University of British
Columbia researchers have produced the first map of the world that
outlines the ease of fluid flow through the planet's porous surface rocks and
sediments.
The maps
and data, recently published inGeophysical Research Letters, could help
improve water-resource management and climate modeling, and eventually lead to
new insights into a range of geological processes.
"This
is the first global-scale picture of near-surface permeability, and is based on
rock-type data at greater depths than previous mapping," says Tom Gleeson,
a postdoctoral researcher with the Department of Earth and Ocean Sciences.
Using
recent world-wide lithology (rock type) results from researchers at the University of Hamburg
and Utrecht University
in the Netherlands,
Gleeson was able to map permeability across the globe to depths of
approximately 100 meters (around 328 feet). Typical permeability maps have only
dealt with the top one to two meters (about 2 to 3 feet) of soil, and only
across smaller areas.
"Climate
models generally do not include ground water or the sediments and rocks below
shallow soils," says Gleeson. "Using our permeability data and maps,
we can now evaluate sustainable ground water resources, as well as the impact
of ground water on past, current and future climate at the global scale."
A better
understanding of large scale permeability of rock and sediment is critical for
water resource management – ground water represents approximately 99 percent of
the fresh, unfrozen water on earth. Ground water also feeds surface water
bodies and moistens the root zone of terrestrial plants.
"This
is really an example of mapping research from a new, modern era of
cartography," says Gleeson. "We've mapped the world, peering well
below the surface, without ever leaving our offices."
The study's
maps include a global map at a resolution of 13,000 kilometers squared (more
than 5,000 square miles), and a much more detailed North American map at a
resolution of 75 kilometers squared (nearly 29 square miles).
The
research also improves on previous permeability databases by compiling
regional-scale hydrogeological models from a variety of settings instead of
relying on permeability data from small areas.
Global Map of Surface Permeability Informs Ground Water Supply
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