community engagement

Urban water underground: How green infrastructure makes it visible

Urban water underground: How green infrastructure makes it visible

Post by Theodore Lim, assistant professor of Urban Affairs and Planning at Virginia Tech. He researches the socio-hydrology of green infrastructure planning and implementation.

In order for people to care about something, to value it, they have to be able to see it and experience it. This point should not be taken lightly. So much about decision-making and policy-making depends on how much public support can be organized around any given issue. So, when it comes to protecting the water resources that sustain society and the natural environment, it is perhaps unsurprising that groundwater is the part of water cycle that most folks tend to ignore.

Historically, urbanization has made it difficult for residents to experience key parts of the water cycle. In Philadelphia, for example, in order to improve sanitation, reduce flooding, and make way for the regular street grid, dozens of streams were channeled into brick sewers that were then buried under roads to make transportation routes more efficient and the city easier to navigate. Today, these historical streams are literally buried underground, and still carry a mix of raw sewage and stormwater runoff, that overflows into neighboring creeks and streams when it rains.

Sewering Mill Creek in West Philadelphia, 1883. Image Source: http://www.phillyh2o.org.

Green infrastructure is an approach to urban water management that reintroduces key parts of the hydrological cycle to the visible urban environment. Green infrastructure can involve surface water, through daylighting streams, but it can also means removing concrete and asphalt, to allow water to trickle slowly into the ground, be soaked up by plant roots, and evaporated back into the air, or to recharge deeper groundwater tables. An example of this is a rain garden, or bioinfiltration facility, which intercepts rainfall with vegetated land, as an aesthetic and low-maintenance alternative to conventional drainage systems.

Bioinfiltration facility installed in a residential neighborhood in Washington, D.C. (Photo by author)

How do urban residents “see” these important elements of the hydrological cycle? One answer is: by their recognizing them as “infrastructures” for modern cities — elements that provide critical services, in addition to environmental amenities. Plants and restored soils are not just “nice to have,” they help moderate surface temperatures, protect water quality, and support biological function. Public investment in street tree planting has been shown to increase pedestrian activity, public health, and property values. Green infrastructure programs in cities can also be integrated with climate action plans, sustainability initiatives, and parks and recreation programs; such programs often attract businesses and residents with their progressive attitudes.

Urban residents can learn about the “ecosystem services” associated with hydrological cycle improvements thanks to scientific signage, infographics, partnerships between  environmental non-profits and community outreach, programs run by municipal water managers (water/wastewater utilities, departments of environmental protection, or stormwater districts). Most of all, residents learn from each other and are more likely to adopt environmentally friendly behaviors when they are surrounded to neighbors who do the same.

Stormdrain art in Philadelphia, designed by children in Philadelphia public schools (Photo by author)

Green infrastructure monitoring and signage in Chicago. Image: https://nextcity.org/daily/entry/chicago-sensors-green-infrastructure-study

Restoring hydrological function within urban areas can be seen as a microcosm of larger-scale environmental policy-making. On the regional scale, “green infrastructure” can refer to the large swaths of undeveloped land in a natural state, or to working lands, such as those used for timber production or agriculture, which all provide critical ecosystem services to society. Environmental planners who work at the state or regional level or with land trust organizations, might use policies, economic incentives, and land regulations to protect these landscapes from low density suburban sprawl or urbanization. However, on both urban and regional scales, the decision-making about land use, management, and development is heavily dependent on co-operation between diverse stakeholders, and relies on a mutual understanding of the value of natural environments for various communities..

Urban and environmental planners tell stories that bring together multiple voices in collaboration.  These stories also give the historical and social context to decision-making around environmental systems, which is vital to ensure equitable outcomes. Unfortunately, despite advances in integrated modeling and the scientific knowledge of complex interrelations between water and society, decision-making still falls back on heuristics and rules-of-thumb. A highly relevant question therefore is: how can we integrate groundwater science into more robust city and regional-scale participatory planning, that is equitable and implementable? The answer will hopefully lead us to a strategy where urban and environmental infrastructures visibly advance the well-being of communities.

