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Community advice to young hydrologists, Part 1

Community advice to young hydrologists, Part 1

We at Water Underground loved reading Young Hydrologic Society’s post titled “Community advice to young hydrologists” – an advice column written by a network of established scientists in the field. We appreciated the column so much, in fact, that we have decided to re-blog the post to you (with YHS’s consent, of course). We’ve split up their post by question, and have added in hyperlinks to all contributors and related material (as has always been our inclination). Happy reading!

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Question: What book or paper has been most influential to your career and why?

Groundwater by Freeze and Cherry – this textbook, now out of print, was a critical reference as I began my graduate training in hydrogeology and I still refer to it today.

Jean Bahr (University of Wisconsin)

 

 

 

 

 

 

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I can think of no single one.  However, papers that were a combination of field observations and clever analyses leading to new insights always are intriguing.  Papers which I find of little value are those that propose a new modeling approach with little to no field verification, or which use existing models to reach some conclusion.  For example, we seem to be seeing a proliferation of papers using complex models to highlight some “new” effect of climate change on the hydrologic cycle, with no grounding in hindcasts. (See this, also) The musings of Keith Beven always have been insightful, including his Advice to a Young Hydrologist.

Jerad Bales (CUAHSI)

 

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I can’t identify single “most influential” books or papers – I learned early to read as widely as possible, and not just within narrow/specific research problems of direct interest. I have been inspired by a range of articles – including books on philosophy, history of physics, etc. – which broadened my approach and ways of looking at a given problem. Indeed, some of my most influential work developed from studying methods and approaches in statistical physics and physical chemistry.

Brian Berkowitz (Weizmann Institute of Science)

 

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The most important influence was a person – Mike Kirkby and particularly the undergraduate course on quantitative hydrology he taught at the University of Bristol when I was taking my degree there (later, I would do a post-doc with him at Leeds that resulted in the development of Topmodel). That gave me a lot of reading to do – but it was probably not the hydrological reading that had most influence, but rather the papers on theoretical geomorphology starting with Horton BGSA 1945, then picked up by Kirkby, Frank Ahnert and others in the late 1960s. I struggled to understand them (at the time I wanted to be a geomorphologist but I have never quite finished getting the water part right) but they left me the idea that it was possible to theorize about environmental processes and systems in approximate but useful ways.

During my PhD the most influential paper was undoubtedly Freeze and Harlan JH 1968, and the papers about the field site I was applying my model to by Darrell Weyman (HSB 1970, IAHS 1973). If I had talked to him a little more (he was doing his PhD at Bristol while I was an undergraduate) or read those papers more carefully, then I might have been more realistic in my PhD modelling.

The most important book at that time was Zienkowicz, Finite Element Modelling (that was the technique I was trying to master). Hillslope Hydrology edited by Kirkby was also important but came later.

Keith Beven (Lancaster University)

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Paper: Scale of Fluctuation of rainfall models by I. Rodriquez-Iturbe. It formed the basis for my MSc research that I did during 11 months in Davis California (As a Dutch Student from Wageningen). It was extremely difficult stuff, but I kept on it and it understanding gave me the stamina to really dig into a subject. It was the basis for my first paper entitled “Analytically derived runoff models based on rainfall point processes” in WRR. To obtain better background I also read in depth the influential.

Book: Random Functions and Hydrology by R. Bras and I. Rodriquez-Iturbe.

Marc Bierkens (Utrecht University)

 

 

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Dooge’ 1986 Looking for hydrologic laws in WRR. This paper gives a broad perspective on science, including scales.

Günter Blöschl (TU Vienna)

 

 

 

 

 

 

 

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Konrad and Booth (2005), Hydrologic changes in urban streams and their ecological significance, American Fisheries Society Symposium, 47:157-177.  This paper is a bit outside my area of expertise, but I think the linkage they make between physically measurable streamflow changes and stream ecology represents a fundamental shift in thinking from engineering hydrology to more of an eco-hydrology perspective.  They illustrated that we need to go beyond analyzing just changes in peak flow or low flows (or fixed percentiles), to look at more derived metrics that better capture hydrologic regime change.

Laura Bowling (Purdue University)

 

 

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That is a very hard question. As a Geography undergraduate student, I had to write a particular essay on the “all models are wrong” theme and this involved critiquing two papers which completely changed my worldview about models and modelling: Konikow and Bredehoeft’s 1992 ‘Ground-water models cannot be validated’ Advances in Water Resources 15(1):75-83.  and Beven’s 1989 ‘Changing ideas in hydrology – the case of physically-based models’ Journal of Hydrology.

But in the last year, I would say it has been Lab Girl by Hope Jahren (2016) who is a gifted and talented scientist and writer and has the knack of intertwining the natural world with tales of remaining brave in your career. I wish I’d had the opportunity to read it earlier in my career.

Hannah Cloke (University of Reading)

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Ecological and General Systems – H.T. Odum. This book explores general systems theory in the context of ecosystem behaviors. It is holistic, comprehensive, and full of important insights about the structure and dynamics of systems.

Matthew Cohen (University of Florida)

 

 

 

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It is a novel by Milan Kundera: “Slowness”. My natural tendency is to rush up, be as fast as possible, quickly fix things… Yet, speed often leads to miserable outcomes. Many lines of Kundera’s book are still in my mind, and they work as a continuous reminder for me that only slowness allows thoughtful consideration, serious reflection, and appreciation of reality. Realizing this has strongly influenced my academic career as it made me focus on the quality (and not the quantity) of my work.

Giuliano Di Baldassarre (Uppsala University)

 

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Several hydrogeology-related texts were very helpful for me.  These include some of Mary Hill’s papers, John Doherty’s PEST manual (as much for the philosophy as the instruction), some of Jasper Vrugt’s early papers, and work by both Wolfgang Novak and Steve Gorelick on measurement design. The real recommendation would be to find authors that you enjoy and read as much of their work as possible – in this category, I would add Shlomo Neuman, Randy Hunt, Hoshin Gupta, Dani Or, Keith Beven and Graham Fogg. I am sure that I am forgetting more than I have listed. I think it is equally important to read broadly. Rather than provide a list, I’ll encourage you to look at my recent paper in Ground Water (Sept 2016) for some suggestions!

Ty Ferré (The University of Arizona)

 

 

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Book:  Groundwater Hydrology by David Keith Todd, 1st edition, 1959. As a 3rd-year undergraduate in hydrology at the University of New Hampshire in 1973, this book (and course by Francis Hall) kindled my interest in groundwater and completely changed my career path, which previously was essentially an aimless sleepwalk through my major in mathematics.

Paper/report:  Kaiser, W. R., Johnston, J. E., and Bach, W. N.. 1978, Sand-body geometry and the occurrence of lignite in the Eocene of Texas: The University of Texas at Austin, Bureau of Economic Geology Geological Circular 78-4, 19 p.  This paper demonstrated in stunning detail how modern borehole geophysical data together with understanding of the geologic genesis of sedimentary deposits could be used to create unprecedented subsurface maps of aquifer/aquitard system heterogeneity and structure. This led me down the long path of better integrating groundwater hydrology and geologic depositional systems.

Graham Fogg (UC Davis)

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My interests have been in predictive hydrometeorology. The following were influential books at the start of my carrier in the late 70s and early 80s: Dynamic Hydrology by Eagleson; by Wallace and Hobbs; Applied Optimal Estimation by Gelb (ed).  These represented the fields of hydrology, meteorology, and estimation theory with applications to prediction, and were the necessary pillars to build predictive hydrometeorology.

