In geography, a confluence is the meeting of two or more bodies of water. Known also as a conflux, it refers either to the point where a tributary joins a larger river, called the main stem, or where two streams meet to become the source of a river of a new name, such as the confluence of the Monongahela and Allegheny Rivers in Pittsburgh, Pennsylvania creating the Ohio River.
The term is also used to describe the meeting of tidal or other non-riverine bodies of water, such as two canals or a canal and a lake. Below is a collection of 10 incredible confluences around the world. For more, there is a fascinating list of notable confluences on Wikipedia that I recommend you check out.
In this incredible photograph we see the confluence of the Rhone and Arve rivers in Geneva, Switzerland. The river on the left is the Rhone, which is just exiting Lake Lehman. The river on the right is the Arve, which receives water from the many glaciers of the Chamonix valley (mainly the Mer de Glace) before flowing north-west into the Rhone on the west side of Geneva, where its much higher level of silt brings forth a striking contrast between the two rivers. [Source]
The Ilz is a relatively small mountain stream and has a blue-ish color while the Inn is a fairly large river flowing in from Salzburg, Austria at the top. The Inn River has more water flow than the Danube, yet flowing away from the city the three combined rivers are called Danube.
This photo is taken from the Oberhaus-fortress (now a city museum) on top of the Ilzstadt cliff above the city of Passau in Lower Bavaria, Germany. It is also known as the Dreiflüssestadt or “City of Three Rivers”.
The Ohio River becomes a tributary of the Mississippi River directly south of Cairo, Illinois, a small city on the spit of land where the rivers converge (at center of this astronaut photograph). Brown, sediment-laden water flowing generally northeast to south from the Ohio River is distinct from the green and relatively sediment-poor water of the Mississippi River (flowing northwest to south).
The color of the rivers in this image is reversed from the usual condition of a green Ohio and a brown Mississippi. This suggests that the very high rainfall in December 2005 over the Appalachians and the northeastern United States has led to greater-than-normal amounts of sediment in the rivers and streams of the Ohio River watershed. The distinct boundary between the two river’s waters indicates that little to no mixing occurs even 5-6 kilometers (3-4 miles) downstream. [Source]
Jialing River on the right stretches 119 kilometers. In the city of Chongqing it falls into Yangtze River. The clean water of Jialing River meets the brownish yellow water of Yangtze River. The Yangtze becomes more powerful after it absorbs the water of Jialing as it continues its path, passing through the Three Gorges and stretching thousands of miles.
The Meeting of Waters is the confluence between the Rio Negro, a river with dark (almost black coloured) water, and the sandy-coloured Amazon River or Rio Solimões, as it is known the upper section of the Amazon in Brazil. For 6 km (3.7 mi) the river’s waters run side by side without mixing. It is one of the main tourist attractions of Manaus, Brazil.
This phenomenon is due to the differences in temperature, speed and water density of the two rivers. The Rio Negro flows at near 2 km per hour at a temperature of 28°C, while the Rio Solimões flows between 4 to 6 km per hour a temperature of 22°C. [Source]
The Green River is a very long stream forming in the Wind River Range of the Rocky Mountains in Bridger Teton National Forest of Sublette County, Wyoming. It winds its way south into Utah, turning east into Colorado and finally back south down into Utah where it terminates at the confluence of the Colorado River in Canyonlands National Park in San Juan County. [Source]
The Thompson River ends here in Lytton, British Columbia, Canada where it meets the Fraser River. The contrast is striking as the clear Thompson River water joins with the muddy Fraser.
Devprayag is a town and a nagar panchayat (municipality) in Tehri Garhwal district in the state of Uttarakhand, India. It is one of the Panch Prayag (five confluences) of Alaknanda River and it is where the Ganges River is formed. The Alaknanda rises at the confluence and feet of the Satopanth and Bhagirath Kharak glaciers in Uttarakhand.
The headwaters of the Bhagirathi are formed at Gaumukh, at the foot of the Gangotri glacier and Khatling glaciers in the Garhwal Himalaya. These two sacred rivers join to form the Ganges (Ganga) in Devprayag. [Source]
In the German city of Koblenz, the Mosel flows into the Rhine river. The Name “Koblenz” itself has its origin in the latin name “Confluentes”. [Source]
Located on the right bank of the river Drava 25 km upstream of its confluence with the Danube is the city of Osijek, Croatia. [Source]