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Contemporary management practices have artificially confined (strangled) river systems in Aotearoa New Zealand to support intensified land use in riparian areas. These practices work against nature, diminishing the functionality and biodiversity values of living rivers, and associated socio‐cultural relations with rivers. River confinement can accentuate flood risk by promoting development in vulnerable locations and limiting the flexibility to adapt to changing climate, prospectively accentuating future disasters. To date, uptake of space‐to‐move management interventions that seek to address such shortcomings is yet to happen in Aotearoa New Zealand. This is despite the fact that such practices directly align with Māori (indigenous) conceptualizations of rivers as indivisible, living entities. Treaty of Waitangi obligations that assert Māori rights alongside colonial rights of a settler society provide an additional driver for uptake of space‐to‐move initiatives. This article outlines a biophysical prioritization framework to support the development and roll out of space‐to‐move interventions in ways that work with the character, behavior, condition, and evolutionary trajectory (recovery potential) of each river system in Aotearoa. This article is categorized under:Water and Life > Conservation, Management, and AwarenessScience of Water > Water and Environmental Change [ABSTRACT FROM AUTHOR]

The granting of rights to the Whanganui River in 2017 emerged as an outcome of Tribunal hearings relating to breaches of the Treaty of Waitangi, signed between Māori chiefs and the British Crown in 1840. As this expression of a river as having legal personhood with rights reflects a distinctively Māori perspective upon river systems, it offers the prospect for a new era of sociocultural approaches to river management in Aotearoa New Zealand. Using the Whanganui River as a case study, this paper explores prospective geomorphic meanings of river rights. The paper asks, "What role can geomorphology play in identifying, articulating and protecting the rights of a river?" Ancestral Māori relations to the river based upon mutual codependence (reciprocity) are juxtaposed against geomorphic understandings of a river's agency as expressed through self‐adjustment, diversity of form, evolution, and catchment‐scale connectivities. Relations between river science and indigenous concepts of rivers, framed under the auspices of river rights, present opportunities for different approaches to river management. [ABSTRACT FROM AUTHOR]

ABSTRACT The paraglacial reworking of glacial sediments by rivers and mass wasting is an important conditioning factor for modern sediment yields in mountainous catchments in formerly glaciated regions. Catchment scale and patterns of sediment storage are important influences in the rate of postglacial adjustment. We develop a quantitative framework to estimate the volume, sediment type, and fractional size distribution of legacy glacial materials in a large (1230 km2) watershed in the North Cascade Mountains in south-western British Columbia, Canada. Chilliwack Valley is exceptional because of the well-dated bounds of deglaciation. Interpolation of paleo-surfaces from partially eroded deposits in the valley allows us to estimate the total evacuated sediment volume. We present a chronology of sediment evacuation from the valley and deposition in the outlet fan, based on infrared stimulated luminescence (IRSL) and 14 C dating of river terraces and fan strata, respectively. The effects of paraglacial sedimentation in Chilliwack Valley were intensified through a major fall in valley base-level following ice retreat. The steepened mainstem valley gradient led to deep incision of valley fills and fan deposits in the lower valley network. The results of this integrated study provide a postglacial chronology and detailed sediment budget, accounting for long-term sorting of the original sediments, lag deposit formation in the mainstem, deposition in the outlet fan, and approximate downstream losses of suspended sediment and wash load. The mass balance indicates that a bulk volume of approximately 3.2 km3 of glacial material has been evacuated from the valley. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Tunnicliffe, J., Church, M. & Enkin, R. J. 2012 (January): Postglacial sediment yield to Chilliwack Lake, British Columbia, Canada. Boreas, Vol. 41, pp. 84-101. 10.1111/j.1502-3885.2011.00219.x. ISSN 0300-9483. Seismic records and evidence from sediment cores at Chilliwack Lake provide the basis for a long-term (postglacial) sediment budget for a 324-km2 Cordilleran catchment. Chilliwack Lake (11.8 km2 surface area), situated in the North Cascade Mountains, near Chilliwack, British Columbia, was formed behind a valley-wide recessional moraine in the final phase of post-Fraser alpine glaciation. Seismic surveys highlight the postglacial lacustrine record, which is underlain by a thick layer of sediments related to deglacial sedimentation. Sediment cores provide details of grain-size fining from the delta to the distal lake basin. The cores also show a record of intermittent fire and debris flows. Magnetic measurements of lake sediments provide information on grain size, as well as a dating framework. The total postglacial lake-floor deposit volume is estimated to be 397 ± 27 × 106 m3. Including estimates of fan and delta deposition, the specific postglacial yield to the lake is calculated to be ∼86 ± 13 Mg km2 a−1. The sediment volume in the uppermost (Holocene) lacustrine layer is 128 ± 9 × 106 m3, representing ∼41 ± 4 Mg km2 a−1 in the Holocene. Compared with other Cordilleran lakes of similar size, particularly those with glacial cover in the watershed, Chilliwack Lake has experienced relatively modest rates of sediment accumulation. This study provides an important contribution to a growing database of long-term (postglacial) sediment yield data for major Cordilleran lakes, essential for advancing our understanding of the pace of landscape evolution in formerly glaciated mountainous regions. [ABSTRACT FROM AUTHOR]

