Impacts of river engineering on river channel behaviour : implications for managing downstream flood risk

Although knowledge of sediment transport has improved over the last 25 years, our understanding of bedload transfer and sediment delivery is still based on a limited set of observations or on models that make assumptions on hydraulic and sediment transport processes. This study utilises repeat lidar survey data of the River Caldew above the City of Carlisle in the UK to investigate the balance of erosion and deposition associated with channel switching from an engineered and managed single thread channel to a naturalising incipient wandering system. Over the 11-year survey period (four bankfull flood events) around 271,000 m3 of sediment were delivered to the river and floodplain and 197,000 m3 eroded suggesting that storage rates of around 7000 m3/annum occurred. The balance of erosion and deposition is influenced by channelisation with very restricted overbank sedimentation and only limited local and transient in-channel bar deposition along the engineered reach (8000 m3 eroded). This contrasts with the activity of the naturalising reach downstream where a developing wandering channel system is acting to store coarse sediment in-stream as large bar complexes and the associated upstream aggrading plane bed reaches and overbank as splay deposits (87,000 m3 stored). Such behavior suggests that naturalisation of channelised systems upstream of flood vulnerable urban areas can have a significant impact on sediment induced flooding downstream. This conclusion must, however, be moderated in the light of the relatively small volumes of material needed to instigate local aggradation in over-capacity urban channels

Recruitment to clinical trials : a meta-ethnographic synthesis of studies of reasons for participation

Peer reviewedPostprin

Why Health and Social Care Support for People with Long-Term Conditions Should be Oriented Towards Enabling Them to Live Well

This research was funded by The Health Foundation (a charity working to improve the quality of healthcare in the UK) via (a) a commission on conceptualising collaborative care, (b) an Open Insight initiative project on re-conceptualising support for self-management (reference 7209), and (c) a contribution towards salary funding for Alan Cribb. At the University of Aberdeen, Vikki Entwistle works within the Health Services Research Unit, which is core funded by the Chief Scientist Office of the Scottish Government’s Health and Social Care Directorates. Health Foundation and Scottish Government staff are among those who have participated in knowledge exchange events related to the two projects. The views expressed in the paper are those of the authors and are not necessarily shared by funders or workshop participants. The authors accept full responsibility for this paper. Open access via Springer Compact AgreementPeer reviewedPublisher PD

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