Thursday, October 29, 2015

Studies on glaciers (snow, permafrost) in Trentino

I was invited to give a talk tonight at MUSE for the general public about the activity of our group in the cryosphere areas.
Please find the presentation (sorry in Italian) clicking on the Figure.
During the last ten years our group of hydrologists started a nice series of tasks, sometimes with higher and sometimes with lower intensity.

As a result, we have now, models, measures, expertise for doing much more. Personally I should go more on field trips! Enjoy

Wednesday, October 28, 2015

Large Scale Hydrology

Large Scale Hydrology is a fact. Its growth  became important especially in conjunction with the studies about the climate crisis and today many outstanding colleagues work in building and managing hydrological models at global or continental scale.
I participated a few months ago to a session of the Globaqua project where I was exposed to some of these researches.  The models mentioned at the meeting  by Alberto Pistocchi of JRC were LISFLOOD e SWAT. Ralph Merz used HBV and mHm. I know,  from other readings, that also VIC and  PCR-GLOBWB are of this kind of global models, an probably there exist many others (JULES can be another).

There are two aspects of these modelling efforts that can be discussed. The science behind their formulations and parameterisations, and the data sets used to drive them. 

Regarding the first aspects,  science, I think the efforts my colleagues do are necessary and, simplifications they work with have to be made. However,  science in their models is far from being assessed (but if I would myself be working on the same topics, I would probably use the same shortcuts to arrive to some result).  My concern is that in these efforts,  sometimes (I say sometimes but I mean often) hydrological models become a commodity, and their quality is given for granted. Maybe the climate change community with its models of everywhere (and everything) which fail locally had some negative influence on this attitude. As a matter of fact, that discarding  details and details of the processes and still the global results obtained are correct remains quite unproven. 

Regarding data, collecting data globally to run the models is certainly an enterprise. The goal of building these large standard datasets to be used by models and modelers is actually important by itself, and it is a pity that people do not think how to share this knowledge base. An effort for open data and open protocols for digesting them in models is a need.
 In turn there are two great data collection domains: the assessment of hydro-meteo forcing and the parametrizations of soil and vegetation properties.
While  the effort of measuring and providing meterorological data  is shared with meteorologists and climatologists, the terrestrial data sets are less available, of more uncertain application, and often too coarse grained. Or, maybe, this is just my impression. My impression actually is that the assumptions of the congruence in the use of the terrestrial data are made for sake of convenience, and according to a mute agreement not to go in deep in the analysis of their usefulness. The representativity of the data used depends mostly on how much heterogeneity  is possible to neglect: it was a topic which had its popularity in the nineties, but seems a little bit behind the scene now.  Probably the goal now, in this phase of the projects, is to have an infrastructure working, more than forecasting precision, or crystal clear science. 

The emergence of the global scale hydrology, was the title of a very beautiful paper by Peter Eagleson (a citation) (WRR, 1986), and the argument also of  Shuttleworth (1988) which I suggest as a must-to-read papers. This long history means that the topic has more than one thread. 

Notable works, instead of being river basin centred are more focused on the water cycle as a whole. For instance, it came to my attention the work of  of Trenberth  (GS) and coworkers, and of  Oki and coworkers.  Eric Wood  and his coworkers pushed the idea that the global hydrological cycle can be studied by high-resolution models driven by high-resolution remote sensing: and this is still another plot of the story.

Anyway, how much it is the uncertainty of these global water and energy budgets is revealed by the comparison of fluxes as given by OKI’s figure (the one you see in this post), which estimates practically null the outflow of groundwaters in oceans, with a recent study by Kwon et al (2014) that suggests that groundwater could be as much as 80% of the whole contribution of water to the oceans from continental masses.

CUASHI recently dedicated one of its cyberseminars series to the topic (see here and these google links).

The matter, as usual, is to discerne, in this "hot" production, what is good and what is better.  Sometimes being wrong is not so important if this makes science to proceed.
Further readings are below. 

