Surface Rock Plays a Role in Natural Water Filtration

UBC researchers have produced the first map of the world outlining the ease of fluid flow through the planet’s porous surface rocks and sediments. The maps and data, published in Geophysical Research Letters, could help improve water resource management and climate modelling, and eventually lead to new insights into a range of geological processes.- Full UBC News Release

Q&A – Bob Brouse, Water Chronicles, UBC Researcher Tom Gleeson

How did you come to do this map? What’s it for?

Groundwater is critical to humans and the environment. More than 99 per cent of the fresh, unfrozen water on earth is groundwater. Groundwater feeds surface water bodies and moistens the root zone of terrestrial plants. Even though it is critical we have a poor understanding of how climate and groundwater interact and how we can sustain groundwater resources through time.

You were saying on the phone that this has something to do with climate change? how come?

“Climate models generally do not include groundwater or the sediments and rocks below shallow soils,” says Gleeson. “Using our permeability data and maps we can now evaluate sustainable groundwater resources as well as the impact of groundwater on past, current and future climate at the global scale.” Even though groundwater represents the majority of fresh, unfrozen water on the planet earth, we don’t know how this huge volume of water affects climate.

We talked briefly about fracking. Most of the experts i have talked to say this is extremely dangerous. What does your map have to do with fracking and what could it help us understand?

Fracking is effectively increasing permeability at great depths to increase fluid flow. Our maps focus on shallow permeability at depths of less than 100 m. So in the future we have to extend our understanding of permeability to greater depths in order to better understand the impacts of fracking.

Does this in some way help us to conserve our water and I would think we are talking about groundwater?

The maps and data could help improve water resource management. For example, we can now model how groundwater flows at national scales which lead to better and more cohesive water resource management. This hopefully will lead to conservation of this valuable natural resource.

Briefly we touched on the United States situation regarding your map and water. Can they use this map? If so why?

Groundwater resources are critical and declining in some parts of the United States especially in the southwest. Our maps could be used to better model these aquifers at very large scales.

This is an incredibly complicated looking map, could you tell us who helped you? how long? a little bit about your method of putting this altogether? Help me read this!

The maps are based on geology maps and the distribution of rock types are often very complicated, so that is why these maps also look complicated. This two year research project was a significant collaboration between researchers at UBC as well as researchers from the US Geological Survey in Denver, Colorado, the University of Hamburg, and Utrecht University. We used recent world-wide lithology (rock type) results from researchers at the University of Hamburg and Utrecht University in the Netherlands to map permeability across the globe to depths of approximately 100 metres. Typical permeability maps have only dealt with the top one to two metres of soil, and only across smaller areas.

Now that you have done this whats next, where do you go from here?

Examine how groundwater and climate interact as well as estimate the sustainability of groundwater resources around the globe.

Read more at The Water Chronicles

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