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?

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

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.

wrote:

The spring tides are higher in March and October -

Why?

"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?

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

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.

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

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)

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
===

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Brunel University. ] Room 40-1-B12, CERN
KotPT -- "for stupidity above and beyond the call of duty".