Wednesday, February 15, 2023

The Hydrological Modelling Class 2023 - the foreseen schedule

 Index

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 Foreseen Schedule (up to Easter)

(boldface dates are those with definitive material, I or directly written in Italian  in for Italian,  unspecified for English. All slides are in English)

To understand better what is below: 
  • A storyboard is a summary, usually in Italian, of the lecture
  • A whiteboard is an explanation of a particular topic made on the whiteboard (using Notability on the iPad)
  • Slides are commented in English (since 2021)
  • Additional  information (only for the brave or the curious) and references are in italics



The 2023 Videos can be found also at here in this Vimeo Showcase

2023-02-27 - I  - Syllabus - Introduction 2 Hydrological Modelling 

Here  I introduced the class. Its learning by doing philosophy (altered by the necessity due to COVID-19 times that impose to do first the all the theoretical parts and subsequently all the practical parts hoping that they can be done in presence). 
 Geomorphometry   - Discussion of previous lesson topics. Summary of the lecture in Italian. (This will be always done, each lesson, but for now on omitted). The rational of introducing these concepts  is that catchments are spatially extended and in this course we are interested to deal with catchments hydrology. 

In this first part we deal with the geometrical (differential) characteristics of the topography. Elevations, slopes, curvatures. They will be necessary later to extract the river network and the parts of a catchment.
In this class we define also what the drainage directions are and how they are computed in the case of DEMs (a topography discretized over a regular grid).  From drainage directions are determined the total contributing areas in each point of  a DEM. These two characteristics are eventually used to determine  the channels head and extract the river network. In turn, the extraction of the channel network allows for the extraction of hillslope and a first definition of  the Hydrologic Response Units (HRU). 
    2023-03-02
    2023-03-06
    Q&A - 


    2023-03-02 -  Interpolations 
    This lecture, assuming that now you have at least the concepts of what a catchment is and theoretically you know how to extract it and subdivide it in parts, deals with the data to feed catchments hydrology models. Because catchments have a spatial distribution, then also the driving data must be distributed. We need therefore methods of interpolation. 

    2023-03-09 -  Interpolations part II. 
    In this class we try to understand how to estimate the errors over the estimates. Besides we introduce a method (the Normal Score) to avoid to obtain negative values when positive interpolated values are required.
    Q&A - 
    Spatial Interpolation (Vimeo2023)

     Hydrological Models. This is a class about hydrological models, so what are they ?

    The title is self-explanatory. A theoretical approach to modelling is necessary because we have to frame properly our action when we jump from the laws of physics to the laws of  hydrology. Making hydrology we do not have to forget physics but for getting usable models we have to do appropriate simplifications and distorsions. The type of model we will use in the course are those in the tradition are called lumped models. Here we also introduce a graphical tool to represent these models.
    Hydrological Models
    2023-03-13 - Hydrological Models - II
    2023-03-16
    2023-03-20 
     Linear Models for HRUs

    Once we have grasped the main general (and generic) ideas, we try to draw the simplest systems. They turn out to be analytically solvable, and we derive their solutions carefully. From the group of linear systems springs out the Nash model, whose derivation is performed.  Obviously, it remains the problem to understand how much the models can describe "reality". However, this an issue we leave for future investigations.
    2023-03-23 - 
     A little more on the IUH and looking at the variety of HDSys models

    We introduced previously without very much digging into it the concept of Instantaneous Unit Hydrograph. Here we explain more deeply its properties, Then we observe that there are issues related to the partition of fluxes and we discuss some simple models for obtaining them. Not rocket science here. The concept that we need those tools is more important than the tools themselves. We also observe that linearity is not satisfactory and we give a reference to many non linear models. Finally we discuss an implementation of some of the discussed concepts in the System GEOframe. 
    2023-03-30
    2023-04-06

