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Overview
New Brunswick has a long history of flooding. With many kilometres of rivers, streams and coastline, and numerous ponds and lakes, many New Brunswickers have settled in areas that are prone to some degree of seasonal flooding mainly caused by:
- heavy rainfall, often coupled with snowmelt
- ice jams that result in increased water levels in rivers
- storm surges along the coastline
Knowing about flood risks and how to prepare for them can help keep you safe and minimize damage to your property.
Flood forecasts
New Brunswick is prone to flooding in the spring. The Government of New Brunswick, through the River Watch Program, provides flood forecasting for the Saint John River Basin during the spring freshet and throughout the year as necessary.
The River Watch Flood Tracker displays flood forecast data as a simple line graph and can be used on a mobile device or computer. Information for specific areas can be accessed from a list or by selecting a location from a map. The application is only active during the traditional flood season typically from March through May each year.
Flood hazard maps
Flood hazard maps help communities and individuals to better understand and plan for the risks associated with flooding. These maps help in finding out if you are in an area prone to coastal or riverine flooding. This information is also useful in helping governments and communities make decisions about the location and design of buildings, roads, and other important infrastructure (like bridges, water supply systems, airports, hospitals, etc.) and to inform emergency planning.
New Brunswick’s updated flood hazard maps cover the coastline as well as many rivers that are prone to flooding. They also incorporate projections regarding the impacts of climate change.
Coastal flooding and storm surges
Land in estuarine areas can be at particular risk of flooding as high river flows, marine tides and storm surge effects can act either alone or in combination to producing high water levels. Storm surges are episodes of high sea level caused by strong winds, often increased further by unusually low air pressure. Storm surges usually affect New Brunswick in the fall and winter seasons, when strong low-pressure systems pass by offshore.
During a storm surge, strong winds drive water toward the shore, raising sea levels, especially when directed into an estuary. The longer the winds persist, the greater the surge. Low air pressure also lifts the sea surface. The worst surges happen when high winds and low pressure align with high tides, raising sea levels by over a meter. Coastal sea ice may reduce flooding, but if it breaks up, it can worsen the damage. Storm surges, often linked to hurricanes, bring strong winds, heavy waves, and flooding, leading to severe damage.
Understanding flood plains
Floodway
The portion of the flood plain, including the area normally occupied by the waterway, in which most of the floodwaters are conveyed. This is the area where water velocities are typically high during a flood and where damage is often greatest. The floodway is defined as that area flooded on average once in 20 years (or an area which has a 5% chance of being flooded in any given year).
Flood hazard area
That area flooded on average once in 100 years (or an area which has a 1% chance of being flooded in any given year). In areas with no flood hazard mapping, the area in a specific community which was inundated by a major flood in the past may be designated as a flood hazard area.
Flood fringe
That portion of the flood plain between the floodway and the outer limit of the flood hazard area.
Flood history database
The Department of Environment and Local Government has created an interactive database containing records from documented flood events in the province. This database can be queried by time or location to discover in-depth descriptions, associated costs of damages, causes of flooding and areas affected by each flood event.
Past events and historical flooding tools
Flood resilience
The provincial flood risk reduction strategy was developed in response to the increasing impacts and costs of flooding. The strategy outlines 3 pillars: accurate flood hazard identification, planning for communities and infrastructure to avoid flood risk and informed mitigation of existing flood risk.
The provincial government has been working with communities on Climate Change Adaptation Plans, including vulnerability assessments which help them understand and prepare for the risk associated with flooding. Communities then have the tools, such as land use plans, to reduce those risks. The land use plans and the approval processes in place for development can help manage risks to future development in flood prone areas.