A water spider can walk on the surface of the water.

There were water striders floating on the pond.

The hippopotamus is a very rare animal.

A whirligig beetle is swimming in the pond.

He is an expert in hydrology, and his research is highly valued around the world.

She bought a new sukumizu.

This 'Mizufuda' is from an old era.

Lye water is necessary to make Chinese noodles.

There is a lot of spirogyra floating in this pond.

This area is rich in subterranean rivers, which serve as a source of groundwater.