WaterWired

Stationarity is Dead! Whither Water Management?

Last summer Chris Milly wrote an article in which he proclaimed "Stationarity is dead!" I noted that we hydrologists have been reluctant to admit that because it would cast doubt on the way we manage water. I commented to a colleague that when I took the late Chester Kisiel's statistical hydrology course on the early 1970s, he discussed why hydrologic stationarity was an invalid concept. Then we proceeded to apply techniques that assumed stationarity to solve water management problems - dam design, etc.

Milly and his colleagues recently published a longer article in Science:

Download milly_et_al.pdf 

So what do we mean by "stationarity", and why should we care?

By "stationarity" we mean, that, statistically speaking, the future looks like the past - whether we are talking about precipitation, runoff, or other flows in the hydrologic cycle, depicted below. The numbers represent relative flow rates (from Hornberger et al., 1998, Elements of Physical Hydrology).

Take this frequency diagram (again, from Hornberger et al., 1998, Elements of Physical Hydrology). It shows the frequencies of annual precipitation in Seattle and Denver.

Stationarity says we can assume that the mean annnual precipitation in Seattle and Denver over the next 50 years, 1990-2039, would be "around" 941 mm and 380 mm, respectively - the same as 1940-1989. In fact, by invoking the stationarity assumption we can assume that over the next few thousand years (or longer), the rainfall distributions for Seattle and Denver will look the same as they do above.   

The same would hold for the distribution of runoff (streamflow), which can also be described by frequency or probability distrbutions.

This assumption makes planning easier. For example, if we need to know runoff so that we can design a large enough dam or big enough reservoir to provide enough water or flood protection for the next 100 years, stationarity allows us to do that with some degree of confidence, provided we have enough data to construct or develop a frequency or probability distiribution.

We know that hydrologic processes do not behave like stationary ones. Why not? Well, we humans have altered the hydrologic cycle. Example: imagine your watershed and what it looked like 200 years ago, or even 20 years ago. It has probably seen much development, which has changed the rainfall-runoff relationship. So if a dam in your watershed was built 50 years ago, the runoff frequency distribution upon which it was based probably is invalid. 

Milly et al. argue that climate change is rendering hydrologic stationarity a quaint concept, and we are grasping for ways to translate observations into predictions. So we are now likely dealing with a nonstationary process - the mean precipitation (or runoff, etc.) in the future won't be the same as it was in the past. So how do we plan?

Global warming will alter runoff patterns. The figure below, from Milly et al.), shows the "winners" and "losers" (median values from 12 climate models) in the volume of runoff from ice-free areas in the mid-21st century, relative to the 1900-1970 period. What you see is nonstationarity: the future is not like the past.

The reds and yellows indicate the greatest percentage decrease.

Look at Mexico, the Southwest USA, parts of Europe, northern and southern Africa, and the Middle East. Could be ugly.

Milly et al. indicate the critical need to develop new probabilistic models for rainfall, streamflow, etc. that are nonstationary.

The hydroclimatologic future is upon us, and we are unprepared.

"Statistics always remind me of the fellow who drowned in a river whose average depth was only three feet." -- Woody Hayes, ex-Ohio State football coach

Trifecta: Las Vegas Water Hearings End, Gov Opposes 'Water Grab', MX Missile Wells

After two weeks, on 15 February 2008 the hearings ended on the Southern Nevada Water Authority's (SNWA) plan to pump more ground water from beneath rural Nevada. I've got more details in my 4 February 2008 post.

I'm behind on this because I was writing a proposal to NOAA, and then headed to Reno for a Great Basin Environmental Program Workshop, where I floated my idea to do a "thinking about the unthinkable" study about what would happen if the Southwest went dry.

You can imagine the reaction. Huh?

One thing I've noticed: people who oppose the SNWA's "water grab" usually report the pumpage figures in millions or billons of gallons per day or year, which results in huge numbers. Supporters of the SNWA  "water plan" typically report withdrawals in acre-feet per year, which produces much smaller numbers.  Doesn't 13 billion gallons per year sound like a lot more (and a lot worse!) than 40,000 acre-feet per year? They're both about the same amount. Go figure.

