PURPOSE: To lower the vertical height of a water intake part by a method wherein a tube body is surrounded elevatably with a space kept from the outer periphery thereof and a water intake means surrounding a screen is provided on the outer periphery in the upper part thereof.

CONSTITUTION: When the water level in a water reservoir part is near the high- water level and the water surface 02 is positioned in the upper part, cylinder gates 8W10 are connected straight with each other and form a long cylinder upward. When the water in the surface part is taken in, a motor 2 is operated and the water intake is conducted by an intake part 7. The water taken passes under a screen 6 and flows in from the upper end of the cylinder gate 8, and then, passing through the cylinder gates 9 and 10, enters a water conduit pipe 16. Next, when the water level lowers,the cylinder gate 8 is raised a little of make a small aperture from the cylinder gate 9 and the height of the intake part 7 is adjusted properly to the water level, whereby water intake is performed.