Supplemental Materials for "Smart-Green Hybrid Digital Twin Framework for Vetiver NbS Scour Countermeasures"

Tables S1-S8 provide: S1) HEC-RAS 2D mesh sensitivity analysis at the abutment; S2) Manning’s n calibration for vetiver channels from literature and field tests; S3) Digital twin alert thresholds for velocity, shear stress, and scour depth; S4) Sources of 140 laboratory cases used for Random Forest model training; S5) RF hyperparameter ranges and optimal values from 5-fold cross-validation; S6) UAV image dataset summary for vetiver health classification; S7) Bill of quantities comparing vetiver NbS vs. riprap, using NHA CSR 2023 rates; S8) Embodied carbon calculations using Ecoinvent 3.9 and ICE v3.0 factors.

Figures S1-S4 include: S1) HEC-RAS 2D mesh layouts showing 4m, 2m, and 1m refinements; S2) Sample UAV training images from DJI Mavic 3E showing classes for healthy vetiver, stressed vetiver, bare soil, and water; S3) Field photographs of vetiver growth stages at Kala Khatai site, Mar-Jun 2026; S4) Lifecycle cost comparison charts for vetiver NbS vs. conventional riprap. All data were generated using HEC-RAS 6.4.1, Python 3.11.5 with scikit-learn 1.3.2, Agisoft Metashape 2.0, and publicly available sources.