Engineering and the Environment

CENV6123 Coastal Flood Defence

Module Overview

Knowledge and understanding
Having successfully completed the module, you should be able to demonstrate knowledge and understanding of:

  • Coastal flooding and defence management issues.
  • Frequency analysis of extreme events. Economic evaluation of flood damage.
  • Hydraulic modelling of channels and simple structures such as gates and weirs.
  • Role of regulatory agencies in the UK (DEFRA, Environment Agency, Local Authorities).
  • Types of flood defences, choice of and design of defence types. Other management options such as managed retreat.

Intellectual skills
Having successfully completed the module, you will be able to:

  • Assemble knowledge on flood defence and management strategies.
  • Select appropriate strategies for coastal management and flood defences.
  • Perform economic and hydraulic calculations.
  • Select suitable flood defence structures.
  • Demonstrate through the design exercise a coherent understanding of techniques
  • Demonstrate ability to work with quantitative and qualitative models
  • Analyse data using appropriate processes
  • Review coastal management options

Practical skills
Having successfully completed the module, you will be able to:

  • Build simple computer based hydraulic models
  • Carry out economic evaluation of flood damage
  • Specify appropriate flood defence strategies
  • Analyse existing data and apply this in a design exercise.
  • Appraise flood risk both qualitatively in terms of extent and quantatively in terms of flood depths and ecomomic damage
  • Calculate extreme tide levels and river flow volumes
  • Perform simple hydraulic modelling with software such as HEC RAS

Key skills

  • Problem analysis and problem solving
  • Numeracy and modelling
  • Communicate effectively
  • Accuracy of problem analysis and problem solving

Module Details

Title: Coastal Flood Defence
Code: CENV6123
Year: 4
Semester: 2

CATS points: 15 ECTS points: 7.5
Level: Postgraduate
Co-ordinator(s): Dr Derek Clarke

Pre-requisites and / or co-requisites

1 . Students taking this module MUST have taken CENV 6084 "Maritime and Coastal Engineering and Energy". 2. Students undertaking this module also need to understand Hydraulics equivalent to Part2 Civil Engineering CENV 2008 (ie open channel flow up to and including critical depth, water surface profile evaluation, knowledge of spreadsheet software to solve expressions such as Manning’s equation.)

Programmes in which this module is compulsory

ProgrammeUCAS CodeProgramme length

Aims and objectives

This Module will introduce you to the range of skills needed in planning, managing and designing coastal defences. These skills vary from "hard" engineering to the "softer" issues of managed retreat and environmental impacts of sea level change. This module will describe current thinking and techniques used in maintaining and managing our coastline, examining the approaches used in the UK and elsewhere. The course will comprise a combination of lectures design studies, computer modelling exercises and if time and weather permit, some field visits.

Syllabus

INTRODUCTION TO COASTAL FLOODING
Overview of coastal issues. Suddenness, damage caused by saltwater and river water. Examples/case studies. Current “state of the art” and “issues” in the UK. Existence of flood risk, numbers likely to be affected. Types of flooding. Environmental impacts e.g. salt intrusion into estuaries, likely impact on sensitive areas. Planning approaches used in flood defence . Foresight implications / Making Space for water/Coastal squeeze – Shoreline Management Plans. Risk Assessment for Strategic Planning (RASP). Role of the Environment Agency, DEFRA. Economic and Financial Analysis of flood damage.

HYDRAULICS AND MODELLING
Frequency analysis of extreme tidal and river flood events. Impact of sea level rise on flood frequency, tidal locking, increased winter river runoff. River outlets into the sea. Description of structures such as gates, culverts, weirs. Control points and critical depth. Gradually varied flow and flow profiles, non-steady flow, tides and hydrographs. Design Exercise Task 1 : Modelling water levels in rivers and estuaries to investigate the impact of sea level rise and river floods at vulnerable sites. Identification of required elevation of flood defences using HEC RAS computer software.

FLOOD DEFENCES
Flood protections structures (2 hrs) a) Earth structures b) Wave recurves. Tsunamis and Tsunami Engineering (4 hrs). Numerical and Physical models in coastal engineering design (2 hrs). Design Exercise Task 2 : choice of appropriate sea defences.

DESIGN EXERCISE
A town on the south coast of England with a known flood defence problem will be used as a case study. You will review existing flooding problems where a combination of tidal and river flood conditions exist as a series of coursework tasks. You will carry out modelling and design of existing and new flood defences and gated outlet structures, investigate existing and future flood risk and select new flood defences.
The case study will include :-
1. Review of historic flood damage.
2. Understanding the existing tidal gate system, measurement of tidal levels, river flows.
3. Simulating behaviour of outlet gates with existing tides.
4. Statistical analysis of extreme tide levels, estimation of flood hydrographs
5. Use of HEC RAS to simulate non steady flow behaviour of existing gates.
6. Calculation of extreme tide and pond levels and comparison with existing defences
7. Modelling the effect of sea level rise.
8. Estimation of the effect of sea level rise on flood economic impact.
9. Design of sea walls to protect against tidal flooding. Levels, Wave actions.

FIELD VISITS and GUEST LECTURES
Weather and time permitting, various half day visits will be made to local and regional sites to illustrate problems and solutions.
Engineers, planners and managers may give occasional guest lectures explaining current thinking and methodology in Coastal Engineering.

Learning and teaching

Study time allocation

Contact hours: 50
Private study hours: 100
Total study time: 150 hours

Teaching and learning methods

The module consists of a series of formal lecturess, a Design Exercise assessed by three pieces of coursework and lectures from visiting professionals.
Field visits - To be confirmed but these may include visits to Lymington, Selsey, Hayling Island, Thames Gateway.
Visiting Lectures - Details to be confirmed.
Lectured topics
INTRODUCTION TO COASTAL FLOODING HYDRAULICS AND MODELLING
FLOOD DEFENCES
DESIGN EXERCISE. This will be used to apply the knowledge learned in the lectures and apply it to a Case Study site in Southern England where a potential flooding problem exists and sea defences need to be re-evaluated in the light of sea level rise. It will include problem scoping, modelling and design. The Design Exercise will be assessed by a series of linked coursework tasks associated with the lectured part of the module.

Resources and reading list

You will be given handouts during the lectures. You do not have to buy a specific book, but you will learn much more if you obtain one of the books from the recommended book list, several of which are available in the Library. An e-book on Design in the Fluvial Environment will be made available on Blackboard.

Assessment

Assessment methods

Assessment method contribution to final mark
Design Exercise 1 HEC RAS modelling (DC) 20%
Examination 70%
Design Exercise 2 Flood Defences (GM) 10%