to help put into context this series of blog posts on water issues, i think it’s important to review aquifers … an aquifer is essentially a ‘gateway’ to accessing deep ground water that flows beneath the Earth’s surface … tapping into an underground aquifer by drilling or digging a well is one of the primary sources of freshwater worldwide … therefore, threats and risks to aquifer resources directly impact billions of people, as well as wildlife and ecosystems …
the global importance of aquifers is impressive when you consider that collectively, the world’s aquifers contain 100 times the volume of superficial fresh water …
many aquifers are located very deep below the Earth’s surface … drilling wells to access these deep aquifers is not always feasible and always imparts some form of environmental disturbance and destruction …
a traditional well in the desert near marsa alam, egypt (may 2007)
if you google search “aquifer risk“, a shocking number of websites provide information about the risks to local aquifers (e.g., currently under threat are some of the world’s largest and most important aquifers, including: south america’s guarani; north america’s ogallala and oak ridges moraine; australia’s great artesian basin — arguably the world’s largest aquifer with an area stretching over 1.7 million km²; malta’s numerous aquifers; the nubian-sandstone aquifer system in north-eastern africa; north-western sahara / djeffara aquifer; et al.) and the alarming rate at which water resources are declining, along with links to the scientific studies and geological research that support these claims …
aquifers that have, for several decades or centuries, nourished and hydrated countless societies are now choking up and sputtering with little to offer thirsty plants and animals, including humans (who have always secured the lion’s share of blue gold) …
risks to aquifers:
* human development over the recharge areas (i.e., people fail to appreciate the importance of wetlands, which help to maintain groundwater levels, minimize soil erosion, and filter chemical pollutants and other contaminants) …
* rates of extraction exceeding rates of replenishment (i.e., unsustainable exploitation, most often due to high demand resulting from over-population and/or unusability of nearby aquifers) …
* decreased water pressure due to falling water table, making water extraction more difficult and less fruitful …
* contamination via:
* salination (often occurs due to over-exploitation causing a lowered water table & subsequent leaching of salt water into the superior or adjacent freshwater layer)
* chemical pollution (e.g., agricultural & urban run-off)
* acid rain
* soil erosion (often due to regional human development and infrastructure, as well as deforestation, agriculture, mining, and other resource extraction)
* climate change (especially changes in precipitation) effecting a decreased rate in aquifer replenishment …
* stochastic events that may affect recharge areas (e.g., earthquakes that result in physical geological obstructions — known as aquitards — to aquifers) …
* recently, CO2 sequestration technology, which involves injecting CO2 gas into saline aquifers, may increase the risk of salination of proximal freshwater aquifers … one Stanford University report states that despite the encouraging interest and financial support from governments and industry in developing CO2 sequestration technology, “at the current pace of progress, convincing answers about safety and effectiveness may not be available for more than a decade” …
this list of risks to aquifers is not exhaustive … there are likely many more factors that compromise aquifer existence and function, which i have not mentioned here …
furthermore, the variable, and often latent, replenishment rates of various aquifer systems heightens the urgency for global attention, political action, and universal water conservation …
statistics for some of the world’s largest aquifers:
| name | area (million km2) |
volume (billion m3) |
replenishment time (years) |
continent |
| nubian sandstone aquifer system | 2.0 | 75, 000 | 75, 000 | africa |
| north sahara aquifer system | 0.78 | 60, 000 | 70, 000 | africa |
| high plains aquifer system | 0.45 | 15, 000 | 2, 000 | north america |
| guarani aquifer system | 1.2 | 30, 000 | 3, 000 | south america |
| north china plain aquifer systems | 0.14 | 5, 000 | 300 | asia |
| great artesian basin | 1.7 | 20, 000 | 20, 000 | australia |
source: world water assessment programme (united nations) unesco. 2003. water for people, water for life.
be water wise … respect and conserve this invaluable resource … YOU are just as much a part of the solution as are governments, industry, and non-government organizations …
Loading ...
Thanks! I appreciate all the statistics you provide in your posts. It shows you research your topics well. I’ve learned a lot from your blog. Keep up the good work! I look forward to future posts.
All the best!
I recently found your blog and I’m amazed at the great info you provide! Thanks for the tips and for teaching us how to care for the planet.
I don’t even know the way I ended up here, but I believed this publish was wonderful. I have no idea who you’re but surely you’re likely to be a popular blogger if you aren’t by now? Cheers!