140 Chapter One – Lesson Four

Lesson 4: Reducing the Risks of Floods

Reducing the risk of floods

With climate change and rising sea levels causing an increase in flood frequency and severity, it is imperative to help your community reduce flood risks. Encouraging local officials to prioritize flood defense initiatives and taking steps to protect your community against flood damage can play a significant role in decreasing flood impact.

By communicating flood risks to constituents and utilizing resources such as Flood Factor’s Community Risk Scores, local officials can gain a better understanding of the flood risk facing their area. Creating a plan to protect essential infrastructure such as schools, hospitals, and roads is also crucial in reducing flood damage.

While there are various solutions to combat flood risks, it is important to find the right one for your community based on local climate, resources, and laws. Investing in flood adaptation infrastructure projects, whether traditional “gray” infrastructure or nature-based “green” infrastructure, can help mitigate flood risk and protect property, the economy, and quality of life. Being proactive in preparing for potential flooding issues can also provide ample time to find and implement effective solutions that work best for your community.

Many Canadian communities adopt and implement the minimum floodplain management standards required for participation in the National Floodplain Management Program (NFMP). Some of the key components of these standards include provisions that communities:

• Require permits for development in the 1 in 100-year floodplain, also known as the Special Flood Hazard Area (SFHA);
• Require elevation of the lowest floor of all new residential buildings in the SFHA to be at or above the projected height of floodwaters in the 1 in 100-year flood;
• Restrict development in the regulatory floodway to limit the increasing risk of flooding;
• Require certain construction materials and methods that minimize future flood damage.

Effective Stormwater Management

The importance of effective stormwater management has become increasingly recognized in recent years. To achieve this, comprehensive planning with input from multiple agencies is necessary to protect human life, property, and natural water sources. The three key components of this planning process include the Watershed, Sub-watershed, and Stormwater Management Plans, all of which should be integrated into the municipal planning process.

1. Watershed Management Plans establish broad water management goals for entire catchments, taking into account physical, chemical, and biological characteristics of the basin. Goals are evaluated and selected to protect or enhance receiving waters and should be integrated into Official Plans to guide development.
2. Sub-watershed Plans address stormwater management at a sub-basin level, using information from Watershed Management Plans. This planning should be integrated with neighborhood plans for optimization.
3. Stormwater Management Plans should be developed jointly with Plans of Subdivision to minimize costs and consider affect layout of subdivision lots, roadways, and services. The minor and major drainage systems should be considered, designed to handle frequent and infrequent rainfall events, respectively.

Detention of stormwater runoff is essential and can be achieved through retention, detention, and infiltration ponds, flat roofs of commercial buildings, large parking lots, local and arterial streets, and subterranean tanks or silos. Rooftop, parking lot, street, and subterranean storage delay and reduce discharge rates to the major and minor systems.

To alter urban drainage, groundwater recharge can be achieved using porous pavement in roads and parking lots. In residential areas, well-designed landscaping techniques and construction materials can make the major drainage system effective yet unobtrusive.

Reducing flood through proper and regular maintenance

To mitigate and prevent flooding, regular maintenance and inspections of key aspects are crucial. The drainage system plays a significant role in collecting and conveying stormwater runoff to prevent water accumulation. To upkeep this system, cleaning the eavestroughs, downspouts, and catch basins regularly is advised, along with checking the sump pump and backwater valve to ensure their functionality. Additionally, maintaining the window wells is vital to allow water to drain away from basement windows.

Floodplain management involves identifying, mapping, and regulating flood-prone areas to reduce the vulnerability of people and property. This process requires flood risk assessments, development of floodplain maps to delineate boundaries and indicate risks, and land use policies to restrict or prohibit high-risk development and encourage adaptation measures.

Flood forecasting and warning are essential to monitor, predict, and communicate the occurrence and severity of floods. To enhance this process, collecting and managing data on hydrological variables, developing techniques to analyze data to generate forecasts, and communicating forecasts and warnings to stakeholders is vital.

Following these maintenance and inspection practices can help mitigate flood risks and their negative effects. It is also crucial to remain aware of potential flooding in the area and take appropriate action during and after flood events. Additional resources can be found on this website to learn ways of protecting property from a flood event.

Reducing the risk of back up in homes

Safety, sanitation, and clean-up are essential in sewage systems during floods. Homeowners must be cautious as sewage can back up into the house, contaminating the drinking water. It is vital not to use or limit the use of the sewage system during floods to minimize waste water pollution. Turning off the sewage lift pump prevents silt from entering the septic system while not pumping sewage system tanks makes them less buoyant. Floor drains should be plugged if necessary to avoid seepage into the basement.

After the flood recedes, using the sewage system must wait until the water level drops below the tank and tile bed to avoid damaging the system. Electrical connections ought to be checked for harm and dryness before restoring electricity. Septic tanks require professional inspection and servicing if suspected of being damaged. A specialist should repair septic tanks as they may contain hazardous gases. A new tile bed may even need to be installed in extreme cases. Finally, it is vital to have the septic system pumped by a professional once the soil is no longer saturated or flooded.

Treating mold issues

If your home was flooded or damaged by water, mold may be present and may pose a health risk. You may see or smell mold on clothing, drywall, and furniture. It may also be hidden under or behind items like flooring, appliances, or walls. Drying your home and removing water-damaged items is the most important step in repairing mold damage.

Problems Associated With Mold
Medical: Mold spores are microscopic organisms that can float through the air and cause problems with allergies, asthma, infections, and other respiratory issues. Anyone can suffer from medical issues related to mold. However, infants and children, the elderly, and those with weakened immune systems may experience more severe reactions. People with breathing problems like asthma or who have weakened immune systems should stay away from moldy sites.
Home: If your home has mold, everything that has been contaminated must be cleaned properly and dried. Items that cannot be properly cleaned and dried within 24-48 hours must be removed and thrown away, including structural and personal property. Children should not take part in disaster cleanup work. It is possible to have mold damage, despite no other visible damages.

How to Remove Mold and Repair Your Home
Mold removal and home repairs are serious projects that may be difficult or dangerous, so it may be best to get help from a professional. If you must remove the mold yourself, follow these steps:
Wear Protective Gear: If you are removing any damaged property on your own, make sure you wear protective eye masks or goggles, filter face masks, gloves, a long-sleeved shirt, long pants, and waterproof boots to avoid contact with the mold.
Dry the Structure: Clean and dry the structure as quickly as possible. If your house has been empty for several days, open the doors and windows to let the house air out for at least 30 minutes before you stay for any length of time. Open inside doors, especially closets and interior rooms. Open kitchen cabinets and bathroom vanity doors, and wipe them clean.
Circulate Air: When electricity is safe to operate, use fans and dehumidifiers to remove moisture. Position fans to blow air out doors and windows.
Remove All Contaminated Materials: Ensure that you have located all contaminated structural materials and personal property. Remove and dispose of anything that was wet and can’t be cleaned and dried completely.
Cleaning the Property: Clean with water and detergent. Remove all mold you can see. Dry right away. If you use cleaning products, do not mix cleaning products together. DO NOT mix bleach and ammonia because it can create toxic vapors. After you finish cleaning the home, shower and change your clothes as soon as possible. This will help you avoid carrying mold and other hazards back to your current living quarters.
Repairing the Property: Painting or caulking over mold will not prevent mold from growing. Fix the water or moisture problem completely and clean up all the mold before you paint or caulk. All mold must be removed and all areas must be disinfected before repairs can begin.