Doing Hydrogeology in R

Doing Hydrogeology in R

Post by Sam Zipper (@ZipperSam), current Postdoctoral Fellow at the University of Victoria and soon-to-be research scientist with the Kansas Geological Survey at the University of Kansas.

Using programming languages to interact with, analyze, and visualize data is an increasingly important skill for hydrogeologists to have. Coding-based science makes it easier to process and visualize large amounts of data and increase the reproducibility of your work, both for yourself and others. 

There are many programming languages out there; anecdotally, the most commonly used languages in the hydrogeology community are Python, MATLAB, and R. Kevin previously wrote a post highlighting Python’s role in the hydrogeology toolbox, in particular the excellent FloPy package for creating and interacting with MODFLOW models. 

In this post, we’ll focus on R to explore some of the tools that can be used for hydrogeology. R uses ‘packages’, which are collections of functions related to a similar task. There are thousands of R packages; recently, two colleagues and I compiled a ‘Hydrology Task View’ which compiles and describes a large number of water-related packages. We found that water-related R packages can be broadly categorized into data retrieval, data analysis, and modelling applications. Though packages related to surface water and meteorological data constitute the bulk of the package, there are many groundwater-relevant packages for each step of a typical workflow.

Here, I’ll focus on some of the packages I use most frequently. 

Data Retrieval:

Instead of downloading data as a CSV file and reading it into R, many packages exist to directly interface with online water data portals. For instance, dataRetrieval and waterData connect to the US Geological Survey water information service, tidyhydat to the Canadian streamflow monitoring network, and rnrfa for the UK National River Flow Archive.

Data Analysis:

Many common data analysis tasks are contained in various R packages. hydroTSM and zoo are excellent for working with timeseries data, and lfstat calculates various low-flow statistics. The EcoHydRology package contains an automated digital filter for baseflow separation from streamflow data.


While R does not have an interface to MODFLOW, there are many other models that can be run within R. The boussinesq package, unsurprisingly, contains functions to solve the 1D Boussinesq equation, and the kwb.hantush package models groundwater mounding beneath an infiltration basin. The first and only package I’ve ever made, streamDepletr, contains analytical models for estimating streamflow depletion due to groundwater pumping. To evaluate your model, check out the hydroGOF package which calculated many common goodness-of-fit metrics.

How do I get and learn R?

R is an open-source software program, available here. RStudio is a user-friendly interface for working with R. RStudio has also compiled a number of tutorials to help you get started!

Other Useful Resources

Louise Slater and many co-authors currently have a paper under discussion about ‘Using R in Hydrology’ which has many excellent resources.

While not hydrogeology-specific, there are many packages for generic data analysis and visualization that will be of use to hydrogeologists. In particular, the Tidyverse has a number of packages for reading, tidying, and visualizing data such as dplyr and ggplot2.

Claus Wilke’s Fundamentals of Data Visualization book (free online) was written entirely within R and shows examples of the many ways that R can be used to make beautiful graphs.

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.

Video: Linking water planetary boundaries and UN Sustainable Development Goals

Video: Linking water planetary boundaries and UN Sustainable Development Goals

Water Underground creator Tom Gleeson prepared this quick research video (with no more than a toothbrush, a file holder, and a doughnut, in one take!) for the Ripples project meeting at the Stockholm Resilience Centre, that was held in April. In this video, he talks about using doughnut economics for linking water planetary boundaries and UN Sustainable Development Goals.


Curious about why a toothbrush features in the video? For the answer, you’ll need to watch Tom’s previous research video from last summer (see below), on “Revisiting the planetary boundary for water”.

Dowsing for interesting water science – what’s exciting at EGU 2019?

Dowsing for interesting water science – what’s exciting at EGU 2019?

Joint post by Sam Zipper (an EGU first-timer) and Anne Van Loon (an EGU veteran).