Konstantine Georgakakos (Hydrologic Research Center in San Diego)

 

 

 

 

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Haitjema and Mitchell-Bruker (2005) which taught me to think of groundwater as a process that interacts with topography, climate and geology in complex but predictable ways.

Tom Gleeson (University of Victoria)

 

 

 

 

 

 

 

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The paper that has been most influential to my career is most certainly  “Johnston, P. R., and D. H. Pilgrim (1976), Parameter optimization for  watershed models, Water Resources Research, 12(3), 477–486. I read this paper during my graduate work in the early 1980’s and was intrigued by their report that “A true optimum set of (parameter) values was not found in over 2 years of full-time work concentrated on one watershed, although many apparent optimum sets were readily obtained.”

On the one hand this paper clearly identified an important problem that needed to be addressed. On the other (as I often remark during talks on the subject), I think it was remarkable as an example of a paper reporting the apparent “failure” of the researchers to achieve their goals … how often do we see people reporting their failures in the literature these days :-). More of this kind of work – reporting a scientific study and accurately reporting both successes and failures … but especially failures … is critically important to the progress of science, so that people can both contribute to solutions and also avoid unsuccessful forays down paths already tried.

In any case, the paper clearly pointed me towards an important problem that led to me adopting a path of research over the past decades, which led to the development of the SCE and SCEM  optimization algorithms (and indeed a whole field of optimization developments), studies into impacts of model structural deficiencies, multi-criteria methods for parameter estimation, the diagnostic model identification approach, and more recently the Information Theoretic approach.

The 1990 paper by Michael Celia et al on the numerical solution of Richards equation, recommended to me by Philip Binning at the beginning of my Honours Project at Newcastle Uni. This paper made a big impression on me because it provided a very clear exposition of how to solve a challenging modelling problem – and played a bigly role in getting me interested in research.

Dmitri Kavetski (University of Adelaide)

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The Ecological Studies Series, published by Springer, was the most influential in my career because several books published in the Series (e.g., Forest Hydrology and Ecology at Coweeta edited by Swank and Crossley and Analysis of Biogeochemical Cycling Processes in Walker Branch Watershed edited by Johnson and Van Hook) sparked my interest in forest hydrology and biogeochemistry. In tandem with the superb mentorship of Prof. Stanley Herwitz (Clark University), I decided to embark upon a career as a forest hydrologist as a sophomore in college. I never looked back.

Delphis Levia (University of Delaware)

 

 

 

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The papers of the series “Plants in water-controlled ecosystems” (2001, Advances in Water Resources 24), by Laio, Porporato, Ridolfi, and Rodriguez-Iturbe have been among the first and most influential I have read. Their clean, analytical approach to the complex interactions among vegetation, soil, and climate remains deeply inspiring. As an example of inter-disciplinary work (actually outside hydrology), I would like to mention the book by Sterner and Elser (2002) “Ecological stoichiometry. The biology of elements from molecules to the biosphere” (Princeton University Press) – a great example of how integrating knowledge from various sources around a common theme can yield deeper understanding and perhaps even lay the foundation of a new discipline.

Stefano Manzoni (Stockholm University)

 

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The Hewlett and Hibbert 1967 conference paper “Factors affecting the response of small watersheds to precipitation…” is perhaps the best paper ever written in hydrology. For a full homage, please look here. The paper is field-based, theory focused and a blend of bottom-up and top-down research, before that was even ‘a thing’. It inspired me in my graduate research in the 1980s; I continued to read it and ponder it in my first years as a professor, as I strived to follow in Hewlett’s footsteps. He was my mentor even though he retired before I could ever meet him.

Jeff McDonnell (U Saskatchewan)

 

 

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 In general, the books that have been most influential to me refer to sister disciplines. The reason is that I found illuminating to study methods and models used in statistics and economics for the purpose of applying them to hydrology for the first time. Thus, the most influential book to me has been “Statistics for long-memory processes”, by Jan Beran. The very reason is that I found there a detailed explanation of models that were useful to get to target with my Ph.D. thesis. 

Alberto Montanari (University of Bologna)

 

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Chamberlin TC. 1890. The method of multiple working hypotheses. Science 15: 92-96 (reprinted in Science 148: 754–759 [1965]). I read this paper as part of a second-year course in Archaeology, which I took as an elective in my undergraduate program. Although the writing style is somewhat archaic, this article introduced me to the value of hypothesis-based thinking in science and the need to avoid favouring a pet hypothesis or model. It is instructive also to read the many follow-up essays to gain a broader perspective on hypothesis-based research and, more broadly, the “scientific method.”

Dan Moore (University of British Columbia)

 

 

 

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I think I was more influenced by my peers, colleagues, mentors, supervisors and friends as I learn better through discussions and challenges. One of the more memorable papers is one of Manning (Manning, R. (1891). “On the flow of water in open channels and pipes,” Transactions ofthe Institution of Civil engineers of Ireland.) and it’s associated history. In this paper he actually suggested a far more ‘complex’ formulation than the formula which is today widely known as the Manning equation – history has it that it was never adopted widely as well as many subsequent more more sophisticated formulations. Science doesn’t work linear and we are sometimes less rational or objective (if the latter is actually possible) than we believe.

Florian Pappenberger (ECMWF)

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“Show me a person who has read a thousand books and I’ll show you my best friend; show me a person who has read but one and I will show you my worst enemy.” I have been influenced by many and I can’t say one is *the* most influential or important alone.  At the moment, I am reflecting on (McCuen RH. 1989. Hydrologic Analysis and Design. Prentice Hall: Englewood Cliffs.) As far as being a hydrology textbook it is not particular special, but it is written extremely clearly with a lot of good step-by-step workflows.  Most importantly, the book integrates throughout its whole development the concept of analysis versus synthesis, and this has been central to how I approach my research.  We do both analysis and synthesis.

Gregory Pasternack (UC Davis)

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This is very difficult to say. I must admit that my academic work started from engineering practice and I only started reading the international literature very late in my career. But a book that has been very influential to me was the book by Fischer et al. (1979) “Mixing in inland and coastal waters”. Fischer soon died in an accident after this book was published. The book introduced me to the fundamentals of mixing processes in estuaries, on which I had done substantial field research and had developed my own practical engineering method, which I still use, but which lacked a fundamental theoretical basis. I am still working on finding this fundamental basis, and Fischer’s book put me on that track.

Hubert Savenije (TU Delft)

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It would be tough to answer what’s been the most influential to my career as a whole, but I could answer what was the most influential to my early career, and that was Menke’s Geophysical Data Analysis: Discrete Inverse Theory.  I labored through that book for years during my PhD. My copy has dog-eared pages and writing throughout as I tried to figure out inversion methods.  Finally getting my head around the mathematics of inversion really opened up some doors for me early on.  Davis’ Tools For Teaching also really helped me think about how to be as effective a teacher as I could be.

Kamini Singha (Colorado School of Mines)

 

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Books are hardly ever influential once you are actually ‘in’ research. Early on, look for the best review articles in your field. They will ‘set the scene’ for you.

Keith Smettem (The University of Western Australia)

 

 

 

 

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Opportunities in the hydrologic sciences”, National Academy Press. This landmark book which defined hydrology as a science appeared right at the start of my PhD. It provided a nice framework for my own research and that of my fellow PhD students in those days.

Remko Uijlenhoet (Wageningen University)

 

 

 

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It is difficult to select one single work from the literature that has been influential over my entire career in groundwater flow and transport modeling.  But, there is one book that I used as a grad student that I still refer to today.  It is “Conduction of Heat in Solids” by Carslaw and Jaeger.  The book is a treatise on analytical solutions to diffusion equations.  The lesson for me is that knowledge from other disciplines (in this case thermal engineering) can be applied to problems in hydrology.  Another lesson is that we can learn a lot and gain important insights through wise approximations that have analytical solutions.

