Alluvial anastomosed channels : the preferred channel type on active UK rivers

Paper presented at 11th International Symposium on EcoHydraulics, 7-12 February 2016, Melbourne, Australia. Abstract: Anastomosing rivers constitute an important category of multi-channel rivers and are characterised by multiple, interconnected, coexisting channels flowing over alluvial plains. They commonly form by avulsion processes, causing the formation of new channels on the floodplain; a process primarily driven by loss of channel capacity and flow breakout linked to local in-channel deposition. This style of channel is presently rare in the UK primarily due to historic channel and floodplain engineering and management. This study examines the character of developing anastomosed channels seen on a number of active gravel-bed channels in the north of England using aerial imagery and metre scale resolution aerial LIDAR data. Aerial imagery of the study sites indicate progressive development of a well-developed wooded valley floor associated with lateral bar extension and succession across stable isolated bar units. The LIDAR data are used to create detailed digital terrain models (DEMs) of the study reaches accurately representing sub-channel planform and morphology. Topographic metrics suggest well-developed underlying morphological features, dominated by an interlinked channel network split by variable length, generally low elevation interfluves and variograms created for each site suggest a common topographic pattern associated with the study sites. The gross morphology does not reflect the classic anastomosed features described by previous research, suggesting that different processes are operating to create these channel types. It is suggested that the anastomosing networks have developed across systems that were initially active meandering and wandering in nature, evolving in line with floodplain vegetative succession to stabilise these planform types. These modes of formation suggest a different origin of these anastomosed sites compared with those previously reported with floodplain management playing a key role in system development

Small unmanned aerial model accuracy for photogrammetrical fluvial bathymetric survey

Fluvial systems offer a challenging and varied environment for topographic survey, displaying a rapidly varying morphology, vegetation assemblage and degree of submergence. Traditionally theodolite or GPS based systems have been used to capture cross-section and breakline based topographic data which has subsequently been interpolated. Advances in survey technology has resulted in an improved ability to capture larger volumes of information with infrared terrestrial and aerial LiDAR systems capturing high density (<0.02 m) point data across terrestrial surfaces. The rise of Structure from Motion (SfM) photogrammetry, coupled with small unmanned aerial vehicles (sUAV), has potential to record elevation data at reach scale sub decimetre density. The approach has the additional advantage over LiDAR of seeing through clear water to capture bed detail, whilst also generating ortho-rectified photographic mosaics of the survey reach. However, data accuracy has yet to be comprehensively assessed. Here we present a survey protocol for sUAV deployment and provide a reach scale comparison between a theodolite and SfM sUAV survey on the River Sprint, Kendal, the River Ehen at Egremont, England and the Afon Elwy, at Llanfair Talhaiarn, Wales. Comparative analysis between theodolite survey and SfM suggest similar accuracy and precision across terrestrial surfaces with error lowest over solid surfaces, increasing with vegetation complexity. Submerged SfM data, captured bed levels generally to within ±0.25 m with only a weak relationship recorded between error and flow depth. Significantly, associated error when linked to channel D50 highlights the ability of unmanned aerial vehicles to capture accurate fluvial data across a range of river biotopes and depths to 2.4 m

Morphodynamics of bedrock-influenced dryland rivers during extreme floods: insights from the Kruger National Park, South Africa

High-magnitude flood events are among the world’s most widespread and significant natural hazards and play a key role in shaping river channel–floodplain morphology and riparian ecology. Development of conceptual and quantitative models for the response of bedrock-influenced dryland rivers to such floods is of growing scientific and practical importance, but in many instances, modeling efforts are hampered by a paucity of relevant field data. Here, we combined extensive aerial and field data with hydraulic modeling to document erosion, deposition, and vegetation changes that have occurred during two successive, cyclonedriven, extreme floods along a 50-km-long reach of the bedrock-influenced Sabie River in the Kruger National Park, eastern South Africa.  Aerial light detection and ranging (LiDAR) data and photography obtained after extreme floods in 2000 and 2012 (discharges &gt;4000 m3 s–1) were used to generate digital elevation models (DEMs) and provide the boundary conditions for hydraulic modeling (flow shear stresses for three discharges up to 5000 m3 s–1). For the Sabie River study reach as a whole, DEM differencing revealed that the 2012 floods resulted in net erosion of ~1,219,000 m3 (~53 mm m–2). At the subreach scale, however, more complex spatial patterns of erosion, deposition, and vegetation change occurred, as largely controlled by differences in channel type (e.g., degree of bedrock and alluvial exposure) and changing hydraulic conditions (shear stresses widely &gt;1000 N m–2 across the river around peak flow). The impact of flood sequencing and relative flood magnitude is also evident; in some subreaches, remnant islands and vegetation that survived the 2000 floods were removed during the smaller 2012 floods owing to their wider exposure to flow. These findings were synthesized to refine and extend a conceptual model of bedrock-influenced dryland river response that incorporates flood sequencing, channel type, and sediment supply influences. In particular, with some climate change projections indicating the potential for future increases in the frequency of cyclone-generated extreme floods in eastern southern Africa, the Sabie and other Kruger National Park rivers may experience additional sediment stripping and vegetation removal. Over time, such rivers may transition to a more bedrock-dominated state, with significant implications for ecological structure and function and associated ecosystem services. These findings contribute to an improved analysis of the Kruger National Park rivers in particular, but also to growing appreciation of the global diversity of dryland rivers and the relative and synergistic impacts of extreme floods