Every April, the European Geophysical Union (EGU) holds an annual meeting in Vienna. With thousands of presentations spread out over a full week, it can feel like you’re surrounded by a deluge of water-related options – particularly since the conference center is on an island!  To help narrow down the schedule! Here, we present a few water-related sessions and events each day that caught our attention. Feel free to suggest more highlights on Twitter (using #EGU19) or in the comments section!

Monday 8 April

Using R in Hydrology (SC1.44)

  • Short course 16:15-18:00.
  • This short course will cover R packages and tools for hydrology with both newcomers and experienced users in mind.

Innovative sensing techniques for water monitoring, modelling, and management: Satellites, gauges, and citizens (HS3.3).

  • Posters 16:15-18:00.
  • Curious about new approaches to hydrological science? This session features citizen science, crowdsourcing, and other new data collection techniques.

Plastics in the Hydrosphere: An urgent problem requiring global action

Tuesday 9 April

Nature-based solutions for hydrological extremes and water-resources management (HS5.1.2)

  • Posters 08:30-10:15Orals 10:45-12:30
  • Nature-based solutions are meant to be ‘living’ approaches to address water management challenges – this session will explore how they are used in both urban and rural areas.

HS Division meeting: If you want to know more about the organisation of the Hydrological Sciences Division of EGU (and you like free lunch) check this out!

Plinius Medal Lecture by Philip J. Ward: Global water risk dynamics

Wednesday 10 April

Large-sample hydrology: characterising and understanding hydrological diversity (HS2.5.2)

Sustainability and adaptive management of groundwater resources in a changing environment (HS8.2.1)

  • Posters 10:45-12:30, Orals 16:15-18:00.
  • This session features examples of groundwater sustainability (and challenges) all over the world, with a particular focus on Integrated Water Resources Management.

HS Division Outstanding ECS Lecture by Serena Ceola: Human-impacted rivers: new perspectives from global high-resolution monitoring

Geoscience Game Night (SCA1)

Thursday 11 April

How can Earth, Planetary, and Space scientists contribute to the UN SDGs? (ITS3.5)

  • PICOs 16:15-18:00.
  • Check out the fun PICO format – a combination of posters and talks – and help figure out what the role of earth science is in meeting the United Nations Sustainable Development Goals.

Urban groundwater: A strategic resource (HS8.2.7)

  • PICOs 10:45-12:30.
  • Urban groundwater is understudied relative to groundwater in agricultural areas – what do we know about urban groundwater, and what remains to be learned?

Henry Darcy Medal Lecture by Petra Döll: Understanding and communicating the global freshwater system

Friday 12 April

Innovative methods to facilitate open science and data analysis in hydrology (HS1.2.7)

  • PICOs 08:30-12:30
  • Learn about how you can make your science more open, whether you are an open science beginner or a long-time data sharer!

History of Hydrology (HS1.2.3)

Social Science methods for natural scientists (SC1.48)

  • Short course 14:00–15:45
  • This short course is for everyone who has some dealings with people in their research, such as stakeholders, citizen science, The aim of the session is to demystify Social Science and give practical tips & tricks.

Other Resources

Several other groups and blogs have also compiled water-relevant sessions. Make sure to check out their recommendations, as well!

Cover image source: https://cdn.pixabay.com/photo/2015/09/09/21/33/vienna-933500_960_720.jpg


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.


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)


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.


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.



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.

Crowdfunding Science: What worked and what didn’t, who pledged and how did we reach them?

Crowdfunding Science: What worked and what didn’t, who pledged and how did we reach them?

Post by Jared van Rooyen, MSc candidate in Earth Science at Stellenbosch University, in South Africa.

Part two of three in a Crowdfunding Science series by Jared.


During March of 2017, myself and a group of students supervised by Dr. Jodie Miller of Stellenbosch University’s Earth Science department (South Africa) completed a 5-week long crowdfunding campaign. The Campaign raised R149 899.00 (€9800) from 120 backers that were both local and international. The campaign used several different mediums to attract potential backers. In this blog I will summarize what engagement methods we used and which ones worked the best.