Al Valocchi (University of Illinois at Urbana-Champaign)

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Abramowitz & Stegun: Math is something you look up, not something you try to memorize.

Nick van de Giesen (TU Delft)

 

 

 

 

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In hydrology, some of the most influential books for me have been Handbook of Hydrology (edited by David Maidment) and Principles of Environmental Physics (Monteith & Unsworth). These two books are so rich in physics, empirical equations, recipes, and references. Of course the times have changed and nowadays you can google almost anything, but some of the chapters in these books are so well written that I still regularly use them. They also have the benefit that they summarise areas of research where things haven’t actually changed too much since the 80ies – the physics we use haven’t become that much more sophisticated, and sometimes in fact less so; whereas the field measurements on which a lot of the empirical rules and equations are based generally also haven’t been added much to since.

Outside hydrology, some books that have made me think differently about the field and my research include

Emergence: The Connected Lives of Ants, Brains, Cities, and Software (Johnson) – one of the first popular science books I read that made me think different (about ecohydrology)

The Sceptical Environmentalist (Lomborg) – I didn’t accept his reasoning but it was seductive and it forces you to really pick apart the logical and rhetorical flaws he uses.

Thinking, fast and slow (Kahneman) – which really made me realise the questionable quality of my analytical rigour and decisions in general (also those of anyone else, though!).

Albert van Dijk (Australian National University)

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Physical Hydrology by Dingman and Elements of Physical Hydrology are both great textbooks. Why: just lots of “basics” well explained, emphasizing the need to understand PROCESSES.

Doerthe Tetzlaff (University of Aberdeen)

 

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House at Pooh Corner, specifically, Chapter VI. In which Pooh invents a new game and Eeyore joins in.  The first paragraph is an awesome description of a classic watershed and affirms my theory that hydrology is truly everywhere… even on Mars.  Indeed, the search for “life” has largely been a search for “water.”

Todd Walter (Cornell University)

 

 

 

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Comparative hydrology, edited by Malin Falkenmark and Tom Chapman (1989). This book is one of the first to examine global hydrology phenomena. It asserts that a comprehensive and systematic description of hydrological processes is (i) possible (ii) not too complicated. Until then I’d thought the task was impossible, so I found the approach inspirational for my research.

Ross Woods (University of Bristol)

Western water wells are going dry

Western water wells are going dry

Post by Scott Jasechko, Assistant Professor of Water Resources at the University of Calgary, in Canada, and by Debra PerronePostdoctoral Research Scholar at Stanford University, in the United States of America.

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Wells are excavated structures, dug, drilled or driven into the ground to access groundwater for drinking, cleaning, irrigating, and cooling. We recently mapped groundwater wells across the 17 western states [1], where half of US groundwater pumping takes place. The western states contain aquifers key to United States food production, including the Central Valley of California and the central High Plains.

Millions of water wells exist in the western US, alone. About three-quarters of these wells have been constructed to supply water for household uses. Nearly one-quarter are used to irrigate crops or support livestock. A smaller fraction (<5 %) supports industry [1].

Western US water well depths vary widely (Fig. 1). The great majority (90%) of western US well depths range between 12m and 186m. The median western US well depth is 55m. Wells with depths exceeding 200m tap deep aquifers bearing fresh groundwater, such as the basal formations in the Denver Basin aquifer system, and the deeper alluvium in the California Central Valley. Shallow wells are common along perennial rivers, such as the Yellowstone, Platte, and Willamette Rivers.

Fig. 1. Western USA wells depths. Each point represents the location of a domestic, industrial or agricultural well. Blue colors indicate well depths of less than the median (55m), and red-black colors indicate well depths exceeding the median.

The wide variability of well depths across the west (Fig. 1) emphasizes the value of incorporating well depth data when assessing the likelihood that a groundwater well may go dry.

We know wells are going dry in the western US: journalists have identified numerous communities whose well-water supplies have been impacted by declining water tables [2-4]. While several studies have assessed adverse impacts of groundwater storage declines—such as streamflow depletion [5], coastal aquifer salinization [6], eustatic sea level rise [7], land subsidence [8]—few studies address the question: where have wells have gone dry?

Here we put forth a first estimate of the number of western US wells that have dried up (Fig. 2). We compared well depths to nearby well water level measurements made in recent years (2013-2015). We define wells that have likely gone dry as those with depths shallower than nearby measured well water levels (i.e., our estimate of the depth to groundwater).

Fig. 2. Schematic of a well that has gone dry (left) and a well with a bottom beneath the water table (blue) that may still produce groundwater (right). Even wells with submerged bottoms may be impacted by declines in groundwater storage because (i) pumps are situated above the well bottom, (ii) pumping induces a localized drawdown of the water table in unconfined portions of aquifer systems, (iii) well yields may decline if the hydrostatic pressure above the well base declines.

We estimate that between 0.5% and 6 % of western US wells have gone dry [1]. Dry wells are common in some areas where groundwater storage has declined, such as the California Central Valley [9] and parts of the central and southern High Plains aquifer [10,11]. We also identify lesser-studied regions where dry wells are abundant, such as regions surrounding the towns of Moriarty and Portales in central and eastern New Mexico.

Dry wells threaten the convenience of western US drinking water supplies and irrigated agriculture. Our findings emphasize that dry wells constitute yet another adverse impact of groundwater storage losses, in addition to streamflow depletion [5], seawater intrusion [6], sea level rise [7], and land subsidence [8].

Some wells are more resilient to drying (i.e., deeper) and others more vulnerable (i.e., shallower). We show that typical agricultural wells are deeper than typical domestic water wells in California’s Central Valley and Kansas’ west-central High Plains [1]. Our finding implies that reductions to groundwater storage will disproportionately dry domestic water wells compared to agricultural water wells, because domestic wells tend to be shallower in these areas. However, in other areas, such as the Denver Basin, typical domestic wells are deeper than typical agricultural wells. This comparison of different groundwater users’ well depths may help to identify water wells most vulnerable to groundwater depletion, should it occur.

So, what option does one have when a well goes dry?

Groundwater users whose wells have gone dry may consider a number of potential, short-term remedies, some of which may include (i) drilling a new well or deepening an existing well, (ii) connecting to alternative water sources (e.g., water conveyed by centralized infrastructure; water flowing in nearby streams), or (iii) receiving water delivered by truck.

Drilling new wells, deepening existing wells or connecting to alternate water supplies is often costly or unavailable, raising issues of inequality [12]. Receiving water deliveries via truck [13] is but a stopgap, one that may exist in parts of the western United States but not elsewhere, especially if high-use activities (e.g., irrigated agriculture) are intended [14]. In places where water table declines are caused primarily by unsustainable groundwater use, a long-term solution to drying wells may be managing groundwater to stabilize storage or create storage surpluses.

Realizing such sustainable groundwater futures where wells are drying up is a critical challenge. Doing so will be key to meeting household water needs and conserving irrigated agriculture practices for future generations [15]. We conclude that groundwater wells are going dry, highlighting that declining groundwater resources are impacting the usefulness of existing groundwater infrastructure (i.e., wells). The drying of groundwater wells could be considered more frequently when measuring the impacts of groundwater storage declines.

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Scott Jasechko is an assistant professor of water resources at the University of Calgary. In November 2017, Scott joins the faculty of the Bren School of Environmental Science & Management at the University of California, Santa Barbara.

