WaterUnderground

Cultural Impacts

Groundwater pumping poses worldwide threat to riverine ecosystems

Groundwater pumping poses worldwide threat to riverine ecosystems

Post by Inge de Graaf, Assistant Professor of Hydrological Environmental Systems at the University of Freiburg.


With the climate strikes happening all over the world, I sometimes wish I had a crystal ball that would allow me to look into the future. Or even better, a crystal ball that could show me different scenarios of what will happen if we change, or not.

Well, I do not have a crystal ball, but I do have a global scale hydrological model. I use this model to glimpse into the future and see what will happen to our rivers and streams if we keep pumping groundwater like we do now. Me and my co-authors recently published a paper on this in Nature.

Over the last 50-years strong population growth and economic development have led to a large increase in freshwater demand, especially for the irrigation of food crops. About half of the water used for irrigation is pumped from groundwater. In many dry regions around the world, more groundwater is pumped than recharged from rain, causing water levels to drop. When the water levels drop, the flow of groundwater to rivers and streams will reduce. As a consequence, river flows will decline (or even completely dry up) and water temperatures will rise, forming a major threat to fish and water plants.

In our study, we used a new global-scale hydrological model to investigate how freshwater ecosystems have been, and will be, affected by groundwater pumping. Using the model, I am able to calculate the flow of groundwater to rivers all over the world. This allows me to study how a reduction of this groundwater flow, when it is pumped, impacts river flow.

Our calculations show that almost 20% of the regions where groundwater is pumped currently suffer from a reduction of river flow, putting ecosystems at risk. We expect that by 2050 more than half of the regions with groundwater abstractions will not be able to maintain healthy ecosystems. Our estimates of when and where critical river flows are first reached are presented in Figure 1.

Figure 1. First year critical river flow is reached and aquatic ecosystems are threatened due to groundwater pumping.

The most striking insight is that only a small drop of groundwater level will already cause these critical river flows (Figure 2). Moreover, the impact of groundwater pumping will often become noticeable after years, or decades. This means that we cannot detect the future impact of groundwater pumping on rivers from the current levels of groundwater decline. It really behaves like a ticking time bomb.

Figure 2. Groundwater level drop that causes critical river flows to be reached.

We already see the negative impact of groundwater pumping on river flows in Central and Western United States and in the Indus river basin in Asia. If groundwater pumping continues as it is now, we expect negative impacts to occur in Southern and Eastern Europe, North Africa, and Australia in the coming decades. Climate change will accelerate this process.

Although seeing the consequences of groundwater pumping on the environment globally is rather shocking, I am still optimistic about the future. I hope we can raise awareness on a slowly evolving crisis. A reduction of groundwater pumping will be the only way to prevent negative impacts, while at the same time, global food security should be maintained. Groundwater should be used more sustainably. It is important to develop more efficient irrigation techniques worldwide and experiment with crops that use less freshwater or can live in salty water.

If you would like to read about this research of mine in more detail, read my publication Environmental flow limits to global groundwater pumping.

I conducted this work with my co-authors Tom Gleeson (University of Victoria), L.P.H. (Rens) van Beek, Edwin H. Sutanudjaja, and Marc F.P. Bierkens (all form Utrecht University).

de Graaf, I. E. M., Gleeson, T., (Rens) van Beek, L. P. H., Sutanudjaja, E. H. & Bierkens, M. F. P. Environmental flow limits to global groundwater pumping. Nature 574, 90–94 (2019).

Update on the groundwater situation in Cape Town

Update on the groundwater situation in Cape Town

Post by Jared van Rooyen, PhD student in Earth Science at Stellenbosch University, in South Africa.


When the Cape Town water crisis first emerged it took almost a year before active contingencies were put in place. Four major ideas were proposed: (1) Intense water restrictions for municipal water users, (2) greywater recycling facilities, (3) groundwater augmentation of water supplies, and (4) desalination.

Although not all the proposed ideas came to fruition, there was a significant increase in the installation of well points and boreholes for municipal and private use. The national and provincial governments began the investigation and development of three major aquifers in the Western Cape. Unfortunately (or fortunately), the initial estimates for extraction were never realized as a result of poor water quality in the Cape Flats aquifer, power struggles between government parties and typical delays in service delivery in South Africa. In contrast, private groundwater consultants are benefiting from the high demand for groundwater use by residents installing private wells to alleviate the pressures of stringent water restrictions.