Before I do this, I have also partitioned backers into three categories that describe to what degree they are separated from myself and the campaign team. Category 1 includes members of family, colleagues and close friends, that would likely contribute to your fundraising campaign regardless of how you marketed it or if they were confident you would succeed. Category 2 included people that myself or the campaign team either are acquainted with, have met before or have been suggested to us by a member of category 1. Category 3 backers are those that myself or my research team have no prior connection to and have been made aware of the campaign through 3rd party methods.

Half of backers fell into category 2 with the other half almost evenly distributed between categories 1 and 3. The distribution of funding received showed a similar distribution with a slightly skewed distribution toward category 3 backers contributing on average more than category 1 backers.

Engagement methods showed some interesting outcomes with direct contact contributing half of the backers as well as half of the funds raised, social media methods, which included Facebook, Instagram and Twitter, contributed the next largest portion of backers (a quarter) but was trumped by word of mouth backer’s average contribution amount. The remaining contributors were those who found out about the campaign through radio/newspaper interviews/articles, internet news and anonymous contributors for whom I have no data (Unknown).

Upon the completion of the campaign, backers were contacted to give feedback on what they believed was effective in the marketing strategy of the campaign. Although radio interviews did not produce a large amount of backers and funds, they produced the largest proportion of category 3 backers.

The data presented above only mentions the successful methods of engagement. In addition, there were several other attempts at fund raising that were somewhat less effective. These included: handing out flyers and putting up posters on campus and surround areas, approaching funding institutions as well as water related government and private entities for support and using mailing robots to send generic emails to large mailing lists.

Before the campaign had ended myself and two honours students had already left on our field sampling trip. In the final part of this blog series, I will break down, what we raised the funds for, what the groundwater sustainability project is trying to accomplish, and what has culminated as a direct result of postgraduate science crowdfunding.


Jared van Rooyen is an MSc student at the University of Stellenbosch in South Africa. His primary field of interest is in isotope hydrology with major applications in groundwater vulnerability and sustainability. Other research interests include postgraduate research funding solutions and outreach as well as scientific engagement with the use of modern media techniques.

Check out Jared’s (and research group’s) thundafund  page here.

A cool new collectible: Water

A cool new collectible: Water

Post by Matt Herod, Waste and Decommissioning Project Officer for the Canadian Nuclear Safety Commission, and Adjunct Professor in Earth and Environmental Science at the University of Ottawa, in Ottawa, Canada.


I have always been a mineral and fossil collector. It was a hobby that stuck and blossomed into a career. I still collect minerals and fossils, although I’ve now added rocks from my field sites to the collection. One thing I should note is that for inanimate, immobile objects it is shocking how quickly rocks can colonize parts of a house, garage, basement, etc.

However, since my early years in geology a very large part of my day is concerned with water; my PhD was almost exclusively about water. Water is my focus and it is truly fascinating. So that got me thinking. Why don’t I collect water?

You may think water is all the same. Turn on the tap, it comes out, drink, wash, whatever. It’s just water. Well, you could not be more wrong. Water is different and changeable. Plus it fits in a small bottle. In short, the perfect collectible.

But maybe you’re not convinced to start collecting water just yet.

Water has types, an identity, just like people. You may be familiar with the notion of people’s personalities being Type A’s, B’s and C’s. Although the types of water are a little more nuanced. That said, so are the types of people.

Water is sorted into types based on its chemistry. The chemistry of water comes from the dissolved salts within it and the relative concentrations of those salts. The isotopic composition of water can also be used to identify its type. Some water types are classed based on their heritage. For example, water found in pore spaces deep underground is often called brine, the precursor to that brine is, or often was ancient ocean water.

Let me give you some examples of water with interesting identities. One thing I should mention is that many of the ways waters are typified only consider their dissolved salt concentration, however, when you factor pH, Eh, and isotopic variation of the many, many different isotopes the number of water types balloons exponentially. For example, a water with a pH of 6 and a total dissolved solids (TDS) concentration of 500 ppm can have isotopic ratios, age and origin totally different from another water with the same pH and TDS. Like I said, it gets complicated fast.

