In message , at 12:49:39 on
Wed, 6 Jan 2016, remarked:

No, it also depends on things like the width of the river and whether
there's enough time for the tidal waters to get that far upstream before
the tide turns.

The rivers in some parts of Sussex are tidal further inland to a
greater extent than some people may realise. This encouraged
connecting Waterways in the area. at one time Petworth, Midhurst and
London could be reached by water,The latter route is better known
especially since two wine drinking thespians featured it recently
between crashing thier boat but Petworth,and Midhurst and some minor
places near them seem unlikely places to reach by boat now.

There's no dispute that Cambridge, 40 miles inland[1], could be reached
by sea-going craft; but that doesn't mean it's tidal.

Where I live, about 30 miles inland on the Great Ouse (which leads
upstream to the Cam), there are numerous broad-beam boats which have
clearly crossed the North Sea to get here.
--
Roland Perry

Roland Perry wrote:
In message , at 12:49:39 on
Wed, 6 Jan 2016, remarked:

No, it also depends on things like the width of the river and whether
there's enough time for the tidal waters to get that far upstream before
the tide turns.

The rivers in some parts of Sussex are tidal further inland to a
greater extent than some people may realise. This encouraged
connecting Waterways in the area. at one time Petworth, Midhurst and
London could be reached by water,The latter route is better known
especially since two wine drinking thespians featured it recently
between crashing thier boat but Petworth,and Midhurst and some minor
places near them seem unlikely places to reach by boat now.

There's no dispute that Cambridge, 40 miles inland[1], could be reached
by sea-going craft; but that doesn't mean it's tidal.

Where I live, about 30 miles inland on the Great Ouse (which leads
upstream to the Cam), there are numerous broad-beam boats which have
clearly crossed the North Sea to get here.

There are plenty of rivers that are accessible by seagoing craft a long way
above their tidal limits. The Rhine, for example, is navigable by ships
capable of coastal navigation as far up as Basel, which is nearly 250 m
above sea level and definitely not tidal.

Robin

In message

, at 18:26:56 on Wed, 6 Jan 2016, bob remarked:
No, it also depends on things like the width of the river and whether
there's enough time for the tidal waters to get that far upstream before
the tide turns.

The rivers in some parts of Sussex are tidal further inland to a
greater extent than some people may realise. This encouraged
connecting Waterways in the area. at one time Petworth, Midhurst and
London could be reached by water,The latter route is better known
especially since two wine drinking thespians featured it recently
between crashing thier boat but Petworth,and Midhurst and some minor
places near them seem unlikely places to reach by boat now.

There's no dispute that Cambridge, 40 miles inland[1], could be reached
by sea-going craft; but that doesn't mean it's tidal.

Where I live, about 30 miles inland on the Great Ouse (which leads
upstream to the Cam), there are numerous broad-beam boats which have
clearly crossed the North Sea to get here.

There are plenty of rivers that are accessible by seagoing craft a long way
above their tidal limits. The Rhine, for example, is navigable by ships
capable of coastal navigation as far up as Basel, which is nearly 250 m
above sea level and definitely not tidal.

That's right. Exactly the point I was making.
--
Roland Perry

In message , Michael R N Dolbear
wrote:
Eh? We have no freight traffic to speak of on the Cam.
Was there ever ?

My understanding is that Quayside was originally a Viking port, so very
probably.

--
Clive D.W. Feather | Home:
Mobile: +44 7973 377646 | Web: http://www.davros.org
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In message , Roland Perry
wrote:
And was the Cam ever tidal, say in Newton's time, at Cambridge ?
It's an awfully long way from the sea, so no.

Irrelevant.

The Great Ouse is tidal up to Brownshill Staunch, about 4 km upstream of
Earith. Though curiously (to the uninitiated) it's non-tidal downstream
of Earith.

--
Clive D.W. Feather | Home:
Mobile: +44 7973 377646 | Web: http://www.davros.org
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In message , at 22:28:39 on Wed, 6
Jan 2016, Clive D. W. Feather remarked:

And was the Cam ever tidal, say in Newton's time, at Cambridge ?
It's an awfully long way from the sea, so no.

Irrelevant.

It is relevant because tidal effects require large amounts of water to
move twice a day, and the further they have to go the less likely it is
to happen.

