Archive for the ‘Groundwater’ tag
Hi folks, here are some of the thoughts that came to my mind over the last few days.
AGU — looking back
The AGU fall meeting happened a couple of weeks ago now. However, it’s still vividly in my mind and there are still thoughts popping up:
it was such a big meeting, so that it was impossible to see or hear everything. Hence it is a great thing for the people who attended the meeting, as well as for people who did not, that some of the lectures are available online. Here is a great example, the online version of of a presentation, the Bjerkens Lecture, given by Richard B. Alley from Penn State University. As it happens, the best live talk I have attended at the meeting was also by Richard B. Alley, when he talked about flying buttresses and ice shelves. The Bjerkens Lecture is on the role of CO2 in earth’s history. Here are a few of my thoughts:
for times when there are no more ice cores available, those earth scientists (that is the climate-earth-scientists as opposed to “us hydrogeologists”) need to do the same thing as we do — look for other sources of data that help them to infer what they were looking for in the first place. One example that Alley presents is that they look for the density of openings in ancient leafs. Leaves “have to decide” if they put many holes in their leaves, which allows them to take in a lot of CO2 which they need for breathing, but which also dries them out quicker – or if they put few holes in their leaves, allowing little CO2 to come in but at the same time allowing only little water to go out. If the atmosphere contains little CO2, plants need relatively more holes in their leaves. I think this is a great example of “complimentary independent data-sets“, a term coined by John Cherry. Call me a geek, but I do like this term!
Alley mentions snowball earth, and there is also a cool picture in his talk from Namibia, which can be found here
- Alley mentions very briefly something along the lines that the mid-range models are right. Well, I don’t think that’s surprising. I would argue that the more important question is, if the extreme models get the extremes right…
There are two other blog-posts related to AGU which I want to point out:
Soil in the News
Two sites, “ScienceDaily” and “ScienceBlog” have the exact same story today, with exact the same heading: “Water hits and sticks: Findings challenge a century of assumptions about soil hydrology”. That sounds quite intriguing. Both articles stat that the research they write about is published on Nature Geoscience, but neither link to the paper. It is here. The “paper” is actually called in Nature Geoscience lingo a “letter”, and I am not sure what that implies.
Here is how I picture the process: it rains, some water enters the soil below the root zone, it continues it’s path towards the water table, some might flow laterally (towards a stream), some other part might be perched, and finally the rest makes it to the water table. On its way to the water table, it is commonly assumed, as the authors point out, that “water entering the soil as precipitation displaces the water that was present previously, pushing it deeper into the soil and eventually into the stream”, a concept referred to as “translatory flow”. Here is my first complaint, as stated above, I don’t think all the water below the root zone must go straight into a stream. But I agree with the (so far commonly used) concept of displacement.
The authors collected isotopic data, which suggests that “a pool of tightly bound water that is retained in the soil and used by trees does not participate in translatory flow, mix with mobile water or enter the stream.” And I think this is the key finding of this letter. Some water of the process I described above, might stay very close to the root zone.
This finding makes the authors suggest that their implications “are perhaps most profound for biogeochemical cycling and transport of nutrients to streams”. At the same time the authors concede that
“(t)his conceptual framework requires further testing to see if the underlying mechanisms are true, and if such separation of water resources holds for different climates and locations.”
I am wondering, how these two blog posts in ScienceDaily and ScienceBlog actually happened. Who wrote them? With what intentions?
More Water-Related News
- WaterWired has put up a great list of “Well-Worn Water Words” in two parts (part 1, part 2). Here is my favourite:
Water is the new oil because whisky is for drinking and water is for fighting, unless you are already in a water war, in which case you are probably already in water-power nexus from which only integrating science and policy will begin to address the fish versus farmer conflict defeating all efforts toward sustainability.
Scott Long on NASW reports on a previously unknown toxin in treated water. This is intriguing, because during the process of trying to eliminate as many bad substances as possible, another and possible quite a few other bad substances are created. Even worse, probably not many people look for those “by-products”.
Waterlogged points to a new documentary about the global water crisis, called “Flow”. Waterlooged links to two videos in which Maude Barlow (author of Blue Gold ) and Amy Goodman (of Democracy Now) http://waterblogged.info/2008/03/02/new-water-crisis-documentary-flow-for-the-love-of-water/
On thursday morning I sat into the “communicating climate change” session, which is not directly related with my work, but is timely, and relevant. It turned out that I saw some of the best talks of the conference so far in this session. As before I will post here some of my notes, again no guarantee for completeness.
