A Hydro-Mechanical Framework for Slope Mounted Agrivoltaic Infrastructure: A RUSLE Based Framework for Dripline Scour Mitigation and Foundation Stability

Bangladesh’s renewable energy roadmap targets 60,000 MW by 2041, necessitating solar deployment on steep,erosion-prone slopes in the Chittagong Hill Tracts; yet the geotechnical implications of hillside PV infrastructure remain critically understudied. This paper introduces a hydro mechanical framework that couples RUSLE-calibrated soil loss prediction with a geometric concentration factor and infinite slope stability analysis to evaluate foundation resilience on a 21° engineered terrace at Alutila, Khagrachhari. Rainfall intercepted by 3m-wide PV panels concentrates at the 0.1m-wide drip edge, creating a 30x concentration factor (CF = 3.0/0.1 = 30) that accelerates localized scour directly around pile foundations. Under bare slope conditions, erosion of 86.62 t/ha/yr translates to 185.6 mm/yr of localized scour, reducing pile embedment from 1.5m to 1.0m over five monsoon cycles and increasing the overturning lever arm by 33.3%. The proposed coupled PV+Vetiver system reduces scour to 1.18
mm/yr (99.4% reduction), preserving 99.3% of design embedment. Infinite slope stability analysis shows the Factor of Safety (FoS) recovering from 0.98 (UNSTABLE) under bare conditions to 1.76 (STABLE) within two years of Vetiver establishment. Sensitivity analysis under extreme conditions
(+25% rainfall, +50% immaturity factor) confirms FoS = 1.23 > 1.2, proving robust resilience. The framework offers three distinct contributions: the first mechanistic “dripline bio-shield” concept using strategically placed Vetiver; the first quantitative linkage between monsoonal soil erosion and pile foundation embedment in agrivoltaics; and a transparent,
software-free methodology calibrated for Bangladesh’s hill slopes. Practical recommendations are provided for engineers, policymakers, and regulators deploying solar infrastructure in monsoon-affected regions.