Find out more about Scott’s research at : http://www.isohydro.ca

 

 

 

Debra Perrone is a postdoctoral research scholar at Stanford University with a duel appointment in the Department of Civil and Environmental Engineering and the Woods Institute for the Environment. In November 2017, Debra will join the Environmental Studies Program at the University of California, Santa Barbara as an assistant professor.

Find out more about Debra at: http://debraperrone.weebly.com

 

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References

[1] Perrone D and Jasechko S 2017 Dry groundwater wells in the western United States. Environmental Research Letters 12, 104002 doi: 10.1088/1748-9326/aa8ac0. http://iopscience.iop.org/article/10.1088/1748-9326/aa8ac0

[2] James I, Elfers S, Reilly S et al 2015 The global crisis of vanishing groundwaters. in: USA Today https://www.usatoday.com/pages/interactives/groundwater/

[3] Walton B 2015 In California’s Central Valley, Dry wells multiply in the summer heat. in: Circle of Blue http://www.circleofblue.org/2015/world/in-californias-central-valley-dry-wells-multiply-in-the-summer-heat/

[4] Fleck J 2013 When the well runs dry. in: Albuquerque Journal https://www.abqjournal.com/216274/when-the-well-runs-dry.html

[5] Barlow P M and Leake S A 2012 Streamflow depletion by wells—understanding and managing the effects of groundwater pumping on streamflow. US Geological Survey Circular 1376 (Reston, VA: United States Geological Survey)

[6] Barlow P M, Reichard E G 2010 Saltwater intrusion in coastal regions of North America. Hydrogeol. J. 18 247-260.

[7] Konikow L F 2011 Contribution of global groundwater depletion since 1900 to sea-level rise. Geophys. Res. Lett. 38 L17401

[8] Galloway D, Jones D R and Ingebritsen S E 1999 Land subsidence in the United States. US Geological Survey Circular 1182 (Reston, VA: United States Geological Survey)

[9] Famiglietti J S, Lo M, Ho S L, Bethune J, Anderson K J, Syed T H, Swenson S C, Linage C R D and Rodell M 2011 Satellites measure recent rates of groundwater depletion in California’s Central Valley. Geophys. Res. Lett. 38 L03403

[10] McGuire V L 2014 Water-level Changes and Change in Water in Storage in the High Plains Aquifer, Predevelopment to 2013 and 2011–13  (Reston, VA: United States Geological Survey)

[11] Scanlon B R, Faunt C C, Longuevergne L, Reedy R C, Alley W M, Mcguire V L and McMahon P B 2012 Groundwater depletion and sustainability of irrigation in the US High Plains and Central Valley. Proc. Natl Acad. Sci. 109 9320–5

[12] Famiglietti J S 2014 The global groundwater crisis. Nature Climate Change 4 945-948.

[13] The Times Editorial Board 2016 When it comes to water, do not keep on trucking. in: LA Times http://www.latimes.com/opinion/editorials/la-ed-water-hauling-20160729-snap-story.html

[14] James I 2015 Dry springs and dead orchards. in: Desert Sun http://www.desertsun.com/story/news/environment/2015/12/10/morocco-groundwater-depletion-africa/76788024/

[15] Bedford L 2017 Irrigation, innovation saving water in Kansas. in: agriculture.com http://www.agriculture.com/machinery/irrigation-equipment/irrigation-innovation-saving-water-in-kansas

What is the difference between ‘water withdrawal’ and ‘water consumption’, and why do we need to know?

What is the difference between ‘water withdrawal’ and ‘water consumption’, and why do we need to know?

Post by Inge de Graaf, University of Freiburg, Environmental Hydrological Systems group

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Last week I had to teach my first class in global hydrology. When I showed the global trend on increasing demands and withdrawals (see Figure) I needed to explain the different terms as sometimes the term “water use” gets, well, misused.

The term “water use” often fails to adequately describe what happens to the water. So I told the students; if you see or hear to term ‘water use’ always ask yourself what’s actually being said. The term is often used for water withdrawals or water consumption, and it’s important to understand the difference.

Water withdrawal describes the total amount of water withdrawn from a surface water or groundwater source. Measurements of this withdrawn water help evaluate demands from domestic, industrial and agricultural users.

Water consumption is the portion of the withdrawn water permanently lost from its source. This water is no longer available because it evaporated, got transpired or used by plants, or was consumed by people or livestock. Irrigation is by far the largest water consumer. Globally irrigated agriculture accounts for 70% of the total water used and almost 50% is lost either by evaporation or transpiration.

Understanding both water withdrawal and consumption is critical to properly evaluate water stress. Measurements of water withdrawal indicate the level of competition and dependence on water resources. Water consumption estimates help to quantify the impact of water withdrawals on downstream availabilities and are essential to evaluate water shortage and scarcity. For example, most water used by households is not consumed and flows back as return flow and can be reused further downstream. However, water is rarely returned to watershed after being used by households or industry without changing the water quality, increasing water stress levels.

Already more than 1.4 billion people live in areas where the withdrawal of water exceeds recharge rates. In the coming decades global population is expected to increase from 7.3 billion now, to 9.7 billion by 2050 (UN estimate). This growth, along with rising incomes in developing countries, is driving up global food demands. With food production estimated to increase by at least 60% (FAO estimate), predicting water withdrawal and consumption is critically important for identifying areas that are at risk of water scarcity and where water use is unsustainable and competition amongst users exist.

Global trend I showed in my class, published in Wada et al (2016).

Ref:

Wada, Y., I. E. M. de Graaf, and L. P. H. van Beek (2016), High-resolution modeling of human and climate impacts on global water resources, J. Adv. Model. Earth Syst., 8, 735–763, doi:10.1002/2015MS000618.

 

Limits to global groundwater use

Limits to global groundwater use

Post by WaterUnderground contributor Inge de Graaf. Inge is a postdoc fellow at Colorado School of Mines, in the USA.

Groundwater is the world’s most important source of freshwater. It supplies 2 billion people with drinking water and is used for irrigation of the largest share of the world’s food supply.

However, in many regions around the world, groundwater reserves are depleting as the resource is being pumped faster than it is being renewed by rain infiltrating through the soil. Additionally, in many cases, we are still clueless about how long we can keep drawing down these water reserves before groundwater depletion will have devastating impacts on environmental and socio-economic systems. Indeed, these devastating effects are already being observed.

The most direct effect of groundwater depletion is the decline in groundwater levels. As a direct impact, groundwater-pumping cost will increase, so too will the cost of well replacement and the cost of deepening wells. One of the indirect consequences of declining water levels is land subsidence, which is the gradual sinking of the surface. In many coastal and delta cities, increased flooding results in damages totaling billions of dollars per year. Next to this, declining groundwater levels lead to a decrease in groundwater discharge to rivers, wetlands, and lakes, resulting in rivers running dry, wetlands that are no longer sustained, and groundwater-dependent ecosystems that are harmed.

Over the past decades, global groundwater demands have more than doubled. These demands will continue to increase due to population growth and climate change.

The increase in demands and the aforementioned negative effects of groundwater depletion raise the urgent question: at what time in future are the limits to global groundwater use reached? This is when and where groundwater levels drop to a level where groundwater becomes unattainable for abstraction, or that groundwater baseflows no longer sustain river discharges.

In my PhD research, I predicted where and when we will reach these limits of groundwater consumption worldwide. I defended my dissertation last year April at Utrecht University, in the Netherlands.

Where and when are the limits reached?

