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Qanats: ancient water management system guaranteed survival

I’ve been talking a lot with colleagues and relatives in Spain. Most of these conversations include a salute or a farewell, commenting or demanding feedback about current extreme weather events affecting daily lives.

It shouldn’t be controversial to claim that geographic differences and extreme events (severe droughts, desertification, war, invasion) can explain broad patterns in human history: for example, as weather patterns in the Near East became more erratic during the Bronze Age, settlements between the Persian Gulf and the Indus Valley developed later on water management techniques that evolved into sophisticated networks of subterranean aqueducts to avoid evaporation, or qanats.

A simple schematic showing a typical qanat system; click on image to access source

Can water management, first developed in ancient Iran by precursors of Persians, teach contemporary Iran (and other countries in the region) some lessons about water management in the long run? When we think of innovation, we reduce the concept to high-tech systems that may increase complexity over issues that often could be dealt with using efficient, easy-to-repair, low-technology alternatives. New York-based designer Julia Watson calls this traditional, multigenerational knowledge “Lo-TEK” (from “traditional ecological knowledge”).

That was then, this is now

Some of the current challenges derived from the impact of extreme weather are unique to our age. Still, comparative analysis could be useful to, say, knowing how qanats guaranteed the survival of ancient Persian cities over millennia despite rapid desertification of ancient watersheds, or how water flood management at a big scale since the Middle Ages turned The Netherlands into an engineering and food production world behemoth.

Yet when we think of “tech,” we don’t seem to consider systems maintenance and simple, repairable solutions to complex problems as something ideally innovative. Is it a problem of perception? Why innovation refers to implementing new systems and not including their life-span, maintenance cost, and resilience when disruptive events halt the perceived “normality”?

Nature recently published an article reviewing in depth the technology, management, and culture of water in ancient Iran from prehistoric times to the Islamic Golden Age. Water management in Persia was so advanced that cities in the desert used water canals diverted from distant rivers to grow food, cool homes, and power water mills (also powered by wind) to mill grain. Such complex infrastructures needed vernacular knowledge but also coordination and a culture fostering maintenance. Such mechanisms seem to have reached a halt after the Mongol invasion when Iranian culture as a whole stagnated.

The goal of the study is to help current designs with a better understanding of prosperity eras during the past across vast desertic areas thanks to the culture of water management through qanats:

“Qanat consists of one or more gently sloping tunnels (galleries) and a series of vertical shaft wells, designed to extract and transfer groundwater by gravity to flatter slopes, particularly for use in arid and semi-arid regions.”

Ancient water management in Iran

Part of the tunnel excavated from an aquifer’s subterranean source, eventually transferring water to the ground surface to allow irrigated land, supply cisterns, etc. Importantly, to decrease water infiltration, the tunnel bed was impermeabilized with traditional, readily available materials like compacted clay and “sarooj” (traditional water-resistant mortar used in Iranian architecture since times immemorial). Sarooj is still made from lime, sand, and ash.

That said, traditional earth architecture from the Iranian vernacular created water tanks mixing “sand, clay, egg whites, lime, goat hair, and ash in specific proportions,” increasing the durability and the impermeable character of the plaster.

In prehistoric Iran, the Neolithic developed next to the floodplains, whereas the arid areas of the Central Plateau suffered because of water unreliability. However, rapid change next to the floodplains made them also more unreliable over time:

“Lowland alluvial rivers, deltas, and alluvial fans, where early settlements were located, might have undergone aggradation due to changing climates, water volumes, and tectonic movements. In response to sediment aggradation and subsequent incision, a relatively unstable river system emerged, where river courses shifted over time, resulting in river terraces of differing ages.”

As a response, people near riverbanks needed to change with watercourses. Also, a harsher environment prone to drought incentivized local populations to experiment with solutions to new challenges:

“The inhabitants of the arid regions began to manage water scarcity by improving their water systems rather than abandoning their homes. Between 2800 and 1100 BC, during the emergence of the first city-states, modest size water systems were designed to collect, store, and supply water, indicating a relatively centralized water management system.”

Building (and maintaining) complex systems

In areas prone to dense alluvial deposits susceptible to low, erratic rainfall and drought, populations opted for irrigated agriculture capable of overcoming periods of immediate water scarcity, though reachable via canals:

“Hence, a complex of water systems, including canals of various sizes (a central canal and a network of secondary, tertiary, quaternary, and field canals), head-gates, distributors, regulators, inlets and outlets, weirs, levees, and storage reservoirs was designed to ensure full irrigation.”

