This is just one post in the Groundwater Category

Measuring groundwater in Nevada: an inexact and controversial science

Posted by: Aqua Blog Maven on February 28, 2008 at 5:13 pm

From Las Vegas City Life:

An interesting story on how things have changed in last 50 or so years. Nevada’s groundwater basins were originally mapped back in the 1960’s, using techniques of the time. Basically back then, they spent a couple of months in a basin studying vegetation and making crude estimates of how much water might lie beneath.

“They spent a couple months in a given basin using a standard approach, but they didn’t have a lot of data to go by,” says Andrew Burns of the Southern Nevada Water Authority. “In terms of an estimate, it’s pretty decent, and since that time a lot of additional data has been collected.”

The statewide “reconnaissance” survey from the ’60s was a piece of thumbnail-sketch science that went broad, but not very deep. But the results are nothing to sniff at; heck, they’re what the state engineer uses as a guide when deciding how to dole out groundwater rights. The comprehensive water portrait shows that Nevada has more than 230 groundwater basins. Now, more than 40 years later — in a rapidly growing state where water is gold — scientists still refer to that dated snapshot of our groundwater situation. There hasn’t been a statewide inventory of water since the ’60s. Since then, a patchwork of studies have offered updates here and there, but the overall picture isn’t as clear as you’d think.

“The interesting thing is that, obviously, some of that data is old,” says Allen Biaggi, director of Nevada’s Department of Conservation and Natural Resources. “And there are some new methods of evaluating basins.”

To date, only 81 of Nevada’s groundwater basins have been mapped using modern technology. The need exists for a more comprehesive evaluation, but finding the funding is difficult. Several bills have been introduced in the state’s legislature, but none have passed as of yet. Another attempt is planned for 2009.

Meanwhile, not only our techniques for mapping groundwater basins has improved, so also has our understanding of groundwater dynamics:

While water officials and scientists offer reassurances that there’s plenty of water out there in Nevada — in fact, many studies have found there’s more than previously thought — the most recent research has shed further light on a new conception of groundwater. It’s decidedly different than the popular idea of groundwater as big bathtubs of liquid, static and placid, just waiting for someone to dip in.

Even when the money’s there to plumb the desert depths for water, the science isn’t always crystal clear. A case in point resides to the north, where from 2005 to 2006, federal scientists were dispatched to study the area where the Southern Nevada Water Authority wants to tap rural groundwater. The $6 million study scrutinized 13 basins straddling the Nevada-Utah border. The Basin Area Regional Carbonate Aquifer System Study (aka BARCASS), paid for by an amendment to the Southern Nevada Public Lands Management Act, was seen by critics of the rural pipeline plan as a scientific sop to skeptics and a Pass-Go card for the water authority — There, there, now. There’s plenty of water in the area, see?

The good news is there seems to “extra” water flowing out of the 13-basin study area. But the study also had the perhaps ironic effect of reinforcing another idea that’s quickly gaining traction — and one that might make water authority officials squirm. The emerging idea is that groundwater, scientists are finding, isn’t merely confined to a basin as though it were sitting in a sink. Rather, the water slips and slides around beneath the earth in larger patterns called regional flow systems. The inconvenient result: Pumping water at Basin A could spell trouble for Basin Z — or, say, the endangered species of fish that call Basin Z home. Indeed, some critics think BARCASS raised more questions than it answered.

“These aquifers are all connected, and they’re the source for surface water, including rivers that feed Lake Mead, and springs and seeps that are critical habitat for rare plants and animals,” says Launce Rake of the Progressive Leadership Alliance of Nevada, a foe of the rural pipeline plan. “We don’t understand what’s happening out there. Some scientists are getting a grasp, and the more we know, the more fragile those interconnected environments look.”