The Holocene volumetric sediment budget is estimated for coarse textured sediments (sand and gravel) in a large, formerly glaciated valley in southwest British Columbia. Erosion is estimated by compiling volumetric loss estimated in digital elevation models (DEMs) of gullied topography and by applying a non-linear diffusion model on planar, undissected hillslopes. Estimates of steepland yield are based on estimates of post-glacial deposition volumes in fans, cones and deltas at the outlets of low-order tributary catchments. Erosion of post-glacial fans and tributary valley fills is estimated by reconstructing formerly continuous surfaces. Results are classed by catchment order and compared across scales of contributing area, revealing declining specific sediment yield (in m km a) with catchment area for the smaller tributaries (<10 km) and increasing specific sediment yield for larger tributaries and Chilliwack Valley itself. Approximately 60% of mobilized sediment is redeposited in first- to third-order catchments, with lesser proportions stored at the outlets of higher order catchments. A simple network routing model emphasizes the significant sediment flux contributions from colluvium, drift blankets and gullies in steeper terrain. As this material is deposited at junctions within the lower drainage network, an increasing proportion of material is derived from remnant valley fills and para-glacial fans in the major valleys. Yield from lower-order, steepland catchments tends to remain in storage, indefinitely sequestered on footslopes. These observations have implications for modelling the post-glacial sediment balance amongst catchments of varying size. After 10 years, the system remains in disequilibrium. The critical linkage lies between low-order, hillslope catchments (

Examines the sediment transport dynamics at the Stuart-Takla Experimental Watershed in British Columbia. Designs of the bedload movement detector used in the research; Functions of the magnetic sensor of the device; Frequency of bedload transport in a year.

The formation of large wood (LW) accumulations during floods represents a major hazard for constricted river cross-sections, e.g. bridges and weirs, as it affects flow hydraulics and sediment transport. To better assess LW accumulations, reliable strategies and techniques are required. There are currently practical limits on monitoring accumulation configurations. Both laser scans and photogrammetric techniques can be used to scan the outer contours of LW accumulations, but cannot practically assess the wood content and porosity. Details of the outer deposit are captured in high resolution, but the core of the deposit remains occluded, and estimation is necessary. This becomes more challenging for deposits of increasing size (relative to wood elements). To develop a more efficient workflow for LW accumulation assessment in the field, we performed a laboratory study to develop a relationship between the envelope volume of water-worked LW jams during a single flood hydrograph and the volume of woody elements within (explicitly accounting for porosity). We used photogrammetric techniques, now in common use for reconnaissance surveys of debris accumulations, on wood accumulations scaled for the laboratory. The study's aim is to develop a semi-automated assessment method, enabling efficient image acquisition, processing and computation of LW accumulation volume. Using a multi-camera array above the laboratory channel, and applying Structure from Motion photogrammetry, we developed 3D models for 16 experimental flow-formed wood accumulations, each with >50 individual wooden dowels. No correlations were found between porosity and flow magnitude; porosity was found to be similar for most deposits (~66%). As a result of this accumulation structure, the envelope volume used in 3D and 2.5D photogrammetric methods tended to overestimate wood content by 3× and 2.6×, respectively. The results obtained here will contribute to a more reliable volumetric assessment for inventories of wood mass in river systems. • Structure from Motion (SfM) photogrammetry is applied to log jam assessment. • Semi-automated computation of large wood (LW) accumulation volume and porosity • Porosity of LW accumulations was found to be similar for most experiments (~66%). • Results reveal consistency of jam porosity with mathematical models of cylinders. • A cost-efficient approach for future application in LW management is presented. [ABSTRACT FROM AUTHOR]

River systems in forested catchments are strongly influenced by wood and sediment loading from both natural (e.g. mass wasting) and anthropogenic (forestry) sources. In order to effectively manage impacts on property, infrastructure and the broader ecosystem, as well as to better assess the interactions between large wood (LW), channel morphology and flow hydraulics, more efficient and accurate surveying techniques are required. We present an evaluation of Structure from Motion (SfM) photogrammetry and point-cloud-based techniques for capturing the geometry and volume of LW in the field. Wood accumulations can be notoriously complex 3D objects, with multi-scalar features, and thus difficult to quantify with photogrammetric methods. We introduce a novel workflow to generate volumetric information of organic material accumulations, using SfM and a suite of meshing algorithms. The volumes of two accumulations are assessed individually, using several meshing techniques, and are compared with more conventional volume estimates. Results show volumetric variations of <19% between the interpolated volumes from point clouds and those of meshes, and a slight overestimation of volumes using simple geometric primitives. We discuss the nature of noise and errors that arise within processed results from SfM software (Pix4D) and offer some criteria for generating high quality point cloud models of highly irregular and complex organic material piles. More detailed 3D mesh representations of LW accumulations will be effective for improving computer-aided modelling of jam-induced floods, backwater effects and impacts on channel morphology. Measuring the size and geometric distributions of wood elements, assessing deposit volume and porosity, or estimating the proportion of organic fine material in the deposit, are important quantities to be assessed for wood accumulations in rivers. The photogrammetric methodology presented herewith will be useful for forestry and freshwater managers to estimate LW quantities, but also to develop accurate 3D models of prototype LW accumulations, independent of camera model and environmental condition, for a range of applications and LW accumulation assessment. • Presenting a novel technique for volume estimation of large wood (LW) accumulations • Introducing Structure from Motion (SfM) photogrammetry for volumetric jam assessment • Discussing observed volumetric deviations caused by using various meshing approaches • A flexible, time and cost-efficient approach for generating high resolution models • Obtained models show potential for application in computational fluid dynamics (CFD). [ABSTRACT FROM AUTHOR]