There are now two plausible scenarios for the groundwater use situation in the Western Cape: either we have not yet begun to abstract any significant amounts of groundwater, or we lack the data to show if we have. It is difficult to provide empirical evidence on whether groundwater levels are indeed declining and if it is a result of the drought (or abstraction or both). The trouble is that, unlike surface water storage where we can see the direct evidence of the drought, how much water is in an aquifer cannot be directly observed and must be estimated via an indirect method.

Estimating changes in groundwater availability usually requires detailed baseline data to be available, meaning that the state of a resource is relative to the baseline data available and can be over/underestimated as a result. One example of this was the subject of a controversial string of news articles released in the first months of 2019.

The Department of Water Affairs (DWS) released an interactive map of monitoring boreholes across South Africa which includes a record of normalized water levels (0% being the lowest measured water level in meters above sea level (masl) and 100% the highest measured water level) averaged over a province (Figure 1) . The graph shows a decline in average water levels in the last three years, but the record only goes back to 2009 and it is difficult to say if this a drought signal, a result of abstraction, or simply a natural fluctuation over a longer timescale.

Figure 1: Plot showing the severity of groundwater levels in the Western Cape of South Africa, averaged groundwater levels are plotted as a normalized percentage of the lowest and highest recorded levels in the borehole history. Credit: NIWIS DWA South Africa

Respected researcher and geochemist Dr. Meris Mills investigated historical data from the national groundwater archive and found that much of the data before 2015 were too sparse to be considered representative of the groundwater level. Data density and availability still is a major limiting factor in groundwater studies in South Africa.

Dr. Mills found that 55% of boreholes show statistically significant declining water levels and 63% of boreholes recorded an all time low water level after 2015 to late 2018 (since 1978). She concluded that fractured rock aquifers were the least affected and that 37% of boreholes with falling water levels were, in fact, not related to the recent drought. The cause for these declines in water levels are still unknown.

It is still difficult to quantify how much groundwater contributed to the recovery of Cape Town’s dam levels, if at all, but the resultant interest in long term groundwater supply has sparked debate surrounding local groundwater resources.

It is also clear that the effects of the drought on groundwater resources remain to be fully realized, however our groundwater, in general, is more resilient to change than we may think. Depending on the angle you look at it, initial findings may either indicate that groundwater is potentially a lifeline to cities crippled by a water supply crisis, or a time bomb with a delayed fuse.

Water: underground source for billions could take more than a century to respond fully to climate change

Water: underground source for billions could take more than a century to respond fully to climate change

WaterUnderground post by Mark O. Cuthbert, Cardiff University; Kevin M. Befus, University of Wyoming, and Tom Gleeson, University of Victoria


Groundwater is the biggest store of accessible freshwater in the world, providing billions of people with water for drinking and crop irrigation. That’s all despite the fact that most will never see groundwater at its source – it’s stored naturally below ground within the Earth’s pores and cracks.

While climate change makes dramatic changes to weather and ecosystems on the surface, the impact on the world’s groundwater is likely to be delayed, representing a challenge for future generations.

Groundwater stores are replenished by rainfall at the surface in a process known as “recharge”. Unless intercepted by human-made pumps, this water eventually flows by gravity to “discharge” in streams, lakes, springs, wetlands and the ocean. A balance is naturally maintained between rates of groundwater recharge and discharge, and the amount of water stored underground.

Groundwater discharge provides consistent flows of freshwater to ecosystems, providing a reliable water source which helped early human societies survive and evolve.

When changes in climate or land use affect the rate of groundwater recharge, the depths of water tables and rates of groundwater discharge must also change to find a new balance.

Groundwater is critical to agriculture worldwide. Rungroj Youbang/Shutterstock

The time it takes for this new equilibrium to be found – known as the groundwater response time – ranges from months to tens of thousands of years, depending on the hydraulic properties of the subsurface and how connected groundwater is to changes at the land surface.

