WaterUnderground

hydrogeology

A do-it-yourself Jupyter notebook to constrain sediment permeability

A do-it-yourself Jupyter notebook to constrain sediment permeability

Post by Elco Luijendijk, Junior lecturer in the Department of Structural Geology and Geodynamics at Georg-August-Universität Göttingen and WaterUnderground founder Tom Gleeson (@water_undergrnd), Associate Professor in the Department of Civil Engineering at the University of Victoria.


Most of the groundwater on our planet is located in sedimentary rocks. This is why it is important to know how easy or hard it is for water to flow through pores in sediments, which is governed by permeability. Unfortunately, permeability is extremely variable. Wouldn’t it be great if we could estimate permeability based on sediment types (for which a decent amount of data exist)?

Enter the 150+ year challenge to estimate the permeability of sediments with universal equations. Most of the equations work well for one sediment type, such as pure sands or clay. For instance, the Kozeny-Carman equation from the 1920s tends to work well for most granular materials such as sand or silt. However, pure sands or clays are rare, and most of what’s out there are mixtures.

Evaluating how well existing and new equations work for mixed sediments is tricky business. Searching high and wide only three datasets with 78 samples were found that contained all the required information (grain size distribution, clay mineralogy). Needless to say, more data are needed to improve the predictive equations. In a paper published a few years ago we found that in most cases, the permeability of the sediments could be estimated in a two-step process:

  • calculate the permeability of clay and granular (sand/silt) components, and
  • calculate the permeability of the mixed sediment by taking the geometric mean of the two components weighed by the clay content of the sediment.

The resulting workflow was published as a series of equations that are not particularly easy to work with. That is why we recently decided to take advantage of the general awesomeness of Jupyter notebooks to publish a do-it-yourself notebook to calculate permeability on GitHub (https://github.com/ElcoLuijendijk/permeability_notebooks). For those of you new to Jupyter notebooks: these are documents that contain a readable mix of text, code, data and figures and can be used to publish studies in such a way that you can reproduce the analysis and make the figures yourself (much like R Markdown).

The Jupyter notebooks to calculate permeability consist of a main notebook and additional notebooks to calculate the specific surface area of sediments. Also included are all the calibration datasets Jthat were compiled for the publication. You can use the data to evaluate how well the permeability equations match these datasets, or you can set up a new spreadsheet with data from your own study area which can then be used by the notebook to calculate permeability. The notebook automatically generates several figures like the one below (Figure 1).

There is also an additional notebook that calculates first-order estimates of permeability from well log data collected by geophysical tools that map the density or water content of sediments. Such well log data can be more widely available than detailed sediment records and may help estimate permeability for the deeper subsurface (>100s of m), where permeability data are generally scarcer than at the surface.

Comparing these datasets and equations with the Jupyter notebooks highlight the gaps in quantifying permeability. These notebooks and datasets are out there for the world, so join the effort to make more accurate predictions of permeability (and groundwater flow) in sediments!

Figure 1: Figure produced by the Jupyter notebook showing measured vs calculated permeability using an example dataset of mixed natural sediments.

 

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.

Modelling:

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.

Data sharing: an update on new and existing initiatives

Data sharing: an update on new and existing initiatives

Post by Anne Van Loon, Gemma Coxon, and Bentje Brauns.


Last year, Anne Van Loon wrote about data sharing initiatives in hydrology (“Data drought or data flood? 28 May 2018). This post gives an update on existing and new initiatives.

CAMELS (Catchment Attributes and MEteorology for Large-sample Studies) 

The CAMELS datasets are expanding: from the United States and Chile to Great Britain and Australia.  The CAMELS-GB dataset will consist of hydro-meteorological timeseries and catchment attributes for 671 catchments across Great Britain and is expected to be released on the Environmental Information Data Centre later this year.

The Groundwater Drought Initiative

The Groundwater Drought Initiative is collecting more and more groundwater level data and groundwater drought impacts. The Initiative is very happy to welcome new partners and supporters from as far East as Ukraine and as far South as Albania, increasing the number of participating countries and countries currently considering to participate to 23 (see map). Additionally, a first getting-to-know-each-other & info meeting was held at EGU19 with participants from Austria, Belgium, Canada, Estonia, Germany, Latvia, Luxembourg, Netherlands, Norway, UK, Ukraine, and Switzerland. If you are from Bulgaria, Greece, Hungary, Italy, Romania, Slovakia or any of the other yellow countries on the map below and you have groundwater data (or contacts in organisations who could help) or you are interested in groundwater drought, please contact Bentje Brauns (benaun@bgs.ac.uk).

The IAHS Panta Rhei Working Group on Large Sample Hydrology

The IAHS Panta Rhei focus on efforts to facilitate the production and exchange of datasets worldwide.  This year at EGU, the group organised a splinter meeting to discuss the generation of large sample catchment datasets in the cloud and a session (HS2.5.2 Large-sample hydrology: characterising and understanding hydrological diversity) that showcased several recent data- and model-based efforts on large-sample hydrology from new global datasets to large multi-model ensembles.  If you are interested in being updated on the activities of the group then please contact Gemma Coxon (gemma.coxon@bristol.ac.uk) to be added to the mailing list.