Results show that many large aquifer systems are already highly depleted, especially for intensively irrigated areas in dryer regions of the world, like India, Pakistan, Mid West USA, and Mexico (see Figure 1). New areas experiencing groundwater depletion will develop in the near future, such as Eastern Europe and Africa. Future predictions show that some areas, like the Central Valley, and the High Plains Aquifer, partly recover when more recharge will becomes available. Notwithstanding, environmental groundwater demands will increase as to buffer more irregular streamflow occurrences due to climate change.

Figure 1: Estimated groundwater depletion (1960-2010) in [m], masked for aquifer areas, and zooms for hotspot regions, which are the intensively irrigated regions of the world.

In 2010, about 20% if the world population lived in groundwater depleted regions, where groundwater dropped below the economical exploitable limit. As a rule of thumb: the economic limit is reached when groundwater becomes unattainable for a local farmer, which is approximately when the water level drops to 100 m below the surface. In 2050, 26% to 36% of the world’s population will live in areas where the economic exploitable limit is reached (see Figure 2). Evidently, this persistence and increasing level of groundwater stress will impair local development and generate tension within the global socio-economic system.

Figure 2: First time that groundwater falls below the 100m limit.

 

Global-scale simulations

To answer my main question, I studied the effects of groundwater abstractions on river low flows and groundwater levels worldwide, as well as which trends in river low flow frequency and groundwater level change can be attributed to groundwater abstractions.

I used a newly developed physically based surface water-groundwater model to simulate i.a. river flows, lateral groundwater flow, and groundwater-surface water interactions at a high resolution (approx. 10×10 km) at the global scale. Total water demands were estimated and account for agricultural, industrial, and domestic demands. I simulated groundwater and surface water abstractions based on the availability of the resource, making the estimate reliable for future projections under climate change and for data-poor regions where we do not know how much groundwater or surface water is abstracted. Next, I developed a global-scale groundwater model. I estimated alluvial aquifer thickness worldwide, as no data at the global scale is available (see Figure 3). Aquifer thickness is one of the parameters you need to estimate groundwater flow and storage.

Figure 3: Estimated alluvial aquifer thickness. White areas are mountain regions, where no aquifers are simulated.

Simulations were done for the recent past and near future (1960-2050) and the results include maps and trends of groundwater heads, groundwater fluctuations, and river discharges.

In conclusion, most of our water reserves are hidden underground and most of our groundwater abstractions rates exceed groundwater renewing rates, leading to depletion. The growing demand and the expected climate change bring our groundwater reserves under mounting pressure. More than two-thirds of all abstracted groundwater is used for food production. Every year the world’s population is growing by 83 million people.

Improving our knowledge about how much water we can use in the near future while avoiding negative environmental and socio-economic impacts is therefore extremely important. A study like this contributes to the knowledge gap and can help guide towards sustainable water use worldwide to overcome potential political water conflicts and reduce potential socio-economic friction, as well as to secure future food production.

Want to read more? Check out the recent AGU press release or if you have more time… read my papers on dynamic water allocation (click here), development of a global groundwater model (click here, or here), or read my PhD thesis (here).

 

Author Inge de Graaf receiving her PhD degree from her advisor, professor Marc Bierkens (at Utrecht University, Netherlands). Note Tom Gleeson’s bald head in the lower left…

The great American groundwater road trip: Interstate 80 over the Ogallala Aquifer

The great American groundwater road trip: Interstate 80 over the Ogallala Aquifer

 


Authored by: Sam Zipper – Postdoctoral Researcher in the Department of Civil & Environmental Engineering at the University of Wisconsin-Madison


In late July, my wife and I loaded the dog into the car, cranked up the water-related tunes, and drove over a few million cubic meters of water. No, we haven’t traded in our sedan for an amphibious vehicle – rather, we were driving west, across Nebraska, on the Interstate 80 highway. While this may be a relatively boring road trip by conventional standards, it does provide an opportunity to drive across the famous Ogallala Aquifer, a part of the High Plains Aquifer system.

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The wide reaching Ogallala Aquifer 1. The red line shows Interstate 80’s route.

While the geological history of the Ogallala is described in more detail elsewhere; the short version is that sediment, eroded off the Rocky Mountains over many millions of years, filled in ancient river channels, eventually creating the flat plains that characterize much of Nebraska today. Despite the flat landscape, however, the sights you’ll see along I-80 exist in their present form almost entirely due to this vast underground supply of water.


Irrigation

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A center-pivot irrigation sprinkler. A common sight over the Ogallala 2.

It’s estimated that upwards of 90% of the water withdrawn from the Ogallala is used for agricultural irrigation. Driving through western Nebraska, 90% seems like an underestimate. Center-pivot systems stretch away from the interstate as far as the eye can see, and it’s hard to imagine what this landscape would look like without the water from the Ogallala. While groundwater levels have declined in the most heavily irrigated parts of Nebraska compared to predevelopment conditions, they’ve fortunately stabilized over the past ~30 years; the most serious drawdowns are occurring further south, in Western Kansas, Oklahoma, and the Texas Panhandle.


The Mighty Platte

PlatteRiver

The mighty Platte River. Photo by Sam Zipper.

The Platte River stretches from the Rockies to its confluence with the Missouri River in eastern Nebraska, and I-80 follows the Platte through most of Nebraska. Along the way, the Platte is receiving water from surrounding groundwater systems.  This process of groundwater discharge to streams (often called baseflow), is particularly important for sustaining flow in the river during dry periods, along with the ecosystems, agriculture, and municipalities that depend on this water supply. For a more beautiful look at the Platte than my cell phone camera offers, check out the Platte Basin Timelapse project, which uses photography to explore the movement of water through the basin.


The Namesake

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Ogallala Nature Park welcome sign. Photo by Sam Zipper.

The Ogallala is named after Ogallala, NE, a tiny town about a half hour’s drive from the Colorado border. The aquifer is named after Ogallala because that’s where the geologic “type locality” is – a fancy way of saying, they found the Ogallala formation here first. While we didn’t venture into the town of Ogallala itself, we did stop at the lovely Ogallala Nature Park just off the interstate for a stroll among the phreatophytic vegetation lining the banks of the Platte. Phreatophytes, such as the cottonwoods common to Nebraska, have evolved to have special roots which can extract water directly from groundwater when soil moisture supplies are low, thus allowing them to survive in the sandy, well-drained banks of the Platte.

Do you have any hydrogeologic highlights we should investigate on our drive back to Madison? Let me know via the comments below!


Picture Sources

https://upload.wikimedia.org/wikipedia/commons/thumb/4/44/Ogallala_saturated_thickness_1997-sattk97-v2.svg/2000px-Ogallala_saturated_thickness_1997-sattk97-v2.svg.png

http://water.usgs.gov/edu/pictures/full-size/irrigation-sprinkler-large.jpg


About the author:

Sam Zipper‘s research interests lie broadly at the intersection of humans and the environment, focusing on feedbacks between subsurface hydrology, vegetation dynamics, soil water retention characteristics, and climate & land use change that cut across the disciplines of hydrology and hydrogeology, soil science, agronomy, and ecology.  He is an ecohydrologist at the University of Wisconsin-Madison.

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Protecting springs from groundwater extraction: is a ‘drawdown trigger’ a sensible strategy?

Protecting springs from groundwater extraction: is a ‘drawdown trigger’ a sensible strategy?

By Matthew Currell – Senior Lecturer at RMIT University

Springs, some of which have been flowing for hundreds of thousands of years, have been disappearing in Australia due to human water use over the past century. Following a hotly contested court case, Australia’s Environment Minister imposed a 20cm ‘drawdown limit’ at a set of springs, to protect them from a proposed coal mine. However, this ignores a fundamental principle of hydrogeology, known as ‘capture of discharge’ and as a result, the springs may still be under threat.