It's like calling the Yucca Mountain site a "nuclear waste disposal site" or  a "nuclear waste dump".

Okay, back to the SNWA water plan hearings.

Here is what the Lahontan Valley News said:

CARSON CITY, Nev. (AP) — State hearings into a plan to pump billions of gallons of rural Nevada water to Las Vegas ended Friday with proponents saying they’re entitled to the water and opponents warning that the pumping could have a catastrophic impact.

State Engineer Tracy Taylor will review the testimony and voluminous paperwork submitted during two weeks of hearings and issue a ruling at a later date on the Southern Nevada Water Authority pumping plan. A final decision isn’t likely for several months.

Paul Taggart, attorney for SNWA which wants to draw more than 11.3 billion gallons of groundwater a year from Delamar, Dry Lake and Cave valleys, argued that the water authority met all requirements for the pumping and critics’ disaster scenarios are unfounded.

Simeon Herskovits, attorney for the Great Basin Water Network which opposes the plan, countered that SNWA tried to hide evidence that the pumping may harm existing water users and the environment in rural Nevada because there’s not enough water in the valleys for long-term
exportation.

The article concluded:

The project is backed by casino executives, developers, union representatives and others who point to water conservation efforts in the Las Vegas area and who warn of an economic downturn affecting the entire state unless the city has enough water to keep growing.

The valleys are all in central Lincoln County, which initially opposed the plan but reached an agreement with the water authority on which groundwater basins can developed. The agreement also allows for use of SNWA’s pipeline, for a price, by the county.

The agency hopes to begin delivering rural groundwater to Las Vegas by 2015. Its eventual goal is to import enough water to serve more than 230,000 homes, in addition to about 400,000 households already getting its water. Cost of its 200-mile-long pipeline project has been estimated at anywhere from $2 billion to $3.5 billion.

It is interesting to note that Lincoln County is on board. But not Gov. Jim Gibbons, trained as a geologist. Check out this story by Phoebe Sweet from the 21 February 2008 edition of the Las Vegas Sun:

Gov. Jim Gibbons is again saying he opposes Southern Nevada’s plan to get water from rural Nevada.

On Tuesday [19 February 2008], Gibbons told the Fallon Rotary Club that the Southern Nevada Water Authority, which has proposed a multibillion-dollar pipeline to eastern Nevada to supply Las Vegas with a backup source of drinking water, should instead build a desalination plant in California and trade that plant’s water for some of California’s allocation of the Colorado River, according to the Lahontan Valley News.

During his nearly 45-minute speech Tuesday, which focused mostly on the state budget crisis, Gibbons pitched the desalination proposal as “a better plan than what Clark County has,” according to reporter Christy Lattin.

On Wednesday Melissa Subbotin, a spokeswoman for the governor, confirmed that Gibbons “wants to bring water to Southern Nevada without taking it straight from Northern Nevada.”

Subbotin said the governor has made no formal proposal of an alternative to the pipeline, but thinks Southern Nevada could meet its water needs “utilizing water from the Colorado River and a desalination plant.”

Okay. The article concluded:

Last February, during a closed-door meeting with environmentalists, Gibbons questioned the need for the pipeline. Scot Rutledge, executive director of the Nevada Conservation League, told the Sun Gibbons prefaced his statement with: “The Southern Nevada Water Authority is not going to like what I’m about to say.”

A week later, an aide for the governor said Gibbons’ comments were only theoretical and had been misinterpreted. Steve Robinson, who was deputy chief of staff and natural resources adviser to the governor at the time, said: “He knows the reality is that the pipeline is the way Southern Nevada is going to have to go to get water.”

And speaking of desal, check out this piece in the 17 February 2008 Nevada Appeal (Carson City) by general contractor Fred Kessler. He wants to run pipelines to northern and southern Nevada from Pacific Coast desal plants.

Later this year, once we elect the next occupant of the White House, we may finally make some progress upon the primary national security issue facing the United States —global climate change — which the Bush administration has been neglecting.

