Rivers Part 2: Confluence!

What with my hometown being in Pittsburgh, I actually can say that I live near one of Wikipedia's 'Notable confluences" - hooray! - the merging of the Allegheny and the Monongahela. However, this meeting point, as much as I am fond of it, is not the most visually stunning, and so let me show you the confluence at Manaus in Brazil, where the 'wedding of the waters' is truly stunning.

So this satellite image shows the city of Manaus as the white blob to the north of the Rio Negro (black because of the tannins dissolved in the water) and the confluence where the Negro merges with the brown, silty Solimoes to form the Amazonas. 

A closer photo shows the stark contrast between the two rivers.

What I find particularly interesting is that the sharp boundary between the two rivers' waters is maintained for nearly four miles.  This is due to a difference in temperature and speed - the warmer Negro flows at around 1mph, while the Solimoes, ten degrees cooler, flows 2-3 times faster.

Anyway, the scientist in me is drawn to the dichotomy (noted, again, by Wikipedia) between a confluence and its opposite, a watershed.  But I've probably bored you enough with numbers and definitions, and the tourist in me wants to point out some other interesting confluences for you to google, if you are so inclined.

I've been to the confluence of the Rhone and Saone in Lyon, France, where the rivers weren't so much the focus but the boundaries of an urban development project...still, historical and lovely.  Some other aquatic meeting points that seem to me worth visiting for their historic worth and natural beauty include: the confluence of the Tigris and the Euphrates (the cradle of civilization...in modern-day Iraq.  Perhaps I might wait a bit for that one), the confluence of the Drava and the Danube, near the city Osijek in Croatia (represent!), and the confluence of the Ganga, Yamuna, and Saraswati at the Triveni Sangam in India (very sacred, very historical - this is where Gandhi's ashes were immersed).  There are many others out there, though - I'll have to rent a little houseboat at some point to check them all out.