Because their main strongholds, including Osaka in Settsu Province, Nagashima-cho in Ise Province (Mie Prefecture today), and the Yahagi-gawa River basin in Mikawa Province were all in the low-lying wetlands, some have suggested the Ikko ikki may have developed advanced flood control techniques (without which it would have been difficult to create prosperous communities in such flood-prone areas).
本拠地とされた摂津国大阪や伊勢国長島町(三重県)、三河国矢作川流域などは湿地帯であったことから、高度な治水技術があったのではないかとの見方もされている。