Flood Risk and Hazard Assessment on Lulu Island By Paul Arthur Jacobs B. Sc. Honours, Simon Fraser University, 1975 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF APPLIED SCIENCE in THE FACULTY OF GRADUATE STUDIES (Department of Civil Engineering) We accept this thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA November 1986 ©Paul Arthur Jacobs, 1986 In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department of The University of British Columbia 1956 Main Mall Vancouver, Canada V6T 1Y3 Date acnwee-K t, i i ABSTRACT Lulu Island contains most of the Municipality of Richmond. Richmond is a growing community with 100,000 population located south of the city of Vancouver in the Fraser River estuary. The flood hazard from both the sea and the Fraser River are well known and to protect against it, an extensive diking system has been built. Despite this diking system a significant residual flood hazard has been created by the extensive development on the island. In addition, concerns have been raised about potential flooding from earthquake damage and a predicted rise in sea level due to global warming. This thesis analyses the extent of the flood hazard from various sources. New techniques of risk analysis and findings on risk perception are used to examine the flood risk. The role of contingency planning for flood control in conjunction with dikes is examined. Finally, the role of flood insurance is discussed as a method of providing information about flood risk levels to floodplain users.. Conclusions are drawn about the adequacy of current flood control measures and recommendations are made to improve them. ACKNOWLEDGEMENTS In the course of this study assistance was received from many sources. I am particularly indebted to the people involved in providing flood protection at all levels of government for their time, access to their documentation, and, most of all, for sharing their expertise with me. From the federal government, I would like to thank Dr. Sandy D'Aquino, Jim Leung, Neill Lyons, and Jim Oakey of the Water Planning and Management Branch of Inland Waters. From the British Columbia government, I would like to thank Eric Bonham, Ron Henry, Robin Round, Sandra Smith, and Jake Wester of the Ministry of Environment and Parks. From the Municipality of Richmond, I would like to thank Alex Jamieson, Don Mclver, and Henry Pelzer. In addition, I would like to thank my thesis advisor S. 0. Russell for his guidance, cooperation, and most of all for his careful listening. Finally, I would like to thank my wife, Maruta Jacobs, for her careful editing and general support. iv TABLE OF CONTENTS Abstract ii Acknowledgements iii List of Tables v List of Figures vi Glossary vii Introduction 1 Literature Review 6 The Flood Hazard 34 Risk Analysis and Perception 48 Contingency Planning and Other Measures to Reduce Damage 59 Flood.Insurance 65 Conclusions 69 Recommendations 71 Bibliography 73 Appendices 78 - Appendix A - Tables 79 - Appendix B - Figures 85 - Appendix C - Expected Flood Damage Calculation for Lulu Island .... 90 V LIST OF TABLES I. Terms for Classifying Hazard Potentials 79 II. U. S. Army Corps Engineers Hydraulic Evaluation Guidelines: Recommended Spillway Design Floods .. 79 III. Value of Commercial Building Permits Issued 80 IV. Annual Probabilities of Combined Flood Hazards .. 80 V. Predicted Changes to Tidal Levels 81 VI. Flood Damage Estimate for Lulu Island 81 VII. Federal-Provincial Flood Damage Cost Sharing Formula 82 VIII. Example Rule of Thumb Flood Protection Level Chart 83 vi LIST OF FIGURES 1 . Map of the Western End of the Lower Fraser Valley 86 2. Risk-Hazard Perception Rating Chart 87 3. Map of Full Tidal Relief Zone 88 4. Raised Road Alignment 89 vi i GLOSSARY Capitation - A method of payment for medical services in which the physician receives a fixed amount annually per patient for all health care services used. Climatological Change - A long term, world-wide, warming trend that has been postulated based on increased levels of carbon dioxide in the atmosphere. The most significant aspect of this change from the point of view of this study is the melting of polar ice sheets and a subsequent 1m rise in sea level. Highway 99 - The freeway running north-south roughly through the centre of Lulu Island. Flood Hazard - The potential damage that would be done by flooding. Flood Risk - The probability that flooding will occur. Level of Protection - The probability of occurrence of a flood event that dikes or other flood control structures are designed to withstand. These' probabilities can be expressed as either an annual probability of