Ancient Bronze Age settlements in the region developed complex systems with “water wells, wastewater facilities, cesspits, and stormwater drainage systems.”

During periods of drought and unrest, societies developed water regulations such as the ones present in Babylon during King Hammurabi (1792-1750 BC), which seem to have inspired later similar Persian water codes. The first Persian Empire may have endured over its 220 years of existence without Alexander the Great of Macedon’s invasion in 330 BC, and it seems their success depended on them mastering water management to minimize famines and unrest:

“During their 220 years of rule, the splendid development of the Achaemenids in all domains was largely dependent upon large-scale government-managed waterworks and vice versa. In the following, we provide a brief portrayal of the critical factors and conditions related to the development of water resources in this era.”

And the need to manage water may have fostered, in turn, an administration trying to standardize “units, criteria, and knowledge.” The Achaemenids guaranteed large-scale development and management of hydraulic infrastructures:

“They dug qanats and constructed dams and networks of water canals, drainage systems, and waterways with state-of-art technology and managerial skills, resulting in agricultural productivity, food security, urban development, trade growth, political stability, and cultural adaptations.”

When southwestern Asia forgot about water management

Eventually, ancient Iranian societies created and maintained dams that included control structures in the upper parts “to stabilize water flow.”

The Achaemenids (First Persian Empire) may have tried to fix not only water reliability but its fair use among those with rights to divert streams to registries, cisterns, homes, gardens, stables, etc. Their work inspired more qanats and water “meters” during later dynasties (Seleucids, Parthians, Sasanians), and the technology was adopted and exported across the Arab world after the Muslim conquest of Persia in 632 to 651:

“Besides, qanat’s technology expanded to more than 34 countries under different names.”

The culture around resilient water management in a semi-arid and arid region that needed to sustain complex cities and networks prevailed until the Islamic Golden Age. However, it seems to have dwindled permanently with the Mongols’ conquest in 1098-1219:

“The loss of ancient water technologies was also caused by the forgetfulness of the past, which allowed non-native alternatives to take their place. The elimination of these technologies, then, led to the elimination of their scientific and technological culture. As today’s users became familiar with modern water technologies, they paid attention only to the positive side of modernization without considering what to do about the negative impacts. Among the many examples of vanishing technologies, the qanat is one of the most obvious. Indeed, the role of qanat in supplying water declined due to the Iranians failure to reduce its systemic disadvantages.”

Modern pumps and deep-pumped wells have created a technocratic culture around water that prevents local development. Like in the rest of the world, in Iran “local, traditional, and indigenous approaches to address water-related issues” have been discarded:

“Such conditions prevent the government from accessing public opinions, experiences, perceptions, expectations, solutions, and feedback.”

Persisting drought in temperate zones

A topic such as water management in ancient Iran from prehistoric times to the Islamic Golden Age is closer to contemporary water management than we think, as the Colorado River Basin tries to survive and Europe experiences a generalized, severe drought (that could be followed by equally erratic floods).

Not long ago, it was Europeans talking to people in the US West about the severe drought in the area; now the commentary in social networks has reversed: Californians share pictures of “superblooms” (impressive images of entire mountain ridges and hills covered in orange, pale yellow, or cream, red and pink of California poppies and other flowers after an extremely rainy winter in the US West Coast); and friends in France and Spain are worried about a prolonged drought and higher-than-normal early Spring temperatures.

The remaining of a water treatment system in “Chogha Zanbil” Complex, Khuzestan, Iran. Click on image to access source

No superbloom hashtag will divert towns, farmers, and Native American tribes that have depended on water usage rights from the Colorado River to cover their needs as the river keeps shrinking and usage claims from States, communities, and individuals grow. Water usage in the Colorado River’s upper and lower basins was designed when the river carried more water, and only a portion of legal allotments were used.

As the population grew in the river basin and agriculture expanded in arid areas of the Lower Basin, farmers in California’s Imperial Valley increased their needs thanks to the acquired rights; California receives the most water from the river of the seven US States, tribal territory and Mexico integrating the basin, with an annual entitlement of 4.4 million acre-feet. Now States, Native tribes, individuals, and organizations begin to wonder whether it makes sense to grow food in the California desert using water from a river that’s drying up.

When patterns become more erratic

With drought and increased usage, water management by acquired rights and seniority could accelerate the demise of the Colorado River, confirming the postulates of the tragedy of the commons: in a free-market framework that doesn’t account for year differences or impact, unrestricted use of limited resources condemns these common resources to depletion. A legally sanctioned depletion, for that matter.