Estimates of response times for individual aquifers – the valuable stores of groundwater which humans exploit with pumps – have been made previously, but the global picture of how quickly or directly Earth’s groundwater will respond to climate change in the coming years and decades has been uncertain. To investigate this, we mapped the connection between groundwater and the land surface and how groundwater response time varies across the world.

The long memory of groundwater

We found that below approximately three quarters of the Earth’s surface, groundwater response times last over 100 years. Recharge happens unevenly around the world so this actually represents around half of the active groundwater flow on Earth.

This means that in these areas, any changes to recharge currently occurring due to climate change will only be fully realised in changes to groundwater levels and discharge to surface ecosystems more than 100 years in the future.

We also found that, in general, the driest places on Earth have longer groundwater response times than more humid areas, meaning that groundwater stores beneath deserts take longer to fully respond to changes in recharge.

Groundwater stores are ‘recharged’ by rainfall and ‘discharge’ into surface water bodies such as lakes. Studio BKK/Shutterstock. Edited by author.

In wetter areas where the water table is closer to the surface, groundwater tends to intersect the land surface more frequently, discharging to streams or lakes.

This means there are shorter distances between recharge and discharge areas helping groundwater stores come to equilibrium more quickly in wetter landscapes.

Hence, some groundwater systems in desert regions like the Sahara have response times of more than 10,000 years. Groundwater there is still responding to changes in the climate which occurred at the end of the last glacial period, when that region was much wetter.


Read MoreThe global race for groundwater speeds up to feed agriculture’s growing needs


In contrast, many low lying equatorial regions, such as the Amazon and Congo basins, have very short response times and will re-equilibrate on timescales of less than a decade, largely keeping pace with climate changes to the water cycle.

Geology also plays an important role in governing groundwater responses to climate variability. For example, the two most economically important aquifers in the UK are the limestone chalk and the Permo-Triassic sandstone.

Despite both being in the UK and existing in the same climate, they have distinctly different hydraulic properties and, therefore, groundwater response times. Chalk responds in months to years while the sandstone aquifers take years to centuries.

Global map of groundwater response times. Cuthbert et al. (2019)/Nature Climate Change, Author provided.

In comparison to surface water bodies such as rivers and lakes which respond very quickly and visibly to changes in climate, the hidden nature of groundwater means that these vast lag times are easily forgotten. Nevertheless, the slow pace of groundwater is very important for managing freshwater supplies.

The long response time of the UK’s Permo-Triassic sandstone aquifers means that they may provide excellent buffers during drought in the short term. Relying on groundwater from these aquifers may seem to have little impact on their associated streams and wetlands, but diminishing flows and less water could become more prevalent as time goes on.

This is important to remember when making decisions about what rates of groundwater abstraction are sustainable. Groundwater response times may be much longer than human lifetimes, let alone political and electoral cycles.The Conversation


Post written by:

Mark O. Cuthbert, Research Fellow & Lecturer in Groundwater Science, Cardiff University;

Mark Cuthbert is a Research Fellow and Lecturer in the School of Earth and Ocean Sciences, at Cardiff University in the United Kingdom. Mark’s work currently focuses on coupled hydrological-climate process dynamics in order to: understand groundwater sustainability; improve interpretations of terrestrial paleoclimate proxy archives;  and understand how Quaternary paleoenvironments influenced human evolution.

 

Kevin M. Befus, Assistant professor, University of Wyoming; 

Kevin Befus leads the groundwater hydrology group in the Civil and Architectural Engineering Department at the University of Wyoming. With his research group, he studies how groundwater systems respond to hydrologic conditions over glacial timescales and in mountainous and coastal environments.

 

 

Tom Gleeson, Associate professor, University of Victoria

Tom Gleeson leads the Groundwater Science and Sustainability group in the Civil Engineering Department at the University of Victoria.  His research interests include groundwater sustainability, mega-scale groundwater systems, groundwater recharge and discharge and fluid flow around geologic structures. Tom is also the founder of this blog, WaterUnderground.

 

 


This article is republished from The Conversation under a Creative Commons license. Read the original article.

