National-scale assessment of decadal river migration at critical bridge infrastructure in the Philippines

Boothroyd, R. J. , Williams, R. D. , Hoey, T. B. , Tolentino, P. L.M. and Yang, X. (2021) National-scale assessment of decadal river migration at critical bridge infrastructure in the Philippines. Science of the Total Environment, 768, 144460. (doi: 10.1016/j.scitotenv.2020.144460) (PMID:33450685)

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Abstract

River migration represents a geomorphic hazard at sites of critical bridge infrastructure, particularly in rivers where migration rates are high, as in the tropics. In the Philippines, where exposure to flooding and geomorphic risk are considerable, the recent expansion of infrastructural developments warrants quantification of river migration in the vicinity of bridge assets. We analysed publicly available bridge inventory data from the Philippines Department of Public Works and Highways (DPWH) to complete multi-temporal geospatial analysis using three decades worth of Landsat satellite imagery in Google Earth Engine (GEE). For 74 large bridges, we calculated similarity coefficients and quantified changes in width for the active river channel (defined as the wetted channel and unvegetated alluvial deposits) over decadal and engineering (30-year) timescales. Monitoring revealed the diversity of river planform adjustment at bridges in the Philippines (including channel migration, contraction, expansion and avulsion). The mean Jaccard index over decadal (0.65) and engineering (0.50) timescales indicated considerable planform adjustment throughout the national-scale inventory. However, planform adjustment and morphological behaviour varied between bridges. For bridges with substantial planform adjustment, maximum active channel contraction and expansion was equal to 25% of the active channel width over decadal timescales. This magnitude of lateral adjustment is sufficient to imply the need for bridge design to accommodate channel dynamism. For other bridges, the planform remained stable and changes in channel width were limited. Fundamental differences in channel characteristics and morphological behaviours emerged between different valley confinement settings, and between rivers with different channel patterns, indicating the importance of the local geomorphic setting. We recommend satellite remote sensing as a low-cost approach to monitor river planform adjustment with large-scale planimetric changes detectable in Landsat products; these approaches can be applied to other critical infrastructure adjacent to rivers (e.g. road, rail, pipelines) and extended elsewhere to other dynamic riverine settings.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Williams, Dr Richard and Boothroyd, Dr Richard and Hoey, Professor Trevor and Tolentino, Pamela Louise
Creator Roles:
Boothroyd, R. J.Conceptualization, Investigation, Methodology, Visualization, Writing – original draft, Writing – review and editing
Williams, R. D.Funding acquisition, Project administration, Writing – review and editing
Hoey, T. B.Funding acquisition, Writing – review and editing
Tolentino, P. L.M.Writing – review and editing
Authors: Boothroyd, R. J., Williams, R. D., Hoey, T. B., Tolentino, P. L.M., and Yang, X.
College/School:College of Science and Engineering > School of Geographical and Earth Sciences
Journal Name:Science of the Total Environment
Journal Abbr.:STOTEN
Publisher:Elsevier
ISSN:0048-9697
ISSN (Online):1879-1026
Published Online:06 January 2021
Copyright Holders:Copyright © 2021 Elsevier B.V.
First Published:First published in Science of the Total Environment 768: 144460
Publisher Policy:Reproduced in accordance with the publisher copyright policy

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
303063Catchment susceptibility to hydrometeorological events: sediment flux and geomorphic change as drivers of flood risk in the PhilippinesRichard WilliamsNatural Environment Research Council (NERC)NE/S003312/1GES - Geography