Abstract: A system which turns at a low speed paddle vanes expanded in the direction toward the water surface can cultivate a vast volume of water with a very little quantity of energy and expose water at the water bed to the sun and winds. This enables flows generated near the water surface to expand indefinitely along the water surface exactly as the law of conservation of angular motion predicts, and there are generated flows converging on the original starting point of the flows. These cyclic flows activate the water bed and enables fishes to increase, and food chain serves to purity the water. This is a simple system of merely cultivating water with sunlight, needing no advanced technology, extra energy or chemicals. The present invention is intended to provide a bottom soil improving apparatus which draws on natural purifying forces and activates a vast stretch of water.