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The true meaning of life … for a hydrogeologist

I am currently on sabbatical with Thorsten Wagener’s group at the University of Bristol. While on campus, I stumbled upon this quote from Nelson Henderson (a farmer from Manitoba).  It encapsulates what I have been thinking about groundwater sustainability for a number of years: “The true meaning of life is to plant trees, under whose shade you do not expect to sit”. For me, as a hydrogeologist, I would re-write it to be something like: “The true meaning of life is to protect recharge and flow in an aquifer, from which you do not expect to pump.

Take a look at the original plaque and my doctored, groundwater-centric version. You never know, groundwater sustainability may just become the next fad in the inspirational quote universe …

Groundwater and Education – Part two

Groundwater and Education – Part two

Post by Viviana Re, postdoctoral researcher at the University of Pavia (Università di Pavia), in Italy. You can follow Viviana on Twitter at @biralnas.

Part two of a two-part series on groundwater and education by Viviana.

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In my last post (“Drawing out groundwater (from the well)”) I wrote about the reasons why, as groundwater scientists, we should engage not only literally, when we collect groundwater samples to perform our research, but also metaphorically, such as raising awareness on the hidden component of the water cycle to stakeholders and civil society.

Education and capacity development can become more integrated in our work, in academia, if we emphasize and increase our attention given to finding the most effective way to train and motivate the new generations of hydrogeologists (e.g. Gleeson et al., 2012). Indeed, in a rapidly changing world where students have mostly unlimited access to information and tools, we cannot simply expect to adopt the “classical” teaching methods and be successful. Additionally, we certainly have to consider life long training of professionals to keep them up to date with respect to new information and contemporary issues (Re and Misstear, 2017).

Even more, I believe that our efforts should not be limited to education and training of groundwater scientists and professionals, but should also aim to bridge the famous gap between science and society.

This can involve a wide range of audiences and goals, but I think the following tips can apply to them all:

  • Consider shifting from a classical hydrogeological approach to a socio—hydrogeological one, particularly if your work entails assessing the impact of human activities on groundwater quality. Strengthening the connection with water end-users and well owners is fundamental to ensure an adequate knowledge transfer of our research results.

Picture 1: When sampling, do not forget to explain to well owners what you are doing and, most importantly, why you are there (photo by Chiara Tringali; Twitter @tringalichiara).

Picture 2: Interviews can be a precious moment for capacity building. If you can sit down with well owners and administer a semi structured interview, not only can you retrieve precious information and embed local know-how in your research, but also you can have time to disseminate results and discuss about the possible implementation of good practices to protect groundwater in the long run (photo by Chiara Tringali; Twitter @tringalichiara).

  • Engage with new media and social networks. It may seem like a waste of time, especially when productivity and “publish or perish” remain dogma in academia, but these are definitely the means everyone uses for communication nowadays. Not fully exploiting their potential can be make us miss a precious occasion for a direct interaction with stakeholders and the public.
  • Keep in mind that people are busy and we all get easily distracted. Try to use visual information as much as possible. Sometimes a short video, a nice picture or an informative graphic are more effective than a thousand words.
  • Improve your science communication skills. In a wold full of inputs, it is not sufficient to have something important to say. It, perhaps, matters more how you say it. For this reason, the time dedicated to learn how to speak in public, how to give an effective presentation (either if you are planning to give a talk in front of a technical audience or at a conference on vegetarianism) and how to write a press release is always well spent.
  • Share your passion. If you choose to work in hydrogeology or groundwater science, you are probably passionate about the environment and protecting our planet. Use these emotions to share your knowledge to civil society and learn how to adapt the content of your research to different audiences without trivializing it.

You can find more on this topic in the chapter Education and capacity development for groundwater resources management” (Re and Misstear, 2017) of the book Advances in Groundwater Governance (Edited by Villholth et al., 2017).

-Cover picture by Cindy Kauss (2018)

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Viviana Re is a post doctoral research fellow at the Department of Earth and Environmental Sciences of the University of Pavia (Italy). Her research interests are: isotope hydrogeology, groundwater quality monitoring and assessment, groundwater for international development.

She is currently working on the development and promotion of a new approach, called socio-hydrogeology, targeted to the effective incorporation of the social dimension into hydrogeochemical investigations.

Twitter: @biralnasPersonal website

Socio-hydrology meets Broadway: Can we survive drought if we stop using the toilet?

Socio-hydrology meets Broadway: Can we survive drought if we stop using the toilet?

