‘InfraRivChange’: a web application to monitor river migration at sites of critical bridge infrastructure in the Philippines

Shifting rivers, particularly with high migration rates, represent a geomorphic hazard at sites of critical bridge infrastructure. Conventional attempts to map and measure shifts in the position of river channels usually requires the manual digitization of riverbanks from satellite imagery using Geographic Information Systems (GIS) – a time-consuming process only feasible at a limited number of bridge sites using a small selection of satellite images. As part of the CDRI Fellowship, the authors leveraged the cloud computing platform Google Earth Engine (GEE) to substantially upscale analyses using Earth observation (EO) data. Focusing on the Philippines, they designed a user-friendly web application for technical and non-technical users to monitor the relative risk of river migration at sites of critical bridge infrastructure by analysing thousands of satellite images. ‘InfraRivChange’ uses openly accessible satellite imagery from Landsat (30mspatial resolution) and Sentinel (10 m spatial resolution) to quantify river channel changes at bridge sites. The study demonstrates the web application at test sites and suggests use-cases relevant to disaster resilient infrastructure. As a low-cost approach for monitoring shifting large rivers in the vicinity of infrastructure, InfraRivChange can be incorporated into bridge monitoring systems (e.g., as a component of bridge stability assessments) and inform the design and placement of future infrastructure. They envision that InfraRivChange can be applied to additional forms transport infrastructure adjacent to rivers (e.g., road and rail) and extended to other dynamic riverine settings.CDRI Fellowship Application no. 201128342

Ground control point distribution for accurate kilometre-scale topographic mapping using an rtk-gnss unmanned aerial vehicle and sfm photogrammetry

Copyright © 2020 by the authors. Unmanned Aerial Vehicles (UAVs) have revolutionised the availability of high resolution topographic data in many disciplines due to their relatively low-cost and ease of deployment. Consumer-grade Real Time Kinematic Global Navigation Satellite System (RTK-GNSS) equipped UAVs offer potential to reduce or eliminate ground control points (GCPs) from SfM photogrammetry surveys, removing time-consuming target deployment. Despite this, the removal of ground control can substantially reduce the georeferencing accuracy of SfM photogrammetry outputs. Here, a DJI Phantom 4 RTK UAV is deployed to survey a 2 × 0.5 km reach of the braided River Feshie, Scotland that has local channel-bar relief of c.1 m and median grain size c.60 mm. Five rectangular adjacent blocks were flown, with images collected at 20° from the nadir across a double grid, with strips flown in opposing directions to achieve locally convergent imagery geometry. Check point errors for seven scenarios with varying configurations of GCPs were tested. Results show that, contrary to some published Direct Georeferencing UAV investigations, GCPs are not essential for accurate kilometre-scale topographic modelling. Using no GCPs, 3300 independent spatially-distributed RTK-GNSS surveyed check points have mean z-axis error −0.010 m (RMSE = 0.066 m). Using 5 GCPs gave 0.016 m (RMSE = 0.072 m). Our check point results do not show vertical systematic errors, such as doming, using either 0 or 5 GCPs. However, acquiring spatially distributed independent check points to check for systematic errors is recommended. Our results imply that an RTK-GNSS UAV can produce acceptable errors with no ground control, alongside spatially distributed independent check points, demonstrating that the technique is versatile for rapid kilometre-scale topographic survey in a range of geomorphic environments.ES was funded by UK Natural Environment Research (NERC) Doctoral Training Grant NE/R007934/1, in partnership with the Scottish Environment Protection Agency (SEPA). GNSS equipment was provided by NERC Geophysical Equipment Facility (GEF) loan 1118

Down-delta hydraulic geometry and its application to the rock record

Data Availability Statement: Data from this paper are publicly available at https://doi.org/10.6084/m9.figshare.19574938.v2.This research was funded by an award from the Indonesia Endowment Fund for Education (LPDP) to Prasojo. The global river discharge dataset is available from The Global Runoff Data Centre (GRDC), 56068 Koblenz, Germany or and via the web (http://www.bafg.de/grdc.htm).Copyright . Palaeodischarge estimation is largely undertaken within fluvial settings. However, there are limited palaeodischarge estimates specifically from delta deposits, despite their significance globally. Estimating water palaeodischarges for deltas using catchment-based approaches developed using data from fluvial settings requires estimating parameters from the rock record (for example, palaeotemperature, palaeoslope and palaeorelief). These may be difficult to determine, leading to under-estimation or over-estimation of palaeodischarge values due to differences in process-form relationships between alluvial rivers and deltas. When a sediment-conveying fluvial channel enters a standing body of water, delta lobes develop through repeating mouth bar deposition due to flow deceleration, forming a deltaic morphology with distributary channel networks that differ morphologically from those developed in unidirectional flowing alluvial rivers. This study provides empirical relationships determined across five climate regions, using 3823 measurements of distributary channel width from 66 river deltas alongside the trunk river bankfull discharge that feeds into the entire delta, using a hydraulic geometry scaling approach. Empirical relationships are developed from the global delta dataset between bankfull discharge and catchment area (Qb–A), and bankfull discharge and median distributary channel width (Qb–Wmed). These empirical relationships produce very strong statistical correlations, especially between Qb and Wmed, across different climate regions (Qb = 0.34 Wmed1.48, R2 = 0.77). However, both Qb–A and Qb–Wmed relationships have outliers that may be explained by particular hydrological or geomorphic conditions. These new empirical relationships derived from modern systems are then applied to Cretaceous outcrops (Ferron Sandstone and Dunvegan Formation). The comparatively simple scaling relationships derived here produced palaeodischarge estimates within the same order of magnitude as palaeodischarge values previously obtained using existing, more complex approaches. This study contributes to source-to-sink investigations by enabling palaeodischarge estimates that intrinsically account for climate impacts on channel geometry at the time of deposition, using measurements of channel width or catchment area of a deltaic outcrop.Lembaga Pengelola Dana Pendidikan. Grant Number: 20190222021387