Why are springs important?

Springs are a groundwater system’s gift to the surface.  They provide a constant source of water to the landscape throughout the year, and many have been doing so for millenia. This is why they are often of great importance to indigenous people and why they play an important part in the history of human settlements. Springs also provide valuable ecological refuges in dry landscapes and are often home to endemic species. However, springs are vulnerable to the effects of groundwater extraction.

The disappearing springs of the Great Artesian Basin

Recently, a group of Australian ecologists and hydrogeologists published a study of ‘lost springs’ that have disappeared from the Australian landscape since European settlers began drilling for water and minerals in the Great Artesian Basin (GAB) – the world’s largest artesian aquifer system (the term ‘artesian’ means that when a wellbore intersects one of the aquifers, groundwater flows freely to the surface, often gushing meters up into the air). Groundwater in the Great Artesian Basin travels many hundreds of kilometres across the Australian continent, before surfacing as clusters of springs, which provide life in otherwise dry landscapes (Figure 1). Research by colleagues of mine estimates that some of these springs have been discharging water (at variable rates) for hundreds of thousands of years.  This is based on dating the minerals that have been continuously precipitating at the spring outlets over geologic time. The drilling of wells in the Great Artesian Basin began in the late 1800s and was encouraged by governments, as a way to ‘open up the landscape’ for further white settlement into the country’s harsh, arid interior. Many of these artesian bores were allowed to flow freely for decades (some are still uncapped), leading to major declines in groundwater pressures throughout the Great Artesian Basin. Sadly, this has also caused many springs to disappear.

Great_Artesian_Basin

Figure 1 – Map of Australia’s Great Artesian Basin, which covers four states, showing the major areas of groundwater recharge and discharge, where springs emerge at the surface.  Source: ABC Science: http://www.abc.net.au/science/articles/2012/04/04/3470245.htm

Recent threats to springs from mining

More recently, another human activity threatens springs – mining. In particular, parts of Australia have recently experienced a boom in coal seam gas and large coal mining proposals. Large volumes of groundwater must be pumped from the aquifers above and adjacent to the coal and gas deposits to allow them to be mined. Extracting groundwater for mining means that some water that could otherwise reach the surface at springs is re-directed towards the gas wells or mine pits.  Figure 2 shows a map of oil and gas exploration and production permits that currently cover the Great Artesian Basin. Many of these are yet to be developed but would involve significant groundwater extraction.

Great_Artesian_Basin2

Figure 2 – Map of the Great Artesian Basin showing active oil and gas leases. From: SoilFutures Consulting, (2015): Great Artesian Basin Recharge systems and extent of petroleum and gas leases (2nd ed)

Recently, a major international company has also proposed the largest coal mine in Australia’s history – the Carmichael Coal Mine & Rail Project. Within 10 kilometres of the proposed mine site is a group of Great Artesian Basin springs – the Doongmabulla Springs. These springs are an ecological refuge, providing an oasis of green in an otherwise dry landscape (as can be seen in drone footage here: https://www.youtube.com/watch?v=RglMko3GwQA). The springs are of high cultural and ecological significance to the local Indigenous Wangan and Jagalingou people, and for this reason (among others) these people are strongly opposed to the mine.

Colleagues of mine recently participated in a hotly contested court case, arguing over whether or not the Carmichael Mine poses a threat to the survival of the Doongmabulla Springs – recognised by the Land Court judge as having ‘exceptional ecological significance’. The argument centred on whether or not the springs are fed by water from the same group of aquifers that will be excavated and de-watered by mining, or shallower aquifers. Ultimately, the Court decided that the mine was unlikely to pose an imminent threat to the springs, and upheld the environmental authority that was earlier granted by the Australian Government. This was in spite of testimony of some expert hydrogeologists that the most likely explanation for the springs is a fault that brings deep groundwater to the surface (more about the case and the mine can be read here).

Protection of Great Artesian Basin Springs

In Australia, the native flora and fauna supported by Great Artesian Basin springs are protected under the country’s highest piece of environmental legislation – the Environment Protection and Biodiversity Conservation Act (1999). This recognises the extraordinary level of endemism in these spring systems – many support species that are found in a single spring pool or group of springs, and nowhere else on earth. If a mining project is located in an aquifer that supports ‘GAB Springs’, the Act specifies that the Environment Minister must impose conditions to protect the springs’ water source. The mining company must then develop a monitoring and management plan, and a set of contingency measures to ensure impacts can be minimised.

In order to protect the Doongmabulla Springs from potential impacts of the Carmichael mine, the Environment Minister chose to apply a drawdown limit or ‘trigger’ level of no more than 20cm, stating:

“I took a precautionary approach by imposing a drawdown limit of 20 cm at the Doongmabulla Springs Complex (condition 3d), to ensure that there are no unacceptable impacts to the springs”

Problems with a drawdown ‘trigger’ to protect springs

Limiting drawdown to 20cm at a spring may sound like a strict criterion to ensure minimal impact from groundwater extraction (as this is a relatively small change in the water level). However, the approach has a number of pitfalls, as I recently outlined in a technical commentary in an article for the journal Groundwater.

The drawdown ‘trigger’, applied at the springs themselves, ignores one of the fundamental principles of hydrogeology, which is that groundwater extraction affects aquifers in two major ways; firstly through depletion of water in storage, and secondly through capture of discharge. All groundwater and surface water systems are subject to a ‘water budget’, whereby an increase in extraction at one point leads to a corresponding decrease in water stored or water available somewhere else. It has long been recognised that when groundwater extraction begins, there is generally a period in which storage depletion – shown by declining groundwater levels in the aquifer near the extraction point – is the dominant effect. However, in the long-term, extraction is balanced mostly by a decrease in the discharge reaching the surface. It is the ‘capture of discharge’ which is the most important effect to consider when protecting springs from pumping – as spring water is entirely composed of groundwater discharge. Unfortunately, this ‘capture’ is not well predicted by monitoring the amount of drawdown, particularly at the point of discharge itself.

As Figure 3 below demonstrates, it is quite possible for a spring (or a gaining stream) to experience minimal drawdown, but for the flow of water from the aquifer to the surface to decrease or even cease entirely. For this reason, by the time 20cm of drawdown has been noticed at the Doongmabulla Springs – which are located about 8 kilometres from the mine site – it is likely that the flow directions and water budget will have been fundamentally changed, and possible that the springs may ultimately cease to flow, as has occurred in many other parts of the Great Artesian Basin.

fig3

Figure 3 – Example of how groundwater levels change during groundwater extraction.  Drawdown may be small at a spring or stream until it is too late (fr: Currell, 2016).

Alternative approaches to management and protection of springs

It can be argued that the setting of a drawdown ‘trigger’ at a spring or stream is a classic case of ‘reactive’ environmental management, whereby management action is taken only in response to an impact when or after it takes place. Because of the relatively high level of uncertainty in most hydrogeological systems, the time-lags that occur between an activity such as pumping and the hydrological response, and the difficulty in directly observing groundwater behaviour, a pro-active approach to monitoring and managing impacts from mining and other activities is needed. As I argue in the technical commentary, a far more effective approach to springs protection would include a program to understand the source aquifer for the springs, an assessment of the water budget before and after the mining development (through modelling), and a monitoring program that maps out water level patterns and flow directions in the aquifer(s) regularly through time and also monitors flow rates at the springs. These activities should be undertaken up-front during the environmental impact assessment. If ‘trigger’ levels are to be used as an effective management tool,  these should be set as specified water levels at a series of points set back some distance from the springs, to identify negative effects before they reach the springs.

