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 attend 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 will be able to understand hydrological data and critically evaluate hydrological reports.
Communication skills:
After the oral examination, the student will have acquired a correct use of technical language, clearly presenting the results of hydrological data processing with the support of technical graphs, tables and texts.
Prerequisites
Some topics described in the courses of Mathematical Analysis and 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
The course mainly deals with the methodologies of flood estimation for the design of hydraulic structures and protection plans. The topics of the course, which represents the natural evolution of that of Hydraulics (of which it requires part of the knowledge), are essential prerequisites for the following courses of Hydraulic infrastructures, River basin management and Hydraulic plants.
Theoretical topics:
1. Statistical hydrology
2. Precipitation
3. River basin characteristics
4. Hydrometry
5. Hydrological processes
6. River floods
7. Direct methods and regional analysis of river floods
8. Uniform and steady free surface flows
Exercises
Carried out in the computer room using some software (Excel, Matlab, QGIS).
Full programme
The course mainly deals with the methodologies of flood estimation for the design of hydraulic structures and protection plans. The topics of the course, which represents the natural evolution of that of Hydraulics (of which it requires part of the knowledge), are essential prerequisites for the following courses of Hydraulic infrastructures, River basin management and Hydraulic plants.
Theoretical topics:
1. Statistical hydrology. Discrete and continuous random variables; elaboration of data series. Extreme value 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. Precipitation. 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; statistical elaborations of short duration rainfalls: depth-duration-frequency curves; areal-reduction factors.
3. River basin characteristics. Hypsographic curve, hillside slope, shape factors, Horton-Strahler laws.
4. Hydrometry. Measurements of water depths and velocities in rivers: level-gauges, current meters; discharge derivation; stage-discharge relationships; information collected in the Italian hydrologic annals (part II); discharge-duration curves; Italian rainfall regimes;
5. Hydrological processes. Control volume, hydrological processes: interception, evapotraspiration, infiltration, surface runoff.
Water balance equation.
6. River floods. Characteristics and causes; 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.
7. Direct methods and regional analysis of river floods. Direct statistical analysis; index flood; indirect methods based on rainfall-runoff models; critical rainfall duration; empirical formulas.
8. Uniform and steady free surface flows. Chezy equation; specific energy; roughness coefficients; mild and steep slope channels; sub- and supercritical flows; momentum equation; hydraulic jump and its location; classification and analysis of flow profiles in prismatic channels and natural rivers; abrupt channel transitions: flows under gates and through contractions and bottom humps.
Exercises:
1. Estimation of the depth-duration-frequency curves.
2. Evaluation of the river basin features using a GIS tool.
3. Precipitation surface generation; baseflow separation techniques and excess rainfall estimation.
4. Estimation of the areal reduction factors for a given river basin.
5. Calibration of a two parameters linear rainfall-runoff model using moments and least squares methods. Discharge estimation via discrete convolution equation.
6. Annual peak and/or annual maxima daily discharges analysis and estimation; fitting of an extreme value distribution.
7. Hydraulic profile evaluation on a prismatic channel via direct-step method with subcritical and supercritical flows and hydraulic jump localization.
Bibliography
Main:
Slides presented during lessons, text and data for solving the exercises (Available at http://elly2022.dia.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 consists of:
-a series of face-to-face lessons (56 hours), making use of the projection of slides;
-a series of exercises (24 hours) carried out in the computer room using some software (Excel, Matlab, QGIS).
Assessment methods and criteria
At least ten days before the date of the exam session, the student must send the teacher a report describing the exercises carried out during the course and their results.
Verification of preparation consists of an oral interview in person (or remotely via Teams if the University will provide directives stating the impossibility of carrying out the exams in person) during which the student will answer two / three questions on topics covered in the lessons / exercises. The student will have to demonstrate that he/she: (i) has learnt the main technical concepts and terms, (ii) is able to analyze problems similar (even if not identical) to those developed during the course, (iii) knows the orders of magnitude and (iv) has adequate language skills. The student should also be able to make the necessary links with other disciplines (mathematics, physics, and hydraulics).
Verification is weighted as follows:
-25% exercises report
-45% theoretical questions (knowledge)
-15% communicative skills
-15% applications of the theory (independent judgment)
Other information
web site at:
http://elly2022.dia.unipr.it
