The Anatomy of Uncertain Terrains: Soil Topography Characterization and Discharge Analysis of the Baroro River Basin, Northern Philippines
Keywords:
Baroro River Basin, River pedology, River remote sensing, Soil taxonomy, Topographic wetnessAbstract
The Baroro River Basin in Northern Luzon is a critical hydrological feature providing irrigation and biodiversity services. However, the watershed faces severe vulnerabilities due to the interplay between high-discharge hydrological behaviors and anthropogenic pressures, specifically rapid Land Use and Land Cover (LULC) changes that fragment forest blocks and compromise soil stability. While socio-ecological baselines and local perceptions of degradation are well documented, there remains a lack of integrated quantitative modeling of the pedological and lotic processes on which human settlements depend. Existing studies do not adequately account for the physical feedback loops among soil properties, river discharge, and landscape fragmentation. This study used the Soil and Water Assessment Tool+ (SWAT+) in QGIS to simulate hydro-pedological trajectories from 1963 to 2063. The methodology integrated remote sensing with descriptive statistics to correlate variables such as Topographic Wetness Index (TWI), Soil Bulk Density (BD), and Soil Water Potential (SWP) against historical rainfall data. The analysis revealed the San Juan Anomaly, a 2–3 km zone of amplified TWI and sediment accumulation acting as a vital hydrological capacitor for riverine agriculture. Statistical modeling showed a decoupling between precipitation and discharge, with high upstream porosity (BD ≈ 0.69 g/cm³) buffering storm runoff. However, a sharp divergence exists between the simulated restorative potential forest recovery and the observed reality of downstream urban compaction and soil densification. The basin demands a management paradigm that treats it as a single functional unit. Immediate policy interventions must zone the San Juan alluvial scar for sustainable agriculture to prevent infrastructure encroachment. Long-term strategies should prioritize deep pedological rehabilitation through upstream reforestation to reduce bulk density, thereby restoring carbon storage and flood-mitigation capacity.
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