References and further links

Aeschbach-Hertig, W., & Gleeson, T. (2012). Regional strategies for the accelerating global problem of groundwater depletion. Nature Geoscience, 5(12), 853–861. doi:10.1038/ngeo1617

Alcamo, J., Döll, P., Henrichs, T., Kaspar, F., Lehner, B., Rosch, T., and  Siebert, S. (2003). Global estimates of water withdrawals and availability under current and future “business-as-usual” conditions. Hydrological Sciences Journal, 48(3), 339–348. doi:10.1623/hysj.48.3.339.45278 

Ball, P. - H2O, a biography of water, Phoenix ed., 1999

Bergström, S., 1976. Development and application of a conceptual runoff model for Scandinavian catchments, SMHI Report RHO 7, Norrköping, 134 pp.

Burek, P., van der Knijff, J., de Roo, A., LISFLOOD. Distributed water balance and flood simulation model. Revised User Manual. JRC Technical Reports - EUR 26162 EN, 2013.

Dai, A., and K. E. Trenberth (2002), Estimates of freshwater discharge from continents: Latitudinal and seasonal variations, J. Hydrometeorol., 3(6), 660–687, doi:10.1175/1525-7541(2002) 003<0660:EOFDFC>2.0.CO;2.

Dai, A., I. Y. Fung, and A. D. Del Genio (1997), Surface observed global land precipitation variations during 1900–88, J. Clim., 10(11), 2943–2962, doi:10.1175/1520-0442(1997)010<2943: SOGLPV>2.0.CO;2.

Dai, A., T. T. Qian, K. E. Trenberth, and J. D. Milliman (2009), Changes in continental freshwater discharge from 1948 to 2004, J. Clim., 22(10), 2773–2792, doi:10.1175/2008JCLI2592.1.

Eagleson, P, The Emergence of Global-Scale Hydrology, Water Resources Research,  1986

eWaterCycle project:

Gentine, P., Troy, T. J., Lintner, B. J., & Findell, K. L. (2012). Scaling in Surface Hydrology: Progress and Challenges. Journal of Contemporary Water Research and Education, 147, 28–40.

Kumar, R., B. Livneh, and L. Samaniego (2013), Toward computationally efficient large-scale hydrologic predictions with amultiscale regionalization scheme, Water Resour. Res., 49, 5700–5714, doi:10.1002/wrcr.20431.

Kwon, E. Y., G. Kim, F. Primeau, W. S. Moore, H.-M. Cho, T. DeVries, J. L. Sarmiento, M. A. Charette, and Y.-K. Cho (2014), Global estimate of submarine groundwater discharge based on an observationally constrained radium isotope model, Geophys. Res. Lett., 41, 8438–8444, doi:10.1002/ 2014GL061574. 

Liang, X., D. P. Lettenmaier, E. F. Wood, and S. J. Burges, 1994: A Simple hydrologically Based Model of Land Surface Water and Energy Fluxes for GSMs, J. Geophys. Res., 99(D7), 14,415-14,428. 

Neltsch, SL, Arnold, JG., Kiniri, JR, Williams, J., Soil & Water Assessment Tool Theoretical Documentation Version 2009. 

Oki, T., and S. Kanae (2006), Global hydrological cycles and world water resources, Science, 313(5790), 1068–1072, doi:10.1126/ science.1128845.

Oki, T., K. Musiake, H. Matsuyama, and K. Masuda (1995), Global atmospheric water balance and runoff from large river basins, Hydrol. Processes, 9(5–6), 655–678, doi:10.1002/ hyp.3360090513.

Samaniego, L., R. Kumar, and S. Attinger (2010), Multiscale parameter regionalization of a grid‐based hydrologicmodel at the mesoscale, Water Resour. Res., 46, W05523, doi:10.1029/2008WR007327. (see also

Seibert, J. and Vis, M. (2012). Teaching hydrological modeling with a user-friendly catchment-runoff-model software package. Hydrology and Earth System Sciences, 16, 3315–3325, 2012 (

Shiklomanov, I. A. (2000). World water resources: a new appraisal and assessment for the 21st century; 1998, 1–40.

Shuttleworth, W.I., 1988. Macrohydrology-the new challenge for process hydrology. I. Hydrol., 100: 31-56. 

Trenberth, K. E., L. Smith, T. Qian, A. Dai, and J. Fasullo (2007a), Estimates of the global water budget and its annual cycle using observational and model data, J. Hydrometeorol., 8(4), 758–769, doi:10.1175/JHM600.1.

