Lecturer: Ugo Moisello  

Course name: Idrologia
Course code: 062131
Degree course: Ingegneria per l'Ambiente e il Territorio, Ingegneria Civile
Disciplinary field of science: ICAR/02
The course relates to:
University credits: CFU 6
Course website: n.d.

Specific course objectives

The course is aimed to give the knowledge necessary to cope with the hydrological problems more often met with in engineering practice: analysis of water availability and analysis of floods. The course gives also the basics of statistics necessary to design the waterworks in accordance with an assigned risk level.

Course programme

Lessons (the length of a lesson is two hours)
1.Introduction to the course. Origin and classification of precipitations. Thunderstorms, hurricanes. The factors of the rainfall regime. Italian rainfall regimes./ 2.Rainfall gauges. Published rainfall data. Computation of the catchment input into the catchment./ 3.Random variables, probability and related axioms, probability function and probability density function./ 4.The catchment: definition and main characteristics. Various flow types. Concentration time./ 5.Parameters of probability distributions, moments. Variables which are functions of random variables. Return period. Binomial distribution./ 6.Catchment losses and different types of water storage. Depression storage (basics). Dalton’s law. Factors affecting evaporation. Evaporation measurement. Different types of evaporation. Evapotranspiration and potential evapotranspiration. Infiltration (basics)./ 7.The normal distribution and other continuous variable distributions./ 8.The practical determination of losses./ 9.The inference problem. Frequency, sample moments. Estimation of the probability function. Probability charts. Parameter estimation. Method of moments./ 10.Discharge and water stage. Staff gauges and water-stage recoders. Current meters. Discharge computation from velocity measurements./ 11.Tests of hypotheses. Pearson’s goodness-of-fit test./ 12.The streamflow regimes of Italian watercourses. Published streamflow data./ 13.Visual illustration, by means of slides, of instruments and methods for hydrological measurements./ 14.Different types of statistical analyses of floods. At-site analyses. Relationship between yearly maxima of peak and daily mean discharge. The distribution of the maximum discharge in N years./ 15.Rainfall depth-Area-Duration curves./ 16.Design hyetographs./ 17.The rainfall-runoff process. Mathematical models and simple relationships. The rational method. Conceptual and black-box models. Complete models and flood models. The determination of storm runoff and effective rainfall./ 18.Linear and stationary systems. The instantaneous unit hydrograph. Applications of the instantaneous unit hydrograph to the effective rainfall-storm runoff process. The discrete instantaneous unit hydrograph./ 19.Linear stationary models in series and in parallel. The kinematic model. The single linear reservoir model and the Nash model./ 20.Model choice and parameter estimation. The least squares method and the method of moments.

Laboratories (the length of a laboratory unit is two hours)
1 (one unit). The estimation of the peack discharge with a given return period by means of Gumbel’s distribution./ 2 (two units). The estimation of the peack discharge with a given return period by means of three different distributions and the estimation of the probability distribution of the maximum peack discharge in a period of N years./ 3 (one unit). The determination of the rainfall depth-duration-frequency curve./ 4 (one unit). The determination of the rainfall depth-duration-frequency curve and of design hyetographs of mean areal rainfall./ 5 (one unit). The determination of the instantaneous unit hydrograph of a conceptual model by the method of moments and the computation of the flood hydrograph./

Course entry requirements

MATHEMATICAL ANALYSIS: Concepts of function, limit, derivative, integral. Combinations. The concept of differential equation (particularly, linear with constant coefficients). The concepts of funtion of more than one variable, partial derivative and partial derivative differential equation. Unconditioned maximum of a function of one or more variables. Practical knowledge: computation of simple derivatives and integrals and use of of mathematical tables of limits, derivatives, integrals and definite integrals. GEOMETRY AND ALGEBRA: Basics of trigonometry. Two- and three-dimensional elementary analytical geometry. The concept of linear and non linear scale. Matrices and systems of linear equations. Practical knowledge: elementary applications of trigonometry and geometry (area computation included). Grahic representation of functions, also with non linear (particularly, logarithmic) scales. PHYSICS: Measurement of physical magnitudes and units of measurements. Basics of matter states of aggregation and physical properties of bodies (density, viscosity, capillarity).

Course structure and teaching

Lectures (hours/year in lecture theatre): 40
Practical class (hours/year in lecture theatre): 12
Practicals / Workshops (hours/year in lecture theatre): 0
Project work (hours/year in lecture theatre): 0

Suggested reading materials

V.T. Chow, D.R. Maidment, L.W. Mays. Applied Hydrology. New York, Mc Graw-Hill Book Company, 1988.

R.K. Linsley,M.A. Kohler , J.L.H. Paulus. Applied Hydrology. New York, Mc Graw-Hill Book Company, 1949.

U. Maione, U. Moisello. Elementi di statistica per l'idrologia. Pavia, la Goliardica Pavese, 1993.

U. Moisello. Idrologia tecnica. Pavia, La Goliardica Pavese, 1998.

Testing and exams

Two written tests are given during the term (one at half term, the other at the end). The average of the two marks, if sufficient, can be adopted as final mark (in this case the two written tests are equivalent to the final exam). If the average mark is not sufficient, an oral exam has to be taken by the student. If only one of the two written tests is sufficient, the student can take the exam only on the subjects of the failed test, and the final mark is the average of those of the successful test and of the passed oral exam. The student can always give up the results of the written test and take an oral exam on all the subjects of the course.