HARVARD GAZETTE ARCHIVES
Investigating canals across time, from space
Ur takes a step back to see ancient networks
By Alvin Powell
Harvard News Office
The view from space of an ancient canal network is recasting archaeologists' understanding of the Assyrian capital of Nineveh and of the farming economy that supported it at its height of power almost 3,000 years ago.
The work of Assistant Anthropology Professor Jason Ur, detailed in the November/December issue of the archaeology journal Iraq, is casting doubt on the long-held belief that canals that brought water from springs and rivers far to Nineveh's north were mainly constructed to support the city's elaborate gardens.
Using declassified satellite photographs taken decades ago, Ur found what he believes is evidence of branches in the canals that indicate extensive agricultural irrigation in the lands north of Nineveh that scholars had thought dependent on rainfall for their annual production.
With irrigation, those fields would have been potentially far more productive than if they had been reliant on the vagaries of natural rain. Ur said the canals indicate that the farming system underlying what was then the Middle East's dominant empire was more complex and organized than previously thought.
There were likely smaller satellite cities in the areas where the canals branched, Ur said, some of which remain undiscovered or buried under modern villages.
"What I would guess is that there are undiscovered population centers there," Ur said. "The irrigation infrastructure is there to support larger settlements. We have to go and find them."
Satellite photographs can be powerful tools for archaeologists in detecting broader patterns of settlement and networks that accompany ancient civilizations, such as roads and canals, Ur said.
An archaeologist trying to piece together these great works can walk the ground, digging to examine a promising mound here or an outcropping there. It helps, however, to step back from the landscape and look for patterns and structures that may be difficult or impossible to detect from the ground, where thousands of years of farming, road building, and urban development obscure all but bits and pieces.
"If you press your nose against a Monet, all you see is a blur. If you take a few steps back, you see lilies, you see bridges," said Ur. "For this reason, remote sensing data is really irreplaceable."
Low-level aerial photographs can serve a similar purpose as satellite photos, Ur said, but some nations don't allow archaeologists in, never mind flying over their countryside with a camera.
Further, he said, Cold War-era photographs allow researchers to look back in time at a landscape that may have been lost in the intervening years through urban development, military action, or other human activities.
Urban sprawl from the nearby Iraqi city of Mosul is a concern around Nineveh, which lies across the Tigris River. Already, Ur said, expansion of Mosul has obscured many features around Nineveh's clearly defined walls that were visible in satellite photos from the 1960s.
In addition to his work on Nineveh, Ur is examining the road system around the Bronze Age city of Tell Brak in northeastern Syria. The roads into the city, about 2,000 years older than Nineveh, probably arose spontaneously, Ur said, as people and goods flowed into and out of Tell Brak. Ur said he's detected a progression from the main city, to smaller satellite settlements, out to farms, to fields, and to pastures beyond.
"I'm interested in urban settlements and in how they were maintained and sustained," Ur said. "Irrigation, agriculture, networks of roads to satellite cities were probably very important to these early settlements because they were too large to sustain themselves."
In contrast to the natural growth of Tell Brak's road system, Nineveh's canals were public works, instigated and controlled by the central government, which at the same time was importing conquered people to act as labor. Ur said the Assyrians brought in not just men from the conquered lands, but whole families and villages, what he called entire "productive units."
"I see this as part of an overall demographic program, not only creating a new landscape, but also importing the labor to work it," Ur said.
Ur is a year into a new project in northwestern Iran, examining a new system of canals there thought to have been built by the Sasanian Empire, which battled Rome and the Byzantine Empire in the Middle East.
The researchers found the Sasanian canals from the satellite photographs, but also noticed small, brightly colored rings of what looked like stones dotting the landscape. On their first field expedition, in January 2005, Ur said they discovered the rings were circles of large holes - each hole about 6 feet wide - dug into the ground with earth mounded around them.
Researchers believe the holes were winter quarters for livestock, and the rings of holes represented winter campgrounds for pastoral people who spent summers in the nearby mountains.
Many of these ancient campsites have been destroyed by farming and development in the years since the photographs were taken, Ur said, making the satellites a valuable resource to understand how the land was used by ancient people. Without evidence from the photographs and a visit to investigate remaining campsites, the visible canals would have left evidence of the landscape's agricultural past, but remained silent on the land's use by ancient herding people.
"This is what I find interesting," Ur said, "how structures emerged."