Institution: DICAR (UNIPV)

Major: HYRIS

Term: 1^st Semester

Instructors: Paolo Ghilardi (ghilardi@unipv.it), Andrea Fenocchi (andrea.fenocchi@unipv.it)

CFU: 6

SSD: ICAR/01

Duration: available here

Schedule: available here

Office hours: by e-mail appointment

OBJECTIVES

The first part of the course is focused on the basics of hydraulics of natural streams, solid transport mechanics and related hydrodynamic processes. In the second part, students will learn how to deal with the one-dimensional modelling of an extended real river reach using software as HEC-RAS, QGIS, Excel.

DESCRIPTION

1. Basics of natural stream hydrodynamics: turbulence, secondary currents, velocity and bed shear stress distributions in steady and unsteady non-uniform flow. Hydrodynamic forces on grains, threshold of sediment motion: dimensionless critical bed shear stress and velocity, nonuniform grain size distribution. Bed-load transport: basic concepts and empirical relationships involving bed shear stress and other flow variables. Bedforms: models for the prediction of bedforms, resistance to flow due to bedforms, methods for stress partitioning. Suspended-load transport: diffusion concept, vertical distribution of sediment concentration in equilibrium and non-equilibrium conditions, threshold of sediment suspension. Total-load transport. Transport of non-uniform sediments. Non-equilibrium transport and bed evolution.

2. Interpretation and processing of GIS and tabular topographical data. Definition of a river centreline and of cross sections. Determination of the roughness coefficients and critical assessment of available methodologies for their estimation. Setup of bridges and inline structures within HEC-RAS. Using preliminary simulations to identify and solve model flaws through comparison against theoretical River Hydraulics. Setup of low-flow and flood simulations through proper boundary conditions. Sensitivity analyses on roughness coefficients and boundary conditions. Interpretation and processing of model results and comparison against field observations and results from other models. Directions for the preparation of a technical report on a river modelling study.

REQUIREMENTS

Basic knowledge of hydraulics and fluid mechanics. Basic knowledge of QGIS and Excel.

REFERENCES

• Dey, S., Fluvial Hydrodynamics: Hydrodynamic and Sediment Transport Phenomena, Springer-Verlag, 2014
• HEC-RAS User and Hydraulic Reference manuals
• Course notes, scientific papers and other material will be provided during the course and made available for download

ASSESSMENT

Final oral exam awarding up to 30 points, including discussion on both parts of the course. Preparation of a written technical report on the case study analysed during the second part of the course is mandatory. Such report should be submitted a reasonable time before the oral exam, inside which it will be discussed, and will be awarded up to 4 further points if the exam is taken at the end of the course. Total awarded points are hence up to 34, overall marks equal or above 32 being granted the 30 cum laude final grade.