the mid afternoon Portsmouth high tides of 02 and 03 Feb ,the tide gauges recorded surges of 0.4m and 0.45m. NOC predictor had given 0.3m and 0.25m.
My widget gave 0.44 and 0.37m in comparison. Widget uses Geernaert 1987, North Sea roughness coefficients and much simplified bathymetry.
08 Jan and the Lymington tide gauge showed the peak residual was 0.56m , Herne Bay maximum was 2.05m. So with the same North Sea wind and sllightly different timing but on a 4.8m tide could be a problem stealth tide here. Similar occurance on 13 Jan 2017 Lymington maximum residual 0.4m and Herne 2.07m then, all
reminiscent of the 1953 Canvey Island disaster, but where the surge coincided with high tide locally there.
21 Nov 2018 GFS model output, if the system came in about 100 miles farther north then a 1.8m surge on the 02:04 4.5m tide of 28 Nov (6.3m !).
*************
Some useful sites for major systems in the Atlantic
https://www.nhc.noaa.gov/?atlc
https://apps.sfwmd.gov/sfwmd/common/images/weather/plots.html
On "Huuricane" Ophelia October 2017
Looks as though the minus 18 hour factor on this paper
http://journals.ametsoc.org/doi/pdf/10.1175/2013EI000527.1
for height of surge from proper hurricanes works quite well out of their area of research for Ophelia.
Curve fitting Fig 5b (R^2= 0.997) , where x is in kph maximum wind 18 hours before, and y is predicted surge in m
y=0.958 * e^0.00707x
Its traverse sped up and arrived nearer CastletownBere low tide than high tide , so of no emergency consequence.
Bit awkward in the BST/GMT and 2.48m Malin Head chart datum offset .
But came out at about 1.84m above their predicted low tide, for the last 18 hour in advance GFS winds prediction.
The previous GFS run, -18hr from Fig 5b of that chart I had determined 2.2m surge, if it had gone over Castletown , not skirted S Eire.
Low tide was 08:10 GMT but no www output after 0800 Castletown .
From the Galway tide-gauge
https://www.marine.ie/Home/site-area/news-events/facts-figures-storm-ophelia
1.6m surge , near their high tide, farther around than Castletown.
***
Sea Surface Temperature (SST) anomaly storminess pointer , most recent status
Based on NOAA SST half-week data output since 12 October 2017,
Storm systems coming into UK airspace
3 digit numbers are the day-number (days from 00:00, 01 jan of the year), this exploration starting at 12 October 2017, MS maximum surge at Portsmouth
October
285, 43
289, 73
292, 66 : 292, (NHC) Hurricane Ophelia, MS 0.35m
296, 58 :294, Storm Brian, MS 0.4m
299, 68
303,58
November
306, 45
310, 49
313, 55 : 312, TS Rina (MS check archives jan/feb 2018)
317, 47 : 314, putative NHC TD/TS 20, dissipated before UK (MS check archives jan/feb 2018)
320, 36
324, 45
327, 48
331, 51
334, 58
December
338, 54: 341 , Storm Caroline affecting Scotland, MS 0.3m
341, 58 : 344, no named storm but 90mph gusts in the English Channel with a 971mB low, MS 0.7m
345, 42
348, 34
352, 59 ( no named storm, very localised force 9 westerlies for Ireland on 14 Dec)
355, 38, p/p 43
The prior month component suggesting a stormy January 2018, considering that (close to the currently negative correlation) component is strongly negative currently.
Processing the selected pair of areas as if it was next month, for the prior predictor p/p value,
so if the other two future current month components are non negative, then the minimum 3 component combined pointer value out of 100 for the next month
359, 35 , p/p 47 (revisiting at the end of January 2018, because of a high combined storminess value, this is the peak p/p value the month before)
362,62, p/p 46,Storm Dylan 30-31 Dec 2017
2018
001, 43 , p/p 44, Storm Eleanor 02-03 Jan 2018
004,44 ,p/p 45
008,51, p/p 46
011, 57,p/p 41
015, 55, p/p 43 snowstorm 16-17 Jan Storm Fionn + Storm with no name,tropospheric baroclinic wave and associated fast moving surface low, and violent storm force 11 in sea area Thames 18 Jan 2018
018,53,p/p 43
022, 52, p/p 30 , Storm Georgina 23 Jan
025, 54,p/p 31
029, 69, p/p 26 (the low p/p values predicting a storm-free last week of February?)
February
032 , 59, p/p 31
036, 61, p/p 6
039 ,68/65?
043, ?,?
