Winnipeg Floodway and the Z-Dike : Duff’s Ditch Saves Winnipeg

When people think of man-made wonders, few would think of a feature affectionately known as “Duff’s Ditch, but this 47-kilomter long channel that runs from the Red River just as it enters Winnipeg long a semi-circle route to a point many kilometers north at Lockport is now a Canadian National Historic Site.

When it was built beginning in 1962, it was the second largest earth moving project undertaken in the world, second only to the Panama Canal.

Designed to protect the city of Winnipeg against the frequent floods in the spring, many mocked its creation and branded it disdainfully as Duff’s Ditch, after the premier of the province, who undertook the project. Yet, numerous times it has helped the city avert catastrophe from spring flooding and now is admired world-wide.

However, in 1997, Manitoba experienced a 1 in 140 year flood, and the province undertook to expand the floodway to between 9-20 meters deep, capable of handling flows of 2,500 cubic meters per second.

That flood also precipitated another engineering marvel, mostly because of the speed with which the Z-dyke was built, when water from the Red River threatened to inundate Winnipeg in spite of the floodway.

This 40-42 km dyke was constructed of old cars, derelict dump trucks and school buses and an assortment of other material, along with huge quantities of earth, to create a barrier against overland flooding.

While BC’s and Quebec’s spring floods are vicious, instant and unpredictable, Manitoba is so flat that flooding can be anticipated weeks in advance. In 1997, though, a major blizzard in April turned flooding forecasts upside down and the province had only a week or so to build this immense wall. It worked, as did the floodway and today, the city boasts that it can withstand a 1-in-700-year flood, thanks to the remains of the Z-dyke and the expanded floodway.

But spring floods are extremely varied, and in 2026, the floodway was opened only for a day or so, with Duff’s Ditch seeing almost no water flow north.

Instead, it had become a favourite place for birders, nature lovers, hikers, cross-country skiers, cyclists and even off-road riders to enjoy the outdoors on its banks year-round.