Flood Mitigation: Improved Flood Forecasting

What is flood forecasting?

Flood forecasting is the process of gathering, reviewing and monitoring data to further disseminate information and flood warnings to local communities and jurisdictions. Weather monitoring stations are established to provide real-time data to flood forecasters who interpret the data in a model then disseminate this information for the public to use. Data includes information on rainfall, snowpack and meteorological patterns that are important to determining the likelihood of a flood[1].

How does this option help to mitigate the impacts of a flood?

Flood forecasting is necessary to flood management. Information of high water levels and increased flow rates are relayed to jurisdictions that are then able to prepare for flooding. Flood forecasting allows downstream communities to initiate sandbagging and evacuation measures while defenses such as flood gates on structures such as dry dams and diversion channels are utilized. Therefore, flood forecasting helps to mitigate the impacts of a flood by providing necessary information and data to jurisdictions that can prepare and respond accordingly.

What flood forecasting policies are already in place in Alberta?

Similar to other Canadian and international jurisdictions, Alberta does have a flood forecasting system in place. Alberta’s River Forecasting Centre (RFC) provides flood warnings, produces monthly water supply forecasts, and models data for flood forecasting. Data is monitored daily and on a real-time basis to ensure Alberta’s water resources are managed appropriately. Data and information gathered and reviewed in Alberta is acquired from weather monitoring stations and stream gauges throughout the province. Various maps that show snow pack and precipitation information are also used[2].

What level of government is responsible?

In Alberta, the RFC is a section within Alberta Environment and Sustainable Resource Development (ESRD). The RFC is mandated to provide Albertans with information related to current and future river and ice conditions so that decisions related to water supply and emergency response planning can be made. The Water Survey of Canada, a federal agency, is also responsible for stream flow and river height measurements while Environment Canada provides data on precipitation[3].

Does flood forecasting account for differences between jurisdictions?

Yes, flood forecasting does account for the differences between jurisdictions and watersheds. In Canada, each Province has the responsibility to monitor river and stream conditions to forecast for potential flooding or droughts specific to their region. Agencies across Canada will monitor specific indicators to produce daily reports and forecasts. For example, in Alberta the RFC monitors river levels, rainfall and snow depth in each water basin[4]. On the other hand, Ontario’s Surface Water Monitoring Centre monitors precipitation, snow depth and conditions on the Great Lakes to provide a forecast[5].

What is the scale and boundary of flood forecasting?

In Canada, flood forecasting is the responsibility of the Provinces, therefore, the boundary of monitoring and forecasting is within each Province. Data produced, however, can be used across borders by other agencies and governments to see what conditions could be expected in their jurisdiction.

What are the enforcement measures?

Often mandated by provincial governments, flood forecast agencies are responsible for data collection, monitoring and warning dissemination. In Alberta, warnings produced by the RFC are provided to emergency responders and municipalities who decide which enforcement measures to take. In the event of a flood this can include evacuation orders and declaring a state of emergency.

What are the effects on the surrounding watershed and environment?

Flood forecasters monitor rainfall, snowmelt, soil moisture, water levels and flow rates. In the event of a flood, erosion to riverbanks often occurs while property, homes, businesses and communities can also be impacted. After the 2013 flood event in Alberta, changes to the Rocky Mountains and foothills landscape were noticed from collapsed mountain sides, changed river channels, and altered fish habitats[6].

Flood forecasting cannot stop flood waters from changing the environment and damaging man-made structures. Instead, flood forecasting can predict the likelihood and severity of flooding to further notify emergency officials, municipalities, and citizens to implement preparedness measures and limit the potential damages of flooding.

Would flood forecasting help in a drought?

Flood forecasting agencies across Canada are equipped with modeling capabilities to determine rainfall, snowmelt, soil moisture and other indicators to predict flooding potential. These modeling systems can also be used to determine the likelihood and extent of drought conditions. For example, Deltares is a Dutch company that produced a Delft-FEWS model capable of flood and drought forecasting. This model is used in various parts of the world including England, Scotland, parts of the United States and Australia[7].

Once drought conditions are determined by the use of a model such as Delft-FEWS, emergency officials and impacted communities can implement water management schemes to prevent water shortages.