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Seine River Watershed
Marmion Sluiceway

Seine River Watershed Information The Marmion Sluiceway was constructed in the early 1950s when the Marmion block dams were constructed. In 1983, Ontario Hydro, now Ontario Power Generation (OPG), rebuilt the block dams. In 1997, Valerie Falls Limited Partnership (Brookfield Renewable Energy Group
) installed the new navigation sluice.

Lower Marmion Lake: The Lower Marmion Sluiceway controls the water levels and outflows of Lower Marmion Lake (3,960 ha). The watershed of the lake is very small (15,570 ha) relative to the size of the lake, which makes up 25% of the watershed area. However, unlike Lac des Mille Lacs, Lower Marmion Lake is not dependent on its local watershed for water replacement. Water from Upper Marmion Lake is used to replace water during the spring refill period. This allows a much larger range of potential level fluctuation.

Reservoir (storage)
382 m3/sec/days
1952, upgraded in 1983 and 1997
# of  sluices
1 6-log sluice; discharge capacity is 10m3/sec; normal operating range is 414.80-415.50 metres
Level at top of log with all logs in
415.60 metres
Level of sill with all logs out
413.50 metres
Lower Marmion drawdown is constrained by agreement with OPG to ensure suction head for cooling water pumps (minimum level 414.80 m). OPG may experience inadequate cooling water flows if the summer level is low.

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2004 level and flow data