An investigation of braided river dynamics using a new numerical modelling approach

Braided Cascade has been developed from Cascade (Braun and Sambridge, (1997), a long-term (dt = 100 years) numerical model that simulates long-term landscape evolution. Herein it has been modified and applied to relatively short term process modelling of the evolution of complex river topography, discharge and sediment load of braided rivers. Braided Cascade is synthesist in spirit, there is no detailed hydrodynamic component to the model, a realistic simplification at the time scales considered. The major advantage of the model is the incorporation of an irregular time-varying grid using a triangulated irregular network (TIN) to represent a terrain surface. Advantages of using TINs include the ability to solve problems with non-rectangular geometeries and/or boundary conditions and the ability of river segments to form in all directions. The model routes water from node to node based on the local topographic slope. Sediment transport depends on the local stream power. Nodal elevation changes after each iteration according to the difference between the amount of sediment entering and leaving the node. Model output includes spatial and temporal (at one point) water discharge, bedload sediment transport, as well as maps of channel networks, erosion and deposition throughout the reach. Sensitivity analysis indicated that the most significant parameters for braiding are erosion length scale, splitting ratios and the allowance of the model to deposit sediment. Therefore an imbalance in the amount of sediment the river is carrying and the carrying capacity AND a reworking of the deposits is needed for a braided network to form. Sediment output from model runs indicate that the similarities between model data and other data sets are weak and all runs tended to reach static equilibrium. Braided Cascade therefore failed to adequately reproduce realistic data sets. It was found that the differences between model results and the flume data indicate that the model does not always match the physical systems as closely as physical systems match each other

Modelling the efficacy of woody debris dams in slowing and reducing peak discharge

As part of Natural Flood Management, networks of engineered woody debris dams are deployed in upper catchments. There is currently a great deal of interest shown in hydro-environmental modelling (hydro-environmental, referring here to the dynamic parameters, i.e. water levels and velocities, and environmental in the context of the catchment characteristics) to overcome upscaling from plot to catchment. However, there is no standard hydraulic unit to simulate woody debris dams in the modelling domain. This study develops and validates a hydraulic modelling unit that accounts for the physical properties of the woody debris dams and tests this unit with real-world empirical data. Pier-loss bridge units were used to simulate a network of woody debris dams. Woody debris dam blockage area and gap sizes were investigated, and seasonal changes and designs of woody debris dams were simulated by altering the pier-loss bridge legs and soffits. The modelling software package, Jacobs Flood Modeller v6.1 (FM) enabled field data to be imported as boundary conditions so the model could represent the real-world. Two storm events were simulated with data obtained from on-site automated monitoring equipment. Results show pier-loss bridge units within FM, 1D simulations, effectively represented varied woody debris dam designs in attenuating peak discharge

Smart DCU digital twin: towards smarter universities

Although both smart city and digital twin are ambiguous and contested terms, there exists a co-creative link between the two. Theoretically, digital twin seems to be a sustainable digital solution for smart cities to achieve ideal city vision by digitization of physical urban spaces. This study investigates and informs the role, benefits and challenges in developing and deploying digital twin solution for efficient decision-making in infrastructure planning and management. This technology is experimented in a 3D cyberspace of Dublin City University, which is also one of the testbeds under the broader Smart Dublin umbrella. It is an ongoing project and expects to develop effective use-cases for monitoring present situations, multi-stakeholder collaboration and action research towards a responsive and adaptive campus environment

Developing, choosing and using landscape evolution models to inform field-based landscape reconstruction studies:Developing, choosing and using landscape evolution models

Landscape evolution models (LEMs) are an increasingly popular resource for geomorphologists as they can operate as virtual laboratories where the implications of hypotheses about processes over human to geological timescales can be visualized at spatial scales from catchments to mountain ranges. Hypothetical studies for idealized landscapes have dominated, although model testing in real landscapes has also been undertaken. So far however, numerical landscape evolution models have rarely been used to aid field-based reconstructions of the geomorphic evolution of actual landscapes. To help make this use more common, we review numerical landscape evolution models from the point of view of model use in field reconstruction studies. We first give a broad overview of the main assumptions and choices made in many LEMs to help prospective users select models appropriate to their field situation. We then summarize for various timescales which data are typically available and which models are appropriate. Finally, we provide guidance on how to set up a model study as a function of available data and the type of research question.</p

