To provide a power generating and flood control water storage device for carrying out the adjustment of river water in heavy rain, drainage of low land, water storage in a drought and power generation in normal times by providing a drainage water storage pipe, a drainage water storage pipe joint, a main drainage water storage pipe and a feed and drainage pipe with solenoid valves, a power generating and drainage turbine and feed and drainage pumps, and combining a river water amount detector, a precipitation amount detector and a control device.

This device is installed inside a bank. In the case of heavy rain, water staying on the low land is pumped up by the feed and drainage pump 1, and discharged to the mouth of a river by the power generating and drainage turbine 2 through the feed and drainage pipes 6, 10, the main drainage water storage pipe 5, the drainage water storage pipe joint 4 and the drainage water storage pipe 3. In the case of water shortage, water is filled in the main drainage water storage pipe with natural flow in the upstream, or by the feed and drainage pump, and the water is supplied by the pressure. In normal times, power is generated by rotating the power generating and drainage turbine by the pressure of the water filled in the main drainage water storage pipe with the natural flow or by the feed and drainage pump.