Irrigation technology has improved so much since the modern times that irrigation and drainage can be made possible by building a waterwheel along the channel even on alluvial plains where the slope is gentle, and as a result, rice cultivation has spread to downstream plains which are called breadbaskets today.
近世以降は灌漑技術が向上し、傾斜が少ない沖積平野でも、水路に水車を設けて灌漑や排水が出来るようになり、現在、穀倉地帯と呼ばれるような河川下流域の平野での稲作が広まった。