046,41, p/p 28
41, 15 Feb 2018
18 Feb ??
49, 26 Feb 2018, p/p 29
I stopped processing the graphic outputs as dropping off in value, just visually inspecting the new outputs, until
June 2018 when a black splodge appeared at the Grand Banks and an orange fringe around the UK. I also took the opportunity to revisit 1999, 2008, 2013 and 2014 SST graphics and slightly shift the sampling squares of interest to correspond to
the week before the flood events rather than day nearest the event.
Year-day number 162 SST anomaly value under previous sampling structure ,60 corresponded to Storm Hector 13-14 June 2018
Day number 162 SST anomaly value with "week before" sampling structure ,57corresponded to Storm Hector 13-14 June 2018
Day number 165, new sampling structure , 60
169, 65.4
172, 42
176, 52
179, 44
183, 42
... (low)
200, 45
... (summer recess, continually low just by looking, not actually calculated)
267, 38
270, 79 (higher than period of Ophelia and Brian of Oct 2017)
https://www.ospo.noaa.gov/data/sst/anomaly/2018/anomnight.9.27.2018.gif
274, 78
277 , 84 Output of 04 Oct, plus 1 week, predicting Storm Callum 12 October
281, 61
284, 65
288, 68
291, 55
295, 78
298, 77 for NHC Oscar
301, 73
304, error processing
308, 67
...
327, 82, Storm Diane
...
344, 64
347, 44
354, 53
(adding El Nino anomaly in degrees C for Nino 3.4 sector/sea area 120 to 165 deg ,+/-5 deg latitude, processed from the same NOAA global image , by colour range pixel counting. During the usa.gov shutdown a few spot ENSO SST anomaly evaluations. )
358, ?; El Nino +0.8
361, 31; El Nino +0.8
365,?; Nino +0.75
2019
...
14,43 ; Nino +0.75
17, ? ; Nino +0.63
21,?; Nino +0.41
24,42; Nino +0.34
28,14; Nino +0.36
31,50; Nino +0.69, Storm Erik 09 Feb
35, 38; Nino +0.37
45, ?; Nino +0.59 (as well on the way to El Nino and return of US gov , abandoned these ENSO evaluations)
58, 32
66, 62
69,52
...
87 , 58
91,48: Nino +0.93 (return of non-updates from NOAA) but output showing 5
red quarters went public 05 April 2019
112,? : Nino +0.93
119,?: Nino +0.91
126,45 :Nino +0.89 [1% in 2.25 deg C bin]
129,?: Nino +0.87 [0.3% in 2.25 deg C bin ]
133,?:Nino +0.88 [0% in 2.25 bin]
136,?:Nino +0.80 [0.3% in -0.25 deg C bin]
140: Nino +0.84
143: Nino +0.93
147: Nino +0.89
150,64: Nino +1.07 [0 in -0.25 deg C bin, 0.7% in 2.25 deg C bin]
154,90 (Storm Miguel, violet storm 11 in Biscay, 3 people killed, 150 miles south of Eng Channel, first validation of the predictive value of this analysis of the index approaching a value of 100) : Nino +1.00 {0.5% in -0.25, 0.5% in 2.25}
157: Nino +0.89
161: Nino +0.91
164: Nino +0.91
168: Nino +0.92
171: Nino +0.77
175: Nino +0.75
178:Nino +0.60
182 : nino +0.68
185 : Nino +0.83
189: Nino +0.81
192: Nino +0.77
196 : Nino +0.76
199 : Nino +0.67
203 : Nino +0.68
206: Nino +0.64
210 (29 July 2019): Nino +0.52
213: Nino +0.48
217:Nino +0.40
220: Nino +0.38
227 (15 Aug 2019): Nino +0.19
231: Nino +0.17
234: Nino +0.20
238 (26 Aug 2019): Nino +0.27
241: Nino +0.26
245: Nino +0.14
248: Nino +0.04
252: Nino +0.02
... (about 0 by eye)
262(19 Sep) : Nino +0.17
266 (23 sep): Nino +0.36
269, 26 sep: Nino +0.37 deg C
273, 30 Sep: Nino +0.48 deg C , El Nino trend again ?
