Churchill River Diversion

The Churchill River Diversion (CRD) was created to increase the water flow to our large generating stations on the lower Nelson River. Most of the water flow of the Churchill River is diverted at Southern Indian Lake into the Nelson River.

The Province of Manitoba approved the CRD in 1973 with the granting of a Water Power Act Licence. We began construction in 1973 and it was in operation in 1976.

The CRD main components:

  • The Missi Falls Control Structure – controls the water flowing into the lower Churchill River and creates an impoundment on Southern Indian Lake.
  • The South Bay Diversion Channel – a 9.3 km long channel that allows the Churchill River to flow into the Rat River–Burntwood River–Nelson River system.
  • The Notigi Control Structure – controls the water flowing from the Rat River into the Nelson River and creates an impoundment on Rat Lake.

The Missi Falls Control Structure controls the Churchill River flow and the water level in Southern Indian Lake. The flow moves through the South Bay Diversion Channel, down the Rat and Burntwood rivers, and into Split Lake using the Notigi Control Structure. The remaining flow is released by the Missi Falls Control Structure into the lower Churchill River. In total, an average 25% more water flows into the Nelson River system due to the CRD.

Augmented Flow Program

In order to test the effectiveness of the CRD project in 1978, we requested approval to test the diversion capacity over a wider range of flows than was set out in the Water Power Act Licence.

After a multi-year testing phase, we received approval in 1986 to change the water flows in winter and summer. This approach became known as the Augmented Flow Program and it continues to the present day under an annual continuance of our Interim Licence. Under this program, maximum flows through the Notigi Control Structure are about 15% greater, and  Southern Indian Lake experiences a greater range of water levels.

For more information about the environmental effects, read the Regional Cumulative Effects Assessment.

Read more about the Water Power Act licensing.