Small Fish-pond Design for Debris Flow Disaster Measure with Kanako-2D

Masato KOBIYAMA, Rossano D.L. MICHEL, Maurício A. PAIXÃO and Gean P. MICHEL

Natural disasters related to debris flows have been increasing in Brazil. This phenomenon occurs mainly in rural and mountainous regions where farmers live without much support from public authorities. Therefore, it is necessary to seek structural preventive measures appropriate to the current situation of rural communities. An alternative is the construction of small fish-ponds along the river channel that support to mitigate the debris flow propagation. Therefore, the present study used the Kanako-2D model to analyze how different geometries and positioning of fish pond can influence on the debris flow propagation and deposition. The case study was carried out with the Böni creek catchment (2.27 km2) which is located in the southern Brazil. The results of 5 different scenarios showed that the fish-pond location was more relevant than its geometry. If a pond is constructed at a less appropriate location, a much larger volume of the pond is required to break the downstream and to stop the debris flow. The fish-pond construction for debris flow disaster reduction can be considered a kind of socio-engineering and should be popularized more widespread in Brazil.

2018/1 264-269