Dams and Drainage in Mycenaean Greece

800px-Tiryns_-_Cyclopean_masonry
The Cyclopean Masonry Walls of Tiryns | CC BY-SA 2.0| Wikimedia Commons

Part of my research into my MA dissertation, I examine some of the amazing feats of engineering that the Mycenaean did in order to adapt to the changing climate. This article is based on the script to my Dissertation presentation. 

This first section is going to provide an overview of recent studies of climate change in the Eastern Mediterranean and the Aegean Sea and to lightly touch upon some of the issues that it would have affected (this will be expanded on in the second section). I will also introduce the Environmental Historical framework that I intend to use throughout my project. Additionally, the first section will introduce what I mean by ‘human interventions in the Environment’ and why they might have been built. The second section will go into more detail about two case studies of particular interventions in the environment, such as environmental condition prior to their construction and possible wider societal reasons for why they were constructed, but with an emphasis on how that related to the wider Environmental Historic narrative.

Climate change in the Aegean Sea has been a suggestion for the collapse of the Mycenaean (and other civilisations of the Eastern Mediterranean) since at least the late 1960s (Carpenter 1966). More recent work by Drake (2012) and Kaniewski and Van Campo (2017) has looked at environmental data and shown that in the Late Bronze Age (hereafter LBA) there was a 300 year period of drought in the Eastern Mediterranean from around 1350 – 1150 BCE caused by cooling ocean surface temperatures which led to decreased rainfall throughout the region (Drake 2011, pp.1865; Kaniewski, Van Campo 2017, pp.162). It has been suggested that the Aegean was hit particularly hard due to the vulnerability of their agriculture owing to the already unpredictable weather patterns, and were destabilised by the LBA draught (Kaniewski and Van Campo 2017, pp.164; Weiberg and Finné 2018, pp.590). It is important to emphasise that this draught event wasn’t a sudden period of aridisation that occurred overnight, but a long-term period of oceanic cooling that slowly led to decreased amounts of rainfall. I believe Drake puts it best when he says that “this shift in precipitation would not have been a crisis event, but rather a continual stress put on human societies in the region for many several generations” (2011, pp.1866. Italics my own).

As well as draught and longer arid periods, there also seemed to be an increase in wetter conditions, while this seems to contradict the idea of a draught, this shows that there was much variety in the climate during the LBA (Weiberg and Finné 2018). The draught followed on from a wetter period where those conditions were likely to have led to an increase in agricultural practices, leading to surpluses and an increased population (Ibid. pp.591). So, what happens when an increased population used to high agricultural yields suddenly experiences a change in climate?

I want to discuss what happens under that ‘continual stress’ particularly through human interventions in the environment, that is, utilities that have been constructed in order to either prevent issues that are caused by environmental factors or to exploit those environmental factors. I want to examine these constructions through an environmental historical framework: the environment itself and its effects on humans, the evaluation of change caused by humans in the natural environment and how humans thought about the natural environment and their attitudes towards it. Because the majority of these large-scale projects occurred during the LBA I want to explore the possibility that they were built as a response to the increased stress during the variance in climate, and sharp change from a wetter more productive period to one with increased aridity, and what other factors might have led to their construction and whether those more indirect factors are also related to Climate change.

This next section is going to look at two examples of the kind of human intervention that I want to discuss throughout the rest of the project. They are the dam constructed at Tiryns in the Argolid and the drainage of Lake Kopais in Boeotia. I have picked these examples as they are perhaps the most striking examples of construction and engineering in the Bronze Age Aegean. In addition, because of their scale it is much easier to think about the environmental trends that I mentioned in the previous section, since that large scale means there is more surviving evidence and a lasting impact on the landscape. Both these constructions were built towards the start of the dryer period, and the fact that both examples are associated with hydraulics, show that unpredictability of water in this period, either through flash floods or through creating more arable land.

