Tidal flooding in Chiswick
 

According to http://en.wikipedia.org/wiki/River_Thames,

"One such example exists at Chiswick Lane South in London's W4 postal
district, where the river now bursts its banks almost daily between March
and September".

Why would tidal flooding be dependent on the time of year?

Tidal flooding in Chiswick
 

John Rowland wrote:

According to http://en.wikipedia.org/wiki/River_Thames,

"One such example exists at Chiswick Lane South in London's W4 postal
district, where the river now bursts its banks almost daily between March
and September".

Why would tidal flooding be dependent on the time of year?

Something to do with the phases of the sun & moon leading to higher
tides
in that period maybe? If it were due to higher rainfall or winds
driving the sea
inland you'd expect it to happen more in winter.

B2003

Tidal flooding in Chiswick
 

Boltar wrote:
John Rowland wrote:

According to http://en.wikipedia.org/wiki/River_Thames,

"One such example exists at Chiswick Lane South in London's W4 postal
district, where the river now bursts its banks almost daily between March
and September".

Why would tidal flooding be dependent on the time of year?

Something to do with the phases of the sun & moon leading to higher
tides
in that period maybe? If it were due to higher rainfall or winds
driving the sea
inland you'd expect it to happen more in winter.

B2003

The spring tides are higher in March and October - but in between I
suppose it must be due to higher flows down the Thames.

Tidal flooding in Chiswick
 

Tidal flooding in Chiswick
 

"John Rowland" wrote in message
...
wrote:

The spring tides are higher in March and October -

Why?


Could it be because that's the period between the Vernal and Autumnal
Equinox (give or take) in the northern hemisphere when the sun is higher in
the sky?

Tidal flooding in Chiswick
 

John Rowland wrote:
wrote:
The spring tides are higher in March and October -

Why?

The declination of the Sun to the Earth's equator is near minimum at
those times (equinoxes) and is a factor which influences the tides.

http://oceanservice.noaa.gov/educati...s01_intro.html

ESB

Tidal flooding in Chiswick
 

John Rowland wrote:
wrote:

The spring tides are higher in March and October -

Why?

equinoxes - ie sun and moon pulling together instead of in opposite
directions.

Tidal flooding in Chiswick
 

On 9 Nov 2006 11:04:38 -0800, wrote:
but in between I
suppose it must be due to higher flows down the Thames.

The differance between summer and winter is quite significant, but the
quote was "now bursts its banks almost daily between March and September"
eg not in winter, maybe the quote just has the period the wrong way round.

Checking the tide tables for london bridge shows no real difference between
the months, excluding the equinox periods. Having a better search found
this[1]

"The closure of the Thames Barrier can be a response not only to tidal
surges but also to heavy rainfall. In the unusual winter of 2000/01 there
were, as was stated above, 24 Barrier closures, as opposed to the usual
three or so, largely in response to the extremely heavy rainfall on the
Thames and its tributaries. We were told that ¡§The volume of tidal water
kept out of London by the Thames Barrier ¡V when closed ¡V is some ten to
twenty times the amount of river water flowing the other way, even after
very heavy rainfall. As a result, closing the gates at low water and
holding out the tide can create a useful ¡¥reservoir¡¦ behind the gates ¡V
into which the rain-swollen river can flow. If the Barrier remains open in
such circumstances, the river would effectively be ¡¥pushed back¡¦ by the
incoming tide. This makes it much more likely that floodwater would be
forced to spill out over the riverbanks in vulnerable areas of West London
such as Hammersmith, Chiswick and Richmond¡¨. It is expected that
low-lying areas and towpaths will be under floodwaters more frequently. "

So it seems that quote must be backwards

Steve

[1]From http://www.london.gov.uk/assembly/re...t/flooding.rtf

Tidal flooding in Chiswick
 

Steve wrote:
On 9 Nov 2006 11:04:38 -0800, wrote:
but in between I
suppose it must be due to higher flows down the Thames.

Steve, for some reason I'm told that your post requires me to install the
Chinese Traditional language pack to display it correctly. Something odd
about the encoding you've used?

The differance between summer and winter is quite significant, but
the quote was "now bursts its banks almost daily between March and
September" eg not in winter, maybe the quote just has the period the
wrong way round.

I think the quote is just wrong. The road is particularly low at this point
as there is a draw dock there (a slope down to the river to enable boats to
be launched), but I doubt very much if it's flooded often in the week or so
centred on the neap tides (roughly at the quarter phases of the Moon).

Checking the tide tables for london bridge shows no real difference
between the months, excluding the equinox periods. Having a better
search found this[1]

"The closure of the Thames Barrier can be a response not only to tidal
surges but also to heavy rainfall. In the unusual winter of 2000/01
there were, as was stated above, 24 Barrier closures, as opposed to
the usual three or so, largely in response to the extremely heavy
rainfall on the Thames and its tributaries.

The PDF version of that report[2] has a photo on the cover of flooding in
Chiswick Mall. The Environment Agency's comment is worth repeating he

"Flooding is a relatively common occurrence at this location on high spring
tides as the flood defences here are set behind the road, which local
residents will be aware of. Essentially this is tidal inundation within the
flood defences. It is a good example of how people need to live with the
natural tides and be aware of where the flood defence line is." The
Wikipedia author perhaps didn't have that understanding.