Post by Samuel Zipper, postdoctoral fellow at both McGill University and the University of Victoria, in Canada. You can follow Sam on Twitter at @ZipperSam.

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How can society best cope with water scarcity?

With Cape Town on the verge of being the first major city to run out of water (a topic for a future post here on Water Underground), this is a question on the minds of many water managers and scientists within the emerging fields of socio-hydrology and socio-hydrogeology.

Low levels in Cape Town, South Africa’s reservoir system. Image source: University of Cape Town News.

Recently, my wife & I had the opportunity to see a more musical exploration of this question at the Langham Court Theatre’s production of Urinetown here in Victoria. This satirical musical envisions a future in which severe droughts have limited water supplies to the point that government (controlled by a corporation) decides the best way to conserve water is to charge people to use the restroom, thus limiting both direct and indirect human consumption (by people drinking less and flushing the toilet less, respectively).

As a scientist, I naturally found myself wondering: how effective would this tactic be?

Fortunately, the data exist to give us at least a rough approximation. Globally, only about 10% of water is used in households; the vast majority (about 70%) goes to agriculture. Once the water reaches your household, however, Urinetown may have a point; in an average US household, toilets are the largest water user, averaging ~1/4 of domestic water use (33 gallons per household per day). Since the US has among the largest per-capita water use of any country, we can use this number as an upper bound for a back-of-envelope calculations: globally, if we collectively stopped flushing toilets today, we’d reduce water use by a maximum of 2.5%.

In contrast, switching to diets with less animal protein (particularly beef) can have a far greater impact, saving well over 10% – it takes 660 gallons of water to make a burger, equivalent to about 180 flushes of a standard toilet (see the water footprint of various foods here). However, water is inherently a local issue – most of the water that goes into your burger was used to grow crops, potentially far away from wherever you live, and does not consume local water resources. Also, the numbers we used for the above calculations have a lot of local variability, with up to ~1/3 of total water use in Europe and Central Asia in the household.

Percentage of indoor water use by different fixtures. Source: Water Research Foundation.

So overall, does the math add up for Urinetown? At a global scale, reducing agricultural water use through improvement in irrigation practices and changes in diet is going to have a much bigger impact. Locally, however, toilets do use a lot of water and restricting their use during times of crisis is a smart approach – and Cape Town has had an “If it’s yellow, let it mellow” recommendation since September. Replacing your toilet with a high-efficiency fixture can help as well – many cities and states have rebate programs to help reduce the costs of this switch.

And how does it turn out for the residents of Urinetown? To answer that question, you’ll have to see the show yourself. Urinetown had a three year run on Broadway, including winning three Tony Awards, and is now a popular choice for theatres all around the world.

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Sam Zipper is an ecohydrologist. His main research focuses broadly on interactions between vegetation and the water cycle, with a particular interest in unintended or indirect impacts of land use change on ecosystems resulting from altered surface and subsurface hydrological flowpaths. You can find out more about Sam by going to his webpage at: samzipper.weebly.com.

On the social responsibility of water scientists

On the social responsibility of water scientists

Post by Viviana Re, a post-doctoral research fellow at the Department of Earth and Environmental Sciences of the University of Pavia, in Italy.

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Should we feel a moral obligation to engage, if our work has real implications on society?

As an environmental scientist, with a PhD in Analysis and Governance of Sustainable development, I grew up “multidisciplinary-minded’ and the three-pillars of sustainability soon become my bread and butter.

However, as I progressively specialized in hydrogeology I had to confront myself with a new world, more technical, definitely interesting, but perhaps a bit suspicious with social sciences (at least some years ago), and where “no quantitative data” was often considered as a synonym of “no substance”.

When, back in 2013, I first presented the concept of socio-hydrogeology at an international congress on hydrogeology I divided this world in two. Some people definitely loved this new approach and found a lot of similarities with their work and research interests. Others, more skeptical, asked me if I decided to quit SCIENCE and dedicate myself to politics instead.

Besides the fact that I generally prefer to be pleased than criticized, I admit I am sincerely grateful to all those who shared with me their perplexities as they made me realize that:

  • I should improve my communication skills;
  • I shouldn’t take anything for granted – multidisciplinary and integrations are the roots of my research but this may not be the case for everyone;
  • I should better engage in promoting the incorporation of the social dimension into hydrogeological sciences and in fostering the connection between science and society.

