Southern Nevada Water Agonistes (SNWA), Part 1

Apologies to my Greek scholar friends for the title; my one semester of high school Greek is painfully obvious. 

Todd Jarvis reminded me of this excellent article by Emily Green in the 29 June 2008 edition of the Las Vegas Sun. I had heard of it but forgot to read it, since I was wandering around Virginia Beach and O'Hare International last week. It is well-written and has some great graphics.Be sure to read the many comments, and also the other articles in the Sun's series on Las Vegas and water.

Everyone involved with water should read this article; Todd said he would strongly recommend it to students, and I concur. It's a cautionary tale about what can happen when a hydrogeologist's results run counter to the interests of the client, but in the public interest. The story tells the tale of consultant Timothy Durbin's computer model of the region from where the SNWA wants to extract ground water. I won't repeat the story here, but just give my perspective based on my experience.  

I enjoyed the article because a big part of me still resides in the Great Basin (I worked at the Desert Research Institute in Reno for 12+ years, 1976-1989) and I am fascinated by Pat Mulroy and the SNWA's plan to pump ground water from the Great Basin aquifer, a remarkable carbonate (limestone and dolomite) aquifer that underlies a lot of Nevada and parts of Utah. The map below is from a USGS publication, and shows the carbonate flow systems in Nevada and California (see this post for more information).

My students and I did a lot of work on the carbonate aquifer's hydrogeology in the 1980s. Steve Kirk, my MS student at the Desert Research Institute and the University of Nevada-Reno, did a great compartment model of the White River subsurface flow system.

Here's a recent example of a compartment model of a portion of the carbonate aquifer by Rosemary Carroll et al., much improved over the ones my students and I did 20+ years ago:

Download DSC_JoH2007.pdf

One thing you need to know about modeling carbonate aquifers: it's very hard, more so than modeling aquifers that are granular porous media (sands, gravels, sandstones, etc.). Carbonate aquifers are generally highly heterogeneous and anisotropic, which means they are very nonuniform in their properties and their permeability may vary depending upon the direction of flow. In addition, the nature of the flow in carbonate aquifers may be such that the traditional equation (Darcy's equation) used to simulate ground water flow may be invalid. Take it from me; that's why I use simple compartment models. But they cannot tell you what you need to know for the case under discussion. 

Keep the above in mind when you read the article and the rest of my post.I suspect that Tim's modeling is based upon the USGS code MODFLOW, which, the last time I used it (admittedly about 6-7 years ago), had not been modified to deal with the kind of conditions that might occur in a carbonate aquifer.

The article was also appealing because I also know several of the protagonists - John Bredehoeft, Tim Durbin, and Terry Katzer. 

I knew Tim (his picture is from the article) when he was the Assistant, then District Chief of the U.S. Geological Survey's Water Resources Division Nevada District Office in Carson City, NV, in the late 1970s-early 1980s. Tim is a Stanford (BS, MS) civil engineer and in those days, I thought of Tim as more of a surface water hydrologist than a ground water guy. I guess in 25 years he's morphed into a hydrogeologist. Terry Katzer also worked for the USGS at that time; I believe he was Tim's Deputy Chief. John Bredehoeft was Regional Hydrologist in the USGS's Menlo Park, CA, office at the time. Tim wound up moving to Sacramento, CA, to become the District Chief of the USGS California District Office, Terry moved to Las Vegas, and John retired from the USGS in 1995. Tim and Terry are now out of the USGS as well.

Of the three, I know John best; I have not seen Tim or Terry for probably 20+ years. I have gotten to know John very well in the past 5-6 years, but I have known him by reputation for over 30 years. I even got into an argument with him (but not about hydrogeology) as a graduate student in 1974. We've both served on the board of directors of the Association of Ground Water Scientists and Engineers, a division of the National Ground Water Association.

If I had to choose one word to describe John, it would be this one: brilliant. If I had to pick one phrase to describe him, it would be: He does not suffer fools. John is a member of the National Academy of Engineering. He was educated at Princeton (BS in Geological Engineering) and the University of Illinois (MS and PhD). I think he should be in the National Academy of Sciences, but when it comes to membership in the National Academies, hydrogeologists are lumped as 'engineers' because they do 'practical' or 'applied' stuff. Not that there's anything wrong with applied work (heck, that's all I've ever done), but John has made some fundamental contributions to earth science as well as the science of porous media flow. He founded The Hydrodynamics Group after leaving the USGS in 1995. I remember seeing a "letter" he wrote several years ago explaining surface water-ground water interactions. It was about 12 pages, single-spaced; the rest of us would have submitted it as a journal article!

As recounted in the Las Vegas Sun article, John expressed doubts about the claims that the effects of the pumping wouldn't cause problems in Nevada's rural valleys. For one thing, you'd be mining ground water, which was forbidden by Nevada law. The pumping might even cause an Owens Valley-type situation, where the desiccation of the valley by Los Angeles has caused unimaginable dust (and health) problems. Katzer disagreed with Bredehoeft, and ultimately quit to work for the Las Vegas Valley Water District. Durbin's model indicated that this "Owens Valley scenario" would likely occur, and Katzer eventually came around.   

So what happened? Read the story.

Here is an earlier post about the possible effects of pumping on regional biodiversity.

I'll talk more about the Las Vegas water project in a day or two (or three).

"Essentially, all models are wrong, but some are useful." -- George E.P. Box and Norman R. Draper, Empirical Model-Building and Response Surfaces, 1987, p. 424

Comments

[Ray Walker]

As a retired Water Court Referee, I found the NV State Engineer's 40 page opinion was based on the facts, law and the evidence that were presented in the 19 year old case before him. Yes, I read it twice.

Strange...All parties in the matter were offered knowledge of a truly new fresh water Source that on average could annually provide Nevada with a million acre feet, which is 50 times the 18000 AF the SNWA was awarded. None chose to investigate or have such an alternative presented for consideration by the State Engineer.

Water from the new Source could be beneficially used in many ways. One of the secondary uses of the water could certainly be for hydroelectric power generation in Lake Mead, especially in light of the fact that it is predicted to dry up soon. Nevada's power company made a preliminary investigation of the new Source and concluded in writing that it was "definitely plausible" and recommended in writing that the SNWA too investigate.

It will take many years before the proposed SNWA wells do or do not mine the desert aquifers. Adequate monitoring is provided for in the State Engineer's ruling. That too will be argued every drop of the way to Las Vegas.

It is interesting that Nevada has no interest in a water resource that ADDS considerable water to the State without damage to the environment or anyone's water rights. Rarely is such an offer ever been made, anywhere. Usually only criticism, conservation and curtailment are offered up for the water shortage dilemmas facing the region.

Region....that's right, remember the new Source could provide enough water for many uses and others who would be willing to assist in its development and infra-structure... which would help pay for SNWA pipeline and plans.

The Bureau of Reclamation could coordinate such a regional approach, but they have not been asked by Nevada to investigate the possiblities.

Hope you find the claim of a truly new water Source equally as intriguing as predicting damage in a case that has already been concluded and likely moot.

Ray Walker (Retired Water Rights Analyst) [email protected]