Archive for June, 2011

Oh Champs Elysées!

Friday, June 17th, 2011

Kathy and I are off for France. First a week in Paris and its museums to see colorful paintings by a one-eared artist, statues sans bras, and a smiling lady. Then, we take off for castles in the Loire Valley, and on to Normandy.

I’m up to date with my current assignments. Susan knows how to get ahold of me should  the need arise, but most editing tasks that arise will just have to wait. Au revoir jusqu’á juillet!

Nonstationary water planning

Friday, June 17th, 2011

June 2011 Article:Nonstationary Water Planning: An Overview of Several Promising Planning Methods,” by Marc D. Waage, Laurna Kaatz. Part of Featured Collection on“Nonstationarity, Hydrologic Frequency Analysis, and Water Management.”

Water industry discussions about climate change are rapidly evolving. They are moving beyond the debate of whether climate change is real, to how to best prepare for uncertain future climatic and hydrologic conditions. Although more sophisticated climate models and methods are being developed, it could be many years before the range of projections, and the uncertainties about the projections, are substantially narrowed. In the meantime, water utilities will have major decisions to make with financial, social, and environmental impacts that can be substantially affected by climate change.

The Water Utility Climate Alliance, in an effort lead by Denver Water, identified and evaluated municipal water planning methods specifically designed to prepare utilities for many possible future conditions. Five methods (see their planning guide) were presented based on their use (or potential for use) in municipal water planning, and are examined briefly in this paper. The authors warn, “Every planning process must be tailored to the needs and capabilities of the utility, and unfortunately, there is not a one-size-fits-all approach.”

[Please note: I have quoted and paraphrased freely from the article, but the interpretation is my own!]

Humble design

Friday, June 17th, 2011

I am a climate-change skeptic. Not about the science, which I think is pretty solid, but about our political will to prevent global warming from happening. CO2 levels have been rising since the Industrial Revolution. A corresponding temperature increase, though masked by large natural variations, is indicated by virtually all atmospheric models.

Will we slow our CO2 emissions? People in China, Brazil, India, and elsewhere want to live like Americans, with all the energy use that implies. Their governments are not about to put on the brakes. Nor, in our current political climate, do I see America taking the lead to reduce carbon emissions. Don’t get me wrong, I’m not knocking prosperity. Rich and happy beats poor and resentful any day. But, it comes with an environmental price.

The impact of a couple of billion more American lifestyles might be tempered and eventually offset by “green” technologies, but the numbers are overwhelming. The upward trend in CO2 seems all but certain to continue for some time. So, our climate is going to change, likely becoming hotter and more violent. What are we, as water professionals, to do?

The first step is to face up to the changes, to think differently about design standards, and move from optimization to robustness and loss reduction. When we realistically consider infrastructure having to last centuries, we must admit the recent past is a poor guide to the future climate and become more humble about our ability to forecast a “worst case” design standard.

Humble design works. Arguably the greatest engineer of the 19th century, John Roebling nevertheless appreciated the limits of his knowledge. He knew nothing about harmonic wind vibrations which would tear apart later bridges, or about today’s traffic loadings, and he would have been horrified at decades of deferred maintenance. He realized, though, his great bridge would be subject to a lot of forces he didn’t fully understand, so he massively overdesigned by today’s standards. I wonder what a modern “bean counter” would say to Mr. Roebling. (“Do you really need all that steel in the truss?” “Why four main cables?”) The Brooklyn Bridge stands proudly well into its second century because its designer was humble.

Enjoy our Featured Connection on Nonstationarity. And, engineers, be humble!

Atmospheric rivers

Thursday, June 16th, 2011

June 2011 Article:Climate Change, Atmospheric Rivers, and Floods in California – A Multimodel Analysis of Storm Frequency and Magnitude Changes,” by Michael Dettinger. Part of Featured Collection on“Nonstationarity, Hydrologic Frequency Analysis, and Water Management.”

Atmospheric river image

Recent studies have documented the important role that ‘‘atmospheric rivers’’ (ARs) of concentrated near-surface water vapor above the Pacific Ocean play in the storms and floods in California, Oregon, and Wash- ington. By delivering large masses of warm, moist air (sometimes directly from the Tropics), ARs establish conditions for the kinds of high snowlines and copious orographic rainfall that have caused the largest historical storms.

Dettinger shows us some pretty scary maps of AR’s which have clobbered the west coast. Moreover, he suggests, “Years with many AR storms become more frequent in most climate-change projections analyzed here, but the average number of such storms per year is not projected to change much. Likewise, although the average intensity of these storms is not projected to increase much in most models, occasional much-larger-than-historical-range storm intensities are projected to occur under the warming scenarios.

[Please note: I have quoted and paraphrased freely from the article, but the interpretation is my own!]

Flood frequency changes

Tuesday, June 14th, 2011

June 2011 Article:Examining Flood Frequency Distributions in the Midwest U.S.,” by Gabriele Villarini, James A. Smith, Mary Lynn Baeck, and Witold F. Krajewski. Part of Featured Collection on “Nonstationarity, Hydrologic Frequency Analysis, and Water Management.”