Quantifying and contextualising cyclone-driven, extreme flood magnitudes in bedrock-influenced dryland rivers

In many drylands worldwide, rivers are subjected to episodic, extreme flood events and associated sediment stripping. These events may trigger transformations from mixed bedrock-alluvial channels characterised by high geomorphic and ecological diversity towards more dominantly bedrock channels with lower diversity. To date, hydrological and hydraulic data has tended to be limited for these bedrock-influenced dryland rivers, but recent advances in high-resolution data capture are enabling greater integration of different investigative approaches, which is helping to inform assessment of river response to changing hydroclimatic extremes. Here, we use field and remotely sensed data along with a novel 2D hydrodynamic modelling approach to estimate, for the first time, peak discharges that occurred during cyclone-driven floods in the Kruger National Park, eastern South Africa, in January 2012. We estimate peak discharges in the range of 4470 to 5630 m3s-1 for the Sabie River (upstream catchment area 5715 km2) and 14 407 to 16 772 m3s-1 for the Olifants River (upstream catchment area 53 820 km2). These estimates place both floods in the extreme category for each river, with the Olifants peak discharge ranking among the largest recorded or estimated for any southern African river in the last couple of hundred years. On both rivers, the floods resulted in significant changes to dryland river morphology, sediment flux and vegetation communities. Our modelling approach may be transferable to other sparsely gauged or ungauged rivers, and to sites where palaeoflood evidence is preserved. Against a backdrop of mounting evidence for global increases in hydroclimatic extremes, additional studies will help to refine our understanding of the relative and synergistic impacts of high-magnitude flood events on dryland river development

Morphodynamic simulation of sediment deposition patterns on a recently stripped bedrock anastomosed channel

Some mixed bedrock-alluvial dryland rivers are known to undergo cycles of alluvial building during low flow periods, punctuated by stripping events during rare high magnitude flows. We focus on the Olifants River, Kruger National Park, South Africa, and present 2-D morphodynamic simulations of hydraulics and sed-iment deposition patterns over an exposed bedrock anastomosed pavement. We examine the assumptions un-derlying a previous conceptual model, namely that sedimentation occurs preferentially on bedrock highs. Our modelling results and local field observations in fact show that sediment thicknesses are greater over bedrock lows, suggesting these are the key loci for deposition, barform initiation and island building. During peak flows, velocities in the topographic lows tend to be lower than in intermediate topographic areas. It is likely that inter-mediate topographic areas supply sediment to the topographic lows at this flow stage, which is then deposited in the lows on the falling limb of the hydrograph as velocities reduce. Subsequent vegetation establishment on de-posits in the topographic lows is likely to play a key role in additional sedimentation and vegetation succession, both through increasing the cohesive strength of alluvial units and by capturing new sediments and propagules

Anastomosing reach control on hydraulics and sediment distribution on the Sabie River, South Africa

Many of the large rivers in southern Africa exhibit a strong bedrock influence, being characterised by a channel incised 10–20 m into ancient planation surfaces. Under alluviated conditions, these channels display downstream sequences of channel types, including alluvial single thread, braided, bedrock anastomosed, mixed anastomosed, and pool-rapid. This sequence of channel types has been reviewed using aerial imagery for the Sabie River, which drains a 6320km2 catchment and flows across the Lowveld of South Africa. Prior to 2000, the river exhibited a downstream sequence of channel types that broadly alternated from alluvial single thread or braided to bedrock anstomosed or mixed anastomosed, with pool-rapid types also present locally. Unconsolidated (predominantly sandy) alluvial sediments were significantly eroded by cyclone-driven extreme floods both in 2000 and 2012, exposing the underlying bedrock template along considerable lengths of the river. This bedrock-dominated state was surveyed using aerial LIDAR following the 2012 flood. Long profile data revealed the strong gradient control exerted by the bedrock anastomosed and mixed anastomosed channel types, which creates hydraulic conditions suitable for deposition in the upstream alluvial reaches. The role of these bedrock-influenced channel types on hydraulic character is also revealed in the results of 2D hydraulic modelling of moderate flood (3500 m3s-1) as the bedrock or mixed anastomosed channel type is drowned out, resulting in dramatically increased velocities along the entire river and a general stripping of unconsolidated and consolidated sediments regardless of initial channel type or location