Applications of Google Earth Engine in fluvial geomorphology for detecting river channel change

© 2020 The Authors. Cloud-based computing, access to big geospatial data, and virtualization, whereby users are freed from computational hardware and data management logistics, could revolutionize remote sensing applications in fluvial geomorphology. Analysis of multitemporal, multispectral satellite imagery has provided fundamental geomorphic insight into the planimetric form and dynamics of large river systems, but information derived from these applications has largely been used to test existing concepts in fluvial geomorphology, rather than for generating new concepts or theories. Traditional approaches (i.e., desktop computing) have restricted the spatial scales and temporal resolutions of planimetric river channel change analyses. Google Earth Engine (GEE), a cloud-based computing platform for planetary-scale geospatial analyses, offers the opportunity to relieve these spatiotemporal restrictions. We summarize the big geospatial data flows available to fluvial geomorphologists within the GEE data catalog, focus on approaches to look beyond mapping wet channel extents and instead map the wider riverscape (i.e., water, sediment, vegetation) and its dynamics, and explore the unprecedented spatiotemporal scales over which GEE analyses can be applied. We share a demonstration workflow to extract active river channel masks from a section of the Cagayan River (Luzon, Philippines) then quantify centerline migration rates from multitemporal data. By enabling fluvial geomorphologists to take their algorithms to petabytes worth of data, GEE is transformative in enabling deterministic science at scales defined by the user and determined by the phenomena of interest. Equally as important, GEE offers a mechanism for promoting a cultural shift toward open science, through the democratization of access and sharing of reproducible code.Natural Environment Research Council. Grant Number: NE/S00331

A decision support tool for assessing risks to above-ground river pipeline crossings

UK Natural Environment Research Council’s Environmental Risks to Infrastructure Innovation Programme (grant NE/P008984/1)

Analysis of the fluvial stratigraphic response to the Paleocene–Eocene Thermal Maximum in the Bighorn Basin, U.S.A.

The appendix contains five sections, each of which shows the summarized raw sedimentary logs for all locations studies. Section A1.1: Sedimentary logs from the Beartooth systems. Section A1.2: Sedimentary logs from the Absoraka systems. Section A1.3: sedimentary logs from Washakie sedimentary systems. Section A1.4: sedimentary logs from the Owl Creek systems. Section A1.5: sedimentary logs from the Axial system.Geological deposits can reveal how environments of the past have responded to climate change, enabling important insights into how environments may respond to our current anthropogenically induced warming. The Paleocene–Eocene Thermal Maximum (PETM) occurred ca. 56 Ma and was a short-lived (approximately 200,000 years) global warming event (5–8°C rise). The PETM has been investigated at several terrestrial and marine localities across the globe. However, many studies are based on single successions, with very few sites being placed within a well-defined spatial and temporal context and with comparisons limited to deposits that lie immediately above and below the event. Due to the inherent variability of sedimentary systems, it is imperative that the appropriate context is provided to fully understand the impacts of climate change on landscapes and subsequent deposits. This study examines 28 locations, totaling over 4 km of recorded stratigraphy, within a newly defined quantified sedimentary basin context (Bighorn Basin, USA) to evaluate variability of fluvial response to the PETM. We show that channel-body and story thicknesses across the PETM are not statistically significantly different from deposits outside the climate event, implying that there is not a consistent sedimentary response to the climate event across the basin. Based on our large dataset we calculate that precipitation would have had to double for statistically significant changes in deposit thickness to be generated. We discuss how climatic signals may be lost due to the self-organization, spatial–temporal varied response and preservation potential in large fluvial systems. This study gives a new quantified perspective to climate events in the geologic record.AO, AH, and GW thanks FSRG 2 sponsors for funding field campaigns. AE thanks University of Aberdeen for funding field work. We thank all residents in the Bighorn Basin who allowed access to private land to study the Paleogene fill, which greatly enhanced the size and quality of this dataset. Isobel Buchanon, Alistair Swan, and Mauricio Santos are thanked for their assistance in the field

