Flood, tide strong combo; TANTRAMAR MARSH
A sea of waving grass links Nova Scotia and New Brunswick. Between the Bay of Fundy and the Northumberland Strait lie some 49,000 hectares of marsh.
Straddling it between Amherst and Aulac are two vital links - about nine kilometres of railway and 10 kilometres of the Trans-Canada Highway.
Aside from those links, "most of what's behind the dikes there," says John Shaw,
"is agricultural land. The problem of salt marshes and building on this low-lying land is the problem of storm surges. Essentially we get a storm surge when we have low pressure and very strong winds, and the storm surge will result in the elevation of the level of the water in the ocean."
The worst flooding of the Tantramar within the last several hundred years was during the Saxby Gale in 1869. Within a few hours, water from the Bay of Fundy swept ashore along the Maine, New Brunswick and Nova Scotia coasts, causing death and destruction of property.
"Storm surges only last a couple of hours and the time at which the tide is at its highest level in the Bay of Fundy is only almost in minutes," explains Shaw. "The storm surge has to strike at that moment and it's not just any tide. It has to be a peragean spring tide, that very special tide which occurs every week or every two weeks. In the Saxby Gale, a storm surge coincided with an unusually abnormal high tide."
"Some day the whole of the Tantramar will go under water," adds Shaw.
"When a hurricane comes up the Bay of Fundy and a storm surge coincides exactly with a peragean spring tide, everything is going to go under water. It probably will happen and it's not something you can predict."
Source: Finance et Investissement, Apr 15, 2007, pS4