Practical Aspects of Integrated 1D2D Flood Modelling of Urban Floodplains using LiDAR Topography Data By Deepak Bhimrao Kharat Submitted for the degree of Doctor of Philosophy Heriot-Watt University School of the Built Environment August 2009 This copy of the thesis has been supplied on condition that anyone who consults it is understood to recognise that the copyright rests with its author and that no quotation from the thesis and no information derived from it may be published without the prior written consent of the author or of the University (as may be appropriate). ABSTRACT Flood risk, a major risk facing mankind today, is projected to aggravate in view of the future predictions pertaining to the assessment of climate change scenarios. Traditionally, flood risk assessment exercises of urban floodplains have been carried out using 1D model as well as 1D model with storage cells. In view of the recent availability of high quality Light Detection and Ranging (LiDAR) topography data, availability of higher computing capacities, developments in the numerical computing techniques and the merits of an integrated 1D2D computing modelling method, integrated 1D2D modelling has gained a momentum for strategic flood risk management (SFRM) and detailed urban flood risk analysis. The research discussed in this thesis evaluates this modelling method using high quality LiDAR data in light of the results from the traditionally used 1D model with storage cells modelling method. The research study was carried out using laboratory experimental observation data, hypothetical urban floodplain data and data for a section of the River Clyde and adjoining urban floodplain in Glasgow, a major city in Scotland, UK. It concludes that, while integrated 1D2D models are of much benefit for a detailed flood risk analysis, specific attention needs to be paid towards the lateral extents of 1D model and the source of the river bank elevations while integrating it with a 2D model, particularly so when such a study is carried out for urban floodplains; and that the high quality LiDAR data significantly facilitates Strategic Flood Risk Modelling (SRFM) of urban floodplains. i DEDICATION To Rani ii ACKNOWLEDGEMENTS With my wife, Sanghmitra’s belief that I can do better and the encouragement by my friend Simon Matthews helped me to look for research opportunities in the field I am passionate about. I take this opportunity to thank them and to thank Dr. G. N. Paudyal, Prof. D. Nagesh Kumar and Prof. S. K. Kar for recommending me to the University. I am very much thankful to Prof. Gareth Pender and Dr. Adebayo Johnson Adeloye for accepting to supervise my research and their constant guidance and support during the research. Without the James Watt scholarship by The Heriot-Watt University, it would not have been possible to undertake this research. I am thankful to Jim Fleming of Glasgow City Council, David Reid of South Lanarkshire City Council and Dr. Pascal Lardet of Halcrow Group Limited for providing hydrodynamic model of the River Clyde and LiDAR data. Thanks to DHI Water, Environment and Health’s Simon Matthews, Morten Rungø, Henrik Kofoed-Hansen and Jørgen Bo Nielsen for providing me with the MIKE FLOOD (MIKE11+MIKE21) software without any limitations, and their technical help. Thanks are due to Sandra Soares-Frazão of Université Catholique de Louvain for providing laboratory experimental observation data set even while being on holidays. I wish to thank the IT and administration staff in the School of the Built Environment for their help. I could not realise that it is been three years in the company of my friends Yahaya Ibrahim Makarfi, David A Kelly and Dr. Christopher Lang. Thanks for their wonderful company. Also thanks to my friend Martin Krupka for sharing thoughts. The excellent support of my family, particularly my wife and daughter has inspired me to finish my studies faster, I can’t thank them less! I owe them a lot! iii DECLARATION STATEMENT ACADEMIC REGISTRY Research Thesis Submission Name: DEEPAK BHIMRAO KHARAT School/PGI: SCHOOL OF THE BUILT ENVIRONMENT Version: (i.e. First, Final Degree Sought: Ph.D. Resubmission, Final) (Award and Subject area) Declaration In accordance with the appropriate regulations I hereby submit my thesis and I declare that: 1) the thesis embodies the results of my own work and has been composed by myself 2) where appropriate, I have made acknowledgement of the work of others and have made reference to work carried out in collaboration with other persons 3) the thesis is the correct version of the thesis for submission*. 4) my thesis for the award referred to, deposited in the Heriot-Watt University Library, should be made available for loan or photocopying, subject to such conditions as the Librarian may require 5) I understand that as a student of the University I am required to abide by the Regulations of the University and to conform to its discipline. * Please note that it is the responsibility of the candidate to ensure that the correct version of the thesis is submitted. Signature of Date: Candidate: Submission Submitted By (name in capitals): Signature of Individual Submitting: Date Submitted: For Completion in Academic Registry Received in the Academic Registry by (name in capitals): 1. 1 Method of Submission (Handed in to Academic Registry; posted through internal/external mail): Signature: Date: iv Table of Contents ABSTRACT.............................................................................................................................................i DEDICATION........................................................................................................................................ii ACKNOWLEDGEMENTS..................................................................................................................iii DECLARATION STATEMENT.........................................................................................................iv Table of Contents ............................................................................................................v List of Tables ..................................................................................................................ix List of Figures...................................................................................................................i Chapter 1 Introduction...................................................................................................1 1.1 Introduction.................................................................................................................................... 1 1.2 Types and causes of floods ............................................................................................................ 1 1.3 Effects of floods............................................................................................................................. 3 1.4 Climate change and floods............................................................................................................. 3 1.5 Flood management......................................................................................................................... 4 1.6 Need for flood modelling............................................................................................................... 5 1.7 Research aims and objectives ........................................................................................................ 7 1.8 Research resources – data and software......................................................................................... 7 1.9 Thesis layout.................................................................................................................................. 7 Chapter 2 Flood Modelling Methods and Tools...........................................................9 2.1 Introduction.................................................................................................................................... 9 2.2 Flood modelling methods and tools............................................................................................. 10 2.2.1 0D flood modelling method................................................................................................ 11 2.2.2 1D flood modelling method................................................................................................ 11 2.2.3 1D+ flood modelling method .............................................................................................. 21 2.2.4 2D– flood modelling method .............................................................................................. 25 2.2.5 2D flood modelling method................................................................................................ 28 2.2.6 Nested grid 2D modelling method ..................................................................................... 33 2.2.7 Integrated 1D2D models .................................................................................................... 36 2.2.8 1D2D model linking options and significance for flood modelling ................................... 38 2.2.9 Hydrodynamics of 1D2D linking ....................................................................................... 44 2.3 Topographic data for 2D flood modelling ................................................................................... 47 2.3.1 LiDAR topography data types...........................................................................................