POWERHOUSE APPROACH FLOW STUDY FOR MISSISSIPPI RIVER LOCK AND DAM NO. 2 HYDROPOWER PROJECT.

A 5 Mw hydroelectric generating facility is currently under construction on the Mississippi River at Lock and Dam No. 2 near Hastings, Minnesota. A 1:72 scale fixed bed model was constructed of a river reach extending 1-1/3 miles upstream and 2/3 mile downstream of the dam. Upon completion of the tests required for the navigation study, it was decided that the model would further be used to study some aspects of the powerhouse approach flow. In particular, only flow separation and flow direction in the powerhouse approach were studied. Flow patterns were documented by overhead photography of dye traces for subsurface flow and confetti motion for surface flow. Velocity profiles were taken with an electromagnetic current meter at 10 positions. It is concluded that intake conditions in the absence of any design modifications will not be ideal. A number of design modification alternatives are suggested.