Eco-physical bioengineering for nature-based landslide mitigation in tropical rural landscapes: a conceptual review and secondary data synthesis from Kaliwiro-Wonosobo, Indonesia

Abstract

In tropical rural landscapes, landslides remain a major geo-environmental hazard due to the interaction of steep slopes, intense rainfall, weathered silt-clay soils, land use pressure, and poor drainage. This article aims to present the development of an eco-physical bioengineering framework for nature-based landslide mitigation. Kaliwiro district, Wonosobo regency, Central Java, Indonesia, is used as a case study. A conceptual review is combined with secondary data synthesis from local landslide risk studies, engineering geology data, disaster records, and international literature on root reinforcement, hydrological vegetation effects, and soil bioengineering. Published soil and landscape parameter data for Kaliwiro, namely an average soil cohesion of 0.205 kg cm−2 (20.10 kPa) and an internal friction angle of 17.47°, are integrated into an unconfined slope scenario analysis. The results indicate that slope stability is highly sensitive to pore water pressure. Without root reinforcement, the factor of safety (FS) for a 35° slope decreases to 0.90 at a high pore water pressure ratio (ru = 0.75). Moderate root cohesion of 6 kPa increased the FS to 1.14, while the combination of root strengthening and ecological drainage increased the FS to 1.25. A comprehensive bioengineering scenario combining strong root cohesion (12 kPa), pore water pressure reduction, contour drainage, ground cover, mulch, bamboo structures, and local stone barriers increased the FS to 1.60, or 77.1% above the critical baseline. This study demonstrates that effective landslide mitigation in Kaliwiro relies not only on tree planting, but on an integrated system of multi-strata vegetation, local natural materials, ecological drainage, and community-based monitoring.