Wylausing State Park in Southern Wisconsin where the Wisconsin River flows into the Mississippi.
According to researchers from Indiana University, Jackson School of Geosciences, University of Texas at Austin and the University of Minnesota, rivers can and do frequently change their course in an event known as an avulsion. The initial stage of this process is often a catastrophic flood costing thousands of lives and billions of dollars.
The authors speculate that these events could be the origin of numerous flood myths throughout history, especially the history of people living in flood plains of major river systems such as the Tigris and Euphrates on which the Epic of Gilgamesh was based.
The Suncook River, New Hampshire, 2006
Ironically, these catastrophic avulsion events, of which the Noah's Ark myth is probably a result, are reminders of just how hostile this planet can suddenly become, giving the lie to parochial creationists assertions that Earth is perfectly designed for life (especially their life). Sudden major river avulsions impact dramatically on people living peacefully in river valleys where soil fertility and water can create the impression of a nicely ordered and well-designed place for life to exist.
A recent paper shows that river avulsions occur if the riverbed becomes silted and if a more direct route across the flood plain exists* What information do you have on these events resulting in catastrophic floods throughout history? River avulsions are significant natural processes that occur when a river rapidly changes its course, often leading to catastrophic flooding. They are typically triggered when the riverbed becomes silted (sediment builds up), reducing the river’s capacity to carry water, or when a more direct route across a floodplain presents itself, usually during periods of high water flow.
Throughout history, avulsions have been responsible for devastating floods, some of which have shaped landscapes, impacted civilizations, and altered ecosystems. Here are a few notable historical examples:
- Yellow River Avulsions (China)
- Recurring Avulsions: The Yellow River, known as "China's Sorrow," has shifted course many times over the centuries, sometimes by hundreds of kilometers. Due to heavy silt deposition in its riverbed, the river has frequently avulsed, resulting in catastrophic floods.
- 1332-33 Flood: One of the deadliest floods in recorded history occurred during this period, killing millions of people. Frequent avulsions of the river have led to widespread devastation over millennia, contributing to social upheaval and shaping Chinese history.
- 1855 Avulsion: The river again shifted its course, moving to a more northerly path, displacing populations and flooding large areas. Efforts to control the river with dikes often exacerbated the problem, increasing sedimentation.
- Mississippi River Avulsions (United States)
- The lower Mississippi River has experienced multiple avulsions, significantly altering its course over time.
- Old River Control Structure: To prevent a major avulsion of the Mississippi River into the Atchafalaya River (which would leave New Orleans and Baton Rouge without a major waterway), the U.S. Army Corps of Engineers built the Old River Control Structure in 1963. If the river had avulsed, it could have caused catastrophic flooding in the region and disrupted trade routes.
- The Mississippi Delta itself is a product of many historical avulsions as the river shifted its mouth into the Gulf of Mexico.
- Indus River Avulsions (Pakistan/India)
- The Indus River has a history of avulsions, particularly in its deltaic region. In ancient times, these avulsions contributed to the decline of the Indus Valley Civilization around 1900 BCE, as major cities such as Mohenjo-Daro were abandoned following flooding and shifts in the river’s course.
- In modern times, avulsions in the Indus basin have continued to cause severe floods, particularly during monsoon seasons when the river overflows and changes its course.
- Kosi River Avulsions (India/Nepal)
- The Kosi River, often referred to as the "Sorrow of Bihar," has shifted its course by over 120 kilometers in the past 200 years, leading to periodic and devastating floods in the northern Indian state of Bihar.
- 2008 Kosi Flood: A breach in the river’s embankment resulted in an avulsion, causing the river to suddenly change course, inundating large areas and affecting over 2 million people. The flood was one of the worst in recent history in the region.
- Nile River Avulsions (Ancient Egypt)
- Historical records indicate that the Nile River occasionally underwent minor avulsions, especially in its delta. These changes in course, though less extreme than in some other rivers, contributed to the prosperity or decline of agricultural regions in ancient Egypt. The periodic flooding of the Nile was critical for the sustenance of ancient Egyptian civilization, but when avulsions caused water to flow away from established farmlands, it could lead to local famines and discontent.