There seems to be a lot going on in the world of hydrological data sharing! To share your own story or initiative, please leave a reply below.



Anne Van Loon (website | @AnneVanLoon) is a Senior Lecturer in Physical Geography  in the School of Geography, Earth and Environmental Sciences at the University of Birmingham.

Gemma Coxon (website) is a Postdoctoral Research Associate and Lecturer in Hydrology in the School of Geographical Sciences at the University of Bristol.

Bentje Brauns (website) is a Hydrogeologist at the British Geological Survey.

Celestial groundwater – the subsurface plumbing for extraterrestrial life support

Celestial groundwater – the subsurface plumbing for extraterrestrial life support

Post by Kevin Befus Assistant Professor in Civil and Architectural Engineering at the University of Wyoming.


Have you ever taken a walk on the beach during a lowering (ebbing) tide and see mini-rivers grow and create beautiful drainage patterns before your eyes? These short-lived groundwater seepage features (Fig. 1A) are tiny (and fast) analogs of how groundwater has shaped some parts of Mars! It appears that groundwater loosening sediments can lead to all sorts of scales of erosion on both Earth and Mars.

Figure 1. A) Beach drainage pattern on the order of 1 meter (Source: https://epod.usra.edu/blog/2017/01/beach-drainage.html), B) Martian “alcoves” suggesting groundwater seepage [1].

Mars is not currently a friendly place for water to exist at the surface or even the subsurface, but an abundance of photographic and topographic evidence point to there having been the right conditions for active groundwater flow on Mars.

But isn’t Mars too cold for liquid water? The answer is generally a strong yes for the past few billion years, but amazingly enough, there appears to have been some local places where groundwater discharged to the Martian surface and left behind telltale signs.

Because Mars is cold at its land surface (mean surface temperature of -50 C with daily swings from 0 C to -100 C) with a thinner atmosphere than Earth’s, water on the Martian surface can exist as ice (as in the polar ice cap), but sublimation and evaporation would quickly wick any water near the surface. So, liquid water on Mars needs both more pressure and a good bit of heat for mobile groundwater based on the phase diagram below (circle with M shows the present day Martian surface conditions).

Figure 2. Phase diagram showing average conditions at the planetary surface for Earth (E) near the triple point, and atmospheric conditions for the frozen Mars (M) and vapor-rich Venus (V). source: http://www1.lsbu.ac.uk/water/water_phase_diagram.html#intr2; License: https://creativecommons.org/licenses/by-nc-nd/2.0/uk/)

It turns out that the most expansive evidence of liquid groundwater on Mars comes from deep at the bottom of craters (…deeper than 5 km!), where the Martian geothermal gradient (~10 C/km [Michalski et al.2013]) heats up to the point where groundwater systems, probably made up of brines, can seep across the crater walls. Without the craters, the groundwater wouldn’t have anywhere to discharge, but extraterrestrial hydrogeologists (really based on the geomorphology, but using E.T. hydrogeology principles) have identified numerous craters with groundwater seepage erosional patterns (Figure 1). The question remains open on how connected the Martian “aquifers” could be, or if the craters represent only local flow systems.

With liquid groundwater transporting the chemical-rich waters from deeper geothermal areas, the conditions could be right for supporting a deep Martian biosphere. Buried in under the Martian ice, soil, and rock microbial life could have evolved in the subterranean shelter from cosmic radiation. Groundwater flow, potentially related to geothermal conditions, could then have served as the conveyor belt for energy-rich molecules to feed microbial life in the subsurface (and still could?).

So far, Earth is the only celestial body in our solar system with an active water-hydrologic cycle, making us the lucky green planet. But, there could be a methane-based hydrologic cycle on Titan with “methanifers” as methane aquifers! For more information on extraterrestrial hydrogeology, Baker et al. (2005) provides a great overview of the planetary, lunar, and exo-planetary potential for water and groundwater, loosely summarized in this table.

At the moment, Earthlings don’t know that much yet about the paleo-hydrologic processes on Mars. But with new boots…I mean wheels…on the ground in two water-focused locations, new clues could start rolling in on Martian groundwater. The recently-arrived InSight lander will probe the Martian subsurface by drilling 5 m deep and listen for acoustic signals for even more information on the interior of Mars. The next Mars Rover is scheduled to take flight in 2020 for the Jezero Crater, where a river delta could help unravel the water-life story of Mars. And could have some groundwater surprises! At only about 1 km deep, the focus in mainly on tracking down signs of life and unravelling surface hydrologic and erosional processes on Mars, but a long list of expected outcomes does show the mission will keep an eye out for evidence of groundwater activities. Keep your feet grounded, eyes in the sky, and visions of Martian groundwater flying high and drilling low!

