How Good Is Your Geographic? [5]

[Rollo]

Where does a river finish and the sea begin? Taking a well-known example, does the Thames end at Gravesend or Southend? There must be some sort of geographers' agreement.

Southend - or to be precise Shoeburyness; which sounds to me like an adjective.

A river ends at the imaginary line where it meets the sea. In the case of the Amazon, that line is more than 300km across.

[D-Type]

Yes, but ......
.........what are the criteria for drawing that imaginary line?

I'm not trying to pick an argument. I'm genuinely curious to know how 'they' - whoever they are - set the rules/criteria. Sometimes you can easily draw an imaginary line continuing the general run of the coast but sometimes it isn't so easy where the river has a funnel-shaped mouth that gradually transitions. To flog this dead horse into a heap of dog food cans: why Shoebury Ness and not Foulness Point - Shell Ness, which also looks good on the map? Is salinity level a criterion?

[anfield5]

The Onyx in Antarctica is (depending on the time of year) between 5 and 20 miles long

[Rollo]

Yes, but ......
.........what are the criteria for drawing that imaginary line?

I'm not trying to pick an argument. I'm genuinely curious to know how 'they' - whoever they are - set the rules/criteria. Sometimes you can easily draw an imaginary line continuing the general run of the coast but sometimes it isn't so easy where the river has a funnel-shaped mouth that gradually transitions. To flog this dead horse into a heap of dog food cans: why Shoebury Ness and not Foulness Point - Shell Ness, which also looks good on the map? Is salinity level a criterion?

I love this question.

They wouldn't let me take a book out of the reference section of the library; so I had to copy it.

A river mouth ends, where there is a free connection with the open sea; where the flow derived from land drainage measurably dilutes sea water.
- International Geographical Union, Field Handbook (2004).

Like IUPAC, the IGU's website is mostly rubbish: http://igu-online.org/

I suspect that the definition is pretty loose though. Water from the Amazon is still detectable as being from the Amazon, many hundreds of miles away in the Atlantic.

[janvanvurpa]

Yes, but ......
.........what are the criteria for drawing that imaginary line?

I'm not trying to pick an argument. I'm genuinely curious to know how 'they' - whoever they are - set the rules/criteria. Sometimes you can easily draw an imaginary line continuing the general run of the coast but sometimes it isn't so easy where the river has a funnel-shaped mouth that gradually transitions. To flog this dead horse into a heap of dog food cans: why Shoebury Ness and not Foulness Point - Shell Ness, which also looks good on the map? Is salinity level a criterion?

That salinity cannot be too big a factor---the 2 places I have lived longest, Seattle in the pacific North West on Puget Sound and Stockholm in Sweden are both on bodies of water of very low salinity due to the enormous amount of fresh water pouring in...

I wondered about tidal influence but depending on how much tide action that can go miles and miles upstream---around here it is often many many feet---15-30 feet miles from river "mouth"..

Little half question while you guys hammer out what maybe can't be answered.
What is the meaning of the common "ness" in all those names?...
What are the French and general Nordic cognates of ness?

Bonus points for other meanings of "ness"...

[Storm]

Maybe it's a type of cape - but inside a bay/estuary rather than the open sea?

[D-Type]

My dictionary says a headland. from Old English or Old Norse. Related to nose.

But we're all dodging Rollo's shortest river question. I can't answer as I looked it up.

[anfield5]

Onyx haven't been told no yet to this answer from Monday

[Rollo]

Onyx haven't been told no yet to this answer from Monday

No.

At 20 miles, it's not even close.

[Grundo Farb]

I had no idea and looked it up as well. You will either know it instantly or not.