Ancient Answers for Future Water Challenges

UC interdisciplinary researchers and global collaborators dig into the past to inspire modern water management strategies that can save time and money and may avoid negative effects on our climate.

Legends of the lost reservoirs

Tucked away in a laboratory in University of Cincinnati’s Braunstein Hall are tubes of rock and dirt that quietly tell a story –– a story that looks back on ancient society’s early water conservation. UC researchers hope the story will aid in the future preservation of our planet’s most precious resource.

In an effort to help manage the world’s water supply more efficiently, an interdisciplinary team of University of Cincinnati researchers from the departments of anthropology, geography and geology have climbed through rainforests, dug deep under arid deserts and collaborated with scientists around the world to look at how ancient humans manipulated their environment to manage water.

“We begin by asking,  ‘What is water to humans, how do we engage with it and how does the environment engage us?’”  asks Vernon Scarborough, professor and department head in UC’s Department of Anthropology. “When we look at the trajectory of our changing climate, we realize that the issue is not just climate change but also water change. Climate and water work synergistically and can affect one another in critical ways.

“Given the current climate patterns, in this and the next century, we will likely face further rising sea levels, less potable water and a compromised availability of freshwater as a result of drought in many areas and unusually heavy rains and runoff in others.

“So we are looking at how the past can inform the present,”  adds Scarborough.

UC grad student Jon-Paul McCool excavates the berm wall of an ancient Chaco Canyon canal while UC Professor Christopher Carr takes notes. photo/Nick Dunning

UC Professor Nick Dunning (on ladder) records alluvial stratigraphy in a Chaco Canyon arroyo while UC Professor Vern Scarborough looks on. photo/Nick Dunning

High-tech collaboration

To face future sustainability and water management issues, UC’s interdisciplinary team of real-world “Indiana Jones” employ modern technology to peek inside ancient irrigation communities in obscure places around the globe like the arid American Southwest and humid rainforests in Central America and Southeast Asia.

“The point of these projects is to help, in part, create effective modern water policy,” says Scarborough, who also works closely with the United Nations Educational, Scientific and Cultural Organization (UNESCO). “Exploring all these unique points on the globe is the only way we’re going to get at it, and  it’s our teamwork, communication and cooperation that will make this project so successful.” 

As a result of their collaboration, several members of UC’s research team will be presenting the outcome of their field work at one or both of two upcoming prestigious scientific annual meetings: the 77th annual Society for Applied Science meeting in Santa Fe, New Mexico, and the 82nd annual Society for American Archaeology meeting in Vancouver, British Columbia, Canada. Both are meeting this week.

For more than two decades, the researchers worked intricately together in remote areas that are known for their seasonal water and environmental challenges.  One core investigation lies deep in the ancestral Puebloan community in Chaco Canyon, New Mexico  –– the ancestors of modern Puebloans that thrived for more than 300 years in a dry desert in the middle of the American Southwest.

Scientists have long debated whether this area was truly a sustainable thriving community based on local resource access or an occasional gathering spot for ceremonial rituals dependent on importing food and related supplies.

To create a comprehensive snapshot for how ancestral Native American Puebloans managed water and survived in the ancient desert, UC’s research team used  aerial surface imaging technology, mass spectrometry and geochemical soil sampling, as well as anthropological behavioral and DNA studies and soil excavations around ancient structures  to help shed significant light on that mystery.

LIDAR images of the elevation levels in Chaco Canyon, New Mexico reveal ancient dunes, canals, building structures and rincon watershed areas as part of a poster presentation by the UC research team at the 2016 Annual Society for American Archaeology meeting. slide photos/Christopher Carr

In the field 

Nicholas Dunning and Christopher Carr, both UC professors of geography, looked broadly at the geographic area documenting and sampling the stratified layers of rock and sediment, while Lewis Owen, also a UC professor of geology, used optical-stimulated luminescence, a unique technique to accurately determine the age of core sand and soil samples.

“We found geochemical evidence for corn grown in the area during this time, which is a very water-intensive crop, as well as sophisticated irrigation and water-management techniques,”  says Kenneth Tankersley, UC associate professor of anthropology and geology.

To get a 3-D look at the surface of the canyon, Carr used sophisticated LIDAR technology, or light, imaging, detection and ranging technology, to measure the surface elevation of the ground from an airplane.

“This technology uses a laser beam to measure the morphology of the surface and is totally revolutionizing archaeology,”  says Carr. “The key thing LIDAR gives us is elevation so we know how the water flows off the mesa tops into the drainage ditches and into the valley floors.

“LIDAR ultimately tells the archaeologists where to excavate and look for evidence of agriculture, canals and water control gates beneath the surface.”

UC professors Lewis Owen (L) and Ken Tankersley (R) collect ancient soil samples at Operation 100 in Chaco Canyon, New Mexico. photo/Nick Dunning

High-flowing Chaco Wash following a heavy rainstorm in present day in Chaco Canyon, New Mexico. photo/Samantha Fladd

 Salty survival

To uncover the thousand-year-old secrets for survival held in the geochemical deep core soil samples, Tankersley, along with Owen and Warren Huff, UC professor of geology, employed laboratory sampling techniques to reveal that the high level of salt in the soil –– once thought by scientists to be harmful –– was in fact a form of a calcium sulfate mineralization that may have functioned to enhance the soil for the maize (corn) grown in that area.

“The surrounding mesas provided water in their springs after the snow melted,” says Tankersley. “During the rainy season when floodwaters hit, the Puebloans would capture runoff water from small canyons known as the rincons and local periodic streams such as Chaco Wash and Escavada Wash.”

The researchers consider this strategy a reflection of risk aversion.  “When it rained in one spot over here the Ancestral Puebloans took advantage of it, and when it rained over there they took advantage of that,” Scarborough says.

Under this expeditious use of landscape, two key members of the Chaco water management project, Stephen Plog, professor of archaeology from the University of Virginia, and Adam Watson at the American Museum of Natural History were also part of the collaborative team that utilized DNA sampling techniques on human remains to reveal a remarkable matrilineal family line connected through the female lineage.

"To effectively manage water requires flexibility and creativity as rainfall is unpredictable in the Southwest,”  says Samantha Fladd, an advanced doctoral student from the University of Arizona, also working on the Chaco project here at UC. “The presence of a hierarchical matriline helps to explain how Chaco residents coordinated these activities in order to practice successful water management and agriculture."

Aerial view of present-day Tikal's ancient building structures in Guatemala, Central America. photo/David Lentz

Illustrated slide portraying ancient water management canals and reservoirs in Tikal, Guatemala. illustration/Vern Scarborough

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