Here in Nevada, the effects of global climate change to date have been both noticeable and costly, but not yet catastrophic. These effects will, however, increase over time and grow in severity. What is obvious, is that precipitation will diminish, and evaporation will increase. The current condition of Lake Mead and Walker Lake are ominous predictors of what Nevada can expect its future water supply to look like.

In populated areas the groundwater supply is rapidly diminishing, as evidenced by dropping water tables, which is good for the well-drilling industry, but bad for municipal water districts, home owners, farmers, ranchers, etc. We all know that there is no more precious commodity than potable water for the people of Nevada. Not gold, not silver, not tourism. If we are to survive as a population, we all must have sustainable reliable potable water supplies, or be blown away by the winds of global climate change.

Given the impending effects of global climate change, the time has come to plan for Nevada’s future water needs, which will be substantial given the past three decade’s population growth. In Roman times when emperors did not have to run for re-election it was much easier to finance, design and construct large-scale public works projects than it is today, when politicians are more concerned with short-term political gain than long-term societal goals affecting future generations.

What is needed is an independent public water authority with a nine-member board to take charge of the situation. The governor, Assembly and Senate should each appoint a single member, and three members should be elected at-large from Southern Nevada and three members from Northern Nevada. This will ensure both equal representation and accountability to all of the people of Nevada. Once constituted, the independent public water authority should be relatively immune from political interference and be able to focus upon long-term intergenerational solutions to Nevada’s future water needs.

The water authority will have to begin the process of raising capital from (1) federal funds, (2) state funds and (3) private capital markets through the sale of public bonds for design, acquisition of land and right-of-way, and construction of public water works projects. The water authority should be a wholesaler of potable water selling to local municipal and private water districts, charging and collecting user fees for the water that they provide. These fees will be the revenue source from which to pay bond holders. The water authority bonds will range from 30 to 50 years in term depending upon financing requirements. User fees also will pay for ongoing operations, maintenance and administrative costs.

The water authority will need to develop vast uninterruptible supplies of drinking water to feed the growing Nevada population. The closest supply to both Northern and Southern Nevada of raw material from which to process potable water is of course the Pacific Ocean. Desalinization plants on the Pacific coast, cross-country pipelines and pumping stations across California and Nevada can produce a steady supply of potable water that is limited only by the maximum flow rate of the system. A northern leg running from the Pacific along the I-80 corridor to service the northwestern Nevada counties, and a southern leg running from the Pacific coast across California to service Clark County will provide potable water to Nevada’s main population centers.

These north and south water authority systems must have at least a 200-year design life with provisions for future technological upgrades as they become available. Luckily, the technology for sea water desalinization has improved dramatically over the past three decades and has now reached a level of efficiency that makes it cost effective to use. There are a number of new desalinization plants around the globe producing potable water.

Moving large quantities of processed water up and over mountain ranges will require substantial quantities of electricity to power the pumps. However, there are recently developed magnetic levitation motors that use substantially less power to perform the same amount of work. As an example of technological innovation these “Mag-Lev” motors use magnetic fields to suspend motor shafts in space creating “frictionless” bearings thereby reducing energy usage. Additionally, the incorporation of wind and solar power generating equipment into the overall design should help mitigate power costs. On down hill slopes, hydroelectric turbines could be used to produce electric power as well.

Hopefully, sufficient quantities of potable water can be delivered to municipal water districts to allow them to stop pumping from local aquifers. This will allow the aquifers to recharge themselves over time from either natural means and/or the collection of storm water that can be injected down recharging wells.

The cost of these water authority desalination plants and pipeline systems will be many billions. It will take more than one decade to raise the capital, acquire plant sites and right-of-way, design the systems and construct them. This will truly be an intergenerational effort on a grand scale and, given that Nevada currently has two U.S. Senators sitting on the Senate Appropriations Committee, now is the time to get the ball rolling while we still have their clout in Washington.

The Romans were smart enough to figure out how to effectively solve the water supply issues of their day. Hopefully, Nevadans will rise to the occasion as well.

The man's a big thinker.

And remember the old MX missile plan from the 1970s? The USA was going to put land-based ICBMs on "racetracks" in desert valleys so that the Soviets would have a hard time targeting them. Well, MX is back, but in not quite the same way. This story from the Las Vegas Review-Journal reports on SNWA's use of data from 40 MX wells drilled in rural Nevada. What goes around, comes around.