References
[1] Malin, M. C., and K. S. Edgett (2000), Evidence for Recent Groundwater Seepage and Surface Runoff on Mars, Science, 288(5475), 2330–2335, doi:10.1126/science.288.5475.2330.
[2] Michalski, J. R., J. Cuadros, P. B. Niles, J. Parnell, A. Deanne Rogers, and S. P. Wright (2013), Groundwater activity on Mars and implications for a deep biosphere, Nat. Geosci., 6(2), 133–138, doi:10.1038/ngeo1706.
[3] Stofan, E. R. et al. (2007), The lakes of Titan, Nature, 445(7123), 61–64, doi:10.1038/nature05438.
[4] Baker, V. R., J. M. Dohm, A. G. Fairén, T. P. A. Ferré, J. C. Ferris, H. Miyamoto, and D. Schulze-Makuch (2005), Extraterrestrial hydrogeology, Hydrogeol. J., 13(1), 51–68, doi:10.1007/s10040-004-0433-2.
[5] Robinson, K. L., and G. J. Taylor (2014), Heterogeneous distribution of water in the Moon, Nat. Geosci., 7(6), 401–408, doi:10.1038/ngeo2173.
[6] Jurac, S., M. A. McGrath, R. E. Johnson, J. D. Richardson, V. M. Vasyliunas, and A. Eviatar (2002), Saturn: Search for a missing water source, Geophys. Res. Lett., 29(24), 25-1-25–4, doi:10.1029/2002GL015855.

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:

Personal Webpage | Twitter Research Group Page | UW Faculty Page

 

 

 

 

 


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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.


Episode 4 – Karst Groundwater: quick and slow at the same time?

We often associate groundwater with large water storage and very slow water movement for instance compared to rivers. But is it possible that groundwater flow can be as quick as stream flow and, at the same aquifer, flow for several months or years before it is reaching the surface again? Of karst, it is possible! When chemical weathering is able dissolve carbonate rock, cracks and fissures may grow to a subsurface channel system that can take vast amounts of water flow (see Of Karst! – episode 2).

The schematic figure below shows how this affects water flow in a karst system. At the surface, water may flow for some distance (external runoff towards the recharge area or internal runoff within the recharge area), before it reaches a dissolution widened vertical crack or fissure. On its way, part of it may slowly infiltrate into the soil but the stronger the rainfall event, the more water will infiltrate quickly into cracks and fissures after being redistributed laterally. Consequently, slow and quick infiltration will be followed by slow and quick vertical flow through the vadose zone. The former through the carbonate rock matrix, the latter through the interconnected system of dissolution caves. Finally, recharge and groundwater flow take place, again quickly through the caves and slowly through the matrix.  When passing the system through the cave network, water can enter and leave the system within several hours. When taking the slow and diffuse path, the transit through the system may take months to years.

Because of this behavior, hydrogeologists often speak about the Duality of Karstic Groundwater Flow and storage, although it is known that there is a wide range of dynamics between quick flow through the caves and slow flow through the matrix and that lateral redistribution between the interconnected caves and the matrix takes place at almost every part of the system.

Figure 1: Schematic description of karstic groundwater flow and storage (Hartmann et al., 2014; modified)

A rather uncomfortable lesson on quick flow processes in karst was learned by a group of school students on a trip through a karstic cave in Thailand. Due to the quick recharge processes explained above, the groundwater tables could quickly rise blocking the return path of the group and resulting in a dramatic rescue mission:

In order to predict the impact of interplay of quick and slow karstic groundwater processes on cave water levels or water resources in general, karst-specific simulation models are necessary. If you are interested in those, follow the Water Underground blog’s postings and wait for Of Karst! Episode 5, which will introduce karstic groundwater modelling.


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  

Further reading: Hartmann, A., Goldscheider, N., Wagener, T., Lange, J., Weiler, M., 2014. Karst water resources in a changing world: Review of hydrological modeling approaches. Rev. Geophys. 52, 218–242. doi:10.1002/2013rg000443

 

 


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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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How deep does groundwater go? Mining (dark) data from the depths

How deep does groundwater go? Mining (dark) data from the depths

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

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3D geologic data can be hard to come by, and can be even more difficult to combine into a continuous dataset. The cross-sections shown here are directly from 3D groundwater models that I compiled [Befus et al., 2017], primarily from USGS groundwater models, for the U.S. East Coast. I kept each of the regional domains (different color swaths on the map) separate, since I ran into the issue of “border discontinuities” between different models where naming conventions and hydrostratigraphic structure didn’t match up. Kh is the horizontal hydraulic conductivity.

We’ve all been asked (or do the asking), “where does your water come from?” This is a fundamental question for establishing a series of additional questions that can ultimately help define strategies for valuing and protecting a particular water resource.

For groundwater, we could phrase this question differently, and I often do when talking to well owners: How deep is your well? If I get an answer to this, then I can dive into additional questions that can help define more about the local groundwater resource: How deep is the well screen? How long is the screen? Do you know what the water level in the well is? Has it changed over some given time? Seasonally?

These are all useful questions, and they serve to begin establishing the hydraulic conditions of a particular aquifer. I ask these whenever I can.

To do this at a larger scale, we can turn to various governmental agencies that regulate groundwater resources and/or water well drilling and often collect and store groundwater data (e.g., www.waterqualitydata.us/, http://nlog.nl/en/data, http://gin.gw-info.net/service/api_ngwds:gin2/en/gin.html, or http://www.bgs.ac.uk/research/groundwater/datainfo/NWRA.html). There is a wealth of information out there internationally on wells when they were drilled and where the driller first hit water. These driller logs can provide a snapshot in time of the water table elevation and can be extremely useful for tracking hydrologic variability [Perrone and Jasechko, 2017], extracting hydraulic parameters [Bayless et al., 2017],  and for testing model results [Fan et al., 2013]. Unfortunately for us earthy nerds, some governments have restricted access to well installation data for either certain types of wells (i.e., municipal) or for all wells, usually for privacy or safety concerns.

