Friday, October 28, 2016

Site and Regional Flood Frequency at USGS

I asked to my Friend Tom M. Over (GS), to contribute something on Flood Frequency. Here it is is enjoable answer:


Sure, but that's a very big topic. How to narrow it down? As I've been with the USGS now for 15 years, you'll get very much a USGS-tinged view of things, which is focused on at-site flood frequency and regional flood frequency (under stationary conditions).

For at-site, as you may know, the general US federal government recommendation is to fit the log-Pearson type III distribution. Along those lines, the long-awaited update to Bulletin17B, called Bulletin17C, has been out for public comment, and has been revised in response to those comments. See:

One big innovation in Bulletin 17C is "Expected Moments Analysis" (EMA) which allows moments for historic or other threshold measurement-based information to be included:

Cohn, T.A., Lane, W.L., and Baier, W.G., 1997, An algorithm for computing moments-based flood quantile estimates when historical flood information is available: Water Resources Research, v. 33, no. 9, p. 2089–2096.

Cohn, T.A., Lane, W.L., and Stedinger, J.R., 2001, Confidence intervals for expected moments algorithm flood quantile estimates: Water Resources Research, v. 37, no. 6, p. 1695–1706.

EMA is already implemented in PeakFQ, at:

On regional flood frequency, the standard technology for USGS has been for ~30 years GLS regression on basin characteristics, computed one quantile at a time, going back to papers by Jery Stedinger and Gary Tasker in the 1980s, now implemented in WREG:

You could start with the manual for the program to see the theoretical background:

A typical product of this type of study might be:

Bulletin 17B-based regional flood frequency work also brings you to the topic of regional skew. A former student of Jery Stedinger, Andrea Veilleux, has been working to implement a new method in the U.S. based on her Ph.D. work using Bayesian regional regression; see, e.g.,

We're not totally ignorant of non-stationarity; you are probably aware of several important descriptive papers from recent years by USGS scientists such as: ("Nature's style: naturally trendy")

and ("Stationarity Is Dead: Whither Water Management?"),

and we do have a new workgroup on the topic that is looking at when and how to address the problem. Since it's so new I can't predict very much about what we'll come up with.

But along the lines of non-stationarity, from a personal perspective, recently a pair of reports from a project that I have been working on for several years came out in which we used regional quantile regression to assess and adjust for the effect of urbanization on flood frequency. I think quantile regression holds a lot of promise for regional flood frequency because it allows you estimate the exceedance probability of a given flood event at a given site based on regional information, even in the presence of non-stationarity (though climatic non-stationary would require a modification of the particular approach we used), without going through the whole at-site flood frequency thing and THEN doing a regionalization analysis. These reports are at:


One other personal perspective is that I am still interested in scaling of floods (and streamflow statistics in general), a la my Ph.D. advisor, Vijay Gupta, (see, e.g,

A couple colleagues and I published a paper last year trying to adapt that thinking to scaling of flow-duration curves, taking into account the effects of omitted variable bias, and trying to make an approach to the unification of quantile versus moment analysis (not very successfully on the last point but perhaps the problem is better demonstrated than in the past):

So I guess that's what I know about, i.e., what the USGS does and what I have been working on recently. Hope it helps! Let me know if you have questions.



Thursday, October 27, 2016

Sssh! GEOtop 2.0 video tutorial in Italian

GEOtop is our process based hydrological model. At the beginning of the year, Mountain-eering, paid by CAMILAB produced a series of video lectures in Italian to train people to use it. Unfortunately this big work is closed in some informatics drawer and nobody can use it. I came to have one copy, and I am temporarily posting it here. Untill CAMILAB will provide the right links and make it available.
To access the video lectures, you have just to understand where to click.

Working with us

After the scaring version, the practical version.  To incoming Ph.D. students

Dear *,

working with us means using our models
Both of them have a consistent history that involves also quite a group of publications. Their main information can be found following the links.

GEOtop,  to say the complete thruth, has a group of video tutorial (in Italian) that you can find here. University of Calabria paid Mountain-eering for doing them, so please use them with confidentiality.

Looking in perspective, I am working to a new incarnation of GEOtop in components. As I already explained here.  There will be then, a convegence of tools towards OMS3 and its evolutions.

So what I suggest ? First start to study the models at the links above. Willing to learn a computer language, start with Java. To start, read here.  To continue, go here.

In this language I invested quite a lot during the years. Why I choose Java can be found here.
I wrote it four years ago, but the concepts are still valid.  Recently I become more moderate, and opened to other languages. Here my opinion.

Wednesday, October 19, 2016

Every breath you take

I found these photographies by Robert Dash of stomata and I could not avoid to share them in this blog. The collections of photo are, at least two:

They were taken with an electronic microscope but preserve artistic values. Clicking on the figures you are redirected to the whole collection.

Monday, October 17, 2016

Hillslope stability tools

Here I am on landslides. I gave some contributions to this topics, and I wrote also something about, however I never tried to put a list of models that can be used.

As a general reading I would suggest certainly 

It is one of the few books that have a modern approach to quantitative hillslope hydrology. Who starts from it, is already a few years behind others.  Fortunately, Ning Lu covered some of the book chapters in the summer school on landslides held in 2013, and you can also learn directly from his voice and video.

If you have red the book, you can then understand that having at least a 2D tool for assessing hillslope stability is a necessity that you cannot avoid. 

