Hydrology and irrigation systems for agriculture

A.Y. 2021/2022
Overall hours
Learning objectives
To learn about the main hydrological processes, the quantities that characterize them, the instrumentation and technologies for their measurement. To learn methods of investigation and monitoring techniques to describe the dynamics of water fluxes in the soil-crop-atmosphere system, in order to be able to estimate the irrigation requirements and schedule irrigation events in a rational way. To learn methods of investigation and monitoring techniques to characterize high intensity precipitation events and to describe processes of flood generation, for the design of hydraulic defense structures and river restoration interventions. To learn about collective and on-farm irrigation systems, with particular attention to high-efficiency irrigation systems (sprinkler and micro-irrigation). To explore the different components of on-farm irrigation systems and their management and maintenance. To investigate the criteria for choosing the proper irrigation method and system in the various environmental conditions. To learn about the general and hydraulic design of on-farm irrigation systems and the evaluation of their irrigation efficiency.
Expected learning outcomes
The student will develop expertise related to the acquisition and analysis of meteorological and hydrological data; to the use of GIS software for the processing of spatial information at the farm and territorial scales; to the implementation of a dynamic water balance model for the simulation of the soil-crop-atmosphere system and its use for the scheduling of irrigation events; to the implementation of a dynamic model for the estimation of the flood hydrogram at the closing section of a hydrographic basin and its use for the design of hydraulic defense structures and river restoration interventions. Moreover, the student will be able to find and process data needed for the design of on-farm irrigation systems, to perform the general and hydraulic design of the systems, also using calculation and GIS/CAD tools. The student will acquire skills for assessing technical and economic implications of the project implementation, and will be able to consult technical and scientific material concerning the irrigation sector.
Course syllabus and organization