Trenberth, K. E., J. T. Fasullo, and J. Kiehl (2009), Earth’s global energy budget, Bull. Am. Meteorol. Soc., 90(3), 311–323, doi:10.1175/2008BAMS2634.1.

Voisin, N., Wood, A. W., & Lettenmaier, D. P. (2008). Evaluation of Precipitation Products for Global Hydrological Prediction. Journal of Hydrometeorology, 9(3), 388–407. doi:10.1175/2007JHM938.1

Vörösmarty, C. J. (2000). Global Water Resources: Vulnerability from Climate Change and Population Growth. Science, 289(5477), 284–288. doi:10.1126/science.289.5477.284

Van Beek, L.P.H., and Bierkens, M.F.P., The Global Hydrological Model PCR-GLOBWB:Conceptualization, Parameterization and Verification, Utrecht University, 2009 (

Wood, E. F., et al. (2011), Hyperresolution global land surface modeling: Meeting a grand challenge for monitoring
Earth’s terrestrial water, Water Resour. Res., 47, W05301, doi:10.1029/2010WR010090.

Xie, P., and P. A. Arkin (1996), Analyses of global monthly precipitation using gauge observations, satellite estimates, and numerical model predictions, J. Clim., 9(4), 840–858, doi:10.1175/ 1520-0442(1996)009<0840:AOGMPU>2.0.CO;2.

Friday, October 23, 2015

A solver for the 1D de Saint-Venant equation in OMS

A simplified but not so simplified way to describe the motion in channels, is to use the de Saint Venant 1d equation. Solving it is not anymore a particularly complex model and almost twenty years ago, I and collaborators implemented one of it based on Vincenzo Casulli work.  This can be seen, from Angelo Zacchia's master thesis (in Italian), which contains the main elements from page 36 to 51. A more scientific treatment of the problem is presented in Casulli and Zanolli [1998], and Aldrighetti's Ph. Thesis [2007].

This work is simpler but implemented inside the JGrasstools, by Silvia Franceschi (of Hydrologis) during her Google Summer of Code 2015 exercise,  and available as open source here.
A little of documentation is in the GSoC 2015 page of the project itself.


Aldrighetti, E., Computational hydraulic techniques for theSaint Venant Equations in arbitrarilyshaped geometry, 2007

V. Casulli and P. Zanolli. A conservative semi-implicit scheme for open channel flows. International Journal of Applied Science & Computations, 5:1–10, 1998.

Zacchia,  A., Master Thesis, Su alcuni metodi per la prevenzione e previsione del rischio idraulico, Trento University, 1997

Wednesday, October 14, 2015


Hydro_gen is the product of an old research by Alberto Bellin (and Yoram Rubin). It is a random field generator, where the variables in different points are however correlated. The theory was presented in Bellin and Rubin, 1996. So it is almost twenty years old. However, is still good, and important. Some similar modelling can be done inside R (see this contribution by Santiago Begueria).

Alberto agreed to share his old FORTRAN 77 code, and it is now on Github, at this site. Our scope is to embed it in OMS and peruse it for our scopes.


Bellin, A. Rubin, Y., Hydro_gen: A new random number generator for correlated properties, Stochastic Hydrology and Hydraulics, 10(4), 1996

Alberto Bellin and Yoram Rubin, HYDRO_GEN, A New Method for the Generation of Random Functions, Code description and User's guide, 1997

Rubin,Y and Bellin, A., Conditional Simulation of Geologic media with Evolving Scales of Heterogeneity, In: Scale dependence and Scale Invariance in Hydrology, Ed. G. Sposito, Cambridge University Press, 1997
Rubin􏰄 Y􏰂 and A􏰂 Bellin􏰄 Conditional Simulation of Geologic media with Evolving Scales of Hetero􏰅 geneity􏰄 In􏰊 Scale dependence and Scale Invariance in Hydrology􏰄 ed􏰂 G􏰂 Sp osito􏰄 Cambridge University Press􏰄 􏰁􏰌􏰌􏰑 
Rubin􏰄 Y􏰂 and A􏰂 Bellin􏰄 Conditional Simulation of Geologic media with Evolving Scales of Hetero􏰅 geneity􏰄 In􏰊 Scale dependence and Scale Invariance in Hydrology􏰄 ed􏰂 G􏰂 Sp osito􏰄 Cambridge University Press􏰄 􏰁􏰌􏰌􏰑 

