With this Earth-cache we are going to explore a bit deeper into the confluence of two rivers: The Indus and the Zanskar. 

In order to log it, you just have to send me the answers to some easy questions and tasks. It will be great if you could upload a picture of the location to see the differences of the spot throughout the year, and you don't need to wait for my approval to log it

ENJOY THE REGION

A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases, a river flows into the ground and becomes dry at the end of its course without reaching another body of water. Small rivers can be referred to using names such as a stream, creek, brook, rivulet, and rill. There are no official definitions for the generic term river as applied to geographic features, although in some countries or communities a stream is defined by its size.

Rivers are part of the hydrological cycle. Water generally collects in a river from precipitation through a drainage basin from surface runoff and other sources such as groundwater recharge, springs, and the release of stored water in natural ice and snowpacks (e.g. from glaciers).

Rivers are a great force of erosion in our planet: River waters processes shape the land in different ways as the river moves from its source to its mouth. Erosion involves the wearing away of rock and soil found along the river bed and banks. Erosion also involves the breaking down of the rock particles being carried downstream by the river. This are the four main forms of river erosion:

• Hydraulic action - the force of the river against the banks can cause air to be trapped in cracks and crevices. The pressure weakens the banks and gradually wears it away.
• Abrasion - rocks carried along by the river wear down the river bed and banks.
• Attrition - rocks being carried by the river smash together and break into smaller, smoother and rounder particles.
• Solution - soluble particles are dissolved into the river.

The chemistry of rivers is complex and depends on inputs from the atmosphere, the geology through which it travels and the inputs from man's activities. Depending on the origin (spring) and locations that the river flows, it could carry on suspension many different minerals and materials that could affect in the density of the waters.

In geography, a confluence is the meeting of two or more bodies of water. Also known as a conflux, it refers either to the point where a tributary joins a larger river (main Stem), or where two streams meet to become the source of a river of a new name.

In hydrology, a main stem is the primary downstream segment of a river, as contrasted to its tributaries. Another common term for the main stem, the final large channel of a riverine system, is the trunk. A tributary or affluent is a stream or river that flows into a larger stream or main stem (or parent) river or a lake. A tributary does not flow directly into a sea or ocean. 

THE INDUS AND ZANSKAR RIVERS

The Indus River, also called Sindhū (सिंधु) or Abāsīn, is a major south-flowing river in South Asia. The total length of the river is 3,610km (1988.38 miles) which makes it one of the longest rivers in Asia. Originating in the western part of Tibet in the vicinity of Mount Kailash and Lake Manasarovar, the river runs a course through Ladakh, Gilgit-Baltistan, and Khyber Pakhtynkhwa, and then flows along the entire length of Punjab to merge into the Arabian Sea near the city of Thatta in Sindh. It is the longest river of Pakistan.

The Zanskar River is a north-flowing tributary of the Indus. In its upper reaches, the Zanskar has two main branches. First of these, the Doda, has its source near the Pensi-La 4,400 m (14,400 ft) mountain-pass and flows south-eastwards along the main Zanskar valley leading towards Padum, the capital of Zanskar. The second branch is formed by two main tributaries known as Kargyag river, with its source near the Shingo La 5,091 m (16,703 ft), and Tsarap river, with its source near the Baralacha-La. These two rivers unite below the village of Purne to form the Lungnak river (also known as the Lingti or Tsarap). The Lungnak river then flows north-westwards along a narrow gorge towards Zanskar's central valley (known locally as gzhung khor), where it unites with the Doda river to form the main Zanskar river. This river then takes a north-eastern course through the dramatic Zanskar Gorge until it joins the Indus near Nimmu in Ladakh. 

Depending on the time of the year, the confluence of both rivers look quite diferent. Here you can see some pictures of the site:

QUESTIONS TO LOG THIS EARTHCACHE

1. What are the colors of the two rivers? Why do you think it could be the reason for that coloring?

2. Are the waters of the two rivers mixing right away at the confluence, or are the two streams flowing independently for a while before the mix? How many meters are they flowing as two different streams? Why do you think this is?

3. Taking in mind the name of the river after the confluence: Which river is the main Stem and which one is a tributary?

4. Take a look at the two valleys where the rivers are flowing: What force do you think created them? A glacier or a river?