Flood warning and forecasting isn’t as simple as assuming that because there is a lot of snow, flooding is to be expected.
There are a number of factors behind the North Bay Mattawa Conservation Authority (NBMCA) flood forecasting and statements which include flooding or safety risks, ice damming, or ice jamming.
Its water resource engineer, water resource scientist and a number of other staff members are all involved in data collection and analysis.
“There is work that goes into gathering that data, there is work that goes into analysing that data, and there is work that goes into interpreting and saying what the risk really is,” said Sue Buckle Communications and Outreach with the North Bay-Mattawa Conservation Authority.
“We look at precipitation and the amount that is happening, the frequency and intensity. So, if you get a lot of rain in a short period of time, and repeatedly, that is a way that would increase the risk,” explained Buckle.
“We look at other factors in terms of wind, sunshine, the soil conditions, its capacity to absorb rain. We look at the water levels, so in Lake Nipissing as well as the stream levels. We monitor the temperature, and throughout the winter we measure the snowpack and assess it for both depth and water content.”
The NBMCA closely monitors the five day forecasts.
“It is the most reliable. We will look further out then that, but that is just giving us a hint about what might come. So, you’re really looking five days ahead, and even the fifth day out, you’re not 100 percent sure that it isn’t going to change, so you have to stay on top of it all the time,” said Brian Tayler Chief Administrative Officer NBMCA.
“We’re flood warning and forecasting, so the municipalities are largely the ones that are responsible for taking a response to the flood conditions. We’re there, sort of the canary in the mine shaft kind of thing, to give them an idea about what potentially might be coming. We’re also aware of where the flood plains are, and the flood plain conditions and where the risk centres are, related to built up structures and things like that. We can give them an idea about where there might be the greatest impact.”
Which is why the authority has a daily planning cycle.
“We look at weather forecasts from several different sources, and that is the MNRF, Environment Canada, and the Weather Network for example,” said Kurtis Romanchuk, water resources engineer at the NBMCA.
”We also look as part of that daily planning cycle at the levels in all our different gauges. We look at the level they’re at, the level they are at relative to the monthly average for this time of year, and if there’s any incoming precipitation. We do site inspections as part of that daily planning cycle if necessary, if we want to look at something in the watershed. And we have conversations with our partners as needed.”
The authority has a plan in place, outlining the roles and responsibilities of its various partners.
Within its jurisdiction, the authority is responsible for 29-hundred square kilometres, based on the flow of the watershed that flows into Lake Nipissing through North Bay and Callander.
“Our jurisdiction includes the shoreline of Lake Nipissing for the City of North Bay and the Municipality of Callander. Our responsibility would be to assess risk for flooding, or damages and to notify the municipalities of those risks,” noted Buckle.
“Outside our jurisdiction it would be the responsibility of the Ministry of Natural Resources and Forestry. So, they are responsible for monitoring those conditions and issuing any warnings to the public about any risk of flooding outside of that area.“
Buckle explained the significance of the surface water monitoring centre operated by the MNRF is significant.
“They provide lots of forecasts and oversights and calculations in terms of some risk factors that we take into consideration for our local conditions. We partner with other conservation authorities in terms of some of our data analysis and looking at what happens with snowbank melt. So, there’s lots of partnerships and collaborations that happen.”
CAO, Brian Tayler says although the snow is above average, there are no specific concerns about this year’s melt at this point.
“There is a lot of water content, but it really depends on those other factors. The greatest thing that contributes to the spring freshet and the potential for flooding is the short term weather.”
The annual removal of ice from Parks Creek to prevent flooding, got underway late in the week.
Logs, which are really steel beams, can be lowered to block the gates from opening, preventing the flow of water back up the creek which could lead to flooding, if Lake Nipissing’s water levels get too high.
“When it is totally closed up, Parks Creek won’t be able to get out, it won’t be able to flow past the structure. So there is a pump built into it that basically carries the water from Parks Creek out of the end of the creek, and into the lake, up over the structure,” said Kurtis Romanchuk, water resources engineer at the NBMCA.
The authority has a plan in place that outlines the duties and responsibilities of its partners including Public Services and Procurement Canada.
“The surface water monitoring centre that the MNRF operates is significant. They provide lots of forecasts and oversight and calculations in terms of some risk factors that we take into consideration for our local conditions. We partner with other conservation authorities in terms of some of our data analysis and looking at what happens with snow bank melt. So there are lots of partnerships and collaborations that happen,” said Buckle.
The authority stays on top of conditions through its daily planning cycle.
“We look at weather forecasts from several different sources, and that is the MNRF, Environment Canada, and the Weather Network for example. We tend to mostly look at a five day forecast,” said Romanchuk.
”We also look as part of that daily planning cycle the levels in all our different gauges. We look at the level they’re at, the level they are relative to the monthly average for this time of year, if there’s any incoming precipitation. We do site inspections as part of that daily planning cycle if necessary if we want to look at something in the watershed, and we have conversations with our partners as needed.”
At this point there are not concerns about this year’s melt.
“There is a lot of water content, but it really depends on those factors we talked about. The greatest thing that contributes to the spring freshet and the potential for flooding is the short term weather,” said Tayler.
Romanchuk explains that the water courses are for the most part "at" or slightly above average.
“That is the result of the thunderstorm we had last week, but Lake Nipissing is at an average level. Our snow water equivalent is at about 160 percent of normal, in the areas around us, they’re also around 160 percent. It has been a bit of a snowy year, but so far I think we’re seeing a nice melt starting in the spring, so far we’ve been okay,” said Romanchuk.
“We’ve had some above zero temperatures, we’ve had some sunny days, and that has allowed some of the snow pack to start to release already. So far, I think we’re all good. We’ll just keep watching the forecast,” said Romanchuk.
The authority will issue anyone of four flood related statements as needed..
An example of a water safety statement is when flooding may not be expected, but as things start to melt, there is a safety issue around water courses. It is a warning to the public to stay away from those areas.
A flood outlook statement gives early notice of the potential for flooding (high runoff, ice jams, lakeshore flooding or erosion.)
A flood watch happens when the potential for flooding has been identified in specific watercourses and/or municipalities, and emergency services are advised to prepare.
A flood warning indicates flooding is imminent or occurring.
“This information that we get out to our partners and municipalities is so the emergency response agencies can get prepared and get information out to the citizens, and we share the information as well to the community in a number of different ways,” explained Buckle.
One of those ways is through the media.
The conservation authority invited news outlets to an information session explaining the science behind the flood forecasting program.