Detecting and quantifying morphological change in tropical rivers using Google Earth Engine and image analysis techniques

Copyright © 2020 The Author(s). Various tools have been demonstrated that are capable of delineating and characterizing river channels, but efforts to scale these analyses up to multi-temporal, catchment-scale applications are in their infancy. Here, we use Google Earth Engine (GEE) to extract the active channel (including the wetted channel and unvegetated, alluvial deposits) from the Bislak and Cagayan Rivers in the Philippines. Using temporal composites of Landsat 5, 7 and 8 satellite imagery over ~30 years, the active channel is resolved at annual intervals. The active channel occurrence frequency is mapped using image analysis techniques to detect large-scale planimetric change. Quantification of active channel centerline change is achieved using the RivMAP toolbox. Over a 135 km reach of the Cagayan River, the average migration rate was 17.5 m.a-1 ranging from 7.7 m.a-1 in 1988 to 37.0 m.a-1 in 2005. The findings quantify patterns of dynamism in tropical river systems and demonstrate the utility of GEE in fluvial geomorphology applications

River Styles and stream power analysis reveal the diversity of fluvial morphology in a Philippine tropical catchment

Availability of data and materials: Following review, all GIS datasets will be made available through the NERC data repository.Copyright © The Authors 2022. 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.Department of Science and Technology—Philippine Council for Industry, Energy and Emerging Technology Research and Development (DOST-PCIEERD)—NERC Newton Fund grant (NE/S003312); Global Challenges Research Fund (SFC-GCRF) grant (2019)

National-scale geodatabase of catchment characteristics in the Philippines for river management applications

Data Availability: The ArcGIS web-application for interactively displaying the national-scale geodatabase is available here: https://glasgow-uni.maps.arcgis.com/apps/webappviewer/index.html?id=a88b9ca0919f4400881eab4a26370cee. Supporting datasets are available here: http://dx.doi.org/10.5525/gla.researchdata.1396. Supporting datasets include: (1) GIS shapefiles with river catchment properties; (2) GIS shapefiles with stream network properties; (3) spreadsheets containing the complete set of morphometric and topographic characteristics (n = 91); and, (4) example MATLAB code and topographic data to replicate the analysis for a selected catchment. The supporting datasets will also be uploaded to the Natural Environment Research Council (NERC) Environmental Information Data Centre.Copyright: © 2023 Boothroyd et al. Quantitative descriptions of stream network and river catchment characteristics provide valuable context for enabling geomorphologically-informed sustainable river management. For countries where high-quality topographic data are available, there are opportunities to enable open access availability of baseline products from systematic assessment of morphometric and topographic characteristics. In this study, we present a national-scale assessment of fundamental topographic characteristics of Philippine river systems. We applied a consistent workflow using TopoToolbox V2 to delineate stream networks and river catchments using a nationwide digital elevation model (DEM) acquired in 2013 and generated through airborne Interferometric Synthetic Aperture Radar (IfSAR). We assessed morphometric and topographic characteristics for 128 medium- to large-sized catchments (catchment area > 250 km2) and organised the results in a national-scale geodatabase. The dataset realises the potential of topographic data as part of river management applications, by enabling variations in hydromorphology to be characterised and contextualised. The dataset is used to reveal the diversity of stream networks and river catchments in the Philippines. Catchments have a continuum of shapes (Gravelius compactness coefficient ranges from 1.05 to 3.29) with drainage densities that range from 0.65 to 1.23 km/km2. Average catchment slope ranges from 3.1 to 28.1° and average stream slope varies by more than an order of magnitude from 0.004 to 0.107 m/m. Inter-catchment analyses show the distinctive topographic signatures of adjacent river catchments; examples from NW Luzon highlight topographic similarity between catchments whereas examples from Panay Island shown marked topographic differences. These contrasts underline the importance of using place-based analyses for sustainable river management applications. By designing an interactive ArcGIS web-application to display the national-scale geodatabase, we improve data accessibility and enable users to freely access, explore and download the data (https://glasgow-uni.maps.arcgis.com/apps/webappviewer/index.html?id=a88b9ca0919f4400881eab4a26370cee). The national-scale geodatabase provides a baseline understanding of fundamental topographic characteristics in support of varied geomorphological, hydrological and geohazard susceptibility applications.This research was undertaken as part of a Natural Environment Research Council (NERC) and Department of Science and Technology - Philippine Council for Industry, Energy and Emerging Technology Research and Development (DOST-PCIEERD) – Newton Fund grant NE/S003312. RDW and TBH are also grateful to NERC grant NE/W006871/1

Fluvial geomorphology and landscape morphology: reconciling concepts across timescales

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