Engineering and the Environment

CENV6123 Coastal Flood Defence

Module Overview

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.

Module Details

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

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

Aims and objectives


Having successfully completed this module, you will be able to:

  • Know the key issues associated with understanding flood risk in coastal regions
  • Understand the policy implications of planning decisions
  • Evaluate the economics of alternate flood defence strategies
  • Determine flood risk probabilities both now and in the future due to climate change
  • Develop and interpret hydraulic models of flooding
  • Design a range of flood defence barriers

Knowledge and Understanding

Having successfully completed this module, you will 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

Subject Specific Intellectual

Having successfully completed this 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

Transferable and Generic

Having successfully completed this module, you will be able to:

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

Subject Specific Practical

Having successfully completed this 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 economic damage
  • Calculate extreme tide levels and river flow volumes
  • Perform simple hydraulic modelling with software such as HEC RAS



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.



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 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.



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.



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

Teaching and learning methods

The module consists of a series of

  • formal lectures,
  • coursework
  • lectures from visiting professionals.
  • field visits -  may include visits to Lymington, Selsey, Hayling Island, Thames Gateway.

Study time allocation:

Contact hours: 46

Independent study: 104

Total study time: 150 hours

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 methods

Assessment Method Hours % contribution to final mark Feedback
Coursework Design Exercise 1 HEC RAS modelling (DC)   20% The Coursework task will be annotated and an overview of the merit of the work will be provided on the front cover.
Coursework Design Exercise 2 Flood Defences (GM)   10% The Coursework task will be annotated and an overview of the merit of the work will be provided on the front cover.
Exam 2 hour(s) 70%

Referral Method: By examination

Method of Repeat Year: Repeat year internally. Repeat year externally.