The environment that Tiryns existed in was one that was closer to the sea that in present times (Maran 2010, pp.722). Due to the low angle of gradation towards the sea, the alluvial deposits are very light weight, mainly gravels, silts and sands, and this means erosion has always been a concern and explains the change in coastline as the erosion and sedimentation progressed (Balcer 1974, pp.141; Maran 2010, pp.722). Although there was always a danger from erosion and flash-floods due to the type of soil and the high-water table (Balcer 1974, pp.142), it meant that the region was fertile and attracted settlement. This combination of a populous territory, high-water table, and a high risk of erosion due to the soil type, meant that flash-floods were at risk of damaging areas of habitation and agriculture particular during events such as earthquakes and heavy rain after an extended period of draught.

It was because of this combination of environmental factors that the northern sections of Tiryns flooded, this shown in the archaeology by deposits of alluvial matter around the northern Lower Town (Balcer 1974, pp.143; Maran 2010, pp.728). This consistent flooding led to the construction of the dam around LH IIIB2, so that the palatial complex could expand outwards to the lower northern area by the acropolis. The dam itself is around 5km away eastwards from the main citadel of Tiryns at the confluence of three streams, which is the point during the flash-flood where the surge of water would become extremely heavy and rush out of the streambed and towards Tiryns. The dam was a construction where earth and gravel were heaped across the path of the stream, and was supported by use of Cyclopean masonry, which supported the embankment and prevented its erosion. The angle of the wall meant that the flood waters were driven to the southwest, away from the main citadel of Tiryns (Balcer 1974, pp.147; Maran 2010, pp. 728-729).

I have discussed the environmental factors that led to the dam being built, but I haven’t mentioned how it relates to the period of Climate change that occurred during the LBA. During the period of wetter climate prior to c.1350 BCE, it is likely that Tiryns experienced somewhat of a population boom, this is because during Late Helladic IIIA, there was development in the citadel, razing the original complex of buildings and starting from scratch, leading to the construction of the Great Megaron, the buildings of this new complex were then plastered and painted (Maran 2010, pp.725). This assertation of population growth can be made due to what we understand about the Aegean state economy, since the Mycenaean palaces appeared to be centres were surpluses where collected in order to finance the operations of state (Nakassis et al. 2010, pp.245). These wetter conditions helped to contribute towards the expansion of the society of Tiryns by increasing the economic potential of the region, and this expansion of the state often goes hand in hand with population increases (Weiberg and Finné 2018, pp.591).

It was due to this agricultural and economic success that Tiryns expanded downwards into what is called the Lower Town, which was in the path of the flood waters from the stream. There is debate surrounding what was the catalyst for the building of the dam itself; was it in response to a cataclysmic flood (Zangger 1994, pp.198-212) or was it as part of a wider building programme that aimed to bring greater focus to the Lower Town? (Maran 2010, pp.728) I personally think that both these reasons are motivated by the ‘continual stress’ factor that would have been placed on the people living in Greece during this long-term period of drying, since the population had increased due to the lushness of the earlier wetter climate, but it would have slowly been feeling the pressure of smaller and smaller crop yields. Any event that would have caused trauma may have led to discontent amongst the majority against the wanax and all the other elite members of Tiryns, and the dam fits into a pattern of large scale building projects in this period that could be seen as measures by the elite to maintain their status and authority (Weiberg and Finné 2018, pp.595).

The other large-scale building project that fits this pattern that I want to discuss is the drainage of Lake Kopais in Boeotia. Lake Kopais is lake in central Boeotia, and is fed by many rivers, the main ones being the Cephissus, Termessus and the Triton. The landscape of Boeotia is contrasted by mountains and flat plains, the primary material is limestone and the soils are derived from this around the plains the soil is often silty, though in the areas there has been drainage there is a thick 4m layer of peat (Rackham 1983, pp.296-297). The drainage out of the lake is interesting and relates to how the Mycenaeans subsequently drained it; as I said, the lake is formed by many rivers flowing into it, the lake forms as there is no where else for the water to go, as there isn’t a direct channel out to sea, this is because the lake exists in a limestone depression, natural drainage occurs through natural sinkholes known as katavothres. The soil of the drained lake as it is today, is mainly composed of silt, with patches of peat and other decomposed organic material (Rackham 1983, pp.315). This lack of drainage is probably what made the drained lake so fertile, since there were millennia upon millennia of deposits of soil and sediment and vegetation that come from the mountains.