[1]From
http://www.london.gov.uk/assembly/re...t/flooding.rtf

[2] PDF version at
http://www.london.gov.uk/assembly/re...t/flooding.pdf

--
Richard J.
(to email me, swap 'uk' and 'yon' in address)

Tidal flooding in Chiswick
 

On Fri, 10 Nov 2006 21:58:38 GMT, Richard J.
wrote in :
Steve wrote:
On 9 Nov 2006 11:04:38 -0800, wrote:
[snip 8]
Steve, for some reason I'm told that your post requires me to install the
Chinese Traditional language pack to display it correctly. Something odd
about the encoding you've used?

===
Content-Type: text/plain; charset="big5"
Content-Transfer-Encoding: 8bit
===

--
Ivan Reid, Electronic & Computer Engineering, ___ CMS Collaboration,
Brunel University. ] Room 40-1-B12, CERN
KotPT -- "for stupidity above and beyond the call of duty".

Tidal flooding in Chiswick
 

On Fri, 10 Nov 2006 21:58:38 GMT, Richard J. wrote:

Steve wrote:
[3 quoted lines suppressed]

Steve, for some reason I'm told that your post requires me to install the
Chinese Traditional language pack to display it correctly. Something odd
about the encoding you've used?

The quote messed with the charset, the rtf version displayed in very odd
fonts.

I think the quote is just wrong. The road is particularly low at this point
as there is a draw dock there (a slope down to the river to enable boats to
be launched), but I doubt very much if it's flooded often in the week or so
centred on the neap tides (roughly at the quarter phases of the Moon).

Does it flood over, or out of the drains? I'm not familiar with the north
side. The two areas I've seen flood loads of times, at richmond front and
the Brewary Tap in brentford (oops trapped in the pub again!), they both
flood out of the drains a long time before the water comes over the bank.
Of course they always flood at high neap tides, unless the barrier is
raised.

Steve

Tidal flooding in Chiswick
 

Steve wrote:
On Fri, 10 Nov 2006 21:58:38 GMT, Richard J. wrote:

I think the quote is just wrong. The road is particularly low at
this point as there is a draw dock there (a slope down to the river
to enable boats to be launched), but I doubt very much if it's
flooded often in the week or so centred on the neap tides (roughly
at the quarter phases of the Moon).

Does it flood over, or out of the drains? I'm not familiar with the
north side. The two areas I've seen flood loads of times, at
richmond front and the Brewary Tap in brentford (oops trapped in the
pub again!), they both flood out of the drains a long time before the
water comes over the bank.

On Chiswick Mall, the flood comes straight in from the river, flowing along
the road from the lowest point. The Brewery Tap at Brentford is actually on
the River Brent. Isn't it upstream of Thames Lock? If so, that may explain
why the drains provide the flood route.

Of course they always flood at high neap tides, unless the barrier is
raised.

You mean spring tides, I assume.

--
Richard J.
(to email me, swap 'uk' and 'yon' in address)

Tidal flooding in Chiswick
 

On Sat, 11 Nov 2006 20:52:42 GMT, Richard J. wrote:

Steve wrote:
[12 quoted lines suppressed]

On Chiswick Mall, the flood comes straight in from the river, flowing along
the road from the lowest point. The Brewery Tap at Brentford is actually on
the River Brent. Isn't it upstream of Thames Lock?

It is, but the section behind the lock up to the main brentford lock N of
the high street is partly tidal, which in this case I guess just means
keeps water in but doesn't keep it out.


[2 quoted lines suppressed]

You mean spring tides, I assume.

yep :)

(watching news)Bugger goddards pie and mash has closed!

Steve

Tidal flooding in Chiswick
 

On Sun, 12 Nov 2006 19:56:33 GMT, Steve
wrote:

On Sat, 11 Nov 2006 20:52:42 GMT, Richard J. wrote:

Steve wrote:
[12 quoted lines suppressed]

On Chiswick Mall, the flood comes straight in from the river, flowing along
the road from the lowest point. The Brewery Tap at Brentford is actually on
the River Brent. Isn't it upstream of Thames Lock?

It is, but the section behind the lock up to the main brentford lock N of
the high street is partly tidal, which in this case I guess just means
keeps water in but doesn't keep it out.


[2 quoted lines suppressed]

You mean spring tides, I assume.

yep :)

(watching news)Bugger goddards pie and mash has closed!

Steve

That would explain why yesterday (Saturday) there was a queue of maybe
20/30 outside the shop even at 14:30.

Regards
JonH

Tidal flooding in Chiswick
 

On Sun, 12 Nov 2006 20:49:15 GMT, wrote:

On Sun, 12 Nov 2006 19:56:33 GMT, Steve
wrote:

On Sat, 11 Nov 2006 20:52:42 GMT, Richard J. wrote:

Steve wrote:
[12 quoted lines suppressed]

On Chiswick Mall, the flood comes straight in from the river, flowing along
the road from the lowest point. The Brewery Tap at Brentford is actually on
the River Brent. Isn't it upstream of Thames Lock?

It is, but the section behind the lock up to the main brentford lock N of
the high street is partly tidal, which in this case I guess just means
keeps water in but doesn't keep it out.


[2 quoted lines suppressed]

You mean spring tides, I assume.

yep :)

(watching news)Bugger goddards pie and mash has closed!

Steve

That would explain why yesterday (Saturday) there was a queue of maybe
20/30 outside the shop even at 14:30.

Regards
JonH

p.s.

AND the Teddy Bear shop on the other side of the market has closed.

(Grumble)
JonH