Back to the original question. How deep is groundwater? I keep this question broad. We can usually answer this question for particular areas where we have access to the right data, but for large parts of the globe, and potentially underneath you right now, we cannot answer this question. The “right data” for a hydrogeologist is some form of information on geologic/stratigraphic layer (or lack of layering) that can be tied to the rock properties. For a surficial, unconfined aquifer, this can be relatively easy, but when we start stacking several geologic units on top of each other or start actually using the groundwater, this question of how deep groundwater is becomes tricky. We could qualify this question by asking how deep “usable” groundwater is, which, of course, depends on our definition of usable water for a specific purpose. Or, we can point (or integrate) through the Earth’s crust, core, and right back to its crust and calculate the huge value of how much water is “in the ground” (and minerals)[Bodnar et al., 2013]. And I haven’t even brought up porosity yet! Or specific storage!

A example of a great public 3D interactive web viewer (https://wateratlas.net/) that integrates groundwater data, geological information, and well construction details produced by the Centre for Coal Seam Gas at the University of Queensland (https://ccsg.centre.uq.edu.au/), which is supported by the University of Queensland and industry partners. For more information on this water atlas, please contact Dr. Sue Vink (s.vink@smi.uq.edu.au) or Alexandra Wolhuter (a.wolhuter@uq.edu.au).

Don’t worry. I won’t go there. I want to harass/encourage the hydro[geo]logic community to get serious about sharing their hydrogeologic data. This does mean metadata (do I hear a collective groan?), but metadata and data management plans are increasingly required to secure funding. CUAHSI’s Hydroshare site (www.hydroshare.org) provides a platform uploading hydro models, and the U.S. Geological Survey has developed a slick web system for exploring hydrogeologic models. But, I’d like to take this further, or at least get a service like that going for anyone who wants to share their models. There is a wealth of crustal structure data out there, and groundwater models are unique in often containing some representation of three-dimensional geology/hydrostratigraphy along with Earth properties. There are some great deterministic, published datasets and models of global hydrogeology [De Graaf et al., 2015; Huscroft et al., 2018], but we can do better. Wouldn’t it be great to have a centralized database to extract an ensemble of hydrogeologic structure used in previous regional or local studies? How about be able to draw a model boundary on a web interface and extract 3D structure for your next model? And compare cross-sections between models in the same area? Want to start fitting your puzzle pieces into the international hydrogeologic puzzle? The question now becomes, how do we do it? A “DigitalCrust” has been proposed [Fan et al., 2015], but is not yet in reach.

Join the movement of a “Digital Earth” [Gore, 1998]!

Here are some examples, initiatives, and free 3D [hydro]geology resources to get you started:

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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:

Personal WebpageTwitter Research Group Page | UW Faculty Page

 

 

 

 

 

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References

Bayless, E. R., L. D. Arihood, H. W. Reeves, B. J. S. Sperl, S. L. Qi, V. E. Stipe, and A. R. Bunch (2017), Maps and Grids of Hydrogeologic Information Created from Standardized Water-Well Driller’s Records of the Glaciated United States, U.S. Geol. Surv. Sci. Investig. Report2, 20155105, 34, doi:10.3133/sir20155105.

Befus, K. M., K. D. Kroeger, C. G. Smith, and P. W. Swarzenski (2017), The Magnitude and Origin of Groundwater Discharge to Eastern U.S. and Gulf of Mexico Coastal Waters, Geophys. Res. Lett., 44(20), 10,396-10,406, doi:10.1002/2017GL075238.

Bodnar, R. J., T. Azbej, S. P. Becker, C. Cannatelli, A. Fall, and M. J. Severs (2013), Whole Earth geohydrologic cycle, from the clouds to the core: The distribution of water in the dynamic Earth system, Geol. Soc. Am. Spec. Pap., 500, 431–461, doi:10.1130/2013.2500(13).

Fan, Y., H. Li, and G. Miguez-Macho (2013), Global patterns of groundwater table depth, Science, 339(6122), 940–943, doi:10.1126/science.1229881.

Fan, Y. et al. (2015), DigitalCrust – a 4D data system of material properties for transforming research on crustal fluid flow, Geofluids, 15(1–2), 372–379, doi:10.1111/gfl.12114.

Gore, A. (1998), The Digital Earth: Understanding our planet in the 21st Century, Aust. Surv., 43(2), 89–91, doi:10.1080/00050326.1998.10441850.

De Graaf, I. E. M., E. H. Sutanudjaja, L. P. H. Van Beek, and M. F. P. Bierkens (2015), A high-resolution global-scale groundwater model, Hydrol. Earth Syst. Sci., 19(2), 823–837, doi:10.5194/hess-19-823-2015.