Although as Denver Sluice predates Newton, that's probably a simpler
answer to the specific question asked.

The Great Ouse is tidal up to Brownshill Staunch, about 4 km upstream
of Earith. Though curiously (to the uninitiated) it's non-tidal
downstream of Earith.

That'll be Hermitage Lock, hiding in plain sight:

https://goo.gl/maps/YKR6xFHVrYq

....for the Great Ouse via Ely. The Environment Agency deems that the
Bedford Rivers are also part of the Great Ouse though, so that bit of
the downstream will be tidal. But it's very hard to see any tidal
component to the levels recorded here, which is about halfway to the sea
from Earith:

http://apps.environment-agency.gov.u...s/120730.aspx?
stationId=6245

As opposed to the next measuring point north of the

http://apps.environment-agency.gov.u...s/120731.aspx?
stationId=6290
--
Roland Perry

In message , at 06:14:30 on Thu, 7 Jan
2016, Roland Perry remarked:
The Great Ouse is tidal up to Brownshill Staunch, about 4 km upstream
of Earith. Though curiously (to the uninitiated) it's non-tidal
downstream of Earith.

That'll be Hermitage Lock, hiding in plain sight:

https://goo.gl/maps/YKR6xFHVrYq

...for the Great Ouse via Ely. The Environment Agency deems that the
Bedford Rivers are also part of the Great Ouse though, so that bit of
the downstream will be tidal. But it's very hard to see any tidal
component to the levels recorded here, which is about halfway to the sea
from Earith:

http://apps.environment-agency.gov.uk/river-and-sea-levels/120730.aspx?stationId=6245

As opposed to the next measuring point north of the

http://apps.environment-agency.gov.uk/river-and-sea-levels/120731.aspx?stationId=6290

I wonder if there's a finesse in the expression "tidal", which means "up
to the first lock", rather than "the part of a river whose level is
affected by the tides".
--
Roland Perry

Roland Perry wrote on 07 Jan 2016 at 11:02 ...
In message , at 06:14:30 on Thu, 7 Jan
2016, Roland Perry remarked:
The Great Ouse is tidal up to Brownshill Staunch, about 4 km upstream
of Earith. Though curiously (to the uninitiated) it's non-tidal
downstream of Earith.

That'll be Hermitage Lock, hiding in plain sight:

https://goo.gl/maps/YKR6xFHVrYq

...for the Great Ouse via Ely. The Environment Agency deems that the
Bedford Rivers are also part of the Great Ouse though, so that bit of
the downstream will be tidal. But it's very hard to see any tidal
component to the levels recorded here, which is about halfway to the sea
from Earith:

http://apps.environment-agency.gov.uk/river-and-sea-levels/120730.aspx?stationId=6245

As opposed to the next measuring point north of the

http://apps.environment-agency.gov.uk/river-and-sea-levels/120731.aspx?stationId=6290

I wonder if there's a finesse in the expression "tidal", which means "up
to the first lock", rather than "the part of a river whose level is
affected by the tides".

The Thames is generally held to be tidal as far as Teddington Lock, but
sometimes the high tide manages to go further, and the flow gauge at
Kingston (upstream of Teddington) gives negative readings.

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

In message , Roland Perry
wrote:
I wonder if there's a finesse in the expression "tidal", which means
"up to the first lock", rather than "the part of a river whose level is
affected by the tides".

Don't know.

The OS 1:50,000 maps show the Great Ouse as tidal from the sea to
Denver, then non-tidal to Earith, then tidal to Brownhill. The New
Bedford is shown as tidal throughout; the Old Bedford and Delph as
non-tidal throughout. The boundaries are all things like sluices.

--
Clive D.W. Feather | Home:
Mobile: +44 7973 377646 | Web: http://www.davros.org
Please reply to the Reply-To address, which is:

In message , at 11:40:10 on Thu, 7
Jan 2016, Richard J. remarked:
I wonder if there's a finesse in the expression "tidal", which means "up
to the first lock", rather than "the part of a river whose level is
affected by the tides".

The Thames is generally held to be tidal as far as Teddington Lock, but
sometimes the high tide manages to go further, and the flow gauge at
Kingston (upstream of Teddington) gives negative readings.

Do they leave both sets of lock gates open?
--
Roland Perry