Khatibi lecture cov.uni

Introduction to Computer-based Flood Risk Modelling in the UK and Overseas –

Coventry University

• Visiting Lecturer on• Catchment Hydrology, Hydraulics and River Flood Modelling• Coventry University

Dr Rahman KhatibiGTEV-ReX29 November 2016

For the best outcome, you may download the presentation and run it in the slide show mode.

• Outputs of construction Industry: – In 2014 the turnover was £115 Bn– In 2013, the UK GDP of £1.6 Tn– So the turnover was 7% of the GDP

• Development Projects: – Facilitated by a planning system– Run by Local Planning Authorities (LPA) of Local Authorities– “Decision-making by participation”– The system is plan-led through National Planning Policy

Framework (NPPF)• Scope of Planning by LPA in the year ending June 2014:– granted 350,200 permissions– 88% of decisions ended up by granting permission

1. Setting the scene (1)

Environment Prudent use of natural resources and effective protection of the

environment

SocietySocial progress which

recognises the needs of everyone

Economy Maintenance of high and stable levels of economic growth and employment

1. Setting the scene (2)

Sustainability Market-pulled Hydraulic Systems Science-pushed Educational Topics

• Water supply systems• Water treatment works• Reticulations systems• Rising mains• Gravity mains

• Irrigation drainage• Irrigation supply systems

Market-pulled: water systems:

• Flood Risk Management systems• Erosion/sediment problems• Water quality problems

• Drainage systems• Sewerage systems• Sewage treatment works• SuDS• Other drainage systems

Modelling Bridges the gap

• Pipes: rigid, elastic• Control valves• Intakes/reservoirs • Surge suppression units• 2D Floodplains• HD Rivers/• Diffusion Analogy• Kinematic waves• Discharge routing• Reservoirs• A host of control units• Inflows/outflows• Hydrological cycle• Hydrology• Modelling software

1. Setting the Scene (3)

Science-pushed:Hydraulics /hydrology

•Basic concepts •Conservation of momentum•Conservation of mass •Forces, hydrostatics•Pipe flows•Pipe control units•Boundary layers•Fluid machines•Open channel flows•Control in O.C.•Sediment transport•Groundwater flows•Flood estimation •River Engineering•Coastal engineering•Modelling•Modelling software

Computer-based Flood Risk Modelling - summary

Setting the scene1. Outline history of modelling2. Purpose/needs3. Types of modelling• A full overview• Model building• Information contents

4. Steady/unsteady conditions5. Functions and usage of models6. Business drivers for modelling

2. Outline history of modelling

•Advent of Computers•Rise of software engineering•Increasing data•Modelling practice

Fundamental thinking of 18th-19th CenturyIntellectual Capital of hydraulic Traditional component hydraulics

Tapping on the intellectual capitalBy a fury of simplified methods • Empirical hydraulics

• Design and operations• Hydrology

• Component analysis

18th-19th

Century

1900

19501960

1980

1990

2000

Beck: risk increasing

Intelligent clients

ModellingModelling and

modelling

Emergence of flood risk management

Turbulence modelling3D

2D1DData driven models

• Models are tools for decision-making• Without models: solutions at risk of being arbitrary, ad hoc• With models: solutions can be defensible

Without models: the onus is on you With the models: the onus is on the models and on modelling practices

• Model defensibility: models must be defensible by:– Employing best practice– Having systematic checks by independent modellers– Putting in place QA procedures and TQM

2. Purpose/needs

3. Overview of types of modelling (1)

Considering Flooding Risk from all sources

•0D

•1D

•1D+

•2D-

•2D

•2D+

•3D

Surfacewater models

Fluvial models(channels + floodplains

Coastal models(tides + surges)

Meteorological modelsGlobal, regional, local

Groundwater models

Sewers models

Reservoir failures models

Hydrologicmodels

Erosion

Data

Remote sensingSpace scale

Time scale

Survey dataSurvey data

LiDAR

Gauges

Modelling systems

ModularityInterfaces

Time scale

Space scale

Trigger eventsOvertopping Breaching

BlockageInundation

Land use

RuralUrban

Greenfield

Semi-urban

Brownfield

New development

Flow regimesSubcriticalSupercritical

Kinematic Role waves

Data-driven models•Regression,•Machine-learning•AI (ANN, GA, GEP, FL) Distributed Models

•Design modelling •Real-time forecasting•Flood modelling•Low-flow modelling•Operations modelling