     Travel Time, Residence Time and Response Time
    Here below we started a little series of lectures about a statistical way of seeing water movements in catchments. This view has a long history but recently had a closure with the work of Rinaldo, Botter and coworkers. Here it is presented an alternative vie to their concepts. Some passages could be of some difficulty but the gain in understanding the processes of fluxes formation at catchment scale is, in my view, of great value and deserves some effort.  The way of thinking is the following: a) the overall catchments fluxes are the sum of the movements of many small water volumes (molecules); b) the water of molecules can be seen through 3 distributions: the travel time distribution, the residence time distribution and the response time distributions; c) the relationships between these distributions are revealed; d) the relation of these distributions with the the treatment of the catchments made through ordinary differential equations is obtained through the definition of age ranked distributions; e) The theory this developed is a generalizations of the unit hydrograph theory. 
    2023-04-20
    Some References (advanced)

    Digressions I - A Glimpse on distributed process-based models

    Digressions II - Radiation -  After all radiation moves it all.
    Digressions III
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    The Hydrological Modelling Class - 2023 Index

     Index

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    Introduction

     The Hydrological Modeling course aims to teach to simulate the hydrological cycle at various spatial scales in order to be able to adequately manage the water resource and to prevent the risk of floods. The importance of these two issues is widely covered by the EU 2000/60 framework directives or "Water directive" and EU 2006/60, "Flood directive". Based on the hydrological knowledge acquired in the course of Hydrology at the Bachelor of Engineering for the Environment and the Territory, the hydrological processes, analyzed as punctual phenomena are extended to the water catchment areas. 

    Precipitation is analyzed as a measured statistical data, both from ground stations and from remote sensing; the other processes are suitably modeled, as briefly described below. At the end of the course, a student must be able to independently model the flow rates, evaporation and transpiration in a river basin of various sizes, after having delineated it starting from digital terrain data. Of course, the student will have to demonstrate that he has critically understood the concepts that underlie the hydrological modeling presented. 
    The knowledge acquired may be used in the River Engineering course for the design of defense works. Hydrological modeling also introduces concepts that are used in the course of Aqueducts and Sewers for the calculation of stormwater networks. The course is partly useful for the Hydraulic Protection of the Territory course.  A more condensed part of the version of the course can be found @GWS.
    An overview of the topics (in Italian) can be found on the seminar done for the District Authority of river Po (here). 




    The lectures of the course will be held in English, according to the methods already followed in the Numerical Modeling course (i.e. with summary in Italian at the beginning of the lesson, lessons in English, questions and explanations in Italian). The first part of the course, until on April 3, will be dedicated to the presentation and discussion of theoretical concepts. The lectures will be recorded and uploaded on the course's YouTube channel (or Vimeo). The lessons will cover 4 of the five hours per week. The fifth hour will be dedicated to the preparation of the data necessary for the projects to be completed in the second part of the course. 

    Students must take care to understand the hydrological concepts and discuss them with the lecturer. The first twenty minutes of each lesson will be devoted to the discussion of the topics covered in the previous lesson and the problems that arose in the preparation of the data (in Italian). Every group had to prepare an appropriate question or comment to which the lecturer will replay. A summary, again in Italian, of the lesson and then the actual lesson will follow. 
    The second part of the course will use the theoretical themes of the first part and using the tools made available by the GEOframe system (https://abouthydrology.blogspot.com/2015/03/jgrass-newage-essentials.html). Students, in groups of two or three, will have to estimate hydrological flows and quantities over a significant period of time and with an hourly time step using a time series of hydro-meteorological data in inputs for period long enough to allow adequate calibration of the models. With the help of the tutor and the reader, students will face problems of missing data, validate the models, discuss and implement an adequate configuration of the GEOframe hydrological system in order to get the hydrological water balance of the basin. 

    The following works by Abera can be taken as an example of the outcomes expected :
    References 

    The lessons will be video recorded and made available. Each lesson will be given through slides in English which will be delivered to students in advance. When necessary, the lessons will be accompanied by appropriate in-depth papers. There is no real text because the course, even in the hydrological tradition, elaborates the concepts in a contemporary way and uses innovative tools.
    As general reference texts we recommend:

    • Beven, K. - Raifall-runoff, the primer, ISBN 10: 047071459X, ISBN 13: 978047071459, Second Edition, Wiley-Blackwell, 2012
    • Dingmann, L., Physical Hydrology, ISBN-13: 978-1478611189, ISBN-10: 1478611189, Third Edition, Waveland Press, 2015
    • Lu, N. and Godt, J.W., Hillslope Hydrology and Stability, Cambridge University Press, ISBN-13: 978-1107021068, ISBN-10: 11070210652010, 2013
    • Bonan, G., Ecological Climatology, concepts and applications, ISBN-13: 978-1107619050, ISBN-10: 110761905X, 2016

    These books represent a shareable review of the phenomena and hydrological modeling but the methods they present are not necessarily those used in the course. The course, cause of time constraints, presents a selected and limited perspective of the subject that the texts cited dissect from various points of view often complementary to the one of the course.