276, 03 Oct: Nino +0.66 deg C
280,07 Oct: Nino +0.63 degC
283,10 Oct: Nino +0.54 degC
287, 14 Oct: Nino +0.64 deg C
290, 17 Oct: Nino +0.70 deg C
294, 21 Oct: Nino +0.74 deg C
297, 24 Oct: Nino +0.72 deg C
301, 28 Oct : Nino +0.75 deg C
304, 31 Oct : Nino +0.79 deg C
308,04 Nov: Nino +0.74 deg C
311, 07 Nov: Nino +0.67 deg C
315, 11 Nov: Nino +0.67 deg C
318, 14 Nov 2019: El Nino +0.75 deg C
322, 18 Nov: El nino +0.74 deg C
325, 21 Nov: El Nino +0.78 deg C
329, 25 Nov: El Nino +0.54 deg C
332, 28 Nov: El Nino +0.51 deg C
336, 02 Dec: El Nino +0.46 deg C
...
346,12 Dec: El Nino +0.38 deg C
(Has ENSO simply stopped oscillating, positive
and negative feedbacks gone outside/inside normal bounds, leading to a relatively steady state?)
NOAA ENSO as 3-month rolling means
2018 -0.9 -0.8 -0.6 -0.4 -0.1 0.1 0.1 0.2 0.4 0.7 0.9 0.8
2019 0.8 0.8 0.8 0.8 0.6 0.5 0.3 0.1 0.1
Anyone else who'd like to try this SST anomaly pointer.
My selection pairs (roughly) and you would have to choose your own area, meteorological factor constituting a storm and the relative weighting, chosen dates, sea area size and shape, exact monitoring days relative to a storm etc. My chosen monitoring areas approximately centred on
42N,50W (week before a storm)
44N,10W, corner to corner
55N,45W (week before a storm)
42N,46W
(reverse SST anomaly gradient of previous month, 5 weeks before a storm, ie east colder than west)
50N,9W
50N,42W
My met-factor was producing a west to east surge in the English Channel but your factor might be the wind strength at a local anamometer
Southampton Quadruple tides per tide cycle
Why "blue book" ABP tide tables do not always agree with UKHO tide tables for Southampton.
From Miss Conway at the ABP Hydrographic section in Jan 2016.
The disparity is due to "typo errors" that they correct on a day to day basis by checking against their graphical tidal plots.
29 Jan 2016 talking to the VTS controller on the phone , they were operationally using 13:56 as high tide that day, not 13:41 of UKHO.
But he confirmed UKHO and VTS source of data are both the Admiralty.
Sometime there is one tide in agreement so triple tides and other times the "traditional"
double tides . When there is a disparity between blue-book and UKHO, times and heights, and it is meteorologically quiet, then looking in the VTS archives it is possible to pick out the 4 tides from the tide-gauge readings, usually 0.1m in height and about half an hour in time. The worst disparity I've seen so far is 0.2m. VTS chooses the heightwise highest pair and UKHO chooses the timewise most-separated pair.
This was to be a project for a student at the NOC to explore this effect, but no idea if anyone ever did. Presumably a shallow water harmonic constant phase and/or amplitude has changed recently. My conjecture is that it started sometime during the construction of the Cowes breakwater ie after May 2014, but could easily be due to deeper dredging in Southampton Water for the largest container ships or even dredging Portsmouth Harbour for the new battleship.
It looks like for predicting Soton full day/double-cycle quadruple tides occur with tides in the mid-spring/neap range , ABP 4.0 to 4.5 (UKHO 3.9m to 4.4m) tide letters H to M , triple tides occur over a slightly wider range.
2x Quadruple (8 tides in 2 adjascent tide-cycles), from the 2 sets of tide tables occured on
29 Jan 2016 (my call to VTS) high tides range was between 4.1 and 4.3m .
09 Dec 2019 , nothing seen in VTS archive table
10 Dec,
2x 2HW only seen ,am only, because of VTS recording to 0.01m resolution, early by 20/25 minutes( but 5 minute VTS sampling)
20 Dec 2019
UKHO
HW HW LW HW HW LW
04:38 07:18 10:59 17:03 19:48 23:34
4.1 m 4.2 m 1.8 m 3.9 m 3.9 m 1.6 m
ABP
05:19, 06:43// 17:41, 19:07
2x 2HW pm only, seen early by 22 minutes and 43 min
19:07 ->18:45
19:48 -> 19:05
Looking at VTS archives for 23 Dec 2019
2 observable peaks were about 45 minutes early
10:23 - > 09:40
10:44 -> 10:00
evening
2 observable peaks about 20 minutes late
20:17 -> 20:40
20:57->21:20
Until full 8 tides per tidal-day return 29 Dec 2019 and hopefully meteorologically calm for a couple of days, looks a bit suspicious that random local wind or eddies around Dock Head or NTSLF type lumps and bumps of seiches would lead to such time-wise lead/lag tide time displacement pairings.