Phase II study of a neutrophil elastase inhibitor (AZD9668) in patients with bronchiectasis

SummaryNeutrophil elastase (NE) activity is increased in bronchiectasis and may play a role in this condition. We wished to determine the effect of AZD9668, a selective oral inhibitor of NE.Efficacy and safety of AZD9668 60 mg twice daily over 4 weeks were evaluated in a randomised, double-blind, placebo-controlled, parallel-group, Phase II, signal-searching study in patients with bronchiectasis. Outcome measures included: waking and post-waking sputum neutrophil counts; lung function tests; 24-h sputum weight; BronkoTest® diary card data; St George's Respiratory Questionnaire for COPD patients (SGRQ-C); sputum NE activity; inflammatory biomarker levels; desmosine levels; adverse events, safety haematology and biochemistry. AZD9668 levels in plasma and sputum were measured to confirm exposure.Thirty-eight patients were randomised: 16 to placebo and 22 to AZD9668. There was no change in sputum neutrophils with AZD9668. Forced expiratory volume in 1 s improved by 100 mL in the AZD9668 group compared with placebo (p = 0.006). Significant changes (defined a priori as p < 0.1) in favour of AZD9668 were also seen in slow vital capacity, plasma interleukin-8, and post-waking sputum interleukin-6 and Regulated on Activation, Normal T-cell Expressed and Secreted levels. Non-significant changes in favour of AZD9668 were seen in other lung function tests, sputum weight and the SGRQ-C. AZD9668 was well tolerated.In this small signal-searching study, 4 weeks' treatment with AZD9668 improved lung function in patients with bronchiectasis and there were trends for reductions in sputum inflammatory biomarkers. Larger studies of longer duration would be needed to confirm the potential benefits of this agent in bronchiectasis.Registration: NCT00769119

ONEDAY Shoes: A Maker Toolkit to Understand the Role of Co-Manufacturing in Personalization

Personalization of shoes is of increasing importance to designers, design researchers, and manufacturers as mass customization progresses towards ultra personalized product service systems. Many attempts have been made to design co-creation platforms that allow end users to personalize their own shoes. Those co-creation platforms primarily concentrate on color selection. This research takes a different approach and designs a toolkit for maker-oriented users to co-manufacture their own shoes. The toolkit was designed in different levels and deployed to makers via crowdsharing worldwide. Backers were surveyed before deployment and interviewed after two years to understand personalization over a larger amount of time with the research product. We find that users who have greater bespoke tools and materials in their toolkits are more likely to personalize their shoes while co-manufacturing. The research provides guidelines for researchers and designers creating toolkits, designing personalization product service systems/configurators and engaging in tangible bespoke processes

Discovery of novel heart rate-associated loci using the Exome Chip

Resting heart rate is a heritable trait, and an increase in heart rate is associated with increased mortality risk. Genome-wide association study analyses have found loci associated with resting heart rate, at the time of our study these loci explained 0.9% of the variation. This study aims to discover new genetic loci associated with heart rate from Exome Chip meta-analyses. Heart rate was measured from either elecrtrocardiograms or pulse recordings. We meta-analysed heart rate association results from 104 452 European-ancestry individuals from 30 cohorts, genotyped using the Exome Chip. Twenty-four variants were selected for follow-up in an independent dataset (UK Biobank, N = 134 251). Conditional and gene-based testing was undertaken, and variants were investigated with bioinformatics methods. We discovered five novel heart rate loci, and one new independent low-frequency non-synonymous variant in an established heart rate locus (KIAA1755). Lead variants in four of the novel loci are non-synonymous variants in the genes C10orf71, DALDR3, TESK2 and SEC31B. The variant at SEC31B is significantly associated with SEC31B expression in heart and tibial nerve tissue. Further candidate genes were detected from long-range regulatory chromatin interactions in heart tissue (SCD, SLF2 and MAPK8). We observed significant enrichment in DNase I hypersensitive sites in fetal heart and lung. Moreover, enrichment was seen for the first time in human neuronal progenitor cells (derived from embryonic stem cells) and fetal muscle samples by including our novel variants. Our findings advance the knowledge of the genetic architecture of heart rate, and indicate new candidate genes for follow-up functional studies

Abstracts from the NIHR INVOLVE Conference 2017

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