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RIVER DYNAMICS

Academic year and teacher
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Versione italiana
Academic year
2022/2023
Teacher
EMANUELE PRECISO
Credits
6
Didactic period
Secondo Semestre
SSD
GEO/04

Training objectives

The course assumes that a river system can and should be considered both as a physical and an historical system. The "physical"part of the course studies how the system works over short periods, while the second part assesses the evolution of the system according to different time scales. The current morphology is clearly given by the combination of past and present processes, where “present” means the time span in which conditions were, regionally, stabilized around mean values. The length of this historical memory depends on the ability of the system to absorb and respond to changes. Changes depend on the sequence of past events and on the intrinsic strength of the system.

The course aims to provide the following competences:

Short and long time scales river dynamic basic processes;
Geomorphology of basins and river networks;
Fluvial discharge and main methods of measurement;
Sediment supply, fluvial sediment transport and sediment transport evaluation via mathematical equations;
The main skills acquired by students are:

Stream order classification and main river basin parameters calculation;
Use of the different techniques for water discharge estimation in the field;
Basic approach to hydraulic modelling by the use of the Hec-Ras software;
Basic approach to modelling of inflows/outflows by the use of the Hec-HMS software

Prerequisites

Fundamental knowledge acquired from the courses of Mathematical analysis (basic concepts of statistics) and Physics (units of measurement, fluid dynamics, potential and kinetic energy); good knowledge of the basic concepts acquired in the courses of Physical Geography and Geomorphology and Hydrogeology (identification of geomorphic forms and features of the landscape by the use of topographic maps and remote sensing images; knowledge of the natural processes of landscape modeling, knowledge of the basic techniques for the study, observation and monitoring of the modelling Earth's surface phenomena; the water cycle and the interactions between surface water and groundwater)

Course programme

The course consists of lectures for a total of 34 hours, during which the following topics will be covered:

Surface water hydraulic principles;
Discharge: methods and measurements instruments;
Basin and river network geomorphology;
Factors affecting river morphology;
Analysis of main river patterns;
Sediment transport;
Sediment production;
Field measurements of solid discharge and sediment supply assessments;
Sediment transport samplers;
Sediment transport equations;
Sandy bed rivers roughness elements;
Human impact and river response;
The concept of dominant discharge;
Morphological survey and bed parameterization

Field activities (6 hours) at a site to be agreed with the students during the course.

Laboratory activities:

Laboratory of sedimentology (2 hours). Students will learn the techniques of river sediments analysis and textural parameterization (wet separation, dry sieving, balance of sedimentation, sedimentation column, specific gravity measurement, organic matter content).
Laboratory of geomorphology (2 hours). Students will observe how to use the water discharge measurement equipment (Crane, sounding reels, current meter, hydrodynamic weight); the sediment transport measurements ones (suspended sediment transport sampler DH-76 bed load sediment transport sampler Helley-Smith); bed sediment sampler (sampler BMH-60).

Field Training (4 hours):

Didactic methods

The classroom lectures will be conducted with the aid of PowerPoint presentations. Training on hydraulic modeling (Hec-Ras) and hydrologic (HEC-HMS) software will be performed by the use of video presentations and will require the use of the personal laptops for each student. The activities at the Sedimentology laboratory will be performed by the lab technician (students will be in front of the equipment during the tests carried out by the technician, and may be individually called to actively participate in ongoing operations). During the activity at the Geomorphology lab, the students will be directly involved to handle the different pieces of equipment.
In absence of restrictions due to the COVID-19 pandemic, a brief field visit to a river of the Ravenna province will take place.

Learning assessment procedures

The aim of examinations is to test the level of learning achieved by the students at the end of the course. The exam consists of a written examination. The written exam, of 2 hours, consists of about 10 open questions on the topics dealt during the course. The presence of graphics or tables to comment or complete is possible. To pass the written test the students must obtain a score = 18 out of 30.

In case of an exam performed remotely, the lecturer may decide to replace the written exam with an oral examination.

Reference texts

Presentations used by the teacher during the course will be available in PDF format on the web page of the course, integrated with the notes taken in class by students.

D. Knighton, 1987, Fluvial forms and processes, Edward Arnold, London.