Wind-Driven Flow in Mississippi River Impoundment

The analysis is made in order to determine: (1)How much of the Sturgeon Lake flow is drawn into the cooling water intake of the plant; and (2)by how much plant effluent cooling water or blowdown water is diluted by Sturgeon Lake effluent before entering the Mississippi River. A channel network analysis, including effects of wind stress on the water surface in addition to bed shear stress and local (minor) energy losses, was made to provide the required information. The Sturgeon Lake/North Lake system was studied before the complete analysis was made. In the absence of wind, flow through Sturgeon Lake amounted to about 22% of total river flow. At low plant withdrawal rates and at zero wind, the flow through the backwater channel in front of the plant outlet (channel 42) was about 10% of total river flow. Winds from 5 mph to 30 mph had a very noticeable effect on flows through Sturgeon Lake, particularly when total river flows were less that 10,000 cfs. The analysis was made without consideration of stratification effects near the plant intake and outlet.