The incident (September, 2016) involving wastewater ingress via a sinkhole to the Floridan Aquifer in Polk County, Florida is yet another reminder of the susceptibility of groundwater to contamination. Other recent events like the 2016 Samarco tailings dam failure in Brazil (caused by loading of weak, groundwater-saturated materials), the 2010 Kolantar red mud dam failure in Hungary (mostly caustic, iron oxide, aluminium oxide, but worrying levels of chromium, lead and mercury), and Imperial Minerals 2014 Mount Polley dam failure tailings dam failure, all had immediate and devastating effects on surface water. In the longer term it is likely that downstream shallow aquifers have also been compromised. Continue reading
The image above illustrates part of a familiar grand cycle; water evaporated from the oceans, precipitates, is gathered in rivers and lakes that eventually return it from whence it came. This accounts for about 2% of earth’s available fresh water. The other 98% resides underground in aquifers. Groundwater is part of this grand cycle, albeit a less familiar part.
Almost half the world’s population lives within 60km of a coast; 75% of large cities are located near coasts. Coastal aquifers are part, in many cases the only part of the water supply equation to these crowds. Unfortunately, as is the case with so many of our water supplies, we have (collectively) failed to look after these resources. Continue reading
“Our water well taps into an underground lake”.
“There’s an underground river running beneath our property”.
“The river under our property comes from that volcano over there” (about 100km away)
These are just some of the explanations and descriptions of groundwater that persist in common discussion. Of course there are ‘underground rivers’ but they are generally restricted to limestone country, along with landforms like karst and sinkholes. But underground lakes…?