1. What gives the Conservation Authorities the right to tell people what they can and can’t do on their own private property?

A. The provincial Conservation Authorities Act grants us the responsibility and obligation to direct development away from low-lying areas beside a water channel, known as the floodplain. We do this to protect people and property from damage or loss from flooding. The Act came into force in 1946, although the RVCA wasn’t created until 1976.

We also have a responsibility to protect wetlands, streams and tributaries from development, interference and alterations, which means projects like dock installations, shoreline repairs and some landscaping could require permits to protect the nearby waterway from contamination or damage.

2. How do you know when we’re going to flood?

A. We never know exactly, nor by how much. But our staff includes highly-trained engineers, hydrologists, technicians and GIS experts who use past and current data to model and predict how water levels and flows may change under certain conditions. Historical data is used to model the river and its tributaries to develop floodplain mapping for floods that statistically take place every five, 10, 20, 50 or 100 years. Using current conditions and forecasted weather, we can estimate how serious we think flooding may become and inform the public. Snow pack measurements, rainfall and temperature all play a role in calculating the risk of spring flooding.

3. I’ve lived on the Rideau all my life and never been flooded. Why should I believe your fancy guesses?

A. We provide the best possible information we can based on the best science we have to help you protect you and your family from flooding danger.

Our estimates are based on the best available scientific information about the shape of the valley, soil conditions, current weather conditions and how these factors help predict the likelihood of flooding. They remain estimates, however, and they are not 100% accurate. Neither is human memory.

4. What is the 1:100 year flood?

A. The 1:100 year flood is the high water level that has a 1% chance of occurring each year. The Conservation Authority is obliged by provincial law to protect Rideau Valley citizens to at least the water level resulting from a 1:100-year event. The highest flow on record on the Rideau was on March 28, 1976. That peak flow was estimated to be a 1:25 year flow

5. If flooding is so serious, why are people allowed to build in the floodplain?

A. They aren’t! Conservation authorities and municipalities are mandated by the Province to regulate development in and around waterways. No new development can be built within the 100-year floodplain. But many homes and cottages existed before those regulations came into force, “grandfathering” their existence. However, these homeowners are required to floodproof their homes when they’re renovating or rebuilding.

6. Shouldn’t flood zones be mapped, and the info kept up-to-date?

A. Yes, and many are! Provincially, Ontario has some of the most extensive flood mapping in Canada, because of the unique existence of conservation authorities and their flood management mandate.

The RVCA now has floodplain mapping on more than 1,000 km of waterways in its watershed, focusing on developed areas. Each year more maps are created or updated in a continuous cycle of improvement. This work is limited only by time and funding. Since 2012, additional funding from the City of Ottawa, and more recently the federal government, has allowed local conservation authorities to ramp up their mapping efforts even more.

7. Why can’t you use the Rideau Canal locks and dams to prevent floods?

A. Parks Canada is responsible for managing water levels on the Rideau Canal, and they do lower levels in the fall to make room for winter and spring runoff. Bobs and Christie Lake are reservoir lakes but, being in the upper watershed, they don’t catch any water that enters the system downstream, where storage capacity is low.

The beautiful historic dams along the Rideau are mainly for controlling navigation levels, not flooding. Enough water from melting snow and rain in the spring will cause flooding despite using the dams as best we can to disperse the water.

Parks Canada also can’t use its locks to release water in the event of a flood. Canal infrastructure is nearly 200 years old in some places, and the bottoms of the locks aren’t protected against erosion. Sending a rush of flood water through them could be very damaging.

For more details, please contact Parks Canada at the Rideau Canal Office (613-283-5170).

8. Why don’t you use the dam at Rideau Falls to control flooding?

A. The dam at Rideau Falls is owned and operated by the federal Department of Public Works and Government Services. It produces hydroelectricity and is operated according to a schedule and an agreement to provide power. This limits its ability to be fully opened when flooding is occurring on the Rideau.

9. Who “lets” the flooding happen?

A. No one – and no one is purposefully directing water away from one community toward another, either. The fact is, you can’t fully prevent flooding. It’s a natural and important part of a healthy river system, which is why the waterway AND its floodplain are considered part of the river. Conservation authorities mitigate the risks to people and property through a mix of floodplain mapping, monitoring, infrastructure upkeep and development regulations.

In fact, Ontario’s 36 conservation authorities have done such a good job keeping new development out of the floodplain, they’ve made their greatest benefit nearly invisible: new communities rarely flood, so their residents may not even recognize the potential danger they’ve avoided.

10. What can we do to prevent more flooding?

A. Flooding is a natural process, and humans must respect a river’s need to contract and expand with the seasons. But we can build natural flood resilience into our environment by supporting healthy forests and wetlands. These areas absorb rain and snowmelt and then slowly release it into waterways over a long period of time. Without forests and wetlands, intense rain and snowmelt would rush directly into already swollen lakes and rivers, making flooding worse.

When images of flooding are fresh, it’s easier to remember the importance of what conservation authorities do, but we need strong public and political support for our work long after the flood waters recede.

In the end, we must all work together to create communities where people and their homes are protected against damaging floods like we saw this year.