Not quadruple tides , but some undefined "high water" period rather than explicit pairs of high tides.
https://www.admiralty.co.uk/AdmiraltyDownloadMedia/easytide/Double%20high%20waters%20and%20high%20water%20stands.pdf
Obviously useful for port operations but not for flooding purposes as occurances are near enough at the time of peak predicted tide levels.
Interesting paper
It shows why the new sometimes-running Cowes chain ferry needs a bodged up bow-thruster on spring tide ebb flows of the Medina, presumably not required in its design brief with the earlier Cowes tide streams.
But whether p61 starting "The results ..." to p62 about a new eddy in the Solent 2014 , not present in 2005, could relate to Soton quad tides, is beyond my analysis ability.
Update March 2020, apparently the Admiralty from a file on their site , via blue-bbok and UKHO site although referring to high tides for Soton, they may in fact be referring to knees/breakpoints in the curve and not the highest points the tide-curve reach. I've not seen anywhere what value of dY/dt they use as the defining criterion and I use dY/dt=0 for defining High and Low waters in the tide tables I've been placing at the top of this page.
But it gives some sort of reason for the apparent quadruple tides business, even if it makes no sense .
NTSLF systemic error.
The following concerns the Pompey section of NTSLF surge predictor, other channel ports not checked so far, may still be a database read problem, that needs a long period of check or consulting NTSLF for weekly "archive" plots as I don't look at or save the combined residual reality and model plots.
Early 2018, I was delving into years of their archives to find an example of extended period of surge at Pompey rather than spikey surge.
It becomes obvious there are many month sections where reality is always higher than the predicted curve, perhaps 99% of the time as though there is a quasi-fixed negative vertical offset for extended periods of months. This is not obvious on the usual 2 day snatches of the 6 hourly outputs.
I suspect the NTSLF thing is internal to NTSLF, as it seems to be extended periods ,ie months, of no vertical displacement, then months of consistent <>0.1m dislacement.
On the archives of NTSLF step anomaly.
I've only checked 2015 , 2016 and march/april 2017 as end of year .
But i suspect a related to GMT/local-time problem as the transition step seems to occur a week or two after GMT->BST and then a week or two after BST->GMT change. Then perhaps due to the asymetric nature of tide plots it gradually feeds through to a full step shift or revert to no error.
Bubbler tide-gauge failure modes.
Lymington and Pompey about 0.3m HT residuals but VTS showed 1HW to be 4.42m for the 23:32 tide 13 Nov 2019, astronomic prediction of 4.6m ABP 1HW and 4.4m for 2HW. As the Priory Rd hard was swashed clean I'd say 1HW was about 4.86m and perhaps a very feint leaf-litter tide line at 4.6m for 2HW, checking the next day. No heavy rain since late evening yesterday to wash avay any traces.
Hopefully the VTS tide-gauge is broke, or very difficult to explain why only 4.42m on 13 Nov . This erroneous reading still in the archives but as a minor surge , no significance as to any record of surges, but does show how easy errors creep into the record.
Looks like the VTS was broken for 1 tide cycle
The EA Woolston gauge about 4.79m 1HW late 23 Nov
But next day , VTS
14/11/2019 11:30 04.6 140 05.8 03.5 993.3 4.83
14/11/2019 11:35 05.5 131 07.4 03.5 993.3 4.82
14/11/2019 11:40 04.7 121 05.0 03.4 993.3 4.81
14/11/2019 11:45 03.7 096 04.3 03.6 993.5 4.79
14/11/2019 11:50 07.4 096 09.2 03.6 993.5 4.77
14/11/2019 11:55 07.1 098 08.1 03.5 993.5 4.75
14/11/2019 12:00 06.1 099 08.1 03.5 993.5 4.72
at 11:50 the Priory Rd vernier tide gauge showed 4.75m , so VTS presumably correctly reading by then.
So reconstructing from ABP blue book, flood Q tide-curve, and using the residual on the Lymington tide gauge and ignoring the ebb overnight as still adrift then.
13 Nov approximately how much the VTS gauge was adrift, in hour steps after low water, except at low water and very little hydraulic pressure , the difference was consistent at about 0.5m as the tide curves are only quoted to +/-0.1m, Lymington not Soton residual etc.