The Biden Administration has proposed two alternatives to the ongoing contingent interpreting water usage rights and seniority among all actors involved in the Colorado River Basin: use the priority system already in place to proportionally cut water; or force cuts in the same percentage across the board.

Agreeing on water supply cuts to address the drought and, ultimately, save the river won’t be easy. The 1,450-mile river serving 40 million people and agriculture in seven US States, dozens of American tribes, and two States in Mexico is a case study of how agreements from decades ago (when the river carried much more water) have to adapt to a dwindling river. Without a cut in water usage between 15% to 30% of the current use, the historic lows in the river could reach critical levels.

It wouldn’t be the first time that apparently rational water usage planning ended in an environmental catastrophe with a point of no return: with the intention of turning the arid area around Central Asia’s Aral Sea into a vast area for cotton production, Soviet planners, many canals diverted water to the desert that was never used due to evaporation. The Aral Sea declined from the fourth-largest lake in the early 1960s to less than 10% of its former size.

With extreme weather events on the rise, former patterns that we gave for granted have become more erratic, compromising resources like water for drinking, irrigation, and energy production.

East of Eden

With little rain in the last year, farmers in France and Iberian Peninsula are concerned about their crops and animals. Parts of Spain’s interior and South are experiencing July temperatures in late April, and the drought in Iberia is already one of the worst ever recorded. To the South, on the other side of the Strait of Gibraltar, Western Africa continues to be immersed in extreme thermal intolerance.

Rainstorms in California alleviate the State’s drought and make the population forget if only for the short present, about erratic weather patterns and the fire season at the end of every summer, aggravated by the combination of the Santa Anna winds and high temperatures. Public opinion, even when informed, does seem to grow skeptical about the links between extreme weather patterns and the effects of human activity on the atmosphere.

A 2023 survey by the Energy Policy Institute and the University of Chicago (EPIC indeed) states that, even when the evidence of anthropogenic climate change has gotten stronger, belief in it has slightly fallen over time.

Water channel of Qanats of Ghasabeh, Iran

Local, temporary effects regarding drought, extreme heat and fire (or persistent rain and floods) are more virulent and happen with a higher frequency, though perceiving a problem associated with environmental changes over time can prove challenging and, as Jared Diamond argues in Collapse: How Societies Choose to Fail or Succeed, they can trigger catastrophic consequences if they aren’t addressed.

We’ve seen that it takes months of heavy rains and snowfall in California to cause collective amnesia on events that won’t go away like persistent drought and a more virulent fire season. Or, as put by John Steinbeck in “East of Eden,”

“During the dry years, the people forgot about the rich years, and when the wet years returned, they lost all memory of the dry years. It was always that way.”

When the faster/cheaper mindset gets in the way

Are we facing the eternal return of inaction or amnesia, or we can learn from past and present challenges in aridity and drought (or heavy rain and floods) to adapt better for the future? Or could the politicization of climate be a deterrent to adopt individual and collective behaviors that could speed adaptation to a world with more extreme and difficult-to-predict weather patterns?

The way we perceive the world is conditioned by how we perceive things: our accelerated culture prioritizes instantaneity over a delayed consideration of things. According to the San Francisco-based Long Now Foundation, an organization that aims at educating public opinion with a long-term approach capable of serving as a counterpoint of today’s “faster/cheaper mindset,” considers that what we see as “present” should be a much richer concept: “now” refers to the 3-day span around this precise moment (yesterday, today, tomorrow); “nowadays,” on the contrary, could encompass a much larger period (last decade, this decade, next decade: 30 years, one human cohort); whereas “the long now” is a geological “now” encompassing 20K years, from the beginning of the Neolithic revolution to 10,000 years from now (12000 CE).

With a more nuanced understanding of geological and natural processes, decisions related to our immediate reality could be more resilient, aligning current interests with heritage and also with the fate of future generations. Most of us have never thought about considering the importance of becoming a “good ancestor,” yet we may enjoy the outcomes of decisions that were taken by others a long time ago.

In some cases, consistent decisions taken at a civilization scale may have prevented its rapid demise in the future, as Jared Diamond argues in Collapse. Forestry in Japan and coordinated use of flood management and water pumps in the Netherlands, to mention two successful examples of successful collective management of uncertainty, may show the way for future big-scale systems that ought to be maintained and created to combat the effects of extreme weather and its derived consequences, from unrest to war or mass migration.