Indus Valley Civilization

Harappan Civilization
(The Huffington Post, 2014)

Cast your mind back to one of the earliest human settlements in what is Pakistan and North-West India today, the Indus Valley.

This civilisation, which is also known as the Harappan Civilization, is one of the most mysterious as archaeologists still haven't been able to decipher what is thought to be their language. At the peak of its population, the Indus Valley had influence over a larger area of land than either Egypt or Mesopotamia did (Khan, 2014). They were known for their advanced sanitation and waterways systems. They had the advantage of a readily accessible water source as the Indus River is ~3000km in length. The civilisation was situated on the adjacent floodplain. Farming settlements started around 4000 BC but religious practices are dated back around as early as 5500BC! It wasn't until 2600 B.C. to 1700 B.C. that major cities and started appearing in the vicinity of the Indus River (Ancient India, 13/09/16). There have been up to 1,052 cities uncovered in the Indus Valley area with the main cities including; Harappa, Ganeriwala and Mohenjo-Daro in modern-day Pakistan, and Dholavira, Kalibangan, Rakhigarhi, Rupar, and Lothal in modern-day India (Boundless, 2016). The villages included brick and stone buildings with drainage systems, wells and storage systems throughout. This was insightful as the annual rainfall for this region was low at an estimated 15-125mm at the time (Cowan, 2014). Therefore they had to make use of the rivers in the surrounding area to supply their ever growing populations. 

Geology Of The Area

The Indus river was most likely influenced by the collision between the Indian Plate with the Eurasian Plate. This was caused by the Indian Plate breaking away from the continent of Gondwana around 100 million years ago. This set it on a journey North towards Asia causing it to collide with the Eurasian plate about 50 million years ago. The collision caused the Indian plate to subduct under the Eurasian plate which was subjected to compressional deformation. The result was the start of the Alpine orogeny that ultimately formed the Himalayans. All three main types of rock were formed; metamorphic due to the subduction and deformation processes, igneous due to the volcanic activity associated with plate motion and sedimentary due to the continuous uplift and erosional processes. After this came a period of multiple uplift and erosional processes which helped to create the plains. Before all this, there was a formation of a volcanic arc which changed the topography of the Indus Valley radically, but for the purpose of the civilisation, the geology of the formation of the river and plains is more relevant.
The Indus River is sourced from the seasonal drainage of an elevated upper basin that lies across  Tibet, the Himalayas, and the Karakoram (Inam, 2007). This is shown in figure 2, which is a google earth image with a very crude labelling done by myself of the approximation of where everything is in relation to each other. The Indus River also gathers sediment and water from a number of other small intersecting rivers. There is evidence of the Indus River periodically changes course as it slowly moves eastward throughout the centuries (Ancient origins, 2013). Due to many glaciers in the area, the peak flow of the river occurs throughout the monsoon season. The timing and length of the monsoons are affected by the glacial melt intensity. A weakening of the monsoons and thus a decrease of water flow in the Indus River could have assisted the demise of the Indus Valley metropolis.

Google Image of the Indus Valley area and where the basins are located in relation to the civilisation locality. Picture produced by Abbey Douglas

How The Hydrosphere Was Influenced

The citizens of the Indus Valley used the water sourced from the basins behind the Himalayans, coming down the river to provide water resources to their people. This water was then distributed into wells throughout the cities that the people would walk to, to collect. Most towns in the Indus Valley had some form of toilets, either personal or public, that would carry the waste away from their houses. Some of these examples of how different cities used their water supplies are listed below.

Indus Valley Demise 

The ancient city of Mohenjo-Daroc was first discovered in 1920 in Pakistan (Ancient origins, 2013). It was the first Indus valley city to be found and uncovered. It was first thought that the downfall of this city in around 2000BC was due to hostile invaders, as there were skeletal remains found throughout the city. With further investigation, major evidence of flooding has been found such as the large quantities of silt and clay layers found throughout the city (Ancient origins, 2013). This could have caused a mass breakout of disease and ultimately the downfall of this city. 
But it is probable that the downfall of the Indus Valley was a result of many unfortunate circumstances. For example, scholars have found evidence that before abandonment there was overcrowding in the cities with houses being built on top of other houses, important buildings such as the Great Bath at Mohenjo Daro was also built over. People stopped maintaining infrastructures such as drains. Some traders were even hiding valuables under their floors (Bitesize, 2016). This makes you wonder, what were they so scared of?

