Portage Diversion
The Portage Diversion () (also known as the Assiniboine River Floodway) is a water control structure on the Assiniboine River near Portage la Prairie, Manitoba, Canada. The project was made as part of a larger attempt to prevent flooding in the Red River Valley. The Portage Diversion consists of two separate gates which divert some of the flow of water in the Assiniboine River to a 29 km long diversion channel that empties into Lake Manitoba near Delta Beach. This helps prevent flooding on the Assiniboine down river from the diversion, including in Winnipeg, where the Assiniboine River meets the Red River.

During flood years such as the 2011 Assiniboine River flood, inlet flows to the Portage Diversion control structure were measured at over . This amount of water would have disastrous effects if left to flood southern Manitoba. During the flood of spring 2011, the Portage Diversion handled roughly half the flow of Niagara Falls.

The Assiniboine River and diking system can handle flows up to approx without a serious breach. However, many properties between Portage la Praire and Winnipeg are flooded once the flows exceed 10,500 cfs, including commercial establishments such as the KOA campground in St Francois Xavier. Over the past few years as high river flows have occurred east of Portage la Prairie, residents have noted significant bank erosion and stands of trees decades old are dying off. In recent years government policy has allowed 12,000 + cfs down the lower assiniboine towards Winnipeg causing major property and environmental damage.

The diversion was originally designed to carry a volume of . Under a state of emergency in early May 2011, Manitoba authorities did extensive work by raising the dikes and were preparing to send up to down the diversion channel with bridges downstream being the determining factor in flow rate.,

The diversion was built at a cost of $20.5 million in 1970. The diversion control dam is 35 feet (11 m) high and 1,400 feet (430 m) long and allows storage.
Q220503
Assiniboine River
LOC
Q1017624
Portage la Prairie
LOC
Q1948
Manitoba
LOC
Q16
Canada
LOC
Q2408452
Red River Valley
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Q645901
Lake Manitoba
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Q2135
Winnipeg
Concept
Q156006
Red River
LOC
Q4620414
2011 Assiniboine River flood
Concept
Q34221
Niagara Falls
LOC
Q7231411
Portage Diversion
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Q7231411
Portage Diversion
LOC
Q7231411
Portage Diversion
LOC
Q7231411
Portage Diversion
LOC
2011-01-01T00:00:00Z^^http://www.w3.org/2001/XMLSchema#dateTime
2011
DATE
2011-01-01T00:00:00Z^^http://www.w3.org/2001/XMLSchema#dateTime
2011
DATE
2011-05-01T00:00:00Z^^http://www.w3.org/2001/XMLSchema#dateTime
May 2011
DATE
1970-01-01T00:00:00Z^^http://www.w3.org/2001/XMLSchema#dateTime
1970
DATE
+29^^http://www.w3.org/2001/XMLSchema#decimal
29
NUMBER
+20.5^^http://www.w3.org/2001/XMLSchema#decimal
20.5
NUMBER
+35^^http://www.w3.org/2001/XMLSchema#decimal
35
NUMBER
+11^^http://www.w3.org/2001/XMLSchema#decimal
11
NUMBER
+430^^http://www.w3.org/2001/XMLSchema#decimal
430
NUMBER
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