So here they are my favorite tools:

Jgrasstools (see also here) - They contain a SHALSTAB implementation that can be used for comparison. They also contains the necessary tools for terrain analysis. 
CISLAM -  model was originally implemented in R by Cristiano Lanni (GS), but it was ported to JGrasstools in a Google Summer of Code by Marco Foi. I cannot guarantee its quality, since I never used it, but it is built on the theory I co-developed with Cristiano that you can find addressed here. (Jgrasstools are migrated to the gvSIG 2.3 now or are available trough S.T.A.G.E.).

Boussinesq - This is not directly a tool for hillslope stability estimation. However, it serves to estimate the water content (neglecting at the moment, the vadose zone). There are two version of it:  a C version by Emanuele Cordano (stable and working) and a Java version by Francesco Serafin (that is in Java, for being inserted into OMS3, and still a project under construction).

RiDI. - This was developed by Fabio Ciervo in his Ph.D.  it has the peculiarity that it implements a double porosity soil water retention curve proposed by Nunzio Romano (GS) and coworkers.

GEOtop - It was used a lot to this scope, conjointly with simple and less simple hillslope stability analysis (we did some papers with it).

At present, all the tools require to become part of a consistent framework. But we (Giuseppe Formetta -GS-, Francesco Serafin and I) are working on it, looking forward to the next EGU General Assembly in Wien (April 2017). Stay tuned. 

Tuesday, October 11, 2016

Reservoirology #2

Because, as we already noticed, often modelling the hydrological cycle is studying the mutual interactions of "reservoirs" of something (which I named "reservoirology"), I tried with my students to have a clean way to represent reservoirs. As we said in the slides below, we try to represent them in a way that, if it is not in a one to one correspondence with the equations that can be derived from the graphs, we are as close as possible to it. This post, left for saving the history, is, however, superseded by the new post reservoirology #3.

Please find above this graphic collection and help us to improve it. One thing to notice is that our representation is mappable, with different expressivity of the concepts to the Petri Networks algebra, which puts in our hands several studies in mathematics, computer sciences, biology and other sciences. 

Friday, October 7, 2016

Freezing-thawing processes studying with numerical models

This is the presentation given by Niccolò Tubini at the Carleton University last October 6th. Niccolò in his Master Thesis is working for a new implementation of the theory of freezing and thawing already covered by Matteo Dall'Amico in his Ph.D. Thesis and in Dall'Amico et al., 2011.
This work is part of the GEOtop project and its new implementations (see also here). The intention is to use the new numerical method implemented by Casulli and Zanolli (2010, 2011) of the extended Richards equation (see also the video here). The new method promise to be faster than the older one, more stable, and implemented for unstructured grids, while at present, GEOtop 2.0 uses a structured grid. Hopefully, the new development will be made in OMS3


Casulli, V., & Zanolli, P (2010). A nested newton-type algorithm for finite colume methods solving Richards' equation in mixed form. SIAM J. SCI. Comput., 32(4), 2225–2273.

Casulli, V., & Zanolli, P. (2012). Iterative solutions of mildly non linear systems, Journal of Computational and Applied Mathematics, 236(16), 3937–3947.

Dall'Amico, M., Endrizzi, S., Gruber, S., & Rigon, R. (2011). A robust and energy-conserving model of freezing variably-saturated soil. The Cryosphere, 469–484.

Tuesday, October 4, 2016


Networks are pervasive in our world and represent often the way energy is dissipated from large to small scale. I have some past in the topics, especially if we look at river networks, for which a all-time reference is Rodriguez-Iturbe and Rinaldo book.
The news is that my research on networks could have some future. We are using networks for commanding our JGrass-NewAGE model, but with the idea that we can, by means of a chain of models, follow energy dissipation across the hydrological cycle.

John Baez  works on the mathematical theory of networks, seen under different perspectives. His blog, Azimuth, is a source of really exciting ideas brought with extreme competence and he and coworkers have interest in networks. This blog post is to bring attention  his page on network theory which is a huge font of information to be read.

Sunday, October 2, 2016

Non-equilibrium Thermodynamics

I am starting to rewrite S.R. de Groot and P. Mazur, (dGM) Non-equilibrium thermodynamics book. Better, at the moment, I am trying the rewrite its PART A. What do I mean for rewriting ? Mostly two things: the first that I want to learn what it says, driving a slower dance with it, and the second is that I do not fully endorse what I understand so far from it. My differentiation is especially about the role of entropy, which, I think, is treated in a way that strongly derives from the idiosyncrasies of the equilibrium thermodynamics. I already wrote jointly with Matteo Dall’Amico something about thermodynamics, and possibly the two flows could merge in one final product. My goal is not thermodynamics, per se, but the thermodynamics of the hydrological cycle, of which I am a scientist. I believe that thermodynamics has to evolve towards a science of dynamical structures that allows for describing fluxes of information, besides energy and mass, with the final goal to understand ”life organisation”. The latter, however, is for future people. I will attack only water movements, and, maybe, some related cycles, as the carbon cycle. However water flows through plants, an plants are life. So let’s see where I will could arrive in the next fifteen years.

In what follows, what between ” ” is a verbatim transcription of dGM book. I believe their material is copyrighted, however, mine is distributed under CC license 3.0

You can follow the growth of the book while I am writing it, and comment it, if you like. To this scope I am using the Authorea tools. So:

Non-equilibrium Thermodynamics

1 - Introduction and motivation
2 - Conservation of mass
3 - Conservation of momentum
4 - Conservation of Energy

Other chapters will follow.