| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a method which can cope with emergency promptly in a drain method when the water level of a water storage area has come down below a drain opening. SOLUTION: Usually, the surface layer water in a water storage area pumped up by a pump 3 in introduced into a pressure tank 4, and after being pressurized at a prescribed pressure for a prescribed time, ejected from a launching nozzle 24 or a sprinkling nozzle 25 to be returned to the area. When the water level of the area has come down below a drain opening, a provisional water conveyance pipe 6 reaching the drain opening is connected to water conveyance pipe 5, and the surface layer water pumped up by a pump 3 is led to the water conveyance pipe 5.</p> |