To start with an easy one:

Seawater: Not only is it familiar, it is pretty important given that 97% of Earth’s water is this type and a significant percentage of Earth’s biomass lives in it. Seawater is about 3.5% saline and one of the most interesting features of the water is that it is pretty much everywhere and chemically very consistent. There are differences in the composition of seawater in the certain places around the world, for example, in restricted basins salinity can be higher or where fresh water enters the ocean in a river delta or estuary salinity is lower. Isotopically seawater is also interesting. Not because it has an unusual isotopic composition, but because seawater has been set as the standard to which all other water is compared. It is the zero point that stable isotopes in all other water is measured against.

Glacial Water: Of the 3% of Earth’s water left after the oceans, 69% is frozen in glaciers. To condense the characteristics of glacial water into one word I’d say clean. It just doesn’t have much in it. The reason for this is that glacial water started its days as precipitation, which is water that was evaporated from a water body and condensed. The evaporation process removes almost all of the dissolved solutes. Therefore, there just isn’t much stuff in glacial water besides the H and the O. That doesn’t mean glacial water is boring though. There is still a lot that if can tell us. For example, the variations in O isotopes can be used to reconstruct past temperatures and gases trapped in the ice can tell us about the composition of past atmospheres as well. The information we get from glacial water is different, but extremely valuable!

Brine: Do not drink a brine. You WILL regret it. I do not speak from experience, but frankly if almost 30% of the fluid is salt, it simply isn’t drinkable. Brines come in a lot of flavours, and technically if it has >5% salt it’s considered brine. However, I have encountered some brines that are over 30% saline. Of course, they were not drinkable as they were porewater in a sedimentary basin. However, there are some extremely salty bodies of water out there as well. Brines are interesting because they have so many stories to tell. There is history there, recorded by the solutes, gases and isotopic composition of the brine that explains how it became more than a simple water and transcended the label of water entirely to become much, much more…a fluid. Typically brines in nature have a history that involves salt dissolution leading to high concentrations of Na and Cl. However, other types may simply be evaporated seawater causing all of the dissolved ions to become more concentrated. For example, brines often have high concentrations of Ca, Br, I, Sr, etc, etc. Isotopes in brines also reveal a lot about their past and can distinguish if a brine is a glacial water that has dissolved salt, or is evaporated seawater or has a hydrothermal component. There is just always more that you can find out about brines.

High and low pH waters: pH plays a huge role in dictating the chemistry of water and the dissolved salts therein. Around the world there are naturally occurring waters that have incredibly high and low pH’s. The low pH waters, typically around 1-3 on the pH scale, occur in areas where natural acid rock drainage is happening. Acid rock drainage, aka. ARD, happens when sulphide minerals, often pyrite, oxidize releasing sulphuric acid leading to seeps with exceedingly low pH’s. On the other hand, high pH waters occur more rarely. Alkali springs occur when water comes in contact with hydroxide minerals, such as calcium hydroxide. Hydroxides form in dry, arid environments or where organics and limestone have been heated and burned such as areas with volcanic activity. One famous alkali spring is the Maqarin site in Jordan where water with pH’s from 11-13 occur!

Hydrothermal waters: HOT, HOT, HOT! These waters are absolutely loaded with interesting chemistry. Spewing out of hydrothermal vents on the seafloor at temperatures of up to hundreds of degrees Celsius with tons and tons of dissolved metals like copper, lead, gold, zinc, silver, etc. Furthermore, many of the world’s metal deposits are related to the movement of hydrothermal fluids within the crust. Hydrothermal fluids get their heat from the mantle or magma chambers within the crust. As they are heated they dissolve the rocks in contact with then leading to highly enriched solute concentrations and then when they discharge and cool, the solutes precipitate leading to black smokers, or mineral precipitates in fractures in the crust.

