Saugeen Conservation predicts spring flooding but maybe
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Ron McManus of the Saugeen Valley Conservation Authority (SVCA) gets ready to take some snow course readings
photos courtesy of Saugeen Conservation
This winter has been one of the coldest in the past 40 years, leaving the area with an accumulated snow pack that has never seen before, according to the Saugeen Valley Conservation Authority (SVCA).
Based on snow course readings taken by SVCA staff at 14 different stations across the watershed, the average snow depth is 17.75 inches (47 centimetres).
There are a number of other factors involved with forecasting spring watershed conditions. Once snow course readings are taken, staff then determine the actual ‘water content’ or equivalent amount of water in the snow. This figure, based on March 1 readings, is 7.3 inches (185 millimetres), a little over double the historical average amount for early March.
Snow density is also an important factor. Snow density values help determine when the snowpack is saturated.
A snow density value of 45 per cent typically indicates that the snowpack is “ripe” or that run-off can be expected at any time favourable temperatures occur. Currently, the average snow density across the watershed is 39 per cent.
Staff also looks at ice cover. This year, the ice cover is the most extensive this area has seen in a number of years. While some areas along the Saugeen River have historically been prone to ice-jamming, jams can occur anywhere along waterways at any time during the initial stages of break-up.
It’s probably no surprise that given the amount of snow and ice in the area this winter, there is a possibility of significant spring run-off. The extent, however, will depend entirely on weather conditions.
Should an abrupt and prolonged period of mild and wet weather prevail, there may be a rapid break-up and melt, that, combined, could generate much higher flows than seen in the last number of years.
Ideally, temperatures above freezing during the day and below freezing overnight (also perfect maple syrup weather), serve to gradually deplete the snowpack over a period of two to three weeks, and allow the rivers to flush out the ice and excess water in a naturally controlled manner.
Does the potential for flood exist? The Saugeen River is 192 kilometres in length, the third largest river system in southern Ontario. The potential for flooding always exists, but usually is most prominent at this time of year as the winter’s accumulation of snow melts.
SVCA staff will be continuously monitoring conditions as spring approaches to inform and prepare municipalities and watershed residents of potential flood events. Should flood-related messages be issued, there are three types of condition statements that watershed residents should be aware of, depending on the severity of the situation.
It is important to know the difference between the three. These are also standard across the province for all 36 conservation authorities.
Interesting Facts on the Saugeen River watershed area:
Ron McManus of the Saugeen Valley Conservation Authority (SVCA) takes snow course readings in the Saugeen watershed
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Saturday, March 08, 2014