Control blasting on the Cross Lake weir project

In 1972 Manitoba Hydro decided to develop the hydro electric potential of the Nelson River. This program included the construction of the Jenpeg Generating Station at the point where the channel of the Nelson River discharged into Cross Lake. The Jenpeg station serves two primary functions: (1) Provides a control structure for the regulation of Lake Winnipeg, and (2) Acts as a 126,000 kilowatt hydraulic generating station. By regulating the level of Lake Winnipeg, Manitoba Hydro was able to: maintain a desirable recreational level in Lake Winnipeg; utilize the huge area of Lake Winnipeg for summer ponding; and maximize water release during fall and winter to satisfy peak power demands at maximum prices. Unfortunately the regulation project adversely affected the water level of Cross Lake and the native community spread out along the shoreline of the lake. Summer ponding at Jenpeg allowed the lake level to drop each summer creating a wide mud flat where docks had been. Fishing and trapping were seriously affected. In winter additional flows would flood the ice cover and create slush under the snow. The Weir Project was designed to maintain the water level of Cross Lake in a natural range. In order to do this it was necessary to restrict the flow through the centre channel and provide excess flood capacity at a controlled elevation through the East channel peninsulas. The paper describes the location and construction of the weir in the centre channel