Young and old waters: My last Water Underground post discussed this in more detail. Suffice it to say when you start analyzing carbon-14, tritium, chlorine-36, iodine-129, krypton-85 and 81, etc. you can find waters ranging in age from just a few years to tens of millions to billions of years old. Each of these, is worthy of a spot on my shelf that is for sure. Excitingly, each of these waters has a story to tell about its origin and experiences over the years. Analyzing these isotopes and putting them in context with the geologic history of where the water is found can explain a lot about the regional hydrologic cycle and how water recharges, and discharges and how vulnerable the aquifer it is housed in is to contamination or over-pumping.

This is just the tip of the iceberg (see above). There are many ways water is sorted into types, often called “facies”, which are then plotted graphically. Here is a nice paper that compares some of the different ways of plotting water [1]. Read all the way to the end an you’ll be rewarded with a somewhat strange smiling face.

Anyway, hopefully I’ve convinced you to grab a bottle and collect a sample or two when you come across an interesting water!

Finally, my only piece of advice if you’re going to start a water collection…make sure the top is screwed on tight.


[1] Güler, Cüneyt, et al. “Evaluation of graphical and multivariate statistical methods for classification of water chemistry data.” Hydrogeology journal 10.4 (2002): 455-474.


Matt Herod is a Waste and Decommissioning Project Officer for the Canadian Nuclear Safety Commission, and an Adjunct Professor in Earth and Environmental Science at the University of Ottawa, in Ottawa, Canada. To keep up to date with Matt, follow him on Twitter or on his own EGU blog GeoSphere!

Bedrock: A hydrogeologist’s devotional

Bedrock: A hydrogeologist’s devotional

Post by Kevin Befus, Assistant Professor at the College of Engineering and Applied Science at the University of Wyoming, in the United States.


I want to share a book with you that has encouraged me through initial academic mires (I was only in graduate school for 7 years…) and inspired me to expand my perception and appreciation of the natural world.

The book is Bedrock: Writers on the Wonders of Geology [Savoy et al., 2006]. It is a carefully curated collection of snippets and excerpts from international literary sources describing geologic processes and outcomes. Most of the writings come from the 20th century with several exceptions extending not quite as far back as the Pleistocene. Each chapter, or collection of writings, is oriented around a theme in the earth sciences, one of which is “Rivers to the Sea”…the creative views of hydrologic, mainly riverine, processes chapter. While the excerpts are the main event in each chapter, a quick introduction to each selection is given within the broader geologic context along with some reasoning in why each was chosen.

Bedrock is not a book about hydrogeology, and it really doesn’t directly talk about water underground. BUT, Earth is explored in the excerpts, and developing connections between groundwater and other geologic processes is our job, not the literary masters who “contributed” tidbits to the book. As you should have expected, John McPhee shows up a number of times, but not too much. Many of the early geologists (e.g., G.K. Gilbert, James Hutton, and John Wesley Powell) and environmentalists (e.g., Rachel Carson and John Muir) also share their reflections of geologic forces on nature.

As someone who reads blogs about groundwater, remember to extend the literary reflections to include how the topics interact with groundwater systems. For example, the cover image evokes excitement (or consternation) from a groundwater hydrologist, as it shows the coastline of Nullarbor Plain in southern Australia, home to the “world’s largest limestone karst area” (http://www.australiangeographic.com.au/travel/destinations/2016/04/hidden-nullarbor).

My suggestion for reading this book is to take it slow: one excerpt in the morning to kick-start the day, remembering why it is you do what you do. Be inspired, awed, and reminded of how geological processes have shaped our world over billions of years. Or, read an entry when the day has taken a turn to the slow or chaotic. Like any good devotional, Bedrock has great re-readability and also points you towards the original documents for more in-depth explorations of literary (hydro)geology.

Happy reading!

Savoy, L. E., E. M. Moores, and J. E. Moores (2006), Bedrock: Writers on the Wonders of Geology, Trinity University Press, San Antonio, TX.




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.  You can follow along with Kevin’s research through any of the links below:

Twitter | Research Group Page | UW Faculty Page








Feature photo image source: