Riparian Civilization

8 January 2014


mesopotamia relief map

The earliest terrestrial civilizations seem to have been riparian civilizations. What do I mean by this? What is a riparian civilization? Here is how Biology Online defines “riparian area”:

An area of land directly influenced by water. An ecosystem that is transitional between land and water ecosystems. Riparian areas usually have visible vegetative or physical characteristics reflecting the influence of water. River sides, lake borders, and marshes are typical riparian areas.

More narrowly, “riparian” is often used to refer to riverbanks, so that a riparian civilization is a civilization of a riverbank. When we consider the earliest complex civilizations on Earth several of them are centered on river ecosystems, most notably ancient Egypt, with its agricultural economy based on the annual flooding of the Nile, but also the Indus Valley civilization, the Yellow River Valley civilization, and the civilizations of Mesopotamia, which region lies between the Tigris and the Euphrates, hosting the legendary cities of Babylon, Uruk, and Ur.

Mesopotamian marshes

While those of us who don’t live in Mesopotamia tend to think of the region as desert, there are extensive marshes — home of the “Marsh Arabs” — fed by the Mesopotamian river system, and here we find conditions exactly as described in the above-quoted definition of riparian areas. Just such conditions made possible the earliest settled terrestrial civilizations.

marsh arabs

There are exceptions to this pattern of riparian civilization (especially when “riparian” is narrowly construed in terms of rivers), such as the ancient civilizations of Peru (Andean civilizations such as the Chavin and the Moche), the Mayans, and Khmer civilization in southeast Asia. Each example has something interesting to teach us if we consider them in the spirit of comparative civilization.

 Fig. 2. The Angkor Ruins as seen on Google Earth. Figure 2 covers the entire view of Angkor. The Western Baray reservoir is visible on the left side of the image. There was a similarly large reservoir on the right, but it has since dried up. Angkor Thom, covered by green trees, is located between them. Angkor Wat is located beneath it, surrounded by a moat. Other ruins are scattered around them. (from Earth Observation Resource Center)

Fig. 2. The Angkor Ruins as seen on Google Earth. Figure 2 covers the entire view of Angkor. The Western Baray reservoir is visible on the left side of the image. There was a similarly large reservoir on the right, but it has since dried up. Angkor Thom, covered by green trees, is located between them. Angkor Wat is located beneath it, surrounded by a moat. Other ruins are scattered around them. (from Earth Observation Resource Center)

The Maya and the Khmer are especially interesting, and might be called the exceptions that prove the rule. Both constitute what archaeologists sometimes call “hydrological” civilizations, since each was predicated upon an extensive regime of irrigation, made possible by the creation of reservoirs and a rigid social organization that enforced the distribution of water. While the water utilized by the Khmer and the Maya was not a grand river system as in Egypt, the Indus Valley, or the Yellow River Valley, the ready availability of water was crucial to the structure of the civilization that emerged in these places.

Cats: essential to maintaining the grain stores of early terrestrial civilization.

Cats: essential to maintaining the grain stores of early terrestrial civilization.

Even more interesting to me in the case of the Maya and the Khmer is that both were tropical civilizations. It is extraordinarily difficult to maintain the institutions of civilization in a tropical climate; the kind of plants that grow are not well-suited to long term storage. In temperate climates, civilizations can begin around the nucleus of grain agriculture surplus. Grains store well, and they can be guarded against rodents who would consume stored grain by the presence of cats, who are obligate carnivores and therefore eat only the rodents and none of the stored grain.

tropic of Cancer

Ancient Egypt might be called a subtropical civilization, as the Tropic of Cancer neatly cuts across the Nile separating lower Egypt from upper Egypt, which latter is in the tropics proper while the former is not. But the great climatological fact of Egypt is the Nile and its ecosystem, rather than the tropics. The Nile ecosystem allowed for the cultivation of wheat and barley for food, and flax and papyrus for textiles, rope, and paper. And, as we know, the Egyptians worshiped cats.


Perhaps what makes Khmer and Mayan civilization stand out in my mind is that these were not only civilizations in the tropics, but civilizations set in the midst of tropical rain forests. The other earliest terrestrial civilizations were either in the tropics or on the cusp of the tropics, but the great river systems upon which these civilizations were based had a climatological role in the formation of civilization that trumped the tropics. In the case of the Andean civilizations of Peru, the altitude of the Andes moderated the tropical climate, and the staple crop became the potato. The Mayans had the “three sisters” as their staples — maize, squash, and beans — sometimes cultivated in “forest gardens.” Both of these examples are interesting: potatoes and maize were the result of human cultivation, and there is perhaps no staple crop in the Old World as genetically transformed by human cultivation as these staples of the New World that made civilization possible in the Western Hemisphere. Thus the peoples of Mesoamerica made civilization possible by the selective breeding of staple crops that would in turn make large scale settled agriculture possible.

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Grand Strategy Annex

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6 Responses to “Riparian Civilization”

  1. Danquebec said

    Is it by chance that a lot of the rivers of these civilizations were in desert? Or is there an environmental factor that helps? Are desert rivers more fertile?