Here are a few theories: war although this has mostly been disproved, trade collapse, or a change of river course. It is possible that it could have been more than one factor. The theory that I believe either caused abandonment or at least helped towards the end result, is climate change. Around 1500-1100 BCE there was a major climatic change event termed the Bond event that destroyed Bronze age civilisations across the world (Viswanathan, 2015). Bond events are North Atlantic climate fluctuations occurring every ≈1,470 ± 500 years throughout the Holocene that is loosely linked to climate change (The chronical of the fall, 2016). 

Another idea is that the monsoon cycle essentially stopped for as long as two centuries (Scientific American, 2014). If you can remember from previous paragraphs, the monsoon cycles are what feeds the Indus River therefore, this implication would be very bad! This was based on isotope dating from the sediment of an ancient lake (Scientific American, 2014). 

References

Ancient India, Indus Valley, viewed: 13/09/2016, http://www.ancientindia.co.uk/indus/home_set.html

Ancient origins, 2013, The Mohenjo Daro 'Massacre', viewed: 13/10/2016, http://www.ancient-origins.net/ancient-places-asia/mohenjo-daro-massacre-00819




Bitesize, 2016, What happened to the Indus Civilisation, viewed: 16/10/2016, http://www.bbc.co.uk/guides/z8b987h




Boundless, 2016, Cities of the Indus Valley Civilization', viewed: 13/09/2016, https://www.boundless.com/world-history/textbooks/boundless-world-history-i-ancient-civilizations-enlightenment-textbook/early-civilizations-in-the-indian-subcontinent-4/the-indus-river-valley-civilizations-23/cities-of-the-indus-valley-civilization-101-13202/


Cowan, M.K., 2014, 'Some Ancient Water System and Patterns of Land Degradation', Ancient Water Systems. 




Inam, A., Clift, P.D., Giosan, L., Tabrez, A.R., Tahir, M., Rabbani, M.M, and Danish, M., 2007, 'The Geographic, Geological and Oceanographic Setting of the Indus River', Large Rivers: Geomorphology and Management. pg 333-346.




Khan, S., 2014, 'Evolution of sanitation and wastewater technologies through the centuries', IWA Publishing, Chapter 2, pg 25-40.




Scientific American, 2014, 200-Year Drought Doomed Indus Valley Civilization, viewed: 16/10/2016, https://www.scientificamerican.com/article/200-year-drought-doomed-indus-valley-civilization/




The chronical of the fall, 2016, Bond Event, viewed: 16/10/2016, http://cof.quantumfuturegroup.org/events/5373




The Huffington Post, 2014, Long-Term Drought Doomed Indus Valley Civilization, Researchers Say, viewed: 13/09/2016, http://www.huffingtonpost.com/2014/03/04/drought-doomed-indus-valley_n_4895673.html




Viswanathan, B., 2015, What was/were the reason/s behind the decline of the Indus Valley Civilization?, viewed: 16/10/2016, https://www.quora.com/What-was-were-the-reason-s-behind-the-decline-of-the-Indus-Valley-civilization




Wheeler, M., 1968, The Indus Civilization Third Edition, Cambridge University Press, New York. 

Bibliography and Recommended Reading

The Indus Civilisation, third edition, Cambridge University Press, New York. 

http://ancient-water-systems.com/wp-content/uploads/2014/06/AWS-4-June-2014-reviewed.pdf

http://www.geol.lsu.edu/pclift/pclift/Publications_files/2007_Inam_etal.pdf

https://books.google.co.nz/books?id=WxXu83RxSNwC&pg=PA554&lpg=PA554&dq=Mohenjo-Daro+influence+on+the+hydrologic+system&source=bl&ots=2o5lVydQXI&sig=bZYhee17KT-Kd3Sk5xD8aECGGu4&hl=en&sa=X&ved=0ahUKEwjW9reS5NbPAhXn0FQKHa-5B-AQ6AEINjAE#v=onepage&q=Mohenjo-Daro%20influence%20on%20the%20hydrologic%20system&f=false

Angelakis, A.N., Mays, L.W., Koutsoyiannis, D., Mamassis, N., 2012, 'Evolution of water supply Through the Millennia', IWA Publishing, 553-554. 

(Possible downfall of mohenjo-daro)