A few weeks ago Abrahm Lustgarten wrote a ProPublica article that contained a quote from Dr. John D. Bredehoeft on the folly of neglecting groundwater-surface water interactions, something both California and Arizona do:
If you don’t connect the two, then you don’t understand the system. And if you don’t understand the system, I don’t know how in the hell you’re going to make any kind of judgment about how much water you’ve got to work with.
I was not surprised by the quote, as hydrogeologists (and John is one of the world's greatest and a member of the US National Academy of Engineering) have known about this connection for quite some time. But after being reminded of John's superb quote by friend and colleague Michael van der Valk, I decided to give more exposure to his sage advice.
Here is a recent paper by John and fellow former USGS hydrogeologist William M. Alley on the behavior of groundwater systems, 'Mining Groundwater for Sustained Yield' (free PDF, p. 33-41).
Might be helpful in understanding the difference between groundwater and surface water. Time is a big deal for the former.
Here are some of my recent (March 2015) thoughts on California's groundwater situation.
Enjoy, and remember the quote.
I'll close with a few salient quotes from Lustgarten's article.
"We know for a fact that pumping aquifers can dry up rivers. But it is the law … it would be a huge upset to the economy to do away with that." - Thomas Buschatzke, director of the Arizona Department of Water Resources
“Those who have unlimited water supply don’t particularly like the idea of changing that. You can’t manage what you don’t measure.” - CA State Sen. Fran Pavley, who worried that recognition of the GW-SW connection would derail recent groundwater legislation.