Evaluating the effectiveness of basin management using agricultural land for ecosystem-based disaster risk reduction

Flood risk reduction is a crucial global issue. Structural measures against floods have an upper limit on their function; thus, when the magnitude of floods exceeds this upper limit, few functions can prevent damage. Non-structural measures such as ecosystem-based strategies for disaster risk reduction (Eco-DRR) are attracting growing interest. In this study, I test the effectiveness of flood mitigation on agricultural land, which is a semi-natural ecosystem, using both municipality and watershed data from 9 years of statistical records on flood damage to test the relationship be-tween flood frequency and land use patterns with terrain conditions in both municipalities and watersheds. I also conduct a simulation in which agricultural land use is reduced to compare the effectiveness of flood mitigation between the two scales. The results indicate that both paddy fields and dry farmland located in a water storage zone are effective in reducing flood frequency. In addition, this function is greater for watersheds than for municipalities. Thus, the conservation of agricultural land in which water storage zones are located could enhance Eco-DRR for flood-ing, especially in watersheds. I conclude that combining structural and non-structural mea-sures-namely, Eco-DRR-is the most effective flood mitigation strategy for watersheds.

Automated summary

This study investigates the effectiveness of flood mitigation on agricultural land, specifically in relation to water storage zones. The results show that paddy fields and dry farmland located in water storage zones are effective in reducing flood frequency. Additionally, this effectiveness is greater in watersheds compared to municipalities. Therefore, conserving agricultural land in water storage zones plays a crucial role in eco-disaster risk reduction for flooding, particularly in watersheds.