Huscroft, J., T. Gleeson, J. Hartmann, and J. Börker (2018), Compiling and Mapping Global Permeability of the Unconsolidated and Consolidated Earth: GLobal HYdrogeology MaPS 2.0 (GLHYMPS 2.0), Geophys. Res. Lett., 45(4), 1897–1904, doi:10.1002/2017GL075860.

Perrone, D., and S. Jasechko (2017), Dry groundwater wells in the western United States, Environ. Res. Lett., 12(10), 104002, doi:10.1088/1748-9326/aa8ac0.

 

A Tanzanian groundwater safari through the last 2 million years

A Tanzanian groundwater safari through the last 2 million years

Post by Mark Cuthbert, Research Fellow and Lecturer at Cardiff University, in the United Kingdom, and by Gail Ashley, Distinguished Professor at Rutgers University, in the United States.

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During the dry season, Lake Masek in Northern Tanzania (see map) is a lovely place to be if you’re a hippo or a flamingo, but for humans it’s an inhospitable environment. We were on ‘safari’ (a scientific one of course, but the wildlife was a massive bonus! Photo 1-left) to try and better understand the distribution of freshwater in this dryland landscape.

Map: Locations on our groundwater safari in Northern Tanzania.

Watching our backs in case of predators, we ventured out of the safety of our Land Rover for Gail to sample the lake water, as salt blew in drifts around us off the desiccated edges of the lake bed (Photo 1-right). It was very salty and not potable for humans. All the streambeds that run into the lake were dry and yet our Masai guide told us that nearby we could find freshwater all year round.

Photo 1: (L) The amazing wildlife in the Ngorongoro Crater & (R) Saline-alkaline Lake Masek.

Intrigued, we set off around the edge of the lake and as we came over the crest of a small ridge were met with the most remarkable site – 1000s of cattle and goats queuing up for water from pools on the edge of the dry river valley just downstream of the lake. We waited for the queues of animals to die down and asked permission from the local guardians of the water source to investigate (Photo 2). The pools turned out to be fed from groundwater flowing out of rocks at the side of the valley. In contrast to the salty water from the adjacent lake, these springs were fresh and potable. We think the water is very old having originally fell as rain on the flanks of the ancient Ngorongoro Highlands (see map) before flowing slowly under gravity through layers of volcanic rocks 10’s of km to the springs. Because there’s so much groundwater stored in these rocks, and because they are not very permeable, the water seeps out quite slowly. So the springs keep running all through even the longest droughts and are vital water supplies for local people.

Photo 2: Asking permission to sample at Eremet springs

We travelled east along the same dry river valley in which we’d encountered the springs. Here the river, which only flows during the wet season, has cut itself into a steep ravine called Olduvai Gorge. We walked down the side of the gorge travelling back in time ~2 million years, the rocks and sediments around us telling a well-documented story of how the environment has changed over that time. Many exciting fossil discoveries have also been made in the gorge including some of our oldest human ancestors (Photo 3-left). For us one of the most interesting discoveries was geological evidence of ancient springs (Photo 3-right) found in the same layers as fossil human ancestors and stone tools which Gail has documented going all the way back to nearly 2 million years ago (read more here). There are clues from the surrounding sediments that there was a lake nearby but it was salty and alkaline, and we think the springs would have kept flowing for 100s or even 1000’s of years during persistently drier periods experienced in the past (read more here).

The springs that were flowing in the Olduvai area 2 million years ago, just like the springs on the margins of present day Lake Masek, would have been the only freshwater for miles around and vital for sustaining life during dry periods. Since there are hundreds of freshwater springs dotted around present day drylands in the East African rift system, we can hypothesise that during dry periods in the past, similar locations would have acted as ‘hydro-refugia’ – places where animals could find the necessary freshwater for survival in an otherwise dry landscape. In dry periods there would be lots of competition for these resources and populations would have become isolated from each other for quite long periods. During wetter periods springs would have enabled our ancestors and other species to move long distances across the East African landscape and beyond, acting like stepping stones connecting river corridors and lakes and enabling populations of different species to encounter one another (read more here). Groundwater was likely therefore an important control on the movement and evolution of humans in this environment.

Photo 3: (L) Paranthropus boisei (‘Zinj’) hominin skull found at Olduvia gorge (Photo Credit: Tim White PhD, Human Evolution Research Center, University of California, Berkeley) & (R) Mark Cuthbert next to a tufa (calcium carbonate) deposit thought to be evidence of groundwater discharging near the site that the Zinj fossil was found.

Groundwater is often ‘out of sight and out of mind’. Our safari gave us a glimpse into its importance in sustaining life in a dryland environment not just in the present day, but also for our ancestors going back at least 2 million years through some climatically turbulent periods. The challenge going forward is how that groundwater resource can be protected to make sure it’s there when it’s needed in the face of an uncertain climatic future.

Acknowledgements: it has been a massive privilege to be able to explore this landscape and ponder how freshwater has shaped life here over millions of years. Particular thanks to our guides Joseph Masoy and Simon Matero, logistical support from Charles Musiba (LOGIFS – Laetoli-Olduvai Gorge International Field Camp) and TOPPP (The Olduvai Paleoanthropological and Paleoecological Project), our hosts at the Ngorongoro Conservation Area Authority, and all our collaborators on the papers cited.

