Although there’s less snow cover on the ground than in most previous years, Grand River Conservation Authority (GRCA) is warning residents to expect spring flooding again this year.

Hardly a year passes without a flood in the downtown of Grand Valley, and flooding there has been known to extend all the way to the Royal Bank.

There, some residents had hoped that the near-lack of snow on the ground this year would mean less flooding, but the opposite may be true.

“The amount of snow on the ground may be low, but the chances of a flood this spring are still high,” says a GRCA report released this week.

“Given the saturated ground conditions in some areas of the watershed, the potential for a major flood is higher than normal if heavy spring rains occur along with a rapid spring snow melt,” Gus Rungis, senior water resources engineer with the GRCA told a municipal and emergency services personnel meeting at the GRCA head office in Cambridge.

“Most winters, a covering of snow will insulate the ground and keep it from freezing. In the spring the snow can soak up some rainfall, slowing the amount of water making its way to a water course. In addition, if the ground is unfrozen, water can soak into the ground rather than run off.

“But this year the amount of snow on the ground is only a quarter to half of normal for this time of year. The ground is saturated from rain in January and there is a consistent frost cover.”

Mr. Rungis said the chance of flooding as a result of ice jams is also high this year. Most of the Grand River and its tributaries are covered with sheet ice because of the steady cold temperatures this winter. There is a risk that, as the ice breaks up in the spring, chunks could become lodged in the river, creating an ice jam that causes water to back up behind it.

“Whether a major flood occurs is dependent on how the spring thaw unfolds,” Mr. Rungis was quoted as saying. “Fifty millimetres (two inches) of rain, in combination with a quick spring thaw or heavy rain on frozen or saturated ground would see the conditions needed for a major flood.”

GRCA measures snow depth in 12 locations throughout the watershed in order to calculate potential flows during the spring melt. In addition, water levels are monitored through more than 50 stream gauges which automatically send their data back 24 hours a day. The information is available in the River Data section of the website at www.grandriver.ca

GRCA using Twitter for flood messages

The GRCA has set up a Twitter feed to distribute flood messages throughout the watershed.

The new feed is called grca_flood_msg . Whenever a flood message is issued to the public, a Tweet will be sent out announcing the message and linking back to the full text of the flood message on the GRCA website.