Satellites & drones – the new way of understanding our water resources (they’re not just killer robots!)

Two identical satellites orbit one behind the other to measure changes in gravitational pull, from which changes in aquifer levels are calculated (Source: NASA Earth Observatory)

While NASA satellites can usually be found zooming around Earth’s atmosphere collecting information on the history of the stars or nearby asteroids, NASA’s GRACE (Gravity Recovery and Climate Experiment) satellites have made a new found and alarming discovery about the planet’s groundwater sources: the world’s largest aquifers (21 of 37) are being depleted at a rate so rapid that groundwater tables have significantly dropped across the world. Meaning that people are pumping water out of them much faster than they are being recharged. The realisation that groundwater resources are not infinite under these conditions is very much dawning on the 2 BILLION people that rely on them as their main source of fresh water, particularly in arid and semi-arid regions of the Middle East (Arabian Aquifer), North Africa (Murzuk-Djado Basin), South Asia (Indus Basin), as well as California’s drought-stricken Central Valley Basin.

(Source: Water Resources Research, Patterson Clark/The Washington Post)

While scientists have long suspected that we have been severely stressing our underground water systems, recent data from NASA has allowed the first detailed assessment to confirm that demands from growing populations, agriculture and industries like mining have been major contributors to the situation (it also doesn’t help that decreasing rainfall has been reducing aquifer recharge rates). Specifically, researchers at the University of California used measurements of subtle changes in Earth’s gravitational pull on the orbiting spacecraft relating to the heavier weight of water to determine changes in aquifer water levels between 2003-2013. Whilst data from such studies are very sobering indeed, the methods of collection are advancing quickly (and from space no less!) and providing us with ever more detailed and accurate information on the past and current state of our water resources.

(Source: Department of Water / West Australian newspapers)

Other very useful technological processes have also allowed us West Australians to investigate the potential of our own local groundwater resources and actually quantify volumes, quality and recharge potential via aerial electromagnetic technology – sending electromagnetic pulses into the ground from a plane, measuring the return signal and converting into useful data. A recent aerial survey in the Pilbara region approx. 100 km east of Port Headland and covering an area the size of Belgium has revealed a potential ~100 GL/year resource in the West Canning Basin expected to be suitable for drinking water. The State Government has used this information to support their case for future expansion of agriculture in regional areas via their Water for Food initiative – the four-year $40 million Royalties for Regions funded program intended to direct state investment in agriculture over the next 50 years or so (and develop a new market for WA given the beginning of the end of the mining boom).

However, Australia’s largest aquifer system, the Canning Basin (of which the West Canning Basin is a part of), was also identified in the NASA study as having the third-highest rate of depletion of aquifers in the world, attributed to the water-intensive activities of mining, and oil and gas exploration in an aquifer of very old water.  We are yet to understand what the expansion of agricultural activity will truly mean for the groundwater systems of the Pilbara, as investigations associated with the Water for Food initiative continue.

The potential applications of drones for water research are far-reaching, here shown collecting samples from a lake. (Source: University of Nebraska-Lincoln)

Drones (or umanned aerial vehicles – UAVs) have also been in the media a lot lately, given their increased use in military warfare by at least 50 countries (however, have been in use since the early 1900s).  What most people don’t know is that they are now increasingly used for ‘good’ in aerial photography and LiDAR surveys, film-making, archaeological studies, crop-spraying and environmental research.

In terms of water management, some consider that they can play a significant role due to their large scale viewing advantages, accessibility of hard-to-get-to locations, regional mapping, data collection, and precision applications.  For example, a recent study in the US used a drone to pinpoint locations of emerging groundwater and seepage areas associated with elevated levels of nitrogen polluting a harbour. Drones are also being used to collect water samples from surface water bodies for analysis, and survey flood restoration projects (such as assessing whether the removal of a levee at the Cosumnes River Preserve south of Sacramento, California, is allow localised flooding to resume natural, historical patterns).  Saginaw Valley State University students have even developed a water sampling drone equipped with a drill attachment that bores through ice for winter sampling. Traditional water monitoring methods are time-consuming, costly and limiting given that they rely heavily on researchers traveling long distances to collect samples/measurements at multiple sites. Whereas drones offer the capability of collecting samples and data over large, inaccessible/unsafe areas much more rapidly, consistently and accurately (given the right set of GPS coordinates), while communicating with their human controllers in real-time over wireless connections.

So while some advances in technology seem to be putting the fear into even Stephen Hawking (granted, this relates to killer robot drones) luddites should take heart in knowing that it is also providing us with incredibly detailed, invaluable environmental information on water resources we can’t always see or access, and significantly helping scientists and natural resource managers in their quest for better and more sustainable water resource management!

Perhaps one day we will eventually find ourselves mining water from asteroids and distant planets if we don’t manage our home-made water resources, but that’s still a while off……