Common Themes in River Avulsions and Floods:
- Sediment Buildup: In most cases, river avulsions are linked to sediment deposition, which raises the riverbed and reduces water-carrying capacity.
- High Water Flows: Flooding often follows periods of intense rainfall, monsoons, or snowmelt, providing the necessary water volume to breach riverbanks or embankments.
- Human Impact: Throughout history, avulsions have impacted human settlements, often leading to displacement, economic loss, and in some cases, societal collapse.
Modern engineering projects like levees, dams, and control structures are designed to mitigate the risks of avulsions, but as climate change intensifies, the frequency of extreme weather events may increase the likelihood of future avulsions.
Could the Epic of Gilgamesh be a folk memory of an avulsion?
Yes, it is possible that the Epic of Gilgamesh, particularly the story of the great flood, could be a folk memory of a river avulsion or a similar catastrophic flooding event. In the epic, the protagonist Gilgamesh learns about a great flood from Utnapishtim, who survived the deluge by building a large boat, similar to the biblical story of Noah’s Ark. This flood narrative is thought to have been inspired by real historical events, and there is speculation that it could reflect the collective memory of massive floods in the ancient Near East.
Possible Link Between the Epic and River Avulsions
The region where the Epic of Gilgamesh originated—ancient Mesopotamia, located between the Tigris and Euphrates Rivers—was prone to catastrophic floods due to the flat and low-lying nature of the alluvial plains. These rivers frequently flooded during the rainy seasons or after snowmelt from mountains. Additionally, because these rivers carried heavy sediment loads, they were prone to avulsions (sudden course changes). A major river avulsion, followed by flooding, could have been remembered in oral traditions and eventually incorporated into the epic.
Key Factors That Support the Avulsion Hypothesis:
- Mesopotamian Geography:
- Mesopotamia’s rivers were historically unstable, with frequent avulsions and course changes. The region’s dependence on these rivers for agriculture and settlement meant that any significant alteration in their flow would have had dramatic consequences for its people.
- The flat floodplains and large-scale irrigation systems in ancient Mesopotamia could have exacerbated the impact of an avulsion, potentially inundating vast areas.
- Flood Events in Ancient Mesopotamia:
- Archaeological evidence suggests that significant floods occurred in the region during the time periods when the Epic of Gilgamesh was composed (circa 2100 BCE). Some researchers have pointed to evidence of major flood layers found in cities like Ur and Shuruppak, which could correlate with the flood described in the epic.
- An avulsion of either the Euphrates or the Tigris rivers might have triggered a widespread flood that was later mythologized as a divine or cosmic event.
- Cultural Transmission:
- Flood stories were common in ancient Mesopotamian mythology and have parallels in other cultures in the region, such as the biblical story of Noah. These stories were likely passed down through generations and could have been rooted in collective memories of devastating avulsions and floods.
- Symbolism of Water and Flooding:
- In Mesopotamian culture, water was often seen as both a life-giving and destructive force. The unpredictability of river flooding or changes in river courses could have been interpreted as the will of the gods, with catastrophic floods serving as a divine punishment or cleansing event.
Notable Examples of Historical Flood Events:
- Shuruppak Flood (circa 2900 BCE): Archaeological excavations in the ancient city of Shuruppak (modern Tell Fara) have uncovered evidence of a significant flood event that may align with the flood described in the Epic of Gilgamesh. This event could have been the result of an avulsion or a breach in a river’s levees.
- Sumerian King List: The Sumerian King List, an ancient text, also refers to a great flood that supposedly occurred before a new dynasty of kings took over. This flood could have been linked to the same event that inspired the Gilgamesh flood story.
