Geologists’ model reveals foundation flaws in bedrock under new urban centers

Before developers decide to make the desert bloom, they better take a look at what’s under the surface of the Earth.

That’s the conclusion of research by Texas A&M University geologist Mohamed Aly, who’s using GIS (geographic information systems) techniques to conduct engineering geomorphology assessments of some of Egypt’s newest urban developments to predict – and thus avoid – foundation problems stemming from instabilities in the underlying bedrock.

The resulting GIS model may also be used to study similar new developments worldwide.

“For the past 50 years, the Egyptian government has encouraged the building of new cities in the desert, away from the Nile valley and its delta, where 96 percent of the Egyptian population lives,” said Aly, a doctoral student in the Department of Geology and Geophysics of the College of Geosciences. “New Minia City is one of 16 developments being built in the desert over the last few years. It is still close to the Nile, from which it gets its drinking water and to Old Minia City, which supplies surface necessities.

“While New Minia City is in the early stages of construction, its planners wanted an assessment of any geo-environmental problems that might occur,” he continued. “Our study revealed that some areas of proposed development were underlain by soft highly fractured and jointed limestone, which is prone to dissolution by acidic rainfall, creating sink holes and caves in the heterogeneous bedrock.”

Other new Egyptian cities had not investigated their bedrock foundations before building, creating later problems and leading authorities to seek the advice of geologists like Aly, who, along with being a student in Texas, holds an assistant lecturer appointment at Zagazig University, Egypt.

Aly and advisers John Giardino, dean of graduate studies and professor of geology and geophysics, and Andrew Klein, professor in the geography department, developed a GIS model to assess New Minia City’s site risk, urban development suitability and land use potentials. Aly presented a paper on their model at this month’s annual meeting of the Geological Society of America.

GIS produces a digitally registered geographic database from data layers obtained from different sources, such as satellite remote sensing and seismic ground testing. Aly’s model system used data layers including geology, land use/cover, soil types, karst distribution, fracture density, slope, stream ordering, roads and administrative boundaries.

“Our GIS model, which was found to be effective at revealing the foundation bedrock problems, was adopted locally to assess the area’s main geo-environmental problems threatening urban development of New Minia City,” Aly said.

“We hope the model will provide a good base for informed decision-making in support of integrated sustainable development for New Minia City, allowing more geologically unstable areas to be used for agriculture or parks, instead of for housing or other structures. Finally, we recommend our GIS model be used not only for this city, but also for new cities with similar geologic and geomorphologic settings across the world.”

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Contact: Judith White, 979-845-4664, jw@univrel.tamu.edu; Mohamed Aly, 979-862-9153, aly@tamu.edu.