Chilliwack: Flood Risk
1
Location in Canada (absolute and/or relative location)
PART 2
Description of vegetation cover around the city/town:
Population
Chilliwack, BC.
Interrelationships and Patterns and Trends
Landform Region
estimated population of 101,700 as of 2022 (including first nation communities)
PART 3
Geographic Perspectives
Western cordillera
The vegetation around Chilliwack includes dense forests, fertile farmlands, and some grasslands. The city is surrounded by forests that do well in the temperate climate of the Fraser Valley, making a sustainable habitat for some plant species. Farmlands are a huge part of the landscape, So, their agricultural areas are filled with crops like berries, corn, and vegetables. While grasslands are not a big part of Chilliwack compared to forests and farmlands, they can be found in some areas along the agricultural fields or undeveloped land.
Average Temperature and Total Precipitation (rain, snow or both)
8.7 °C | 47.6 °F - Temperature
2488 mm | 98.0 inch - Precipitation
Description of physical environment:
The land of Chilliwack is described as having beautiful natural scenery loved by everyone who lives there. It's settled in the Fraser valley of British Columbia surrounded by farms and huge mountain like the cascade mountain to the east. As like in most places in Canada its covered in long cascading rivers and lakes fullfed with an abundance of wildlife. Chilliwack is mostly coverd in vegetation because of its mild weather, which makes plants grow to be healthy and full.
How does the local physical environment affect the occurrence of flooding?
How does local human activity contribute to the occurrence or intensity of flooding?
In Chilliwack, BC, the local physical environment significantly affects flooding due to its close quarters with the water and its unpredictable weather. Firstly, because of climate change we’re having more storms and extreme rainfall events. So, factors such as the town's low elevation and its closeness to bodies of water can increase flood risk during these heavy rainfalls or snowmelts. Additionally, changes in natural drainage patterns caused by factors like soil type also play a role in flood occurrence.
The local human activity has worsened flooding to some levels. Urban development has replaced natural surfaces with impermeable ones, increasing runoff into waterways. Deforestation and soil erosion destabilize soil, leading to sedimentation in rivers and streams, which can build up over time leaving less room for water. Poor drainage systems and river modifications can change water flow, raising flood risk.
Description of human environment
In Chilliwack, BC, the landscape around them plays an important part in how they go about making this city a place where people can live happily. The city is in the Fraser Valley, covered by farmland, huge mountains, and the Fraser River. Over time, the layout of the city has been shaped by these natural features. For example, fertile farmlands have changed where residential areas, businesses, and industries are placed. The mountains in this city are used by the people for outdoor activities like hiking and skiing, which is one of the reasons this city was built there. Also, the Fraser River is used as a transportation route and recreation source for the people of Chilliwack. Despite land developments, these people want to preserve agricultural lands and natural habitats.
Brief history of Natural Hazards near your city/town
Explain which natural hazard poses the greatest risk to your chosen community by describing the environmental conditions
PART 1
Geologic Processes at work in this region
Chilliwack has had many natural hazards over its history. The Fraser River's proximity to the area makes it prone to floods, The biggest ones being in 1894, 1948, and 2007, with the "Great Flood of 1948" leaving damage on the landscape that can still be seen today. The rugged terrain also makes it prone to landslides, caused by heavy rains, leaving damage to infrastructure and homes (there were mentions of landslides but no exact years). While wildfires are not as common, they are a threat during dry summers. Small wildfires have occurred there but no mentions of dates, yet the city of Chilliwack has many systems to prepare them for when they do happen. In the seismic zone of the Cascadia Subduction Zone, there have been some earthquakes, like the 1946 Vancouver Island event, which has made Chilliwack more cautious about earthquakes.
Spatial Significance of the city/town
Geologic processes at work in the Chilliwack region are plate tectonics, erosion, and glaciation. Plate tectonics have shaped the landscape over millions of years, like the formation of the Cascade Mountains to the east. The motions of the plates can shape and deform rocks through many processes that include folding, faulting, extension, and on a massive scale, mountain building. Erosion, caused by water and ice, continues to change the land, shaping things like valleys and riverbeds. Additionally, glaciation played a role in carving out valleys and shaping the terrain, leaving features like U-shaped valleys and moraines.
How will climate change impact the occurrence or intensity of flooding?
In Chilliwack, the biggest risk comes from flooding, mainly along the Fraser River. Floods happen when heavy rain and melting snow from nearby mountains raise the river's water levels. Chilliwack's location near the river and its flat terrain makes it prone to flooding, as seen in past events like the floods in 1948 and 1972. Flood risk is influenced by weather changes, so it's important for the community to stay prepared and watch for rising water levels.
REFERENCES
What are the impacts that a large-scale hazard would have on the people of your chosen city?
Climate change will impact the frequency and severity of precipitation amounts, causing some bodies of water to be overwhelmed by the amount of rain and therefore make flooding occur.