Limitations of the Avulsion Hypothesis:
While it is plausible that the flood story in the Epic of Gilgamesh is based on real historical floods or avulsions, it is important to remember that the epic is a mythological and literary work. The flood may have been embellished for dramatic or symbolic purposes, and it could represent a composite of many different flood experiences, rather than a single event.
Conclusion:
The great flood in the Epic of Gilgamesh could very well be a folk memory of a river avulsion or similar catastrophic flood event, especially considering the geographical and historical context of ancient Mesopotamia. While the exact event that inspired the flood narrative remains uncertain, the frequent and unpredictable floods in the region likely shaped the collective memory and myth-making of its people.
An explanation of why these frequent catastrophes happen - and it has nothing to do with sin or angry gods or humans having sex with mythical beings, as in the Bible myth - and none of them are global for obvious reasons, was produced by using a new satellite laser technology called lidar, which accurately measures surface topography. The team concluded that the cause of these avulsions is a combination of a rising riverbed due to silting and the availability of a shorter, steeper course for the river to follow. Their findings are the subject of a paper in Nature and are explained in an Indiana University College of Arts & Science news release:
Breakthrough study from IU scientists predicts catastrophic river shifts that threaten millions worldwide
Indiana University researchers have uncovered key insights into the dangerous phenomenon of “river avulsion,” offering a way to predict when and where rivers may suddenly and dramatically change course. Published in Nature, this breakthrough study sheds light on a process that has shaped human history through devastating floods and continues to threaten millions of people worldwide.
Study sheds light on phenomena that have shaped human history
Indiana University researchers have uncovered key insights into the dangerous phenomenon of “river avulsion,” offering a way to predict when and where rivers may suddenly and dramatically change course. Published in Nature, this breakthrough study sheds light on a process that has shaped human history through devastating floods and continues to threaten millions of people worldwide.
Led by James “Jake” Gearon, a Ph.D. candidate in the Department of Earth and Atmospheric Sciences (EAS) within the College of Arts and Sciences at Indiana University Bloomington, the research team has outlined for the first time the conditions that create river avulsions. Co-authors include Harrison Martin (Ph.D. EAS ’23), a post-doctoral fellow now at CalTech, Clarke DeLisle (Ph.D. EAS ’23) now at EVS, Inc, Eric Barefoot, a post-doctoral researcher at IU Bloomington and now a faculty member at UC-Riverside, and Professor Douglas Edmonds, the Malcolm and Sylvia Boyce Chair in Geological Sciences in the Earth and Atmospheric Sciences department.
Using advanced satellite technology, the team mapped how certain landscape features make avulsions more likely.
Measuring topography around a river is difficult and time-consuming because of the dense vegetation. We took advantage of a new satellite that uses lasers to measure topography.
James H. Gearon, lead author
Department of Earth and Atmospheric Sciences
Indiana University, Bloomington, IN, USA.
This technology, called lidar, penetrates vegetation to find bare-earth elevations, allowing for accurate topographical measurements.
The study presents a novel framework for predicting when avulsions will occur, a problem humanity has dealt with for millennia.
Avulsions which are possibly the inspirations for ancient flood myths, have created the largest floods in human history, and continue to threaten millions of people today. As climate change alters global water cycles and human expansion into flood-prone areas increases, understanding and predicting avulsions has never been more critical.
Professor Douglas A. Edmonds, co-author
Malcolm and Sylvia Boyce Chair in Geological Sciences
Department of Earth and Atmospheric Sciences
Indiana University, Bloomington, IN, USA.
What Causes River Avulsions?
Avulsions occur when a river’s water rises above the surrounding landscape, often due to the buildup of sediment in the riverbed. When this happens, the river may spill over its banks and carve a new path across the floodplain. This can lead to severe flooding, as the entire river rushes through areas not typically designed to handle such volume. For example, the 2008 avulsion of the Kosi River in Northern India directly affected over 30 million residents, killed hundreds of people, and caused over $1 billion dollars in damage.
Traditionally, scientists believed avulsions happened due to two main factors: either the riverbed became elevated above the floodplain, or the land on either side of the river offered a steeper, more appealing path for the water to follow.