Single session

Lesson period
Second semester
The teaching method may vary depending on the state of the COVID-19 health emergency. For both the UDs (UD1 and UD2) the frontal lectures alone (3 CFU) or also the practical lessons (3+1 CFU) could be conducted through distance teaching methods (through MS Teams). The course lecturers will be responsible for informing the students on the ways in which the lessons will be carried out well in advance of the beginning of the 2nd semester.
Course syllabus
3 CFU (Frontal lessons) - Study of the hydrological cycle and basis of hydrological processes such as precipitation, rainfall interception, evapotranspiration, infiltration and percolation. Methods of physical and mechanical soil analysis and study of soil hydrological properties. Analysis of water movements in saturated and unsaturated soils. Measurement of the main hydrological variables. Calculation of crop water and irrigation needs and irrigation scheduling (irrigation amount and frequency). Estimation of the hydrological balance at a field scale. Statistical analysis of the extreme hydrological events. Calculation of the river discharge duration curves. Assessment of project precipitation. Calculation of hydrological losses using models based on Horton or on Curve Number. Evaluation of the critical rainfall duration. Analysis of runoff processes. Evaluation of the river catchment peak of discharge through rational method, lag-time method and statistical analysis of observed flows.
1 CFU (Practicals in computer lab) - Calculation of crop water needs according to FAO-56 method for different crops and soils, assessment of the irrigation water need at the irrigation district scale (8 hours). Estimation of the river peak discharge under conditions of different rainfall return time and land use changes (8 hours).
3 CFU (Frontal lessons) - Irrigation systems (irrigation intake structures; supply and distribution networks; irrigation methods; drainage networks; irrigation service). Gravitational irrigation methods. Pressurized irrigation methods and systems: sprinkler irrigation with static irrigators and irrigation machines. Pressurized irrigation methods and systems: micro-irrigation (drip irrigation and micro-sprinklers). Advantages and limitations of gravitational, sprinkler and micro-irrigation methods. Theoretical efficiency of irrigation methods and systems. Hydraulic and technological characteristics of irrigators (sprinklers) and micro-irrigators (drippers and micro-sprinklers). Uniformity of distribution. Main components of pressurized systems: pumping group, water quality and filters, pressure reducers, special components, automation components, fertigation systems. Fundamental concepts for the irrigation scheduling: evapotranspiration, hydrological balance in agricultural soils and crop irrigation requirements. Irrigation scheduling: how to determine the amount and frequency of irrigation events with the different irrigation methods. Preliminary design of pressurized irrigation systems. Hydraulic design of pressurized irrigation systems. Examples of calculation.
1 CFU (Practicals in computer lab) - Preliminary and hydraulic design of a drip irrigation system for a maize farm, with the support of a spreadsheet with the implementation of all the main calculation steps, and using GIS and CAD software.
Prerequisites for admission
In order to successfully follow the course, students should meet the following requirements: (a) good basis of hydraulics; (b) good familiarity with personal computers (Windows environment, word processing and spreadsheets).
Teaching methods
Both UDs are articulated into 3 CFU of frontal lectures (24 hours) and 1 CFU of practicals in a computer lab (16 hours). During the computer classroom training hours, the following software will be mainly used: Excel (spreadsheets with the implementation of calculation procedures), QGIS, CAD, Matlab. The attendance at lectures and practicals is strongly recommended. Missed lessons can be substituted by self-study using the reference material indicated by the course lecturer.
Teaching Resources
· Lecture notes available on line (http://ariel.unimi.it)
· Ferro V. (2006). Elementi di idraulica e idrologia per le scienze agrarie ed ambientali. Mc Graw Hill
· Moisello U. (1998). Idrologia tecnica. La Goliardica Pavese.
· Maione U. - Moisello U. (1993). Elementi di statistica per l'idrologia. La Goliardica Pavese.
· MIPAAF - Paolo Sequi/Marcello Pagliai. Metodi di analisi fisica dei suoli. FrancoAngeli
The material for the course is available on the ARIEL site, and consists of the slides shown during the lectures and of supplementary material, such as reference to book chapters, text of laws, scientific and technical papers and documents, websites. The reference textbook for the course is: PROGETTAZIONE E GESTIONE DEGLI IMPIANTI DI IRRIGAZIONE - Criteri di impiego e valorizzazione delle acque per uso irriguo. Antonina Capra e Baldassarre Scicolone. Edagricole Editore, 2016.
Assessment methods and Criteria
UD1: HYDROLOGY - The exam consists of a short, written test (15 min) with multiple choice questions, the passing of which gives access to the oral exam. The latter mainly focuses on the discussion of a report on the tasks assigned during the practicals in the computer lab; the report must be drawn up individually or in pairs and delivered within the deadline for registering for the exam. The final evaluation will be the sum of the evaluations of the written test (max 5 points), the report (max 10 points) and the oral exam (max 15 points). The outcome of the written test, that will be communicated short after its conclusion, is valid only for the appeal in which it is taken.
UD2: IRRIGATION SYSTEMS FOR AGRICULTURE - The exam consists of a written test and an oral test. It is more precisely articulated as follows: (a) written test with 2 exercises to choose from 3 assigned (2 hours); (b) written report of the practical exercise carried out in the computer lab (project of the drip irrigation system), to be submitted by the exam registration date; (c) if the student has passed the written exam, oral test aimed at discussing the two previous points and at exposing the theoretical parts of the course not covered by the written test or the report. The three issues will constitute respectively 1/3, 1/3, 1/3 of the final grade. Consultation of supporting materials (slides, notes, textbooks, etc.) will not be allowed during the written test. The result of the written test will be communicated to the students by uploading on the ARIEL website of the course a document containing the candidates' matric numbers and the exam results. During the oral exam the student will be allowed to consult both the written report and the selected scientific article.
The following aspects will be assessed during the exam for both UD1 and UD2: acquired knowledge, level of understanding, reasoning and connection skills, communication skills using appropriate sector terminology, ability to organize a detailed and effective technical document.
The final grade (UD1 + UD2) will be computed as the average those obtained for the single UDs.
Computer room practicals: 16 hours
Lessons: 24 hours
Professor: Gandolfi Claudio
Progettazione e gestione degli impianti di irrigazione
Computer room practicals: 16 hours
Lessons: 24 hours