    • geopolicraticus said

      That is a good question. The study of the origins of civilization hasn’t converged on a consensus. Some theories of the origin of civilization hold that it is not an accident. If a people settle in a river valley and then find themselves too numerous to support themselves by hunting and gathering, and the desert poses a barrier to egress, then the desert “traps” the people within the river valley and they are forced to invent agriculture to keep themselves alive.

      It could also be observed that there are a lot of deserts around the equator, close to which most pristine civilizations got their start, so it may be a partial coincidence that early civilizations appeared near the equator and several fertile rivers near the equator pass through deserts.

      I don’t know if desert rivers are more fertile generally speaking — this might be a good idea to research. I know that the Humboldt current that flows along the extremely arid west coast of South America is especially fertile, bringing cold water filled with fish up from Antarctica, but this is a current in the ocean and not a river. It is possible that there is a climatological mechanism that makes desert rivers fertile, but I am unaware of anything like this.

      Maybe it is something about the desert itself — I have been planning for some time to write about desert civilizations, but I haven’t gotten to this yet.

      Best wishes,


      • Danquebec said

        Awesome reply, thank you.

        The idea about people being trapped is interesting. It corresponds to Carneiro’s circumscription theory, that states that primary states form where people are “trapped” as you say.

        I know that the Amazon rainforest gets nutrients from the winds from the Sahara desert (because of the sand transported). If you think about it, in a forested land or grassy land, there won’t be any sand transported by winds. It might be an advantage for fertility.

        Can’t wait for your post about desert civilizations, I love this kind of thing.

        • geopolicraticus said

          Thanks for mentioning that about the sand from the Sahara desert being transported to the Amazon; I hadn’t heard that, but it makes sense.

          The Amazon, interestingly, is a river running through a tropical rainforest, and tropical rainforests haven’t tended to produce many civilizations. I wrote about civilizations of the tropical rainforest biome in a post that was intended to be one of series of posts on civilizations in distinct terrestrial biomes, but I haven’t yet followed up on this. “Civilizations of the Desert Biome” was to be the next installment. I will try to return to this at some time.

          It was thought for a long time that no pristine civilizations emerged in the Amazon, but relatively recently this consensus has shifted with increasing archaeological evidence to the contrary (e.g., cf. Searching for the Amazon’s Hidden Civilizations by Lizzie Wade). However, it has to be said that the tropical rainforest climate is not especially clement to the preservation of human artifacts. Perhaps the apparent productivity of deserts in terms of civilizations is a selection effect produced by the ability of deserts to preserve the works of human beings.

          Best wishes,


    • A. Karhumaa said

      Response to Danquebec: I don’t know whether the desert rivers as such are more fertile. I guess it all depends where they ultimately flow from. Eufrat and Tigris have their sources in the mountains of Eastern Anatolia, and the Nile gets the most of its water from the Blue Nile branch, from the volcanic highlands of Ethiopia where it brings (or used to bring, before Aswan and other dams) fertile sediments. On the other hand, I recall that Jared Diamond in his “Guns, Germs, and Steel” mentions that the rivers of Australia are very nutrient poor, because that continent is geologically very old (no new mountain chains), and thus there are no fresh mineral material for the rivers to erode on.

  2. A. Karhumaa said


    Any alien observing the distribution of megacities on Earth would deduce that they are caused by some water-borne organism, as most of them seem to be situated, on the coast, and especially near the mouths of rivers or nearby. However, the largest rivers in the tropics (Amazon, Congo, Zambezi), and some even in Europe (Rhône, ends in a marshy delta, Camargue) and of course in Arctic seem to be devoid of any large cities (see ).

    Thus, alien archaeologists with experience about similar life forms on other watery planets, and coming to our planet say, 50 million years from hence, would probably try to deduce the locations of the past rivers, especially their deltas. Similarly, if we ourselves seriously tried to find relicts of any hypothetical ancient terrestrian civilization, it might be a good idea to locate where the ancient river deltas were ( is another very interesting list. I didn’t know that Amazon and Congo are actually one river broken in two by plate tectonics, that rivers can outlive the continents they flow upon!)

    Jan Zalasiewicz in his book “The Earth After Us” gives a good account how some of the current megacities might get fossilized under the sediments:

    “What city? It might be New Orleans, or Haiphong, or Shanghai,
    or Amsterdam, or Venice, or Port Harcourt, or Dhaka. These
    are just a few of the cities and megacities that today spread
    across coastal plains, and over river floodplains and estuary
    margins. These, hence, are firmly sited on downgoing tectonic
    escalators, the weight of the deltaic sediment that they are
    built on inexorably dragging them down. And all are at or just
    above sea level (or just below it, in some cases, behind
    protective walls), so making them vulnerable to drowning by
    even the slightest of sea level rises. Once drowned, they will be
    removed from the realm of erosion into the realm of
    sedimentation, as if placed in a pickling jar.” (p. 166)

    The book is delightful, as are some of his scientific papers. (He has a wicked sense of humour I like).

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