While this may sound onerous for the mining company, the importance of the springs to the indigenous people and ecological environment means that it is worth making the effort to use the best hydrogeological science possible to protect them.

Bonus Figures
bonus1

Artesian well in the Great Artesian Basin providing a constant flow of hot water. (Source: Wikipedia commons)

bonus2

Evidence of springs that have gone dry, from sites in Australia’s great Artesian Basin.  From: Fensham, R. et al., 2015 In search of lost springs: a protocol for locating active and inactive springs. Groundwater Volume 54, Issue 3, pagese 374-383, 5 October 2015 DOI: 10.1111/gwat12375 (link)

Human Drought?

Human Drought?

By Anne Van Loon – a water science lecturer at the University of Birmingham

Recently I published a commentary in Nature Geoscience with the title ‘Drought in the Anthropocene’. In that commentary, my co-authors and I argued that in the current human-dominated world, we cannot study and manage natural drought processes separately from human influences on the water system like water abstraction, dam building, land use change, water management, etc. To fully integrate human processes when studying drought we should change the definition of drought, test new methodologies and include social science. This sounds quite logical, but if you look at the history of drought science, it is not so obvious. In the natural sciences, drought research is a young field compared to research on floods. Floods are of course much more conspicuous, but drought causes more loss of life and economic damage worldwide. Because drought research is such a young field, the basic processes needed to be studied first before complex systems (including humans) could be understood. Additionally, much of the drought research in the last decades has focused on questions related to the effects of climate change, which needed natural case study regions, uninfluenced by people, for an undisturbed climate change signal.

So why do I think it is time for a change now? Well, partly because the drought research field is a more mature field now and because we realize that direct human influences on drought might be significantly bigger than the effects of climate change, but there is a personal story too. That story starts when I started my PhD on the processes underlying drought propagation at Wageningen University (the Netherlands) in 2007. I was going to focus on natural processes and five case study regions were selected in the EU-funded project I was working in. One of those ‘unfortunately’ was not a natural, undisturbed catchment. In the Upper-Guardiana catchment in Spain abstraction for irrigation in the 1980s and 1990s was so massive (see pictures below) that it decreased groundwater levels with 50 meters in some parts of the aquifer and groundwater-dependent rivers dried up (see pictures below).

A

Large-scale agriculture (mainly grapes) requiring large-scale irrigation in the Castilla-La Mancha region in Spain

 

B

Dried-up rivers in the Guadiana catchment. The name of the river is even crossed out because there has not been any wate rflowing for 20 years. (Photos by Henny Van Lanen)

When the important Ramsar wetland Tablas de Daimiel dried up (see pictures below), this led to a debate between farmers and nature organisations. The nature organisations claimed this disaster to be caused by the agricultural abstractions, whereas the farmers defended themselves by arguing that the wetland dried up because of the severe multi-year drought that Spain was experiencing at the time and that their abstraction was only minimal. Since I was interested in the natural processes related to the development of that drought, I needed to exclude the effect of abstraction. I developed a methodology for that and discovered that the drying up of the wetland was caused by both a lack of precipitation and groundwater abstraction, but that the effect of groundwater abstraction on decreased water levels was, on average, four times as high as the effect of the lack of precipitation. This meant that both the farmers and the nature organisations were right, but the farmers had more influence than they claimed to have.

C

Dried-up wetland Tablas de Dimiel. (Photos by Henny Van Lanen)

This approach of separating between the human and natural causes of a lack of water solved the problem for my PhD and I could comfortably go back to studying the natural processes of drought in all my case study regions. And I did so successfully, judged by the positive evaluation of my PhD thesis and defence in 2013 (see pictures below). However, something kept bothering me, because I realized that my results were not applicable to most of the world, since there are almost no places left without significant human influence on the water system.  Take the current multi-year drought in California. Politicians, farmers, water managers and the media keep asking the question: “how much rain is needed to end the drought?” This would already be quite a difficult question in a completely natural system, but it is un-answerable in a hugely complex system like California, dominated by human activities like agriculture, water abstraction, water storage in reservoirs, water transfer, and urbanization. How much rain is needed to end the drought is for example highly dependent on how much we abstract. With a simple water balance you can evaluate that the amount of water storage (in for example groundwater or reservoirs) is related to how much water comes in and how much water goes out. If we take out more, we also need more input to recover from a drought in storage. So, if the farmers in California keep on abstracting huge amounts of groundwater, the system will take much longer to recover. We as natural scientists cannot answer questions about the recovery of drought in these kind of human-dominated systems if we do not take into account human activities in our calculations. To be able to do that we need to adapt our methodologies. We could for example use the tools I used to get rid of human aspects of drought in my Guadiana case study, to instead focus on the effect of abstractions.

D

PhD thesis and defense.

But it is not all bad. We can also have a positive influence on drought. Last year (already moved on to a Lecturer post at the University of Birmingham, UK), I visited Santiago de Chile for a project workshop. Santiago is a very big city (see pictures below). For its water supply the city is dependent on snow and reservoirs in the mountains. Decreasing snow accumulation related to climate change lead to worries about future water resources. One of the solutions the Chileans are investigating is artificial aquifer recharge projects, in which surface water during high-flow periods is led to infiltration ponds and allowed to recharge the underlying aquifer (see picture below). In times of low water availability in the mountains this groundwater can be used as alternative source of water.

E

The city of Santiage de Chile and their Artificial Aquifer Recharge project.

Also in Upper-Guadiana, people have found a solution to the problem. Measures are in place to reduce groundwater abstraction for irrigation. However, these take a long time to implement and to have an effect on groundwater levels and the wetland. Until that time, a temporary solution saves the important wetland from drying out completely. Groundwater is pumped up to keep the Tablas de Daimiel wetland wet (see pictures below). Hopefully this is a bridge to a more sustainable solution that results in a full recovery of the aquifer and the wetland.

F

Re-wetted wetland Tablas de Daimiel.

These positive influences of humans, alleviating drought conditions, should also be included in our drought research, because then we can investigate the effectiveness of certain measures to reduce the impacts of drought. Responses to drought, such as water use restrictions, can lead to feedbacks between the natural and social systems that are very complex, but also very interesting and crucial to understand if we want to solve our drought problems. That is why I wrote the Nature Geoscience about such an obvious topic ‘Drought in the Anthropocene’. I am ready to work on more complex drought processes (see pictures below) and I encourage my colleagues to do the same so that our results are useful where they are most needed.

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Me looking towards a bright future … (Photos by Henny Van Lanen)

Read the paper ‘Drought in the Anthropocene’ here: http://www.nature.com/ngeo/journal/v9/n2/full/ngeo2646.html


Van Loon, A.F., Gleeson, T., Clark, J., Van Dijk, A., Stahl, K., Hannaford, J., Di Baldassarre, G., Teuling, A., Tallaksen, L.M., Uijlenhoet, R., Hannah, D.M., Sheffield, J., Svoboda, M., Verbeiren, B., Wagener, T., Rangecroft, S., Wanders, N. and Van Lanen, H.A.J. (2016). Drought in the Anthropocene. Nature Geoscience, 9(2), pp.89-91.


~ A repost from the TravellingGeologist blog ~

Baseflow, groundwater pumping, and river regulation in the Wisconsin Central Sands

Baseflow, groundwater pumping, and river regulation in the Wisconsin Central Sands

By Sam Zipper, postdoctoral fellow at Madison and author of tacosmog.com

We often think of groundwater as a nonrenewable reservoir, deep underground, and with good reason – less than ~6% of groundwater globally entered the ground within the past 50 years. However, where a river or stream intersects the water table, water is able to move from the aquifer to the stream (or vice versa). This supply of shallow groundwater to streams is called ‘baseflow’, and is an important supply of water for many streams worldwide, especially during dry seasons or periods of drought. Below, we can see that baseflow makes up more than 50% of total streamflow over most of the world:

global_baseflow

Global estimates of baseflow index – the proportion of streamflow that comes from groundwater or other slowly varying sources, like upstream lakes and wetlands.

