Irrigation and drainage systems are disclosed, including a saturated zone and at least one pipe in communication with the saturated zone. A very quick and at the same time easily controllable augmentation or reduction of the shaft power of the gas turbine unit can be achieved by providing at least one liquid droplet injection device on the upstream side of said compressor for injecting liquid into the stream of intake air in order to increase the shaft power generated by the gas turbine unit. Each projection set can then be independently processed based on the type of task andor the patient size to allow reduced and modified X-ray doses dependent on the task andor specific patient to be scanned.