It has long been apparent that the water supply of the Colorado is inadequate for all the demands that will be made upon it, as is the case with many other streams in the West.

That is G.E.P. Smith of the University of Arizona, writing in the Proceedings of the American Society of Civil Engineers in November 1924.

Colorado River hydrologist E.C. LaRue, courtesy USGS

I’ve long been of the belief that it was the unusual wet period of the first two decades of the 20th century that led early westerners to believe there was plenty of water in the Colorado, and that misunderstanding was at the core of the set of problems we now face. But an intriguing volume I’ve been reading suggests a more complex picture – that even then there were substantial voices arguing there was not enough water in the Colorado. The book is a doctoral thesis written in 1926 by Reuel Leslie Olson on The Colorado River Compact (which I picked up over the summer at Sam Weller’s, an epic western bookstore in Salt Lake City which I had the strange fortune to visit just days after Weller’s death). Olson’s account has the charming virtue of immediacy, written in the years after the Compact was signed, but before the concrete to implement it had been poured.

My belief regarding the unusual wet period is not wrong. It is clear that the compact’s framers only had twenty years of river records to go on when they divided up the Colorado’s waters, but that they assumed that was sufficient to capture the full range of natural variability. Here, for example, is Delph Carpenter, the state of Colorado’s representative and the real genius behind the Compact:

The hydrographers and experts advise me that a twenty-year record on a river is adequate in its completeness and includes enough years to warrant an assumption that the average there deduced would be the average flow of the river in the future.

And we know from the tree ring record that those 20 years were “one of the wettest periods in the past 5 centuries” (Woodhouse, C.A., S.T. Gray, and D.M. Meko, 2006. Updated streamflow reconstructions for the Upper Colorado River basin. Water Resources Research, 42, W05415. doi:10.1029/2005WR004455).

That right there was a recipe for disaster, a misunderstanding of the amount we had in the bank as we were writing the West’s great check.

But Olson’s on-the-spot 1926 analysis makes clear that, even then, there was widespread fear that even given what we now know was a rosy streamflow scenario, there were people who thought there was simply not enough water in the Colorado to do what they were contemplating.

Most powerful among those voices was E.C. LaRue, the hydrologist who laid the groundwork for the subsequent development of the Colorado. Testifying before the U.S. House of Representatives in March, 1924, LaRue said this:

On page 167 of my report, Colorado River and its Utilization, published in 1916 by the United States Geological Survey … will be found the following conclusions: “Evidently the flow of Colorado River and its tributaries is not sufficient to irrigate all the irrigable lands lying within the basin….”

That is the conclusion I reached in 1916.

Additional data collected by myself and others in recent years prove that this conclusion is correct….

It is something that should have been broadcast six or eight years ago … instead of saying that there is plenty of water for all.

As an addendum to Emily Green’s year-end look at Lake Mead (High good, low bad) I’d like to extend the analysis back a bit farther in time.

Emily points out that, while population has risen over the past decade in the region served by Mead (one of the two large storage reservoirs on the Colorado), the lake’s levels have been steadily dropping:

While federal Bureau of Reclamation records show that the elevation of Lake Mead, the major “lower basin” Colorado River reservoir serving Arizona, California and Nevada, fell more than 117 feet, the population of the US states served by Mead rose. The US Census Bureau estimates that the population of the driest state in the country, Nevada, climbed 32.3%, while Arizona’s increased 28.6% and California’s 9.1%.

In fact, you can extend that back in time. While the population in those states is the highest it has ever been, Mead, as measured by the amount of water currently in storage, is the lowest it has been since the lake was first filled:

(Data available here)

The Jan. 1, 2010 number shown above is preliminary and subject to change, but as it stands now Lake Mead appears to be starting 2010 with the less water in storage than at the start of any year since it was first filled. Previous years with similarly low levels: 1956 and ’57 (the heart of the drought of the ’50s) and 1965 (when Mead dropped because water was being held upstream to fill Lake Powell, behind the newly completed Glen Canyon Dam).

David Zetland posted on the Salton Sea today, arguing that we should just give it up:

Today’s Salton “Sea” is NOT natural. It’s replenished by irrigation runoff, of dubious quality. As water evaporates, it leaves behind higher concentrations of salts and other nasty stuff. Time to dry out the Salton Toilet, clean up the mess (yes, users pay) and restore real wetlands where they naturally occurred — in Mexico, at the Colorado River Delta.

To which Imari Nuyen-Kariotis responded:

The Salton Sea is here and people live around it.

Which is why, whatever merits David’s argument may have in the abstract (and I’m not sure I buy David’s approach), the Salton Sea will not go quietly.

Pat Mulroy on how Las Vegas (Nevada) plans to meet its long term water needs – desal! I know, I know, you’re saying, “But don’t you have to be by, like, an ocean or something?” Here’s the scheme: build big desal plant down on the Gulf of California, give that water to Mexico to meet their entitlement to the pittance of the Colorado that’s legally theirs, and let Vegas (and whoever else shared the cost of building the plant – some folks in Arizona also like the idea) use the water that would otherwise have gone to Mexico:

By 2020 I think we will have developed partnerships with Mexican entities for desalination plants and exchanging water on the Colorado River.

As far as the pipeline to bring water from Northern Nevada to Southern Nevada, you tell me what the hydrology in the Snake Valley Basin looks like in 2020 and I’ll tell you if we’re going there. If Southern Nevada has to fend for itself, I think we’ll have no choice but to develop that water supply. We can’t desalt our way out of this problem; the solution has to be larger and more dramatic.

As long as water supplies on the Colorado River stay relatively stable, Southern Nevada has lots of opportunities for water exchanges and desalination. But if climate scientists’ worst-case scenario on the Colorado River were to materialize and lake levels were to drop significantly, this conversation would change dramatically.

(Note to non-New Mexico readers: We have a “Las Vegas” in New Mexico, a lovely little down on the east slope of the Sangre de Cristo mountains. Hence my habit of clarifying which Vegas I’m talking about.)

From Shaun McKinnon, a must-read story for water geeks on Arizona’s thinking about its water future – specifically where to get more (or use less?):

Drop 2 is no Lake Mead, the huge reservoir outside Las Vegas that holds Colorado River water until cities and farms in Arizona, Nevada and California need it. The new project is unlike almost any other on the river, designed not to store large quantities of water for long-term use but to hold smaller amounts for a few days or weeks.

It is a fitting symbol of the challenges of stretching a water source – the river – that has little stretch left in it and of the mounting costs to do so.

The reservoir is an attempt to wring every last drop of water from the Colorado. It will act as a catch basin, holding water that flowed past the last traditional dam on the river without a user ready to take it. That can happen if, say, a farmer in California’s Imperial Irrigation District requests water for a particular day and then it rains in the time it takes the water to flow south from Parker Dam, south of Lake Havasu City.