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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 & quantify groundwater sustainability; to improve interpretations of terrestrial paleoclimate proxy archives; to understand Quaternary paleoenvironments & how they influenced our evolution as a species. Read more on Mark by clicking on the links below.

TwitterResearch website

 

 

 

Gail M. Ashley is a Distinguished Professor and Undergraduate Program Director of Quaternary Studies Program at Rutgers University, in the United States. Gail studies modern physical processes and deposits of glacial, fluvial, lacustrine, arid landscapes, and use this information to interpret paleoenvironments. Read more about Gail by going to her research website.

An alternate career path for Groundwater Science-Engineering PhDs

An alternate career path for Groundwater Science-Engineering PhDs

Post by Jim Roy, Research Scientist at Environment and Climate Change Canada.

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A recent editorial in Nature highlighted the relative scarcity of academic positions available to graduating PhD students (Many junior scientists need to take a hard look at their job prospects; 25 October, 2017). It notes that “it has been evident for years that international science is training many more PhD students than the academic system can support”. Firm figures aren’t available, but the article suggests maybe < 5 % will land a full-time academic job. That number may be somewhat higher for Groundwater-related disciplines, but the point remains that many should “make plans for a life outside academic science.”

However, it’s not all doom and gloom; indeed the article goes on to state that “it is good for PhD students and postdocs to pursue careers outside academia. Many will find similar challenges and rewards in industry.” There are a lot of options for Groundwater PhDs in industry and the plethora of supporting consulting firms: in mining, oil and gas, tunnel and dam engineering, municipal water supply, and contaminated site remediation, to list a few. However, there is an additional career path to consider, especially if you want to continue doing research – the government scientist, like me.

According to Wikipedea: A government scientist is a “scientist employed by a country’s government, either in a research-driven job (for example J. Robert Oppenheimer on the Manhattan Project), or for another role that requires scientific training and methods.” I’ll be focusing on those that do research (encompassing science and engineering), at least for much of their work.  And in this blog, I’ll be comparing their job duties and conditions to that of the professor, the research job with which the majority of students and post-docs are most familiar and traditionally aiming for.  It’s what I thought I would be too, coming out of grad school. Now it’s been 10 years since I took up my position as a Research Scientist focusing on groundwater contamination/quality with Environment Canada (now Environment and Climate Change Canada) – enough time to have experienced the ups and downs of the Canadian economy and the changing of the governing party, with repercussions of both for federal science priorities and budgets. The discussion below is based largely on my own experience, with insight gleaned from talking with colleagues in other government agenciesa over the years. It’s also highly generalized; the exact situations will vary by country, agency, and even by individual scientist, and may change over time. But hopefully it’s good enough for a light-hearted introduction to this alternate career area.

So here goes – my Top 10 list of how a government scientist job is different than academia:

  1. Freedom

                All scientists want to do work that is meaningful, but not all scientists get to choose on what topic that work will focus. In general, government scientists undertake research on issues of government priority that will advise on federal policy, regulations, and management activities, or that will provide service to important national industries or the public. So their work should have a meaningful impact on their country, if not more broadly; they just don’t get to decide on the priority topics (with exceptions for certain agencies or programs). However, often these priority topics are general enough that there is some range of projects that can fit within them, giving the scientist some flexibility on their research focus. Also, by advising their management and government representatives of important topics, government scientists may influence the direction of government priorities. Also, a government scientist may be afforded some leeway to work on additional topics outside these priority areas with a small fraction of their time. Government research usually targets short- to intermediate-term achievements, as fits the common government election cycle. However, some priority topics may last for decades – see North American Great Lakes eutrophication and algal blooms – waxing and waning in importance with the severity of the problem (costs!) in relation to the other pressures on the government (the economy!). For those who choose this career path – beware, though, when government priorities change, your research area may have to change too.

                For academics, their options are typically much broader, encompassing everything between applied research with immediate implications to research so basic that nobody can predict what may eventually come of it. The caveat to this is that an academic’s research topic often has to be deemed important enough and applied enough for “someone” to fund it. Industry funding is usually quite applied. But even government funding agencies, which are usually the primary support for more basic academic research, are increasingly imposing greater direction over the acceptable topics of proposed research. So perhaps this extra freedom isn’t so vast in practice.

  1. Trading places?

                Many government scientists are appointed to one or more adjunct professor positions at universities where their academic collaborators reside. These could be at nearby universities or those across the globe, and these locations may change over a career. It isn’t a paid position, but allows for closer research ties, including the (co-)supervision of undergraduate and graduate students, which benefits both the university and the government agency. Such positions may also afford access to laboratory space on campus or to additional research funding (held at the university, but directed by the adjunct professor).

                I haven’t heard of a case of the opposite arrangement – adjunct government scientist – but it might exist. Academics may pop in and be given some office space and support during a sabbatical while collaborating with a government scientist, but they’re really just temporary squatters.  If anyone out there knows of such a situation, feel free to post below.

  1. No teaching ( 🙂 or  🙁 )

                An obvious difference, this can be viewed as good or bad news depending on how much you like it.  I enjoyed teaching while I was a grad student. Many scientists give guest lectures or even short-courses at local universities. I taught an entire hydrogeology course for a university colleague during his sabbatical – so this can be an option for some in government who have an interest. Not having required teaching does provide greater flexibility in scheduling your work (especially field trips) and leaves more time for research and/or other important activities, like playing hockey or “family life”.

