We can start close to home in this passing
consideration of water resources, with the Sand Hills of Nebraska
that cover some quarter of the state. The Sand Hills of Nebraska
have a distinctive shape and composition., and their geology speaks
to water resource issues in multiple ways. Their form is that
of sand dunes, in some places Sahara size dunes, now covered by
the thinnest veneer of delicately stabilizing grasslands. Once
they marched across the landscape as part of a desert scene,
advancing and encroaching, filling valleys. They tell of a time
of greater aridity in the American midwest, and remind us that
on a regional scale the hydrologic behavior has changed significantly.
They are one of a great myriad of geologic witnesses to past climate
Perhaps ironically, they also sit atop a world
class groundwater resources - the High Plains (or Ogallala) aquifer.
The Sand Dunes are a huge sponge that sucks up the moisture that
does fall. The sand is so permeable the water doesn't collect
and run on the surface, and it doesn't have much time to evaporate.
It mainly sinks into the ground. Locally the water bleeds to the
surface giving life to the wetlands, lakes and the few rivers
that do flow here, giving life to rich riparian corridors and
ecologic oases. The moisture sinks deeper into the High Plains
Aquifer, recharging it.
Nebraska has an incredibly valuable groundwater resource. Should we pump water to other water hungry areas? Who 'owns' the water? How can we protect it from contamination? Do we understand the behavior of this aquifer? When might the climate change again so that the dunes move once more? These are some of the questions that arise.
We can live quite well without oil, gold and
diamonds, but we die without water.
What to avoid: The Ancient Mariner's plight "Water water everywhere and not a drop to drink."
Solutions: We will come to view water as precious, not to be squandered.
Sources of water:
Factoids: (taken from Sci. Am. articles Feb. 2001)
The solution is a combination of technology and behavioral changes.
Jill Schneiderman (ed.), 2000, The Earth Around Us @ Maintaining a Livable Planet; Freeman, N. Y., 455 p. This is a very readable collection of 31 essays by geoscientists addressing theory, policy, and practice related to keeping this planet a good place for all, with some very interesting case histories highlighted.
Scientific American Feb. 2001 issue with focus on water resources.