These things follow from my belief that, as scientists, we should all have a key role in ensuring that the results of our hard work are really used to foster the long-term protection of groundwater resources worldwide.

This is part of our social responsibility, right?

As Stephanie J. Bird says in her paper Socially Responsible Science Is More than “Good Science

“[…] as members of society, scientists have a responsibility to participate in discussions and decisions regarding the appropriate use of science in addressing societal issues and concerns, and to bring their specialized knowledge and expertise to activities and discussions that promote the education of students and fellow citizens, thereby enhancing and facilitating informed decision making and democracy.”

Therefore, as groundwater scientists, part of our responsibility is to commit to share the results of our investigations outside the academic sphere and to find the most appropriate way to engage with civil society. This can be done in several ways, like through public speaking, social networks, media release and active involvement with local communities relying upon the water resources we are studying.

Academics-ivory-tower (Frits Ahlefeldt)

But, is this enough? Is outreach sufficient to ensure that we effectively bridge the famous gap between science and society?

 

What if we also engage to live more sustainably and to help driving the changes we aim to inspire with our research?

As scientists, every time we write about our work and research results, we almost always find ourselves discussing water distribution on Earth, the global water crisis and the need for sustainable water resources management. We often tell people the importance of saving water, recycling and reducing pollution, and certainly we aim to use the best available scientific tools for providing this information. But then, in our minds, it should also lead us to question whether we, the scientists, actually live sustainably and act responsibly.

Are we really acting to ensure safe water resources, for future generations? We know our food and good consumptions depend on energy and water, but still the global water demand is rising. Still, is there something we can do to diminish our water and ecological footprint? Is there something that we can do to bring the scientific knowledge in our everyday life? What if we would better engage to inspire people, our friends and local communities, and become true advocates of (ground)water protection and management?

We’ve decided to take action on these issues through Responsible Water Scientist, a project launched almost a year ago my myself and my friend and colleague Raquel Sousa. Responsible Water Scientist, is a space where we aim to encourage a broader discussion on the little changes in the daily routine that can make scientists real advocates of groundwater conservation for a more sustainable world. These changes can involve our dietary choices, shopping attitudes and consumption patterns, but are all closely related to our water footprint and the future of global water resources.

Bulk shopping saves plastic packaging and reduces our carbon and water footprint.

Drinking tap water (if safe and available) and bringing our own water bottle will significantly reduce the amount of plastic bottles produced per year.

 

Shopping bulk, reducing our meat consumption or engaging for a zero waste lifestyle may seem really challenging at first, but the effort is really worth it, indeed, every drop matters! Don’t you agree?

Find out more on Responsible Water Scientists here, and join our community on social networks by sharing your ideas and experience! All comments and inputs are more than welcome!

Facebook  | TwitterInstagram

Presenting Responsible Water Scientist with a keynote lecture at the 44th congress of the International Association of hydrogeologists (Croatia, September 2017).

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Viviana Re is a post doctoral research fellow at the Department of Earth and Environmental Sciences of the University of Pavia (Italy). Her research interests are: isotope hydrogeology, groundwater quality monitoring and assessment, groundwater for international development. She is currently working on the development and promotion of a new approach, called socio-hydrogeology, targeted to the effective incorporation of the social dimension into hydrogeochemical investigations.

TwitterPersonal website

Of Karst! – short episodes about karst

Of Karst! – short episodes about karst

Post by Andreas Hartmann Assistant Professor in Hydrological Modeling and Water Resources at the University of Freiburg.

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Episode 3 – Learning about karst by … KARST IN THE MOVIES!

Before writing about karst hydrology in “Of Karst! Episode 4”, I have been urged to present some more visual information on karst landforms. Of Karst! Episode 1 focused on the abundance of hilarious karst landforms in nature. This episode focusses more on the appearance of karst features in famous movies and TV programs that may be familiar to some of us, although we may not have watched them through the eyes of a karst fanatic at the time.

In the next episode, we follow the path of the water from the karstic surface with karstic towers and dolines, through caves and conduits, to spectacular karst springs where waters emerge to the surface.

