INNOVATION July-August 2017

T op : Flood damage in northeastern BC. P hoto credit : BC M inistry of T ransportation and I nfrastructure , CC by NC-ND. B ottom left : Severe floods such as this one trapping a car in 2009 have become the “new normal” for many BC communities. P hoto credit : C owichan V alley R egional D istrict B ottom right : Dike construction underway to protect communities from flooding. P hoto credit : C owichan V alley R egional D istrict

to $6 billion in insured losses and damaging buildings and infrastructure that may take decades to fully repair. If a similar disaster were to occur in southwestern BC’s densely- populated Fraser Valley, with its pipelines, farmland, industry, and diverse major transportation infrastructure, losses would exceed tens of billions of dollars. Matthias Jakob, P.Geo., principal geoscientist at BGC Engineering Inc. and a contributor to the new flood guidelines, arrived at this number in a study he and his colleagues published in 2014. It was the first flood-risk assessment for the City of Chilliwack, located 80 kilometres upstream from Vancouver on the Fraser River. The research team assessed the direct and indirect economic losses for three hypothetical scenarios for 100, 500, and 1,000 flood return periods. Flood return periods are estimates of how often a flood event will occur. A mega-flood “would cripple the BC economy,” Jakob says. He points out that the key difference between this and previous studies is that the 2014 project used a hazard-based approach rather than a risk-based approach. The magnitude of loss and the full consequences of a major flood event are not fully analyzed in current methods, he says, and these risks are not properly communicated to governments and the public. Also, these scenarios do not include cultural losses, such as the destruction of ancient graveyards or cultural sites, emotional costs such as the resulting human grief, suffering and stress, or the value of lost habitat or lost species diversity. A more recent 2016 study by the Fraser Basin Council corroborates the earlier estimates. According to the council’s Lower Mainland Flood Management Strategy, Phase 1 report, a 1-in-500-year large- magnitude flood in BC’s Lower Mainland region would trigger losses as high as $33 billion. “Every hydro-climate has its own responses to climate change,” says Jakob. “One cannot generalize and say, ‘in British Columbia, climate change will make things

In May 2017 APEGBC released the professional practice guidelines, Flood Mapping in BC. The guidelines provide clear direction for APEGBC members who prepare flood maps for rivers, creeks, and coastal areas around the province. The document describes data requirements and input, appropriate use and interpretation of data and flood modelling, and typical hazard assessment methods. In addition, it recommends including a combination of outputs from different climate and environmental simulations in flood maps. The timing of the release coincided with major flooding events around the province. Spring 2017 saw BC residents filling sandbags and evacuating homes as warmer weather melted thick snowpacks, and bursts of heavy rain caused rivers and lakes to swell and overtop their banks. As a result, homes were flooded, roads, bridges, and highways were washed out or closed, drinking water supplies were put at risk, and sadly, several people lost their lives. Global becomes local Severe floods have become the “new normal” for many communities around BC, explains Kate Miller, manager of Environmental Services for the Cowichan Valley Regional District (CVRD). “Historically, ‘normal’ would involve wearing rubber boots or your basement filling up with water. Now, we settle our communities very differently and the impact of flooding on infrastructure is very different,” says Miller. Miller is responsible for protecting water resources, responding to climate change, and working with partners to protect environmental resources in the CVRD, one of 27 regional districts in BC. The 3,470-square kilometre district stretches from the east coast to the west coast across southern Vancouver Island. Forestry is the major industry in the area, with fisheries along the coasts and rivers. Tourists flock to the area in summer, and it is a popular area for retirees to settle. More than 80,000 residents call the Cowichan Valley home, and all are seeing the real effects of climate change first-hand. “We’re starting to see more fire-prone communities,” says Miller. “We’re seeing a shift in ecology, particularly after the last series of droughts, putting stress on the

forests and ecosystems, and impacts on the fisheries and agricultural community. Last year, crops were coming into season three weeks ahead of schedule, and this year, we’re much further behind.” Rivers that flood during spring in the CVRD, says Miller, are also too dry in late summer for fish to move up the system. Global climate change symptoms that once seemed theoretical and far away are now being seen and felt at the municipal, community, and individual home scale. Responding to a changing climate In late 2016, APEGBC shared its position paper, Human-Induced Climate Change , acknowledging the compelling evidence that human activities, particularly those that emit greenhouse gases, are contributing to global climate change. Mean annual temperatures across the province will, on average, be 1.4°C to 3.7°C higher by the mid-2050s. Warmer summer and winter temperatures will increase the risk of flooding, forest fires and air pollution events, and threaten supplies of fresh water throughout western North America. “Floods are the most common natural disaster in BC,” says Markus Schnorbus, lead hydrologist at Pacific Climate Impacts Consortium (PCIC) in Victoria. “As rainfall becomes more extreme, flooding will become more of an issue for smaller basins and urbanized catchments.” In addition to increasing the frequency and intensity of severe rainstorms and snowmelt rates, climate change will increase the likelihood of flooding around the province as insect infestations and forest fires reduce slope stability, and higher storm surges in combination with sea level rise cause increased flooding and erosion in low- lying coastal areas. Overall, climate change will result in greater areas being vulnerable to flooding, endangering more lives, homes and businesses, and costing residents and In 2013, unusually intense rainfall that fell over a few days in southwestern Alberta coincided with the annual snowmelt time in the mountain headwaters west of Calgary and already rain-saturated ground. The resulting flood crippled the city, causing up the province billions of dollars. The cost of flood damage

worse everywhere.’” What can we do? To protect communities and

23

J U LY/AU G U S T 2 017

i n n o v a t i o n