When ice caps start to melt because of the sheer amount of Co2 in the atmosphere, the sea will start to rise making for dangerous weather patterns like floods.
City of Chilliwack. (2017). Population and Development Statistics. City of Chilliwack. Population and Development Statistics - City of Chilliwack
City of Chilliwack. (2017). History of Chilliwack. City of Chilliwack. History of Chilliwack - City of Chilliwack
City of Chilliwack. (2017). Urban Forests. City of Chilliwack. Urban Forests - City of Chilliwack.
Life in Chilliwack. (2019). Life in Chilliwack. Life in Chilliwack.Life In Chilliwack – Life In Chilliwack
NDAA. (2023). JetStream Max: Plate Tectonics and Earthquakes. NDAA. JetStream Max: Plate Tectonics and Earthquakes | National Oceanic and Atmospheric Administration (noaa.gov)
BCcampus.(2020). BRITISH COLUMBIA IN A GLOBAL CONTEXT. BCcampus.Hazards – British Columbia in a Global Context (opentextbc.ca)
ClimateReadyBC
ClimateReadyBC. (2023). Most communities in B.C. are exposed to some flood risk. ClimateReadyBC | ClimateReadyBC (gov.bc.ca)
Immigrant. Today. (2022). 15 Canadian cities at high risk of flooding. Immigrant. Today. 15 Canadian cities at high risk of flooding — Immigrant.Today
City of Chilliwack. (2017). Types of Emergencies. City of Chilliwack. ypes of Emergencies - City of Chilliwack
Hernandez, J.A. (2023). Owners of destroyed Chilliwack properties still waiting for help 2 years after historic flooding. CBC News. Owners of destroyed Chilliwack properties still waiting for help 2 years after historic flooding | CBC News
Waddington, S.D. (2017). CHILLIWACK – A COASTAL RAINFOREST. Tourism Chilliwack. Chilliwack - A Coastal Rainforest | Tourism Chilliwack
What strategies are cities around the world using to protect themselves from this type of hazard?
What strategies is your chosen city using to protect itself and its people from flooding?
Social Impact:
People may have to be evacuated from their homes because of floods, which can be stressful and upsetting.
Floodwater can be a health risk due to contamination from sewage, chemicals, and debris. This can cause more sickness, injuries, and make people feel down, especially older folks and kids.
Economic Impact:
Damage to Property: Floods wreck homes, stores, and roads, costing a lot of money for owners and insurance companies. The cost of repairing or replacing damaged buildings, roads, and utilities can be a lot.
Businesses and Jobs: Floods mess up farming, factories, and shipping, so companies lose money and might have to lay off workers. This makes it harder for everyone to buy and sell things, making money even tighter in the community.
Amsterdam, Netherlands: Constructing flood barriers and levees.
Tokyo, Japan: underground drainage systems and elevated buildings .
New Orleans, USA: Building and reinforcing levees, floodwalls, and pumping stations.
Dhaka, Bangladesh: Developing early warning systems, flood shelters, and raised plinths for homes.
Singapore: drainage systems, green infrastructure, and land reclamation to manage stormwater and prevent urban flooding.
Floodplain Management: The city has strict regulations and land use planning to stop building in flood-prone areas.
Riverbank Protection: they are making "riparian vegetation restorations and erosion control structures" along the banks of the Fraser River to lessen bank erosion and reduce flood risk.
Stormwater Management: Chilliwack maintains and upgrades stormwater drainage infrastructure, including culverts, ditches, and retention ponds, to manage stormwater runoff and mitigate urban flooding during heavy rainfall events.
Public Awareness and Preparedness: The city makes education campaigns to raise awareness about flood risks and encourage residents to take proactive measures, such as installing flood barriers and purchasing flood insurance, to protect themselves and their property.
Emergency Response Planning: Chilliwack talks closely with local emergency services and agencies to develop flood response plans, ensuring fast and coordinated action in the event of a flood emergency, including evacuation procedures and temporary shelter arrangements for affected residents.
Based on all of the research completed about your location and its risk of disaster, rank the level of hazard on a scale of 1 -10
Chilliwack: Flood Risk
Based on past events and geographical factors, I'd rate the risk of flooding in Chilliwack a 8 out of 10 . The Fraser River, which is very close to the city, has a long history of flooding, with significant events happening in the past century. The "Great Flood of 1948"was a occurance that Chilliwack will not be forgetting, causing widespread devastation. This event leaves you wondering if and when something like that could take place again. Additionally, Chilliwack's location in a low elevantion area of the Fraser Valley increases the risk, as heavy rainfall and snowmelt can overwhelm the river's ablity to hold the water, leading to flooding. Even with efforts to manage flood risk through infrastructure upgrades and floodplain zoning, flooding it still a threat, especially when thinking about the impacts of climate change, which could cause more precipitation and increase the likeliness of extreme weather events. Therefore, an 8 out of 10 is a fair analysis in the ongoing risk of flooding in Chilliwack. (On the map Chilliwack is in the 94% chance of flooding range)