River Styles and stream power analysis reveal the diversity of fuvial morphology in a Philippine tropical catchment
Characterisation of hydromorphological attributes is crucial for effective river management. Such information is often overlooked in tropical regions such as the Philippines where river management strategies mainly focus on issues around water quality and quantity. We address this knowledge gap using the River Styles Framework as a template to identify the diversity of river morphodynamics. We identify eight distinct River Styles (river types) in the Bislak catchment (586 km2) in the Philippines, showing considerable geomorphic diversity within a relatively small catchment area. Three River Styles in a Confined valley setting occupy 57% of the catchment area, another three in a partly confined valley setting occupy 37%, and two in the remaining 6% are found in a laterally unconfined valley setting. Five characteristic downstream patterns of River Styles were identified across the catchment. We observe that variation in channel slope for a given catchment area (i.e., total stream power) is insufficient to differentiate between river types. Hence, topographic analyses should be complemented with broader framed, catchment-specific approaches to river characterisation. The outputs and understandings from the geomorphic analysis of rivers undertaken in this study can support river management applications by explicitly incorporating understandings of river diversity and dynamics. This has the potential to reshape how river management is undertaken, to shift from reactive, engineering-based approaches that dominate in the Philippines, to more sustainable, ecosystem-based approaches to management.
a The Bislak River, like many rivers in the country, serves multiple purposes in Philippine communities, including: b agriculture on floodplains; c aquaculture/fish pens in channels; and, d the provision of construction materials from gravel mining on riverbeds and bars. Semi-permanent/permanent structures such as bridges, embankments, dikes, and gabions (e–g) are commonly constructed along Philippine rivers. Examples shown are from the Bislak Catchment; locations are indicated by the corresponding labels (a–g)
Tolentino, P.L.M., Perez, J.E.G., Guardian, E.L. et al. River Styles and stream power analysis reveal the diversity of fluvial morphology in a Philippine tropical catchment. Geosci. Lett. 9, 6 (2022). https://doi.org/10.1186/s40562-022-00211-4
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