Do you realize that Pat Mulroy has not been mentioned once in this post?

"There have always been people who have wanted to put things here that other people won't put up with in other places." -- Louis Benezet, rural Nevada resident

Manual on the Right to Water and Sanitation

Colleague Robert Adamski sent me this link about an important publication: Manual on the Right to Water and Sanitation. The picture and text below are from the WWW site.

Here is some background information from the Centre on Housing Rights and Evictions (COHRE), the manual's publisher, on the right to water.
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There is growing interest in the contributions of human rights to efforts to extend access to water and sanitation, but little practical information is available at present on how this can be achieved. The Manual on the Right to Water and Sanitation is designed to assist policy makers and practitioners in implementing the right to water and sanitation.

The Manual has been produced by the Centre on Housing Rights and Evictions (COHRE)(COHRE), Swiss Agency for Development and Cooperation (SDC), American Association for the Advancement of Science (AAAS), Science and Human Rights Programme and the United Nations Human Settlements Programme (UN-HABITAT). 

This essential publication, written in non-legal language, addresses the vital need to demonstrate how human rights can be practically realised in the water and sanitation sector. The Manual demonstrates that implementing the right to water and sanitation is not limited to legal recognition or allocation of funds. Rather, it provides the basis for practical reforms in many areas of water supply and sanitation and in water resource management that can help make the water and sanitation sector operate in a manner that is more pro-poor, accountable and inclusive.

The Manual will be useful for practical implementation as it:

• Explains key components of the right to W & S and their implications for governments.
• Describes a range of practical policy measures that could be adopted by governments, in particular those in low-incomes countries, to achieve the right to W & S in the shortest possible time.
• Illustrates examples of policy measures that have been taken to achieve particular components of the right to W & S.
• Provides a checklist by which governments can assess their achievements in relation to the right to W & S.
• Decsribes the roles of other actors, in particular, individuals and communities, in contributing to the achievement of the right to W & S.

The Manual and executive summary can be downloaded here. I have also posted the executive summary below.

Download RWP-ExSumm.pdf 
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"By polluting clear water with slime you will never find good drinking water." -- Aeschylus

Georgia-Tennessee Border War for Water Access

The 20 February 2008 NBC Nightly News had a feature on the Georgia-Tennessee "border war" for access to the Tennessee River. Here is the video clip (you will have to watch a 30-second commerical).

Colleague Aaron Wolf sent me this story from the 17 February 2008 issue of the Atlanta Journal-Constitution. The accompanying picture is from the story.

The article reports that some Tennesseans are sympathetic to Georgia's argument and its drought-stricken plight. Here's one:

"It's not necessarily our water," said Kate McBryar. "I don't see why Georgia can't use our water if they are having a drought. Why not help our countrymen?"

I suspect most of her fellow Tennesseans might not be so generous towards Georgia, and Atlanta, the "Las Vegas" of Southeastern water.

"I was pretty much just having fun. I didn't expect anything to come from it." surveyor Bart Crattie, commenting on the 1818 surveying error he pointed out.

I (Heart) Tap Water - Student Video Competition

Food & Water Watch has announced a student competition: produce a 1 to 2 minute video proclaiming your love for tap water and post it to YouTube.

The contest ends at 11:59 AM EST on 14 April 2008. Winners will be announced on Earth Day - 22 April 2008.

Your video should be inspiring, entertaining, and with a clear message. Easy, right?

Your video must be an original creation with the following three elements:

• a declaration of your love for tap water;
• some discussion about bottled water consumption; and
• make the case for why your school or any campus should give up bottled water.

The winner will get $1,500, the second place finisher will get $500, and the third place finisher will get a "Take Back the Tap" gift bag.

The winning video will also be featured prominently on the Take Back the Tap
WWW site.

Please - "family-friendly" videos only (that eliminates me).

And while we are extolling the virtues of tap water, take a look at
Tappening.com.

"Differential equations are like deodorants; more people who don't use them should." -- Steve Wheatcraft