The system for the drainage regulated the flow of the rivers I previously mentioned, through the use of dykes, drainage canals and the creation of a permanent reservoir. There was a grand canal, 40m wide and 25km long formed through the use of stone lined dams, and there was also a smaller canal that went past the fortress at Gla. The water from these constructions, as well as draining away from the lake, also directed water towards the katavothres, ensuring that there was a constant flow of water, one that could deal with a sudden deluge and not harm the 90km2 of new arable land that was created. In all 400,000,000m3 of stone and 200,000,000m3 of earth for the dams are estimated to have been shifted in order to complete the project and it has been further estimated that it would have taken 100 men 8 years to complete (Dakouri-Hild 2010, pp.622-623; Kramer-Hajos 2016, pp.117).

It is thought that the drainage was instigated by the ruling faction at the palace of Orchomenus and administered at the fortress of Gla, which was based on a former island in the drained lake. Gla was part of series of fortresses within the Kopais basin (Buck 1979, pp.41; Kramer-Hajos 2016, pp.119), which has been seen as a protective measure against the might of Thebes (Buck 1979, pp.41; Dakouri-Hild 2010, pp.621; Kramer-Hajos 2016, pp.118). However, Kramer-Hajos suggests that although relations may have been frosty between the two palaces, they might have worked together to drain Lake Kopais, she suggests that the presence of lapis lazuli at the fortress at Gla suggests a connection with Theban seals due to the rarity of the material, though she does conclude that at the very least the constructions would have occurred during a time of peace (Kramer-Hajos 2016, pp.118).

The fertility of the land is clearly a factor as to why the lake was drained, but what was the process that led to this? The drainage of the lake is likely earlier than the construction of the dam at Tiryns, around 1450-1300 BCE for the drainage as opposed to 1250-1200 BCE for the dam (Koutsoyiannis and Angelakis 2004, pp.416). What this means is that the drainage of the lake would have occurred during the wetter period of the LBA, and due to the unpredictable water levels that the lake could experience, sometimes overflowing into the neighbouring basin (Kountouri et al. 2013, pp.710). These unpredictability in a wet climate would meant the lake would have encroached on important farmland during times of heavy rain, and during the summer, when evaporation rates were higher, it is likely that the humans who lived would have seen the potential in the soil quality at the bottom of the lake. The drainage of the lake would have solved two problems, eliminating the issues of flooding in the arable land surrounding the lake and produced even more arable land to support an increased population due the increased productivity of the land as I have shown earlier in the essay.

As the climate became dryer, the drained lake would have become more important in the landscape as it would have been a more reliably fertile farmland. But this would have attracted jealous glances from Orchomenus’ neighbours, which explains the system of fortresses that were constructed during the original draining of the lake. Within the fortress at Gla, there was capacity for storage of over 2000 tons of wheat. Showing that as well as protecting the region, Gla also acted as a storage and possible distribution centre. Analysis of the grains that have been found at Gla show them to be Einkorn, a hardy primitive grain that survives well in dry conditions and stores well (Kramer-Hajos 2016, pp.119). However, there was the risk that with a monoculture (which evidence suggests is the case), adverse weather conditions or disease could decimate a crop and put pressure on food supplies (ibid. pp.123), couple this with the risk of older dykes and canals collapsing and overwhelming the crop in the basin, the risk of an unproductive harvest and starvation increased massively, putting immense pressure on both the ordinary people who farmed the land who might grow angry with the conditions and the elites in the palace who had to deal with an angry populace; another example of the ‘continual stress’ that occurs due to this type of climate change.