Annual maximum peak discharge time series from 196 stream gage stations with a record of at least 75 years from the Midwest United States is examined to study flood peak distributions from a regional point of view. Change-points rather than monotonic trends are responsible for most violations of the stationarity assumption. The abrupt changes in flood peaks can be associated with anthropogenic changes, such as changes in land use?land cover, agricultural practice, and construction of dams. The trend analyses do not suggest an increase in the flood peak distribution due to anthropogenic climate change.

[Please note: I have quoted and paraphrased freely from the article, but the interpretation is my own!]

Getting from here to there

Friday, June 10th, 2011

June 2011 Article:Getting From Here to Where? Flood Frequency Analysis and Climate,” by Jery R. Stedinger and Veronica W. Griffis. Part of Featured Collection on“Nonstationarity, Hydrologic Frequency Analysis, and Water Management.”

The authors note, “Flood-risk computations by United States (U.S.) federal agencies follow guidelines in Bulletin 17 for which the latest update 17B was published in 1982. Efforts are underway to update that remarkable document. Additional guidance in the Bulletin as to how to address variation in flood risk over time would be welcome.”

If stationarity is dead, what should we do? The authors address this question by showing some possible ways Bulletin 17 could be modified to account for some concepts of climate change. They don’t reject the value of historical data, but realize we can’t take it at face value: “Does climate change mean we are not interested in historical records? Of course not: historical data tell us what flood series look like and help us to estimate where we start. We then need to estimate what would change, which describes where we go from there. The critical concern is whether the contribution of nonstationarity to our uncertainty is large enough, and the signal sufficiently clear, that we would do better by including it in our analyses.”

They conclude, “In water-supply management, we often use period-of- record planning, which hides uncertainty. Now with climate change, we need to project from the uncertainty of our current knowledge based upon the past record to estimate the risk in the future. … Change in flood risk is not new.”

[Please note: I have quoted and paraphrased freely from the article, but the interpretation is my own!]

Still wanted: AE, Water Quality Modeling

Thursday, June 9th, 2011

[Incredibly, I've received NO RESPONSE to this earlier post. So, I'll do it again, changing the date.]

JAWRA Associate Editors (AE’s) serve as primary advisors to the JAWRA Editor. Responsibilities fall into two areas: reviews and subject development. The Water Quality Modeling position handles between 15 and 20 papers per year. All manuscripts are handled through our ScholarOne Manuscripts™ system, with the AE selecting reviewers and, when reviews return, making a recommendation to the Editor. AE’s are encouraged to seek out qualified authors in their subject areas and encourage them to submit papers to JAWRA. These could be individual submittals or as featured collections of related papers organized around an introduction.

Although JAWRA publishes papers in all aspects of modeling, we have particular interest in the SWAT, HSPF, and SPARROW models.

Associate editorship is a volunteer position earning our heartfelt thanks and an invitation to our annual AE luncheon. It also offers the opportunity to make a difference on the cutting edge of multidisciplinary water resources. The term of an AE is three years, but may be extended by mutual agreement.

Interested individuals should email the Editor at editor@awra.org. We are happy to answer any questions. We will hold this position open at a minimum until July 6, 2011, but early application is encouraged.

Climate change litmus test

Thursday, June 9th, 2011

Since we’re covering our recent featured collection on nonstationarity, I call your attention to an article in today’s Washington Post, “Romney in hot seat on climate change.” Republican presidential hopeful Mitt Romney’s position on climate change, as described by the Post, hardly is extreme, and he doesn’t advocate any radical action. Nevertheless, his alignment with science seems a definite liability with voters in the primaries.

To me, raised in the post-Sputnik, scientists-as-saviors world, this all appears like a regression to the dark ages. Chilling stuff. How did willful ignorance become mainstream politics?

Humility vs. complexity

Thursday, June 9th, 2011

June 2011 Article:Stationarity: Wanted Dead or Alive?,” by Harry F. Lins and Timothy A. Cohn. Part of Featured Collection on“Nonstationarity, Hydrologic Frequency Analysis, and Water Management.”

If we do not understand the long-term characteristics of hydroclimatic processes, how does one find the prudent and reasonable course needed for water management? Lins and Cohn conclude, “In such circumstances, humility may be more important than physics; a simple model with well-understood flaws may be preferable to a sophisticated model whose correspondence to reality is uncertain.”

The authors aim to demonstrate that trendy time series behavior is neither predicated upon, strictly indicative of, nor relevant to nonstationarity. A stationary process with long-term persistence – which seems to describe accurately the variability of natural hydroclimatic systems – can appear indistinguishable from a nonstationary process with a deterministic trend.

[Please note: I have quoted and paraphrased freely from the article, but the interpretation is my own!]

Flood magnification

Wednesday, June 8th, 2011

June 2011 Article:Nonstationarity: Flood Magnification and Recurrence Reduction Factors in the United States,” by Richard M. Vogel, Chad Yaindl, and Meghan Walter. Part of Featured Collection on“Nonstationarity, Hydrologic Frequency Analysis, and Water Management.”

This study takes a different approach by exploring trends in floods in watersheds which are subject to a very broad range of anthropogenic influences, not limited to climate change. A simple statistical model is developed which can both mimic observed flood trends as well as the frequency of floods in a nonstationary world. Nonstationarity in floods can result from a variety of anthropogenic processes including changes in land use, climate, and water use, with likely interactions among those processes making it very difficult to attribute trends to a particular cause.

[Please note: I have quoted and paraphrased freely from the article, but the interpretation is my own!]