01/05/2023 University of Glamorgan: - Rahman Khatibi

1D Reservoir

Medium Resolution

2D Domain 22D Domain 3

Low Resolution

Contours

Extended 1D Sections

Contours

High Resolution

2D Domain 1

Embedded 1D Model

Flood Relieve

Channels

Road

Schematise and divide the system into domains

3. Types of modelling – model Building (2)

Hydraulic Units• Basic concepts• Forces – conservation of

momentum• Storage – conservation

of mass• Pipes: rigid, elastic• Control valves• Intakes/reservoirs • Surge suppression units• 2D Floodplains• HD Rivers/• Diffusion Analogy• Kinematic waves• Discharge routing• Reservoirs• A host of control units• Inflows/outflows• Hydrological cycle• Hydrology• Modelling

3. Types of modelling – model Building (2)

• No equations

• Continuity+ 1-momentum

• Mass balance

• Mass balance + Diffusive FP


• Continuity+ 2-momentum + a good solver


• Longitudinal variations• Classic 2-stage channels • Attenuating floodplains

• Hydraulic jumps/Roll waves

• Mixing required

• Storage floodplains

• To model lateral variations

• Urban, coastal, floodplains

• Slow overland flows

• Fast spreading• 0D

• 1D

• 1D+

• 2D-

• 2D

• 2D+

• 3D

3. Types of modelling – 1D/2D/3D & integrated modelling (3)

• There are many brands of models now • For open channels these include: FEH, HEC-RAS, Flood Modeller Pro,

TUFLOW, JFlow, MIKE-21, InfoWorks• We use one brand but this should change as we should extract

consensus from models

Order 1 Order 2 Order 3KEY

Rules of thumb

Heuristic rules

Blackbox modelling

Conceptual modelling

Hydrological Routing

Kinematic routing

Hydrodynamic routing

Models with updating

Empirical approaches

Uncertainty

Reliability

Models used for Rivers

Reso

lutio

n, re

liabi

lity,

info

rmati

on co

nten

t

Overall Attributes

Individual Attributes

Uncertainty, Susceptibility to problem

s

3. Types of modelling – information/uncertainty (4)

• Steady state: No variations in time dimension – a special case of unsteady flows– Some problems can be approximated to steady flows– gives fast and conservative solutions

• Unsteady state: Variations in time dimension– Most of the problems are unsteady– Modelling unsteady flows is an involved activity– Simulating unsteady flows give a deeper insight into the

complex flow processes• Real-time modelling

4. Steady/unsteady conditions

• Each solution by modelling is an anecdote and good to gain an insight into processes

• Models do more: tools of risk-based decision-making:• So, what is risk? (hazard * its probability)

5. Functions and usage of models

Model uses:• Study system operations• Carry out design works• System performance under extreme conditions• Performance under proposed developments• Assess impacts of changes (EIA and ES)• Study conditions under predefined events• Detect acts, which have triggered adverse

conditions

5. Functions and usage of models

• The European Flood Directive• The European Water Directive • The EIA Directive (85/337/EEC)• Flood and Water Act 2010• Replacements should come in due

course

• National Planning Policy Framework(NPPF) – England

• Technical Advice Note 15 (TAN15) – Wales• Scottish Planning Policy (SPP) 7

6. Modelling Business Drivers: Legal Drivers (1)

• Flood Risk Management Plans

• River Basin Management Plans

• Catchment Flood Management Plans (CFMP)- EA• Shoreline Management Plans (SMP) – LA• Surface Water Management Plans (SWMP) – EA?• Regional Flood Risk assessment (RFRA) – LA• Strategic Flood Risk Assessment (SFRA) - LA

6. Modelling Business Drivers: Competent Authorities (2)

• Flood Maps (Zone 1, Zone 2, Zone 3)• Flood hazard maps:

– the flood extent;– water depths or water level, as appropriate;– flow velocity

Approx. Location of the Site

6. An example of information issued by competent authorities (3)

• A masterplan:– the process, to undertake analysis & prepare

strategies– the proposals, to plan for major change– Includes buildings, spaces, movement strategy, land use– focussed on sustainable principles

• A masterplan is a sophisticated model and shows, among many things, ways of integrating communities into the built/natural environments

6. Modelling Business Drivers: Masterplanning (4)

6. Examples of Masterplanning (5)

6. Setting the scene: Quantitative Modelling (6)

6. Examples of Masterplanning – Urban Flooding (7)

6. Examples of Masterplanning: SuDS (8)

Conclusion• Open eyes from the past to the future• A critical mind as everything changing• Academic education and industrial training go hand-in-hand• Prior to 2000: deterministic modelling, implying certainty and the

delivery of truth• Since 2000: models regarded as information tools –uncertainty estimation becoming integral to modelling–Models serve as tools of risk-based decision-making

• There are many brands of models now (FEH, HEC-RAS, Flood Modeller Pro, TUFLOW, JFlow, MIKE-21, InfoWorks)•We use one brand but this should change and we should extract

consensus from models

Thank you andSee you later for questions