16:50 -0.35m
17:50 - 0.59m
18:50 , -0.46m
19:50, -0.55m
20:50 , -0.42m
21:50 , -0.52m
22:50 , -0.45m
And 14 Nov
05:10 , -0.42m
06:10, -0.55m
07:10, -0.48
08:10, -0.43m
09:10, -0.14m
10:10, 0.0m
11:10, -0.13m
Average of the main sequence determinations, ie not LW and before purging, reading low by 0.49m. Best guess , VTS should have read about 4.91m 1HW and 4.76m 2HW rather than 4.42m and 4.27m. As all a bit iffy, for my log of my widgetting versus NTSLF surge predictor , see below, I'll use the Priory Rd hard vernier reading of 4.76m
I suspect the whole system was unpowered sometime between 10:50 and 16:20 and with no pump in action, seawater passed backwards through a silt compromised flap-valve on the bubbler output. About half a vertical metre in total of water and bubbles in the air pipe plus whatever in the horizontal section. Then the pipe was not purged with dehumidified compressed air or nitrogen
until the day shift next day at about 09:00.
End result very similar to the erroneous record introduced 26/27 November 1924,
completely different tide-gauges but both suffering a fixed or nearly fixed drop in readings.
Doesn't help with , for marine flooding purposes, the firmware failure mode, from an instrumentation engineer at the NOC .
Where a surge comes in at a higher rate than the maximum allowed flood tide rate,(to minimise turbulence in the delivery air pipe and readings jitter from that). When bubbling still has not returned after the period set by
the worst-case likely wave action, the firmware decides there must be a leak in the air pipe and stops outputting data until a manual reset,
rather than continuing to send the deemed erroneous output with some sort of flag attached to the recorder until a human checks/resets.
I'd have thought the firmware would ,say, double the air delivery rate for 10 minutes , outputting a flag and the inferred height which is probably affected by the higher air delivery rate , but probably assessable. Return to normal and repeat if no bubbles situation returns and after 10, say, such excursions , drop out beause likely to be due to an air leak.
Log of my widget predictions of any significant surge for Southampton, placed at the top of this file when imminent, compared to the NTSLF surge prediction for Pompey.
My predictions are independently logged , to avoid shamanism. The final widgetting , from the last GFS meteorology model isotach output, prior to any surge.
As no
NTSLF output for Soton, it seems the EA etc use the Pompey figure for Southampton, usually the residual is not much different, but certainly not the same.
The newspaper references here , used as part of the "soft-data" underlying this thesis by Ximena Boza, a printed copy held at the library of the National Oceanography Centre, Southampton, their reference 00665229 NOL,
Boza, X. (2018). The Reconstruction and Analysis of Historical Coastal Flood Events from 1800s in the Solent, UK. Southampton MSc Dissertation.
With 100 being the notional highest status, ie likelihood of a surge in the Solent area bracketed either side of that date by a week or two . Whether any more use than just ranking the months of the year for storm surges, or looking at 10 day in advance global meteorological models along with the neap-spring tide cycle, surges that come through around low-tide etc, we'll have to see.
Based on this paper , Julian Orford
"Storminess and surges in the South
Western Approaches of the eastern North
Atlantic: The synoptic climatology ... "
https://www.researchgate.net/profile/Conor_Graham/publication/253247101_Storminess_and_Surges_in_the_South-Western_Approaches_Eastern_Atlantic_the_Synoptic_Climatology_of_Recent_Extreme_Coastal_Storms/links/57975d4d08aec89db7b99f64/Storminess-and-Surges-in-the-South-Western-Approaches-Eastern-Atlantic-the-Synoptic-Climatology-of-Recent-Extreme-Coastal-Storms.pdf
and this image, from historic NOAA SST data
http://diverse.4mg.com/noaa99_08_13_14+scale_r.jpg
relating to previous surges.
Using the twice weekly updates (excluding weekends ,not outputted then) of SST anomalies and sampling the same
patches of North Atlantic sea areas as selected on that combined plot and then the same sample patches on the recent and previous month from
http://www.ospo.noaa.gov/data/sst/anomaly/, ala paper above, selecting patches ,about 160x160 miles, that gave the maximum correlation on 4 surge events.
Then applying a weighting (42%:35%:23% arbitrarily as not in that paper, only the ranking order) to each of the 3 pairs of sampling temperature anomalies for current west to east, previous month west to east (negative correlation ) and current north to south, for the 4 main surge events, covered in the NOAA SST archive) in the Solent area of ,26 Dec 1999,10 Mar 2008,03 Nov 2013, 14 Feb 2014. Giving the 2008 a value of 100, 1999 gave 82, 2014 gave 78 and 2013 gave only 26.
I see the big boys are also into this Newfoundland SST clairvoyance malarchy
http://www.bbc.co.uk/news/science-environment-42403000
Contact name Nigel Cook
A reserve email account is scicafsoton(commercial at)gmail.com
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'92
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