  1. Professors have grad students; government scientists have technicians

                The model for academic research is based on students and post-docs (a team of them often) carrying out the primary duties of research under the supervision of their professor. Certainly there are exceptions where the professor carries out their own study, but generally they lack the time for this. However, professors may have technicians too. It’s common for some to hire current or past students as technicians for a few years after they graduate, while (senior) professors may have dedicated technicians.

                In contrast, the model for government scientists is to have one or more dedicated and highly-experienced technicians available to assist in their research. Separate analytical laboratory or field teams may also be available. Although, with tightening budgets this technical support seems to be dwindling. It’s also fairly common for post-doctoral fellows to be hired by government agencies to work with their scientists – I’ve worked closely with 2 post-docs over my 10 years at Environment and Climate Change Canada. And what’s more, through adjunct professor positions or just collaborations, government scientists may also work with and (co-)supervise students from a partner university, just not to the same extent as for the academics.

                Thus, there can be a fair bit of overlap between these two models, especially when collaborations extend between academics and government researchers; and this integration, I think, makes for better science all around.

  1. Both are sought out by regulators and policy-makers

                Government scientists might have the inside track to the ear of policy-makers, but advice from academics is often gathered via workshops and contracts for reviews and reports as well.  Sadly, in large departments especially, some bureaucrats may not realize they have internal expertise in an area like hydrogeology. Which leads us to the next point…

  1. Governments typically do a poorer job of selling/showcasing their scientists

                Academics have much more freedom to showcase themselves and their work to the public, the science community, and business/industry. This can be through personalized research web pages, starting a blog (like this one!), and greater freedom to speak to the media (depending on the presiding-government’s rules for their scientists).  They also tend to attend more scientific conferences, where they and their students can advertise their scientific wares to a range of audiences.

  1. No consulting on the side

                Not all professors consult, but many do, which can provide a boost in income and lead to funding or in-kind support opportunities for their research or to job opportunities for their students. I haven’t heard of any government agencies that allow their scientists to consult as a side profession. In part, they want all your time devoted to your job working for them; but it also runs into “conflict-of-interest” concerns.  Now that doesn’t mean you can’t have a side-job (e.g., selling pottery, repairing dishwashers, stand-up comedy, teaching Yoga), but it can’t relate to your science profession.

  1. Border-crossing restrictions

                Working on national (or state/provincial) priority research commonly means government scientists work predominantly on sites in their own country (region), unless inter-jurisdictional agreements are made to combine or share research expertise. In contrast, academics are able and encouraged to work at international sites, which can expand the range of research topics and potentially funding sources available to them.

  1. Less competition for funding (except when the coffers are bare)

                Much of my funding is internal, requiring much shorter (i.e., less onerous) proposals than is typical for my academic colleagues seeking funding through centralized national funding agencies (e.g., NSERC in Canada) or from industry partners. My proposals may still go through a competitive process, though, sometimes with external reviews.  How substantive this internal funding is compared to academic funding will depend on the agency, how science is viewed by the current government, the state of the economy, and the importance of the topic. When internal research budgets are tight, there may not be sufficient funding to go around, especially for those not working directly on key priorities. Of note, some government agencies allow their scientists who have adjunct status at a university to apply for the same set of grants as academics. Whether such proposals are frowned upon or judged differently by funding agencies is up for debate.

  1. Joy in their work

                Frustrations with too-much time devoted to administrative tasks and seeking funding are prevalent in both government and academic research areas. But still, the opportunity to do research on interesting, challenging, and important topics at the edge of our current scientific understanding brings enjoyment / fulfillment to both government scientists and academics. We all feel that slight quickening of the pulse when “the data is in” and we learn if the expected outcomes were realized or (better yet) something different (new!) might be going on.  It’s why we do what we do. In hydrogeology, there remains much to explore, especially at the inter-disciplinary mixing zones around the edges of our specialty. And we’ll need new concepts, new methods, and new connections to move our understanding forward. Scientists from academia and government and industry and other groups can all contribute to this quest. For graduating PhDs, hopefully this leaves you with multiple career path options for joining in the fun.

a In Canada, besides Environment and Climate Change Canada there are also PhD-holders doing groundwater-related research in Natural Resources Canada, Agriculture and Agri-Food Canada, and the National Research Council. In the U.S., much great groundwater research is carried out by the U.S. Geological Survey, with research also carried out by other federal and state agencies. Many other countries have similar geological or environmental departments or agencies with PhDs doing some or much research.  You can look these up on the web, though often government scientist pages aren’t nearly as good as those for academia.

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Jim Roy is a Research Scientist at Environment and Climate Change Canada. His current research focuses on: groundwater contaminant impacts on surface waters and aquatic ecosystems, groundwater contributions of phosphorus to surface waters, potential leakage of Alberta oil sands tailings ponds to the Athabasca River, and groundwater and gas systems. Find out more about Jim by clicking on the links below.