occurrence or a return period. (.005 annual probability of occurrence is equivalent to a 1 in 200 year return period.) Low Pressure Systems - Weather systems characterized by low barometric pressures and high winds. The highest tidal levels around Lulu Island result from severe low pressure systems occurring during the winter months. vi i i Normal High Tide - Any high tide that occurs from the gravitational pull of the sun and the moon alone, rather than in conjunction with a low pressure system. MCE - Maximum Credible Earthquake - The largest earthquake that can be expected to occur in an area. Morbidity - The average number of people sick at any one time. Mortality - The expected number of deaths per thousand in a population. For example, the mortality of males from 45 to 54 is the number of deaths that can be expected to occur in a group of 1000 males 45 years old before they reach 55 years old. PMF - Probable Maximum Flood - A hypothetical flood derived from physical criteria that is the largest flood that could reasonably be expected to occur. Ponding - The filling of a diked area to the level of water entering through a dike breach, characterized by deeper water levels than would have occurred without the dikes and a loss of velocity through the breach. In effect, the diked area becomes a pond with the dikes as banks. Primary Care - The type of health care first sought by patients as opposed to health care delivered as a result of a referral by a physician. Typical examples of primary care are the family physician and hospital emergency wards. River Stage - A river level with respect to a known datum or elevation. ix Spring Freshet - The high river levels caused by the spring snowmelt. Tidal Relief - The drop in water levels around Lulu Island that occurs during low tide. Full tidal relief occurs when the water level at low tide is lower than the land level inside the dikes. 1 INTRODUCTION This is a study of the flood hazards and flood risk in the Municipality of Richmond, specifically Lulu Island. The Municipality of Richmond is located primarily on Lulu Island, south of the City of Vancouver, in the Province of British Columbia. For a flood hazard to exist, two conditions must be met: there must be development that can be damaged by inundation and there must be a path for water to inundate the development. Richmond's location and geology have been excellent for the development of a flood hazard. The Province of British Columbia is mountainous and contains relatively little flat or agriculturally productive land. The existing flat land is concentrated in river valleys. Most of the rest of the province is made up of steep, forested land. As a result, most of the land outside of settled areas is uninhabited. The Atlas of British Columbia describes and explains the population distribution this way: "Three features characterize the distribution of population in British Columbia - heavy concentration in the southern coastal lowlands, valley oriented lines of settlement with larger clusters along them in the southern and central interior and large areas of unpopulated land. "The essentially unpopulated areas are those which by reason of topography, climate, soil conditions, vegetative cover, or relative isolation have offered little inducement to settlement."(Farley, 1979, p. 4) In a province with this type of topography and population distribution, it is no surprise that a flat area with a mild climate, prime agricultural soil, and located within easy 2 commuting distance of Vancouver (metropolitan population 1.2 million) has attracted development. Between 1950 and 1960 Richmond's population growth was more than 5% per annum. Since then the growth rate has slowed, but it is still approximately 4% per annum. Monetary value of flood damages was last estimated for Richmond in 1971. At that time, the population was 62,000 and potential flood damages were estimated at $100 million. Since 1971, the population has increased to 104,000. In addition, Richmond has been more closely integrated into the Greater Vancouver Regional District's economy and has become a major shopping and warehousing area. Over $500 million of building permits for commercial developments have been issued since 1971. Assuming that flood damages would increase proportionately with population and inflation, the maximum flood that the dikes were designed for, would cause about $500 million in damage today (1986). Since, as was mentioned above, the character of development has changed, these assumptions are probably conservative. Lulu Island is a low lying island located in the mouth of the Fraser River estuary.