Movie makers have their reasons to pick spectacular landscapes for their stories and, Of Karst!, those landscapes are crowded with karst features. Let’s begin with James Bond. Created in the 70s, “The Man with the Golden Gun” finds a spectacular showdown just in front of a lovely tower karst at the Khao Phing Kan island in Thailand. Tower karst is a karst landform that is, characterized by residual hills of limestone rising from a flat plain or the ocean.

Figure 1: Bonds‘ duel with villain Scaramanga in front of a tower karst rock (Khao Phing Kan, Thailand; http://www.criminalelement.com, http://www.marinaaonang.com)

Similar landforms were chosen as scenery for a recent remake of the King Kong saga. Fighting with intruders and evil monsters from the deep subsurface (karst caves?), Kong had the pleasure living on the beautiful Cat Ba Island in Northern Vietnam, whose characteristic landscape evolved due to the strong dissolution of limestone.

Figure 2: Silhouette of Kong between the Tower Karst mountains of Cat Ba Island located at Ha Long Bay, Vietnam (https://c1-zingpopculture.eb-cdn.com.au, http://www.baolau.com).

The opposite landform to tower karst landforms are karstic dolines, which occur commonly as funnel shaped depressions on the surface, also formed by carbonate rock dissolution. These depressions do not only funnel the water downwards to the subsurface, but also create favorable conditions for the installation of (very) large radio telescopes. The largest of those was built a couple of years ago in China but a similarly impressive one can be found in Puerto Rico, where James Bond had to deal with his evil competitor Trevelyan in “Goldeneye”.

Figure 3: Bond fighting with evil Trevelyan in Goldeneye high above the Arecibo Observatory in Puerto Rico that was built just in the middle of a karst doline (https://i.pinimg.com, http://www.si-puertorico.com).

Underneath the tower karst and dolines, karst dissolution creates wide networks of karstic caves and conduits. With increasing dissolution of the carbonate rock, these features may also emerge at the surface, which was probably the case for the Azure Window at Malta. This karst landform was chosen as the background of a conversation of the famous Khaleesi and her spouse Drogo in “Game of Thrones”. Unfortunately, this amazing land form is not available for further movies as it was recently destroyed by a storm.

Figure 4: Khaleesi speaking to her beloved Drogo in Game of Thrones in front of the Azure Window in Malta (http://nypost.com).

Deeper in the subsurface, the famous Devetàshka cave in Bulgaria set the stage for a dramatic showdown in “The Expendables 2”, when Stalone’s plane crashed through the cave entrance that used to be the exit of groundwater flows emanating from karst. Imagine the tremendous amounts of water filling the karst system over thousands of years that are capable of forming a cave that can (almost) host an entire airplane!

Figure 5: Stalone’s plane crashing into the Devetàshka karstic cave in Bulgaria in The Expendables 2 (www.huffpost.com, www.wikipedia.org).

Due to the formation of dolines, caves and channels, karst springs are usually quite large in terms of their discharge. They also provide amazing sets for fantasy movies. Even though the springs of the St. Beatus Caves in Switzerland only inspired Tolkien for the scenery of the Rivendell, the town of the elves, their similarity is obvious.

Figure 6: Elves’ town Rivendell in Lord of the Rings, whose scenery was inspired by the karst spring of the St Beatus caves in Switzerland (http://www-images.theonering.org, http://tilomitra.com).

This movie-based tour through karst systems may have given you an impression how rainfall becomes discharge in karst systems. Of Karst!, Episode 4, will combine this impression with the hydrological, and more scientific point of view. It will speak to the complexity of these specific surface and subsurface land forms, and elaborate on why exploring and understanding these processes is worthwhile.

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Andreas Hartmann is an Assistant Professor in Hydrological Modeling and Water Resources at the University of Freiburg. His primary field of interest is karst hydrology and hydrological modelling. Find out more at his personal webpage www.subsurface-heterogeneity.com

Everything is connected

Everything is connected

Post by Anne Van Loon, Lecturer in Physical Geography (Water sciences) at the University of Birmingham, in the United Kingdom.