M. Mann’s talk
- The scientific basis for climate change has been around for longer than many think, mostly since the early 19th century:
- Jim Hansen has been one of the first people to try and validate a climate model – and he didn’t do poorly
- there is a thing called the “Luntz Memo“. It is a memo written by a politician called Luntz who outlines in this memo how to argue against climate change in the public. Similarly, there are other politicians who are against climate change, including Senator James Inhofe and Sara Palin. This is nothing new, but was interesting in this clearness. Palin recently established a thing called “Climate Gate” in which she called for president Obama to boycott Copenhagen. Not to confused with Watergate.
R. Alley’s talk
- to be a scientist is one of the greatest jobs available: you discover things that nobody knew before, you share, and you help. On the other hand, scientist argue like crazy every time. Which might be necessary to “keep shaking the info until it’s solid”. To non-scientists, this usually looks like scientists do nothing else other than arguing. And that’s not good!
- The National Research Council was established to “investigate, examine, experiment, and report upon any subject of science or art”. Later came similar institutions for health and engineering. Now, after the initial IPCC report, the US government asked the NRC, if the IPCC predictions might be ok. The NRC responded that yes, the IPCC predictions look good.
- Then he got into sea-level rise, the main topic of his talk
- in 2001, sea level rise was predicted, excluding dynamics. In 2007, “scientists went like ‘Oh crap'” — sea-level rose faster than they expected. — “There’s the big gorilla out there that we don’t understand”
- “it’s not hard to get 1m sea-level rise by 2100”
- the underlying science: “all piles tend to spread, if you crank up the heat things melt, and if it snows it might accumulate”
- Sara Das does cool research in Greenland
- The Larsen B ice-shelf was one flying buttress for the ice of Greenland. Without a flying buttress, some ice might move up to 8x faster than with one. The less flying buttresses there are around Greenland, the “faster the whole thing goes”
- melting goes up faster than increased snow fall
- Regional Meteorological–Marine Reanalyses and Climate Change Projections by Weisse et al., 2009 in BAMS
- Geochemistry and the understanding of ground-water systems by Glynn and Plummer, Hydrogeology Journal 2005
- What indicators can capture runoff-relevant connectivity properties of the micro-topography at the plot scale? by Antoine et al., 2009 in AWR
- Zhu and Lin, 2009: preferential flow paths via EM in HESS
- Hydrodynamic Dispersion by Rose in Soil Science
- The original Pfannkuch, 1963 paper seems to be in french, not available online, but cited by many
- Berkovitz and Scher, 1995 in Water Resources Research
I’m sitting in Moscone West. As Apple aficionado, this is right where Apple’s Worldwide Developer Conference used to be! 😉
Day 1 of 5 is almost over. I’ve been to a few talks, I’ve been to a few posters. I’ve never been to a conference of a comparable size, so I am a little overwhelmed. The online calendar was really helpful. Scientifically, what was interesting?
- I saw C. Meirovitz’s poster on modelling alluvial fans with TPROGS. He’s trying to use borehole-log data to model hydro-facies in space. Channels that deposited gravel up to bolder size form preferential flow paths, and the simulation of those continuous features is not a trivial task; however, it is important because those are the pathways critical for non-linear processes such as solute transport. Very much related to my own work!
- I have never spent much time learning about fractals, but the concept of “self similarity” popped up at least twice today. Once in F. Schwartz’s talk on modelling prairie potholes, where he uses tho model the size of potholes in simulation by using two parameters (length and water-hight, if I remember correctly), and once in S. Neuman’s talk.
- Using insane amounts of data seems to become quite standard.
- Why are people so crazy about linear regression? And why do people who call themselves scientists refer to what they’re doing as linear regression, if both of their axes are log-scale? Similarly, I’ve seen at least two people who plot some measurement against some measure of scale. For small scales there are a lot of measurements, for large scales there are few measurements. Their argumentation is that measurements on the larger scale result in an average measurement. I am not 100% sure on this. It might also be that there simply are not many measurements on a larger scale, temporal or spatial.
- I saw a map of accumulated daily precipitation intensities, that is accumulated at a given location over a year, then spatially interpolated. That seems like a neat idea. Probably also for temperatures.
- This is nothing new, but well presented presentations are just so much better. 🙂
Now I’m off to the “frontiers of geophysics” lecture!
Bei Bauarbeiten am Finanzministerium in Wiesbaden ist es zu einem spektakulären Unfall gekommen: unerwartet wurde ein gespannter Grundwasserleiter angebohrt. Das unter Druck stehende Wasser bahnte sich seinen Weg durch das Bohrloch nach oben, was in einer relativ imposanten Fontäne resultierte:
Das Wiesbadener Tagblatt berichtet hier und hier. Siehe auch Berichte in der Sueddeutschen und vom Hessischen Rundfunk. Interessant ist dass bei spaeteren Meldungen von einer “Wasserblase” die Rede ist, und nicht mehr von einem gespannten Grundwasserleiter.
