Geomorphometric Characterization and Analysis of the Bued Watershed Using Advanced Spaceborne Thermal Emission and Reflection Radiometer – Global Digital Elevation Model V3 through Geospatial Techniques

Abstract

The present study analyzed and quantified the linear, areal, and relief geomorphometric aspects of the Bued Watershed in Benguet, Philippines using a 30-m spatial resolution digital elevation model. The study was carried out using geospatial techniques to describe the hydrogeological processes acting on the watershed including its landforms, geologic structure, and terrain features that are relevant in watershed conservation and natural resources management. The study site has a total area of 146.46 km² and a basin length of 23.38 km. Based on the linear parameters, it has four stream orders generated using a 1.5-ha critical source area (CSA). Stream order three, with a total of three stream segments, contributes much higher sediment loads to the Bued River. These stream segments are also controlled by geologic structures with a high possibility of flash floods during a high rainfall intensity. For the areal parameters, the study area was categorized as medium-watershed and less elongated. It has a low drainage density value (1.16 km/km²), which is characterized by a good vegetative cover. The study site has permeable subsurface material and lower relief, which turns out to have a more infiltration capacity. Whereas the drainage texture and form factor values (0.812 km and 0.27, respectively) described the study area with a lower peak flow of longer duration, these values indicate that the flood flows are easier to control. The linear parameters showed that most of the Bued Watershed area (44%) is located at an elevation of > 1000 masl with moderate to steep slopes, which make it more susceptible to erosions and landslides. This is consistent with the relief ratio and relative relief results (0.08 and 0.03, respectively), which suggest that the area is vulnerable to erosion.