The concept of transport capacity in geomorphology

The notion of sediment-transport capacity has been engrained in geomorphological and related literature for over 50 years, although its earliest roots date back explicitly to Gilbert in fluvial geomorphology in the 1870s and implicitly to eighteenth to nineteenth century developments in engineering. Despite cross fertilization between different process domains, there seem to have been independent inventions of the idea in aeolian geomorphology by Bagnold in the 1930s and in hillslope studies by Ellison in the 1940s. Here we review the invention and development of the idea of transport capacity in the fluvial, aeolian, coastal, hillslope, débris flow, and glacial process domains. As these various developments have occurred, different definitions have been used, which makes it both a difficult concept to test, and one that may lead to poor communications between those working in different domains of geomorphology. We argue that the original relation between the power of a flow and its ability to transport sediment can be challenged for three reasons. First, as sediment becomes entrained in a flow, the nature of the flow changes and so it is unreasonable to link the capacity of the water or wind only to the ability of the fluid to move sediment. Secondly, environmental sediment transport is complicated, and the range of processes involved in most movements means that simple relationships are unlikely to hold, not least because the movement of sediment often changes the substrate, which in turn affects the flow conditions. Thirdly, the inherently stochastic nature of sediment transport means that any capacity relationships do not scale either in time or in space. Consequently, new theories of sediment transport are needed to improve understanding and prediction and to guide measurement and management of all geomorphic systems

Your Dublin Your Voice. Detailed results of phase 1, April 2011.

Almost 2,300 people, representing all ages and backgrounds, over 60 nationalities and every county in Ireland, replied to the survey between October and December. Some of the "Your Dublin, Your Voice’ findings include; Dublin is a great place to live and work in, a fun place to be with lots to see and do. Its friendly people, compact size, thriving arts scene and cultural diversity are among its top assets. However, Dubliners want cleaner streets, improved public transport and to feel safer at night. They also want more action on street begging, drink and drug abuse and anti social behaviour. Not surprisingly, finding a job is perceived as difficult in today’s economic climate. This is the first local government-led opinion panel in Ireland. The survey sought the views of people who live, work, study or visit the Dublin Region. Selected Topline Results: Remarkably in spite of all the economic turmoil of recent times Dubliners are upbeat about living, working and studying in Dublin. Almost 90% (over 2,000) of respondents were positive about the fact their job or place of study was in Dublin A similar percentage would recommend Dublin to family and friends as a great place to visit. The majority felt so strongly about Dublin that over 70% would prefer to live in the capital than anywhere else in Ireland In the opinion of one respondent Dublin’s strength was that its “a vibrant international city with a small town feel” Respondents identified Dublin’s key strengths as it’s people (31%) in particular their humour, friendliness and warmth, it’s culture and arts (17%), It’s compact size (15%) and its diverse cosmopolitan feel (13%). Some 88% of respondents welcomed diversity in the city and felt that this was one of Dublin’s key strengths. One respondent commented that “It’s the people that count. They have never lost their generous warmth” Another respondent observed that Dublin is a place “where you can see a city, a fishing harbour, and the mountains in one day.” Not surprisingly only 16% of respondents felt that Dublin is an easy place in which to find a job today. Some of the worst things about Dublin highlighted included the perception of significant levels of anti-social behaviour, street begging, drink and drug abuse. These aspects were identified as a negative by 36% of respondents. Many of the panel members feel that drugs use has had a serious impact on the image of the city centre and is something that needs urgent attention from all stakeholders that operate in the city Other areas of concern were Litter/Cleanliness/Appearance (17%) and Public Transport (11%) were other areas of concern 98% of respondents rated LUAS positively. 95% and 89% of respondents respectively rated dublinbikes and Dublin Port Tunnel positively 85% of respondents are positive about Metro North and 74% approve of taking water from the Shannon for the Dublin Region

The effects of shift schedules in nursing staff on sleep, job satisfaction, general health and stress

This research was designed to examine the differences in sleep disturbances, job-satisfaction, stress and general health, between rotating shift workers and fixed shift workers. A snowball technique was used to find the nursing sample; invitations to complete an online survey were sent to different social websites, who then invited others to take part. Sixty five people, aged from nineteen to sixty-five; fifty-nine females and four males, participated. Results showed a significant difference between the groups in relation to job-satisfaction, stress and general health. No statistic differences were found between the groups in relation to sleep. The relationship between stress and years of employment in the rotating group were also examined and a moderate, positive relationship was found. Author keywords: Shiftwork, Nurses, Fixed shift workers, Rotating shift workers, sleep, job satisfaction, general health and stres

When Smart Bins Meet a Smart City

Smart Bins have appeared in cities all around the world to help manage public waste collection more effectively. How are local governments reacting to this piece of technology? Do they serve solely as optimised/glorified waste receptacles, or contribute more than that? Moreover, is there a case to further scale up its use across the city?</jats:p