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    Monday, February 6, 2023

    Glimpses of Environmental Engineering for the students of QUADRI Lyceum High School

     Looking for excellent students of our degrees in Environmental Engineering, last Wednesday, February 1, I went to the QUADRI Lyceum High School in Vicenza to talk about Environmental Engineering, Flood prevention and all of this. With me dr. Paolo Ronco of Viacqua made also an excellent presentation the work they do for water supply and water resource protection in Veneto (Italy). Here below you can find my presentations. 


    The slides cover these topics (click on the links for the PDFs:

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    Saturday, January 21, 2023

    One year position (hopefully extensible to two or three years) for working on the Po Project is open until January 31st.

    One year position (hopefully extensible to two or three years)  for working on the Po Project is open at the University of Trento, Department of Civil, Environmental and Mechanical Engineering. Information about the project can be found at:



    We search  for a skilled candidate able to boost the work on the project and eventually start  new researchers among the various challenging research lines which were better defined in the so called DARTH4MED project:


    PI of the Project are Riccardo Rigon (riccardo.rigon@unitn.it) and Giuseppe Formetta (giuseppe.formetta@unitn.it). Please do not hesitate to ask for information and clarifications and note that we encourage to apply also to students who do not have yet discussed their Ph.D. Thesis.

    The call details are at:


    The net salary is around 1700 Euro/Months. Other submitted projects, including the already mentioned DARTH4MED are synergic to the this project and they could provide further financial support for the next years. An ideal reference for the framework used in the project is the paper on Digital eARth Twins of Hydrology (DARTHs) recently published on HESS


    To the potential applicants:

    Please observe that the use of our system GEOframe is mandatory for that project. After January 31 we will be evaluating the submission. For incoming possible postdoc, I wrote this

    Please observe that you are a little late but you can browse our Winter School on GEOframe to understand what we require. 
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    Monday, January 16, 2023

    A Commentary on transit (travel) times theory

    We were recently to  produce a commentary on a review paper by Benettin et al. 2022. The preprint of the paper is here below clicking on the Figure. 

    The understating of the dynamics of tracers and water transit times at catchment scale has increasingly grown in the last decades, becoming a consolidated approach in the field of hydrological and ecohydrological research. Recently, a benchmark contribution has been given in the work by Benettin et al., 2022, which reviews the state of art on the topic, also addressing present and future challenge, pointing out some open questions in transit time research. This commentary tries to contextualize the above article, highlighting the most focal points and relating it to a broader context in the field. A brief overview on the main concepts of backward transit times, StorAge selection functions and forward transit time distributions is given in a logical-historical order, giving to the reader the primary instruments for a later comprehensive understating of the Transit Time Theory. Eventually, a numerical example helps to clarify the above concepts in a very simple and effective way. 

    References

    Benettin, Paolo, Nicolas B. Rodriguez, Matthias Sprenger, Minseok Kim, Julian Klaus, Ciaran J. Harman, Ype van der Velde, et al. 2022. “Transit Time Estimation in Catchments: Recent Developments and Future Directions.” Water Resources Research 58 (11). https://doi.org/10.1029/2022wr033096.

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    Sunday, January 1, 2023

    Hydrological CVs and Research

     It happens to me, but I suppose the same happens to most of my colleagues to receive many CV, especially from excellent guys developing countries. Some of them are remarkable but they usually do not  meet my requirements. What is the problem ? They are clearly very motivated and smart persons. However there is a constant in their backgrounds. They were trained in using models like HEC-RAS-HMS or SWAT or even MODFLOW and they wrote papers about case studies (regional studies they call them now).  This is not bad at all obviously and that “standard knowledge” should be part of any robust professional. There are other two variations the CVs: the use of machine learning techniques (under standard frameworks) to infer something or the use of Earth observation "products" to extract something of information (often without ground check). Sometimes their work is valuable and again, how can we say that they should not be part of the professional CV ?

