A large number of sensors are deployed to ensure reliable operation of the generators and turbines in the hydroelectric power plant. They monitor the pressure in the hydraulic lines, the lubricant supply for turbine bearings, vibration, temperatures and many other parameters. At the lowest point of the plant, cooling water from the generators and any leakage water from the Kaplan or Francis turbines is collected in a seepage water shaft, pit or sump. To prevent a flooding of the shaft and thus of the turbine building, with disastrous results for equipment, the sensors are often installed redundantly. As additional protection, the maximum water level is monitored with a point level switch.