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In recent years the human dimension of hydrology has become increasingly important. Major flood and drought events have shown how strongly water and society are intertwined (see here and here). The hydro(geo)logical research community is increasingly including this human dimension, for example within the IAHS Panta Rhei decade (link), which focuses on the interface between environment and society and aims to “make predictions of water resources dynamics to support sustainable societal development”. Previous Water Underground blog posts have shown the importance of this topic and highlighted opportunities and methodologies for scientists to engage with socio-hydro(geo)logy and humanitarian projects. Viviana Re, for example, introduces the term socio-hydrogeology and promotes sustainable groundwater management in alliance with groundwater users (link). And Margaret Shanafield argues that humanitarian groundwater projects are “an opportunity for scientists to have an impact on the world by contributing to the collective understanding of water resources and hydrologic systems” (link).

In our interdisciplinary project CreativeDrought (link), which uses local knowledge and natural and social science methods to increase local preparedness for uncertain future drought, we are applying these ideas and we realise how important different types of connections are in our two-way learning process. We just completed our second fieldwork phase of the project that consisted of workshops in which groups of people from a rural community in South Africa experimented with potential future drought scenarios and created stories about how they would be impacted by the drought and what they could do to prepare for and adapt to it. Our scientific team consisted of hydrologists and social scientists from local and UK-based institutes and the groups in the community who participated were the village leaders, livestock farmers, irrigation farmers, young mothers, and elderly people.

Young women collecting water from communal standpipe (photo: Sally Rangecroft).

Both the scientific team and the community groups were interested to learn from each other’s knowledge and experience (or just curious, see photo below of our Zimbabwean colleague Eugine measuring irrigation canal discharge with an apple). During the time we spent in the community (four weeks in March/April and two weeks in July) we both learned about important connections. As hydrologists and hydrogeologists we know that different parts of the hydrological system are connected and that these connections are extremely important if you want to understand, predict, and manage the system. Knowledge about the connection between groundwater and surface water is what we as hydrologists could bring to the community. The community was getting their water from different sources: drinking water from a groundwater well, irrigation water from a reservoir that releases water into the river, and water for bathing, washing, brick making, and cleaning cars from the river. By showing how a drought would affect each of these water supplies and discussing amongst groups that would be affected differently by a drought, they learned about the connection between the water bodies and how abstraction in one would affect the other.

Researchers measuring discharge with help of schoolchildren and collecting stories about previous droughts and floods (photos: Anne Van Loon and Sally Rangecroft).

We scientists also learned some important connections from the community. For example, our project focuses on drought but when we asked the community to tell us about droughts they had experienced in the past, many also told us about flood events. For the community, both are water-related extreme events that often even impact them similarly, with crop loss, drinking water problems, diseases, etc. Even though floods and droughts are governed by different processes (floods by fast, mostly near-surface pathways and droughts by slower, sub-surface storage related pathways) and different tools and indices are used to characterise both extremes, people at local scale have to deal with both floods and droughts when the hydrological system goes from one into the other or when both occur simultaneously in different parts of the hydrological system. We realised that our academic world is so fragmented that we often forget about connecting floods and droughts in our scientific work. Furthermore, we forget that we may affect one hydrological extreme when trying to manage our resources for the opposite hydrological extreme.

The most important, but unintended connections we discovered, however, were the connections between people. During our stays in South Africa, we connected as hydrologists and social scientists and between the UK-based and local researchers, learning to communicate across different disciplines, languages and audiences. The project also helped the community rediscover some connections between generations (young mothers and elderly ladies) and between different sectors (livestock farmers and irrigation farmers). And finally, we as a scientific team connected with the community. As a token for our newly established connection, the children’s dance group performed traditional dances during our final visit with the chief and the village leaders (see below), only bestowed on very special guests. That is the best confirmation we could get that personal connections are important and that our water management and our science depend on them!

Everyone connected: researchers, village leaders, dancers (photo: Khathutshelo Muthala).

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Anne Van Loon is a catchment hydrologist and hydrogeologist working on drought. She studies the relationship between climate, landscape/ geology, and hydrological extremes and its variation around the world. She is especially interested in the influence of storage in groundwater, human activities, and cold conditions (snow and glaciers) on the development of drought.

Bio taken from Anne’s University of Birmingham page.