I think this serves well as a precursor to the rest of my project. I have introduced how human interventions in the landscape were often responses to climate change, sometimes to capitalise on the much more favourable conditions and sometimes to respond to disaster. In the case of the dryer conditions brought on due to ocean cooling sometime around 1350 BCE, it meant that the factor of ‘continual stress’ was constantly building, putting pressure on all aspects of society and making life increasingly uncomfortable for all. In the period prior to this, it seemed that the elite exploited the improved fertility of the land to such an extent that it created a population boom, which is indicated by the increased number of settlements and the expansion of older ones (Dakouri-Hild 2010, pp.619; Maran 2010, 726), which led to an expansion of the economy, an expansion which left them overstretched and couldn’t deal with a reduction in production, which Weiberg and Finné describe as a “recipe for disaster” (2018, pp.594). I think the examination of the long-term trends that led to construction of these interventions in the landscape, helps to ground them in reality and gains a greater understanding of how ancient societies reacted when the climate changed. I think it is important to study when what happens when the climate is favourable, since it is clear that the Mycenaeans overstretched what was possible when they had it good, so that when the bad times came they struggled to deal with the continual stress, leading, with other factors, to the collapse of the palaces. Human interventions in landscape show that humans know that their exploitation of the natural environment can have benefits which will make life easier for them, and show the complex relationship that humans in the Bronze Age had with the environment, that they were aware that changes needed to be made, but not understanding that every action has a consequence.

Bibliography

Balcer, J. (1974). The Mycenaean Dam at Tiryns. American Journal of Archaeology, 78(2), 141-149.

Buck, R.J. 1979. A History of Boeotia. University of Alberta Press: Edmonton

Dakouri-Hild, A. 2010. ‘Boeotia’ in The Oxford Handbook of the Aegean Bronze Age, ed. Cline, E. Oxford University Press: Oxford. 614-630.

Drake, B.L. 2012. The influence of climatic change on the Late Bronze Age Collapse and the Greek Dark Ages. Journal of Archaeological Science, 39(6), pp.1862–1870.

Galaty, M.L. Nakassis, D. Parkinson, W.A. 2010. ‘State and Society’ in The Oxford Handbook of the Aegean Bronze Age, ed. Cline, E. Oxford University Press: Oxford. 239-250.

Hughes, J.D. 2006. What is Environmental History? Polity Press: Cambridge.

Kaniewski D, Van Campo E. 2017. ‘3.2 ka BP Megadrought and the Late Bronze Age Collapse’ in Megadrought and Collapse: From Early Agriculture to Angkor, ed. Weiss, H. Oxford University Press: Oxford.

Kountouri, E., Petrochilos, N., Liaros, N., Oikonomou, V., Koutsoyiannis, D., Mamassis, N., Zarkadoulas, N., Vött, A., Hadler, H., Henning, P. and Willershäuser, T., 2013. The Mycenaean drainage works of north Kopais, Greece: a new project incorporating surface surveys, geophysical research and excavation. Water Science and Technology: Water Supply, 13(3), pp.710-718.

Koutsoyiannis, D. and Angelakis, A.N., 2004. Agricultural hydraulic works in ancient Greece. The Encyclopedia of Water Science, pp.415-417.

Kramer-Hajos, M. 2016. Mycenaean Greece and the Aegean World: Palace and Province in the Late Bronze Age. Cambridge University Press: Cambridge.

Maran, J. 2010. ‘Tiryns’ in The Oxford Handbook of the Aegean Bronze Age, ed. Cline, E. Oxford University Press: Oxford. 722-734.

Rackham, O. 1983. Observations on the Historical Ecology of Boeotia. The Annual of the British School at Athens, 78, 291-351.

Weiberg, E. Finné, M. 2018. Resilience and persistence of ancient societies in the face of climate change: A case study from Late Bronze Age Peloponnese. World Archaeology, 50(4), pp.584-602.

3 thoughts on “Dams and Drainage in Mycenaean Greece

  1. Thank you, this was a fascinating read. Why is it thought that Gla was subservient to Orchomenos, rather than the other way round, given the size of the former and presence of a megaron, etc?

    Liked by 1 person

    1. That’s a good question, Gla is a massive settlement, but I think the current thinking is that it was a military/storage installation as opposed to a palatial centre. In Kramer-Hajos’s book about networks between palace and province in Mycenaean Greece, she argues that Gla was built at the same time as the drainage works as part of a system of fortifications to protect the newly created agricultural land, this line of fortifications leads back to the closest palace, which is Orchomenos. The dates and the structure of these fortifications are what is suggestive of Orchomenos being the dominant citidel in the region

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