Flood Plain Management in British Columbia

1. Flood Plain Management in British Columbia Tamsin Lyle - northwest hydraulic consultants tlyle@nhc-van.com REM 356 November 24th, 2004

2. What is Flooding • The spilling over of water from a river or other water body onto land that is normally dry • A natural process

3. Why does it Flood? • Because there is more water in the watershed than can be accommodated by rivers, lakes and wetlands • In BC, riverine floods occur as a result of freshet (snowmelt flows), winter or spring rain-on-snow events, or intense summer rain events

4. Why is this a Problem? • Humans have traditionally lived on flood plains because: • They provide a water source • They are near water transportation • They are flat and therefore easy to build on • They are very fertile • Therefore, there are lots economic and social investments on the flood plain that stand to be damaged when flooding occurs “Building on the floodplain is like setting your tent up on the highway when no cars are coming” (Watson nda)

5. What do we do about it? • Traditionally, people would leave the floodplain temporarily • In some countries, flood plain residents will sit it out. This is possible because of construction methods – houses on stilts for example • In the western world we tend to try to control floods with structures such as dams and dikes

6. Who Manages Flooding? • Federal • Federal Flood Damage Reduction Program (Canada Water Act) • Canada-BC Agreement Respecting Floodplain Mapping • Various other bodies under a variety of legislation • Provincial • MWALP – Flood Hazard Management Section • PEP (Provincial Emergency Program) • Lots of relevant legislation e.g.: • Local Government Act • Drainage, Ditch and Dike Act • Dike Maintenance Act • Fish Protection Act • Many, many more • Local • Varies from government to government • Some by-laws more extensive than others • Generally quite poor (e.g. Urban Exempt Areas)

7. Problem Background:Fraser River Valley • Fraser River flooding is inevitable • Lower Fraser Valley population is on the rise; flood plain development has not been curbed by government • To date, adjustments to flooding have been primarily structural

8. Extent of 1894 Fraser River Flood Cost of flood damage in 1894 in 1999 dollars: $40 million Cost of flood damage if 1894 water levels were reached today:  $1.8 billion

9. Structural Flood Control • Dams, dikes, levees, channel “improvements”, flood boxes and pumps • Reactive approach • “Flood protection is entirely feasible and is a rational method of meeting flood problems - provided one does not expect too much from it” (Hoyt and Langbein 1955)

10. The Problem with Structural Flood Control • Increased flood damage risk • Vulnerability • Hazard • Increased long-term cost • Increased post-disaster costs • High maintenance and capital costs • Environmental Degradation • Flood plain separation • Wetland desiccation • Loss of disturbance regime • Altered hydrologic regime • Fraser River specific problems

11. “Serial Engineering” Reduction in perceived vulnerability to flood loss Spiralling costs and environmental degradation Construction of structural flood control Increased floodplain development Increased vulnerability of floodplain development

12. What is Natural Flood Control? • The return of flood plains to their natural state • A “more informed kind of flood management, one that involves working with the forces of nature instead of simply trying to eliminate them” (Haeuber and Michener 1998)

13. How Does Natural Flood Control Work? • Flow control • Energy dissipation • Water volume reduction • Flood loss reduction

14. Some Examples of Non-Structural Options Flow Control Benefits Property Damage

15. The Benefits • Decreased risk • Decreased long-term costs • Environmental benefits • Additional benefits • Agricultural benefits • Fisheries improvements • Recreation • Environmental education • Economic revitalisation

16. Decreased flood risk for riparian developments through flood and flow control ? Return hydrologic features to flood plain Decreased long-term financial costs Environmental and social benefits How Do We Break the Cycle? Reduction in perceived vulnerability to flood loss Spiralling costs and environmental degradation Construction of structural flood control Increased flood plain development Increased vulnerability of flood plain development

17. Some Obstacles • High flood plain land values resulting from historic development • Private property rights versus common property resources • Inter-jurisdictional complexity • Responsibility • Current analysis frameworks • Policy making under uncertainty

18. Flood Plain Management Policy Alternatives

19. Steps to a Solution Enable appropriate legislation and remove legislative barriers Create basin-wide planning institutions Overcome obstacles + Implement policy alternatives Non-Structural Flood Plain Management Serial Engineering Citizen involvement Responsibility shift to flood plain benefactors

20. Legislation • Lack of pro-active, long-term thinking legislation • Minimal use of available legislation • Make better use of current legislation • Simplify and merge legislation under flood plain management act

21. Basin-Wide Planning Institutions • Co-ordination and Co-operation • Basin-wide planning institutions with power • E.G. Conservation Authorities, Ontario and Fraser Basin Council, BC

22. Responsibility Shift • Lower level government has benefit without responsibilities and senior level governments are liable without control • Private citizens bailed out with post-disaster payments • Discontinuance of post-disaster payments • Creation of government aided flood insurance program

23. Citizen Involvement • Poor understanding amongst publics regarding hydrological processes and alternatives to flood structures • False sense of security and lack of personal responsibility resulting from post-disaster payments • Private property rights versus common property resources • Increase flood awareness through public campaigns • Shift financial costs to flood plain dwellers

24. Probability of Success • The concept is old – yet not much has changed • Change will occur when we have: • Enlightened governance, or • An opening of a “Policy Window” when the next big flood strikes

25. Some Flood Plain Management Resources • Fraser Basin Council – Flood Hazard Management (www.fraserbasin.bc.ca) • BC Gov (wlapwww.gov.bc.ca/wat/flood) • Provincial Emergency Plan (www.pep.bc.ca) • US Federal Emergency Management Plan (www.fema.gov) • UK Environment Agency (www.environment-agency.gov.uk/)