Learning objectives
Knowledge and understanding:
At the end of the course the student will complete the fundamental knowledge concerning flood hydrology, preparatory to the more practical courses the student will deal with in the second cycle degree in “Civil Engineering” or in “Environmental and Land Management Engineering”.
Applying knowledge and understanding:
At the end of the Course the student will be able to statistically estimate heavy rainfalls and flood discharges, to apply rainfall-runoff models and to determine steady-state flow profiles in rivers. Ultimately, the student will be able to develop a hydrological report, preparatory to river planning projects.
Making judgments:
The student should be able to understand, with critical mind, hydrological data and to critically evaluate hydrological reports.
Communication skills:
After the examination the student will have acquired a correct use of technical language and should be able to explain in a clear and convincing manner the results of hydrological data processing with the support of technical graphs, tables and texts.
Prerequisites
Some topics developed in the teaching of Hydraulics, which it is therefore advisable to have studied previously, are considered acquired,
It is useful to have a basic knowledge of Excel software.
Course unit content
Contents:
The main part of the course deals with the methodologies of flood estimation for the design of hydraulic structures and protection plans. The course topics are essential prerequisites for the following courses of Hydraulic structures, River basin management and Hydraulic plants. The last part of the course concerns steady flows in natural rivers.
Theoretical topics:
1. Probabilistic treatment of hydrologic data; statistical parameters; probability distributions and their application in hydrology. Parameters estimation: method of moments and least mean squares. Plotting of experimental data on probability charts. Return period.
2. Non-recording and recording rain gauges; rainfall information collected in the Italian hydrologic annals (part I); time scales of hydrologic processes; Italian rainfall regimes; areal rainfall estimation: Thiessen polygons, isoiethal curves, grid based methods; statistical elaborations of short duration rainfalls: point and spatial depth-duration-frequency curves; areal-reduction factors.
3. River basin main characteristics: hypsographic curve, hillside slope, shape factors, Horton-Strahler laws.
4 Excess rainfall estimation (Horton, SCS-CN and Fi index).
5 Measurements of water stages and velocities in rivers: level-gauges, current meters; discharge derivation; stage-discharge relationships; stage and discharge information collected in the Italian hydrologic annals (part II); discharge-duration curves; Characteristics of Italian rainfall regimes;
6 hydrologic cycle: control volume, processes, equations. Time-scales of main hydrological phenomena and return periods for design purposes.
7. Origins and causes of floods in natural rivers; flood hydrograph analysis, base flow separation; rainfall-runoff mathematical description. Linear models: hypotheses and limits, convolution integral, IUH theory; IUH of more than one linear model in series and/or in parallel. Conceptual models: hypotheses and equations; IUH for the linear reservoir model, Nash model, time-area method; parameter calibration of linear models: method of moments and least mean squares.
8. Direct methods and regional analysis; indirect methods based on rainfall-runoff models, critical rainfall duration; empirical formulas and order of magnitude for the main Italian rivers.
9. Mild and steep slope channels; sub- and supercritical flows. Hydraulic jump and its location. Classification and analysis of flow profiles in prismatic channels and natural rivers; abrupt channel transitions: flows through contractions and bottom humps.
Exercises:
1. Estimation of depth-duration-frequency curves
2. Baseflow separation techniques and excess rainfall estimation.
3. Calibration of a two/three parameters linear rainfall-runoff model by moments and least squares methods. Discharge estimation via discrete convolution equation.
4. Annual peak and/or annual maxima daily discharges analysis and estimation.
5. Hydraulic profile evaluation on a prismatic channel via direct-step method with subcritical and supercritical flows, hydraulic jump localization.
Full programme
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Bibliography
Main:
Slides presented during lessons, video recordings of the lessons, class notes, text and data to develop the exercises (Available at http://elly2021dia.unipr.it)
For further information:
Maione U., “Le piene fluviali”, La Goliardica Pavese, 1995 (Available in Library).
Moisello U., “Idrologia Tecnica”, La Goliardica Pavese, 1998 (Available in Library).
Citrini D., Noseda G., "Idraulica", Ed. CEA 1987 (Available in Library)
Teaching methods
The course is divided into:
-a series of face-to-face lessons, making use of the projection of slides, with the possibility of remote use in asynchronous mode (video lessons loaded on the Elly page of the course).
-a series of exercises carried out in the computer room on an electronic computer with the help of Excel software.
Assessment methods and criteria
At least two weeks before the exam, the student must send the teacher the (electronic) notebook of the exercises carried out during the course.
Verification of preparation consists of an oral interview in person (or remotely via Teams, should it become impossible to carry out the exams in person) during which the student will be asked two / three questions on topics covered in the lessons / exercises. The student will have to demonstrate that he has assimilated the main technical concepts and terms, that he is able to analyze problems similar (even if not identical) to those developed during the course, that he has clear orders of magnitude and that he has sufficient language properties . The student should also be able to make the necessary connections with other disciplines (mathematics, physics, hydraulics).
Verification is weighted as follows:
-25% exercise book
-45% theoretical questions (knowledge),
-15% exposure properties (communicative skills),
-15% original applications of the theory (independent judgment)
Other information
web site at:
http://elly2021.dia.unipr.it
