The seasonal distribution of precipitation is changing throughout the province. As the climate changes, BC is seeing increasing average annual rainfall. It’s also experiencing more frequent intense rainfall events and more rapid snowmelt.
These conditions create challenges with runoff and erosion management and increase flood risk. In many parts of the province, agricultural land is in valleys and along streams or rivers, making it particularly susceptible to flood.
Climate and other factors
Climate changes in BC that are contributing to an increase in wetter conditions and flood risk include:
- Increasing average spring and autumn rainfall in many areas
- Increasing frequency and intensity of extreme precipitation events
- Shifting precipitation patterns, for example, less precipitation falling as snow and more falling as rain
- Earlier and more rapid snowmelt due to warmer winter and spring temperatures
Other factors that increase runoff and flood risk in the province include:
- Loss of vegetation due to wildfire and/or forest die-off due to mountain pine beetle
- Development and forestry practices that increase runoff, particularly in upland areas
- Damage to natural flood control and drainage capacity, such as loss of riparian areas
Impacts to agriculture
Challenges caused by wet conditions
Increasing seasonal precipitation, particularly more extreme precipitation events, leads to more runoff onto and off farms. These conditions can lead to erosion, leaching of soil nutrients, soil compaction, and crop loss and damage.
Wetter conditions can increase the chance of saturated soils. This can affect timing of critical farm operations such as planting, harvesting and crop or nutrient management activities.
Excessively wet conditions can also impact the health of both crops and livestock. Many fungal diseases are linked to damp and wet conditions and can affect both productivity and yield.
As wetter conditions become more common and/or extreme, producers will be faced with extra costs to manage for these conditions. For example, they may need to invest in infrastructure or management solutions.
Agricultural land and practices can play an important role in supporting flood plain resilience, but this is likely to require time, effort and costs for producers.
In some cases, landscape-level solutions will be needed to reduce runoff or enhance drainage. For example, landscape-level practices can help reduce, capture or redirect upland runoff. This type of solution would require the involvement of a range of stakeholders and government partners.
Consequences of flooding
The impact of flooding on agriculture depends partially on the extent, depth and timing of flooding events. The level of impact also depends on the vulnerability of property and infrastructure.
Farms and ranches with high value structures, livestock that can’t be relocated and/or perennial cropping systems are more likely to experience big losses during floods.
As well, recovery and return to profitability after a flood may be slow and costly. If perennial crops are lost, there is a large replacement cost. It takes many years for crops such as blueberries and tree fruit to become productive. If livestock are lost or livestock housing is damaged, returning to production will be costly.
Flood waters can also result in pollution of agricultural water sources and soils. This is a concern for all producers, but it’s particularly challenging for organic producers.
Long-term risks of coastal flooding
Coastal, or storm surge, flooding poses a longer term risk. It has the potential to impact a much smaller — but high value — area of B.C.’s agricultural land base.
This type of flooding is most likely to occur in winter with high tides and storm conditions. Post-flood, waters may recede more quickly than with river flooding.
However, for coastal farm operations, the risk of flood is likely to become more problematic over time as sea levels rise.
Resources and tools
Highlighted below is a selection of CAI resources and tools to support adaptation to wetter conditions and flood.