The ability of groundwater to contribute to streamflow depends on the water level of the aquifer in the area surrounding the stream. Therefore, human actions that lower groundwater levels (such as pumping for urban or agricultural use) can impair the ability of an aquifer to supply water to streams during dry periods, with potentially devastating consequences for streamflow.

One example close to my home is the Central Sands region of Wisconsin, which is a large region found (not surprisingly) in the center of the state with particularly sandy soils. The sandy soils are perfect for growing potatoes, and the Central Sands is primarily an agricultural region; however, because water drains quickly from sandy soils, irrigation has become an increasingly important part of the landscape:

centralsands

In addition to agriculture, however, the Central Sands region is home to many rivers, lakes, and streams. Recently, one river in particular has become a microcosm of the debate surrounding the impacts and trade-offs of agricultural water use: the Little Plover River. While only 6 miles long, the Little Plover is a prized brook trout fishery and important ecosystem within the region. According to American Rivers, which listed the Little Plover as one of America’s 10 most endangered rivers in 2013, streamflow in the Little Plover has been decreasing since the 1970s and flows today are roughly half of the historical normal. The situation in the Little Plover came to a head in 2005, when several stretches of the Little Plover dried up, with predictably negative consequences for the fish.

Over the past decade, the Little Plover has been mired in legal controversy. In 2009, the Wisconsin Department of Natural Resources established what they call a “Public Rights Flow”, or a required amount of streamflow that the public is entitled to flow through the river. The advocacy leading to the establishment of this Public Rights Flow was primarily by conservation groups like the River Alliance and Trout Unlimited, with the goal of protecting fish and the rest of the stream ecosystems. In order to set the threshold, the Wisconsin Department of Natural Resources first established a baseline level as the 7-day average low flow with a 10% probability of occurring in a given year, and then adjusted this value upwards based on estimates of the flow necessary for to provide fish habitat and recruit trout. Despite the positive step of establishing a Public Rights Flow, measurements during the 2012 drought were consistently below the thresholds set by the Department of Natural Resources, and the Little Plover even dropped below the thresholds in 2013 and 2014, both of which were relatively wet years for Wisconsin.

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The Little Plover in 1997 and the first time in ran dry in 2005 (Friends of the Little Plover)

The current debate surrounding the Little Plover hinges on whether the Department of Natural Resources is legally allowed to consider cumulative impacts when permitting new high capacity wells in the region. Previously, the Department of Natural Resources was not considering cumulative impacts, which means that for every well application, they are only allowed to think about that well in isolation – and the effects of a single well are typically small enough that the Department of Natural Resources does not have sufficient grounds to deny a permit. However, the relatively small impacts of many individual wells can add up to cause a big overall effects on local groundwater resources. This changed in 2014, when a judge ruled that the Department of Natural Resources should be considering cumulative impacts. The effects of this ruling remain to be seen, but it improves the DNR’s ability to manage groundwater and surface water resources while considering the interactions between the two.

Thus, the Little Plover River provides a powerful example of a case where a little bit of groundwater drawdown can lead to big environmental, political, and economic issues. Currently, hydrogeologists at the Wisconsin Geological Natural History Survey and USGS Wisconsin Water Science Center are working on developing a groundwater flow model of the region to help understand the impacts of groundwater withdrawals on the aquifer, and what that means for local surface water features like streams and lakes. Because the waters of the Central Sands are valued for many different uses, including farming, urban supply, and outdoor recreation, the team building this model has been working closely with different groups of users to determine the priorities and needs of the various water users the region, and make sure that their scientific tool they develop is both useful to and trusted by the decision-makers in the region. As the future of the Little Plover and other rivers unfold under increasing human pressures and climate change, it is critical that water scientists work together with the public to conduct fair and unbiased science that provides timely and useful information for the decision-making process.

Fantasy Bottled Water Brands of Tomorrow: Ogallala Water

Fantasy Bottled Water Brands of Tomorrow: Ogallala Water

We are peering into the not-so-distant future to imagine what the brand geniuses of the future will be serving up for discerning water consumers!

The Brand: Ogallala
Source: Great Plains
Why? Deep down, you know you love it.

Promotional Copy:

Ogallala Water: GET PUMPED.

Swill waters run deep so we go deep, deep, deep into the Great Plains water table to pipe this ancient, undisturbed water to your table. No raunchy reuse here. Ogallala Water is guaranteed free of questionable recharge sources and serves up 30% less* in every freshly-pumped bottle.

*50% less in some areas. Supplies are limited.

Parody Ogallala Bottled Water

Consume less fantasy and more facts at:

Reposted with permission from thristyinsuburbia.com.

Is groundwater depletion keeping California fruit and veggies cheap during the severe drought?

Is groundwater depletion keeping California fruit and veggies cheap during the severe drought?

Food prices in the United States are increasing slightly but not as significantly as one might expect given the severe drought in California. Margret Munro, a science journalist with Postmedia, recently asked me a great question: is grounveggiesdwater depletion keeping California fruit and veggies cheap during the severe drought? Following up on her article, here is what I found and what it means for the Central Valley aquifer system in California.

What is the Central Valley aquifer?
The Central Valley aquifer system is a large, complex aquifer system.  Permanent loss (or depletion) of groundwater in the Central Valley aquifer may pose a threat to the agricultural economy of the U.S. since market value of agricultural products grown in there contributed up to 7% of the nation’s $300 billion in agricultural revenue in 2007. Recently,  we have shown how different crops lead to groundwater stress across the Central Valley.

centralvalley

http://academic.emporia.edu/schulmem/hydro/TERM%20PROJECTS/Gunther/stanislaus.html

Why are food prices not increasing?
According to NPR’s Dan Charles there are three reasons why food prices are not increasing: 1. some farmers have backup water supplies, and much of this is groundwater;  2. some parts of California are less dry than others; and 3. the limited water is going to crops that consumers are most likely to notice.

Is groundwater pumping increasing?
Previous studies by the USGS have shown that groundwater pumping increased during previous. During the last drought, this increase in pumping was even seen in GRACE satellite data, which was updated in a more recent report.   Another recent study from University of California Davis suggests surface water deliveries will be reduced by an estimated 6.5 million acre-feet and partially replaced by an increase of 5 million acre-feet of groundwater pumping (compared to the normal quantity of 20 million acre-feet). The research team estimates nearly 410 thousand acres being fallowed, resulting in a reduction in gross farm revenue of $738 million.

1977-Poland_telephonepole

Groundwater depletion caused the land to subside at the rate highlighted by the years on the telephone pole (USGS)

What are the potential impacts on the Central Valley aquifer?
A study of major aquifers in the United States suggests only 20% of the pumpage of the Central Valley aquifer comes from the depletion of stored groundwater. Most of the pumpage comes from increased recharge due to artificial irrigation. This can lead to groundwater contamination by fertilizers or pesticides and or decreased baseflow to rivers, which can impact the environment. Other potential impacts are aquifer compaction, which causes land subsidence and increased pumping costs. As a previous post described, this may even be moving the nearby Sierra Nevada Mountains!

What is next?
This drought seems to be encouraging California to modernize water management. Now, California seems to poised to pass new groundwater regulations. Go Governor Jerry Brown, Go!