CENV6164 River Engineering
Module Overview
Rivers and estuaries provide people with food, water, energy, communication paths and ports. However, they can also cause major damage through flooding. Understanding and engineering rivers is thus immensely important. River beds are composed of granular material that can be displaced by the water flow and transported from one location to another. Quantitative prediction of sediment erosion and accumulation rates is crucial for many applications in Civil and Environmental Engineering, including dam silting and bridge scouring, to name just a few. Furthermore, fluvial sediment transport can result in the formation of large bed-forms (e.g. ripples, dunes), which, along with the aquatic vegetation present in many natural streams, need to be accounted for in order to quantify flow resistance, which is of great relevance when designing river embankments to contain flood events. This module covers aspects of fluid and sediment mechanics that will allow you to critically assess the stability of a river bed and effectively design a variety of river engineering works.
Aims and Objectives
Learning Outcomes
Knowledge and Understanding
Having successfully completed this module, you will be able to demonstrate knowledge and understanding of:
- Qualitative behaviour of river and estuarine dynamics (e.g. river meanders)
- Relevant hydrodynamic equations of open channel flows
- Sediment transport mechanics and modelling approaches
- Design notions of the most common river engineering works
- Numerical models used in river engineering
Subject Specific Intellectual and Research Skills
Having successfully completed this module you will be able to:
- Critically analyse the fundamental equations of fluid dynamics and appreciate how they relate to approximate equations commonly employed in the study of open channels
- Appreciate the importance of bed shear stress in open channels, particularly in connection to sediment transport
- Identify the coupling between turbulence and sediment dynamics in fluvial environments
- Utilise the principle of sediment-mass balance to predict the evolution of the river bed (morphodynamics)
- Identify the most appropriate theoretical and practical tools for solving a given problem of engineering interest in rivers
Transferable and Generic Skills
Having successfully completed this module you will be able to:
- Problem analysis and problem solving
- Team work
- Report writing
- General theory of fluid dynamics
- Knowledge on numerical modelling
Subject Specific Practical Skills
Having successfully completed this module you will be able to:
- Determine river bed/banks stability and propose diverse alternatives for river training
- Quantify bed-form and grain roughness effects on flow resistance
- Identify different modes of sediment transport and quantify their rates as functions of hydraulic variables
- Estimate the rate of siltation in a given dam
- Critically assess local and general scour around bridge foundations
- Use numerical models to predict the morphological evolution of a river
- Use numerical models to assess the impact of flood events and dam breaks
- Exercise technical judgement and make decisions
- Carry out and present engineering calculations
Syllabus
INTRODUCTION Historic importance of rivers and estuaries; General overview of rivers in the world; Qualitative behaviour of the river-estuary system; Classification of rivers. OPEN CHANNEL HYDRODYNAMICS Revision of basic concept of fluid dynamics (e.g. conservation laws, viscosity, drag, etc.); Basic equations of fluid dynamics (Navier Stokes) and their useful simplifications for open channels (e.g. the Shallow Water equations); The velocity profile; Introduction to turbulence; Bed shear stress; Steady and unsteady flow. SEDIMENT TRANSPORT Modes of sediment transport (bedload and suspension); Key sediment parameters (diameter, grain size distribution, etc.); Fundamental mechanics of sediment motion; Initiation of motion (Shields criterion); Empirical estimates for sediment transport rates; Bedforms; Sediment transport modelling; Suspended sediment concentration (the Rouse profile); Bed evolution modelling (Exner equation). RIVER ENGINEERING WORKS River training; Design of stable channels; Water level control; Introduction to ecohydraulics and ‘green engineering’; Dam siltation; Bridge pier and abutment scour; Flood control; Introduction to river navigation and hydropower; Dam break. NUMERICAL MODELLING Overview of numerical modelling in river engineering; Introduction to numerical modelling (finite differences); Discussion of different mathematical models and their pros & cons (steady vs unsteady, 1D vs 2D vs 3D, fixed vs mobile bed, etc.); Overview of available free and commercial software for river engineering; Computer labs.
Learning and Teaching
Teaching and learning methods
The module consists of conventional lectures, computer labs (tutorials on numerical modelling), one hydraulic laboratory session and occasional lectures by guest speakers.
| Type | Hours |
|---|---|
| Wider reading or practice | 25 |
| Completion of assessment task | 20 |
| Lecture | 36 |
| Independent Study | 50 |
| Tutorial | 4 |
| Follow-up work | 15 |
| Total study time | 150 |
Resources & Reading list
Graf W. H. (1971). Hydraulics of Sediment Transport.
Tritton D.J. (2007). Physical Fluid Dynamics.
MaysL.W (2001). Water Resources Engineering Wiley.
Assessment
Formative
Laboratory Assignment
Summative
| Method | Percentage contribution |
|---|---|
| Coursework | 20% |
| Exam | 70% |
| Quizzes (10 minutes) | 10% |
Repeat
| Method | Percentage contribution |
|---|---|
| Exam | 100% |
Referral
| Method | Percentage contribution |
|---|---|
| Exam | 100% |
Repeat Information
Repeat type: Internal & External
Linked modules
Pre-requisite: CENV2008