The early modern era of Japanese history (ca. 1570-1868) has bequeathed to us a rich array of documents that describe increasingly ambitious efforts to reduce the impact of floods through combined use of dikes, overflow channels, the creation of new streams, and altering the course of rivers as engineers found them. The methods employed reveal a sophisticated use of natural materials and the existing topography to engineer reduced flood risk in ways that were quite different from those employed in places like Europe. Nonetheless, these works achieve some significant results. This reliance on natural materials and geography suggest ways in which modern riparian engineering might alter its environment-damaging “hard” approach in order to reduce environmental costs while still promoting reduction of disruption, damage and loss of life due to flood hazards.