Twitter Page | Research Profile

Hydraulic fracturing close to groundwater wells

Hydraulic fracturing close to groundwater wells

Post by Scott Jasechko, Assistant Professor of Water Resources with the Bren School of Environmental Science & Management, at the University of California, Santa Barbara, and by Debra Perrone, non-resident Fellow at Water in the West and an Assistant Professor, also at the University of California, Santa Barbara, in the United States.

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In December, 2016, the Environmental Protection Agency finalized a report [Ref. 1] on hydraulic fracturing and drinking water resources that, among other conclusions, states:

(a) Quote from [Ref. 1]: “scientific evidence that hydraulic fracturing activities can impact drinking water resources under some circumstances”

(b) Quote from [Ref. 1]: “When hydraulically fractured oil and gas production wells are located near or within drinking water resources, there is a greater potential for activities in the hydraulic fracturing water cycle to impact those resources.”

Tens-of-millions of Americans rely on groundwater stored in aquifers for drinking water. Because it is possible that hydraulic fracturing activities can impact water resources (i.e., quote (a) above), and because groundwaters located close to hydraulic fracturing activities are more likely to be impacted than those farther away should a contamination event occur (i.e., quote (b) above), it is important to assess how many domestic groundwater wells are located close to hydraulically fractured wells.

In a recent study [Ref. 2], we assessed how close domestic groundwater wells are to hydraulically fractured wells, and to oil and gas wells (some hydraulically fractured, some not). Due to consistencies limitations in both oil and gas and groundwater well datasets, we limited our analysis to groundwater wells constructed between 2000-2014, hydraulically fractured wells likely stimulated during the year 2014, and oil and gas wells producing in 2014.

Our study has two main findings.

First, we found that most (>50 %) recorded domestic groundwater wells constructed between 2000 and 2014 exist within 2 km of at least one hydraulically fractured well in 11 US counties (Fig. 1). Further, about half of all recorded hydraulically fractured wells that were stimulated during 2014 are located within 2-3 km of at least one domestic groundwater well. We suggest these regions where groundwater wells are frequently located near hydraulically fractured wells might be suitable areas to focus limited resources for further water quality monitoring.

Figure 1. The percentage of domestic groundwater wells that were constructed between 2000 and 2014 that have a recorded location that lies within a 2 km radius of the recorded location of at least one hydraulically fractured well that was stimulated during the year 2014.

Second, we assessed the proximity of oil and gas wells being produced in 2014 – some hydraulically fractured but others not – and groundwater wells. We found that many domestic groundwater wells are located nearby (<1-2 km) at least one oil and gas well, and, that actively-producing oil and gas wells are frequently located nearby at least one domestic groundwater well (Figure 2). Many of the potential contamination mechanisms associated with the construction, stimulation and use of hydraulically fractured wells are also associated with conventional oil and gas wells, including potential for spills on the land surface and well integrity failures [Ref. 3]. Therefore, assessing potential water quality impacts resulting from activities associated with oil and gas production derived from both hydraulically fractured wells and from conventional oil and gas wells is important.

Figure 2. The upper panel shows the distance between recorded oil and gas wells producing in 2014, and recorded domestic groundwater wells constructed between 2000 and 2014. The lower panel shows the distance between recorded domestic groundwater wells constructed between 2000 and 2014 and the nearest recorded oil and gas wells producing in 2014 (see Ref. [2] and references therein for data sources).

We conclude that (i) publicly-available groundwater well construction data are critical for managing groundwater resources and completing water quality risk assessments (see Ref. 4 for data quality information), and emphasize that not all states currently provide access to digitized groundwater well construction records (e.g., Figure 2), (ii) hotspots exist where activities related to oil and gas production occur nearby domestic groundwater wells, and these regions may be targeted for further groundwater quality monitoring, and (iii) assessing how frequently activities in the hydraulic fracturing water cycle impact groundwater quality may be vital to securing high quality water pumped from many domestic water wells where oil and gas production is common.

Figure 3. Hydraulically fractured well situated close to an irrigation system in California’s San Joaquin Valley.

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References:

[Ref. 1] U.S EPA. Hydraulic Fracturing for Oil and Gas: Impacts from the Hydraulic Fracturing Water Cycle on Drinking Water Resources in the United States (Final Report). U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-16/236F, 2016. Accessed from https://www.epa.gov/hfstudy November 15, 2017.

[Ref. 2] Jasechko S., Perrone D. (2017). Hydraulic fracturing near domestic groundwater wells. Proceedings of the National Academy of Sciences.

[Ref. 3] Vengosh A., Jackson R. B., Warner N., Darrah T. H., Kondash A. (2014). A critical review of the risks to water resources from unconventional shale gas development and hydraulic fracturing in the United States. Environmental Science & Technology 48, 8334-8348.

[Ref. 4] Perrone D., Jasechko S. (2017). Dry groundwater wells in the western United States. Environmental Research Letters 12, 104002.

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Scott Jasechko’s research focuses on fresh water resources, and uses large datasets to understand how rain and snow transform into river water and groundwater resources.

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

 

 

 

Debra Perrone  is interested in the multifaceted interrelationship between water, energy, and food resources. Her research explores how the interactions among these resources affect decisions and tradeoffs involved in water resource management.

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