Sunday, October 11, 2015

Workshop on coupled hydrological modeling in Padua, 23-24 September 2015

At the beginning there were the CATHY DAYS among friends working around the CATHY model. With time the crew has grown to include close friends of CATHY's authors, like me, Alberto Bellin, Aldo Fiori (GS). Then the group even become larger including a lot of people working with PARFLOW or Thetis-Chloris or various aspects of hydrological modelling with process based models or, like me this year, with travel times approaches. Many thanks to the organizers, Matteo Camporese (RG,GS), Mario Putti (GS) and Stefano Orlandini (RG,GS).

The two days experience was pretty good, an here you can find the contributions of those who gave the permission to publish their slides. Slides include interesting references. Clicking on the slides images brings you to the slideshare site of the workshop. I subdivided the talks in; CATHY related, PARFLOW related, GEOtop related, On Travel time approaches, and on General/Various topics.


Marcello Fiorentini (University of Modena and Reggio Emilia, Italy)
Control of coupling mass balance error in the CATHY model

Laura Gatel (INRS-ETE, Canada, and IRSTEA, France)
Reactive solute transfers in Cathy: first work on adsorption

Damiano Pasetto (EPFL, Switzerland)
Data assimilation for distributed models: an overview of applications with CATHY

Carlotta Scudeler (INRS-ETE, Canada, and University of Padova, Italy)
Hydrological modeling of coupled surface-subsurface flow and transport phenomena: the CAtchment-HYdrology Flow-Transport (CATHY_FT) model


Gabriele Baroni (UFZ, Germany)
On the role of subsurface heterogeneity at hillslope scale with Parflow

Reed Maxwell (Colorado School of Mines, USA)
Integrating models and observations to understand the hydrology and water quality impacts from beetle-impacted watersheds

Mauro Sulis (Bonn University, Germany)
Assessment of the catchment-scale energy and water balance using fully coupled simulations and observations
On GEOtop

Giacomo Bertoldi (EURAC, Italy)
Eco-hydrological modeling in a mountain laboratory: the LTSER Matsch/Mazia

On travel time theories

Gianluca Botter (University of Padova, Italy)
StorAge Selection Functions: a tool for characterizing dispersion processes and catchment-scale solute transport

Paolo Benettin (EPFL, Switzerland)
On the integrated solute response of catchments: benchmark applications using chloride and isotopic tracers

Riccardo Rigon (University of Trento, Italy)
Implementing a travel time model for the entire river Adige: the case of JGrass-NewAGE

On General topics

Alberto Bellin (University of Trento, Italy)
The value of aggregated measurements of state variables in hydrological modeling
Giorgio Cassiani (University of Padova, Italy)
Minimally invasive monitoring of soil-plant interactions: new perspectives

Simone Fatichi (ETH Zurich, Switzerland)
Soil moisture spatio-temporal variability: insights from mechanistic ecohydrological modeling

Aldo Fiori (University of Roma Tre, Italy)
Lessons learned from integrated, physically-based hydrological models
Claude Mugler (LSCE/IPSL, France)
Darcy multi-domain approach for coupling surface-subsurface flows: Application to benchmark problems

Sylvain Weill (University of Strasbourg, France)
A dimensionally-reduced approach for coupled river-subsurface flow modeling

Alfonso Senatore (University of Calabria, Italy)
OpenCAll: A New Library for ciomputational science on parallel computers based on cellular automata paradigm

Wednesday, October 7, 2015

Geomorphological modelling in 2020

This presentation, I gave in Perugia for the Italian Days of Hydrology 2015, is part of the long march towards the construction of a reasonable and modern physico-statistical theory of the water budget at catchment scale. This includes previous talks and posts on Residence/Travel time theories that were recently renewed by the work of my friends Rinaldo, Botter, Bertuzzo, Benettin (the younger scientific brother) and others.
It starts with a little of history, and it follows, at the beginning, the recent paper on GIUH theory.
 I do not pretend the presentation is very clear. Without any doubt it requires more than one reading, and the new ideas are just sketched in the last slide, not fully developed. Personally, however, I fill pretty satisfied with these seeds today, also because I feel that I could grab the core of the travel time distribution theories in a way that is understandable by most.