Saturday, June 23, 2018
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Johnson Lake level to fall for hydro project

The Central Nebraska Public Power and Irrigation District will lower the water level at Johnson Lake beginning after Labor Day in preparation for a maintenance project at the Johnson No. 1 (J-1) Hydroplant.

The lake’s water level will begin dropping on Sept. 6 and will be down by about three feet by Sept. 26.  After reaching its low point, the lake will then begin to return to normal non-irrigation season levels.

Central will be replacing a circuit breaker and disconnect switches in the switchyard at the J-1 Hydroplant during the maintenance outage. The breakers are used to interrupt any short-circuits or overload currents that may occur on the electrical transmission network.  Disconnect switches interrupt power to electrical circuits so workers can safely work on electrical equipment.

The timing of the maintenance outage was coordinated with power generation at other power plants on the state’s electrical grid and during a period of lower demand for electricity that typically occurs in the fall.  In addition, the maintenance project in the outside switchyard needs to be completed before the possibility of inclement weather increases.

Johnson Lake is the regulating reservoir for two hydroplants on the Supply Canal below the lake.  During outages for maintenance or repair projects at the hydroplants, the lake is lowered to create space for water that enters the lake while releases through the hydroplants are suspended.