Hier ist eine Fotostrecke.
Ist jemand vor Ort und kann Erfahrungen schildern?
the response to the regression line post was straight out phenomenal and mind-blowing. In the next sequel, we will look at some real data. I had this planned for today, but unfortunately preparing for the NUPUS conference, at which I will take part next week, takes longer than anticipated. I promise I will post on monday again.
However, I do have a suggestion for your weekend (if you’re not planning to climb up any mountains or if you are sick at home): read this!
I just found out that “the economist” has a sequel of classic debates, on various topics. The debate I’m suggesting for you to read is entitled “The value of H2O” — This house believes that water, as a scarce resource, should be priced according to its market value. Defending the motion is Mr Stephen J. Hoffmann, who recently published a book which is called just like this blog (more about this really soon). The arguments against the motion are represented by Dr Vandana Shiva.
The course is over. Instead of blogging immediately about day 4, I spent the evening in Torino and hung out with some people from the course. At this point I have to point out how nice the city of Torino is, how nice and willing to help the people are. In the town, during the days of my visit, I was asked at least three independent times, if I needed help! On the final evening, we sat down on a bench on one of the plazas, and an elderly man started to talk to us in Italian, slowly and very well understandably. He ended up walking with us through the old city four over an hour and pointed out places of interest. It was just wonderful!
On the last day we covered heat transport and transport with fluids of variable density, especially sea water intrusion. From a historical point of view it’s interesting that because of sea water intrusion, density dependent models were the first “contamination” models to be developed. That is before dispersion was developed, and hence sea water intrusion was treated with sharp interfaces. We learned about the “Hele Shaw Model“, which Jacob Bear has used to model sea water intrusion before the use of computers was feasible. Bear developed during his M.Sc. thesis a horizontal Hele Shaw model. His first bookhas a full section on constructing Hele Shaw models. The idea seems from a former time, but such a model could have its uses for education!
In the afternoon, Dr. Rajandrea Sethi gave a presentation on how his group models colloid- and nano-particle transport under saturated conditions.
These were just amazing four days in Torino. It was such an interesting approach – to hear essentially a short but complete version of porous media theory in four days. Jacob Bear as teacher for this short course was amazing. Every word he uses has a meaning, everything he says builds up consecutively, and he stresses the important points. I will have many ideas to write about in the next little while for sure! 🙂
Climate Change and Groundwater
On a global scale, water levels are rising. The author of a recent Spiegel article claims that the effects of increasing saltwater intrusion has been neglected so far. Well… the US National Groundwater Association (NGWA) has saltwater intrusion covered since quite a while in their list of “Current and potential impacts of climate change” (part of this document). However, the author continues to mention that guys at Ohio State modelled how far saltwater extends from an ocean’s shore inland. And they found out that saltwater stretches further under continents than one has thought before.
Another point the author makes, one that I completely agree with, is that people don’t see the effects that global climate change has on groundwater resources. And people depend largely on groundwater. The author quotes a number from the USGS, according to which half of the US population derives its drinking water from groundwater
Latest UN Report
The latest UN report regarding Climate Change (and here) is a summary of the three reports that were published earlier this year. This summary will be the basis for discussion at the climate conference in Bali in December. Generally, the pictures painted in this summary-report are fairly dark: inundations, draughts, infectious diseases are all going to increase in magnitude and frequency.
This is not a new story, but it is a main article in the online edition of “Der Spiegel” today: The fact that pharmaceuticals, such as cough sirups, antibiotics, or pain killers are not totally taken up by the human body. The part that is not being taken up, usually ends at a wastewater treatment plant, and more often than usually can’t get treated there. So all these medical substances get released into the environment.
The article talks about the research group around Andrew Singer at the University of Oxford. He is a mathematical modeler, and wanted to know what would happen to “Tamiflu” – concentrations in british rivers. Tamiflu is supposed to treat people during an influence pandemic, which is when millions of Britons would use it.
Singer’s group showed that under such epidemic conditions, significant concentrations of Tamiflu would exist in rivers. There, lots (unimaginable many) of other life-forms would get into contact with Tamiflu, and the consequences can’t be imagined. As one consequence however it seems pretty certain that a few organisms that are believed to play a key role in transmitting influenza (the waterfowl) might develop a resistance against Tamiflu, and hence magnify the epidemic problem.