Predicting avulsion hazards – A new way to map flood risksWe can now actually test these two 80-year-old ideas with the topography data we have collected from space, and we were surprised to find that both factors work together and play different roles depending on the river’s location.
Professor Douglas A. Edmonds.
Researchers analyzed data from 174 river avulsions around the world, using satellite imagery to track river movements over the past several decades. The study authors reveal that avulsions are much more common near mountain ranges and coastal areas than in the middle sections of rivers. They discovered that 74 percent of these avulsions occurred near mountain fronts or coastlines, areas where sediment tends to build up quickly.
Further, using topographic data, the researchers developed a new model to map what they term “avulsion corridors”—paths that rivers might take if they break from their current course. This tool could help governments and planners identify areas at high risk for sudden flooding, especially in regions with limited flood management resources.
The study also highlights the importance of considering avulsions in flood hazard assessments, something that current flood models don’t usually account for.
Implications for the Global SouthTraditional flood models focus on rising water levels from heavy rains, but avulsions can occur without warning, even in areas where rainfall isn’t a major concern. This makes them particularly dangerous and difficult to predict, much like earthquakes.
Professor Douglas A. Edmonds, co-author.
The findings could be especially valuable in the Global South—less developed parts of Africa, Latin America, and Asia—where avulsions are more frequent and often more deadly. In many of these regions, a combination of geological factors and infrastructure challenges makes communities more vulnerable to sudden river changes. The 2010 avulsion-related flooding on the Indus River in Pakistan, for example, affected over 20 million people.
The new model, which relies on minimal data, could help countries prepare for avulsion-related disasters, potentially saving lives and reducing economic damage. By offering scientists, policy makers, and practitioners a new way to think about and plan for flood risks—and as climate change continues to reshape weather patterns and increase flood hazards worldwide—the study provides essential tools for understanding and mitigating the dangers posed by river avulsions.Example of an ongoing river avulsion on the Zulia River, Venezuela that began in 2022
AbstractSo, it is entirely possible, even probable that the flood from which the biblical global genocide myth grew was one of those rare but still too frequent catastrophic river avulsions that give the lie to creationists assertions that Earth was perfectly designed for (human) life, by an omnipotent, omnibenevolent god. In fact, it’s a place subject to frequent devastating natural disasters that result in mega-deaths and, on occasion, mass extinctions.
Avulsing rivers create new pathways on the floodplain and the associated flooding can profoundly affect society1,2,3,4. River avulsions are thought to occur when the water column becomes perched above the floodplain5 or when the slope down the flanks of the channel provides a steeper descent than the existing river channel6,7. We test these classical ideas by quantifying the topography around avulsing rivers and show that these mechanisms, historically invoked separately, work together. Near coasts, rivers avulse when the slope away from the channel is steeper, not because they are perched. The opposite is true near mountain fronts; on fans, the alternative paths are similarly steep to the downstream path, so rivers avulse when they are perched above the surrounding landscape. We reconcile these findings and present a new theoretical framework that identifies which rivers are vulnerable to avulsion and predicts the path of an avulsing river. These first-order rules of avulsion suggest that avulsion risks are underestimated in many coastal environments8 and that probabilistic predictions of avulsion pathfinding can efficiently map hazards with minimal information. Applying these principles for risk assessment could particularly benefit the Global South, which is disproportionately affected by avulsions.
Gearon, J.H., Martin, H.K., DeLisle, C. et al.
Rules of river avulsion change downstream.
Nature (2024). https://doi.org/10.1038/s41586-024-07964-2
©2024 Springer Nature Ltd.
Reprinted under the terms of s60 of the Copyright, Designs and Patents Act 1988.
One of the reasons a puny African ape evolved intelligence was probably because it gave us a better chance of surviving on a hostile and unpredictable planet. Ironically, creationists favourite genocide is probably a folk memory of just such a catastrophe.
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