    However all of this has just a little to do with the research gold medal which stand in investigating processes, learning from them, disentangling their feedbacks, implementing new tools. Their trying to do something new remains within the very limited scope which is allowed by something built by others and not open to modifications and evolutions.  That's what I would like to see instead: these solid bases but also a little spark that try to go out for this standard comfort zone. 

    For my critics, it is true that I push my activities  to the extreme, to the point that all discusses, not only processes, but also tools, the way to build them, the way to share them with others. It is true that, it can be seen as an act of high presumption, which prepares, for normal people like me, to a destiny of failures, low productivity and frustration, far away out of the highways of the industrial success of some paradigms.  Then if you do not have to imitate me to the limit, at least take the good of my perspective and do not stay still in a cycle which all renews for nothing change.

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    Saturday, December 31, 2022

    Niemi's identity and celerity

    There are at least two distributions that describes the hydrologic response, the backward travel (transit)  time distribution and the hydrologic response (e.g. Rigon et al., 2016b). The first accounts for the water age, the second is used to forecast the discharge or to summarize the history water follows along its path, i.e Rigon et al. 2016a. The second, projected into the future, is the statistics of life expectation of water parcels inside the control volume,  Rigon and Bancheri, 2021a,b.

    Recently, in a beautiful review paper on transit times (Benettin et al. 2022),  to describe the difference between the two distribution, was used the concept of celerities by saying that the backward transit time distribution deals with the velocity of water, the response time distribution deals with the celerity. 

    However, this is not the case.  The simplest form (one single output) Niemi's relation reads in fact:$$  IUH(t-t_i|t_{i}) J(t_{i}) \equiv p_Q(t-t_i,t_{i}) Q(t)  $$

    where $IUH$ is the travel time distribution, $T=t-t_i$ is the transit time, $t_i$ the precipitation instant, $J$ is the precipitation,  $p_Q(T,t_{i})$ the backward travel time distribution and $Q(t)$ is the discharge.

    Therefore if the $IUH$ is affected by celerities, also the $p_Q$ must be, unless precipitation and discharge are nor mysteriously related in a way to cancel its effect on the right side of the identity. It is much easy to understand that  the effect of celerities is inscribed in the time variability of both the distributions, $IUH$ and $Q$

    References

    Benettin, Paolo, Nicolas B. Rodriguez, Matthias Sprenger, Minseok Kim, Julian Klaus, Ciaran J. Harman, Ype van der Velde, et al. 2022. “Transit Time Estimation in Catchments: Recent Developments and Future Directions.” Water Resources Research 58 (11). https://doi.org/10.1029/2022wr033096.

    Rigon, Riccardo, Marialaura Bancheri, Giuseppe Formetta, and Alban de Lavenne. 2016a. “The Geomorphological Unit Hydrograph from a Historical-Critical Perspective.” Earth Surface Processes and Landforms, EGU Reprint Series, 41 (1): 27–37. https://doi.org/10.1002/esp.3855.

    Rigon, Riccardo, Marialaura Bancheri, and Timothy R. Green. 2016b. “Age-Ranked Hydrological Budgets and a Travel Time Description of Catchment Hydrology.” Hydrology and Earth System Sciences Discussions, May, 1–22. https://doi.org/10.5194/hess-2016-210.

    Rigon, Riccardo, and Marialaura Bancheri. 2021. “On the Relations between the Hydrological Dynamical Systems of Water Budget, Travel Time, Response Time and Tracer Concentrations.” Hydrological Processes 35 (1). https://doi.org/10.1002/hyp.14007.

    Rigon, Riccardo, and Marialaura Bancheri. 2021b. Supplemental material of “On the Relations between the Hydrological Dynamical Systems of Water Budget, Travel Time, Response Time and Tracer Concentrations.” Hydrological Processes 35 (1). https://doi.org/10.1002/hyp.14007.


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