Now showing 1 - 10 of 32
  • Publication
    Integrated modelling of urban, rural and coastal domains for bathing water quality prediction – Smart Coasts and Acclimatize Projects
    This paper presents the results of the Interreg funded SMARTCOASTS project in which an integrated catchment (MIKE11) and coastal (MIKE21 and MIKE3) modelling tool was developed for predicting the bathing water quality, at Bray, Co. Wicklow, on the east coast of Ireland. The Bray bathing waters had historically been prone to episodic short-term pollution, caused primarily by rainfall related catchment run-off. Accounting fully for the complexity of the pollution inputs for water quality prediction in the system required an integrated modelling approach. The approach for integrating the individual component models (NAM, MIKE 11, and MIKE 3 FM) was simple but efficient. The component models, interfaced to the core of the forecasting system, were run sequentially, i.e. in the form of a cascade with the forcing of each downstream model being the result of the model upstream of it. Rainfall (both forecasted and measured) drives the hydrological processes in the NAM model, which produces runoff that generates sub-catchment inflows into the river network. The output from NAM serves as the input to the MIKE 11 model which routes the flow and water quality variables in the river network and transports them to the coastal waters. Finally, the MIKE 3 FM coastal model uses flow and water quality outputs from MIKE 11, together with tidal and meteorological data, to simulate the current flow, transport and fate of water quality variables in the marine environment. Models were calibrated using measured data. Adjustment of the tidal constituents of the MIKE global model resulted in a markedly improved fit to measured water levels at five reference tidal gauges, used for calibration. Bottom friction was calibrated to produce good correlations of measured and simulated current speed and direction. When applied to water quality prediction, results of the transport model showed that the model adequately replicated measurements of E.coli and Intestinal Enterococci within the coastal domain. Computational simulations of bathing water quality are not without difficulty and a significant challenge in this work involved incorporating real-time meteorological data from a sensor network within the catchment into the model predictions. The work of Smart Coasts is currently being built on in the Interreg funded Acclimatize project. Acclimatize is focussing on the bathing waters of Dublin Bay and involves the development of a modelling platform that will facilitate a longer-term assessment of the likely pressures on bathing water quality in the context of a changed climate.
  • Publication
    Extreme wave overtopping at ecologically modified sea defences
    Damage to coastal structures and surrounding properties from wave overtopping in extreme events is expected to be exacerbated in future years as global sea levels continue to rise and the frequency of extreme meteorological events and storm surges increases. Approaches for protecting our coastal areas have traditionally relied on the development and ongoing maintenance of ‘hard’ defences. However, the longer-term sustainability of coastal flood management that is underpinned by such defences is increasingly being questioned both in terms of dealing with climate change and in the environmental/ ecological consequences and associated losses of biodiversity that comes with these structural defence lines in coastal areas.
  • Publication
    A European review on Critical Thinking educational practices in Higher Education Institutions
    Within the scope of CRITHINKEDU project, this report is directed to university teachers, pedagogical support teams and institutional leaders, providing an overall understanding on how European Higher Education Institutions (EHEI) foster Critical Thinking (CT), taking into account both the current educational intervention studies reported in the literature and teachers' educational practices. Adopting a mixed method research design, 46 papers from the literature were reviewed and 53 interviews with university teachers from 9 European countries were carried out. The analysis comprised both studies and teachers' interviews from 4 different professional fields, namely Biomedical Sciences, STEM (Sciences, Technology, Engineering and Mathematics), Social Sciences and the Humanities.
  • Publication
    Influences on flood frequency distributions in Irish river catchments
    (Copernicus Publications on behalf of the European Geosciences Union, 2012) ; ;
    This study explores influences on flood frequency distributions in Irish rivers. Generalised Extreme Value (GEV) type I distributions are recommended in Ireland for estimating flood quantiles. This paper presents the findings of an investigation that identified the GEV statistical distributions that best fit the annual maximum (AM) data series extracted from 172 gauging stations of 126 rivers in Ireland. Analysis of these data was undertaken to explore hydraulic and hydro-geological factors that influence flood frequency distributions. A hierarchical approach of increasing statistical power that used probability plots, moment and L-moment diagrams, the Hosking goodness of fit algorithm and a modified Anderson-Darling (A-D) statistical test was followed to determine whether a type I, type II or type III distribution was valid. Results of the Hosking et al. method indicated that of the 143 stations with flow records exceeding 25 years, data for 95 (67%) was best represented by GEV type I distributions and a further 9 (6%) and 39 (27%) stations followed type II and type III distributions respectively. Type I, type II and type III distributions were determined for 83 (58%), 16 (11%) and 34 (24%) stations respectively using the modified A-D method (data from 10 stations was not represented by GEV family distributions). The influence of karst terrain on these flood frequency distributions was assessed by incorporating results on an Arc-GIS platform showing karst features and using Monte Carlo simulations to assess the significance of the number and clustering of the observed distributions. Floodplain effects were identified by using two-sample t-tests to identify statistical correlations between the distributions and catchment properties that are indicative of strong floodplain activity. The data reveals that type I distributions are spatially well represented throughout the country. While also well represented throughout the country, the majority of type III distributions appear in areas where attenuation influences from floodplains are likely. The majority of type II distributions appear in a single cluster in a region in the west of the country that is underlain by karst but importantly, is characterised by shallow of glacial drift with frequent exposures of rock outcrops. The presence of karst in river catchments would be expected to provide additional subsurface storage and in this regard, type III distributions might be expected. The prevalence of type II distributions in this area reflects the finite nature of this storage. For prolonged periods of rainfall, rising groundwater levels will fill karst voids, remove subsurface storage and contribute to recharge related sinkhole flooding. Situations where rainfall intensities exceed karst percolation rates also produce high levels of surface runoff (discharge related flooding) that can promote type II distributions in nearby river catchments. Results therefore indicate that in some instances, assuming type I distributions is incorrect and may result in erroneous estimates of flood quantiles at these locations. Where actual data follows a type II distribution, flood quantiles may be underestimated by in excess of 35% and for type III distributions, overestimates by over 25% can occur.
      2985Scopus© Citations 21
  • Publication
    Distribution of Individual Wave Overtopping Volumes on a Sloping Structure with a Permeable Foreshore
    (Coastal Engineering Research Council, 2020-12-31) ; ; ; ;
    Maximum wave overtopping volumes on sea defences are an indicator for identifying risks to people and properties from wave hazards. The probability distribution of individual overtopping volumes can generally be described by a two-parameter Weibull distribution function (shape and scale parameters). Therefore, the reliable prediction of maximum individual wave overtopping volumes at coastal structures relies on an accurate estimation of the shape factor in the Weibull distribution. This study contributes to an improved understanding of the distribution of individual wave overtopping volumes at sloping structures by analysing the wave-by-wave overtopping volumes obtained from physical model experiments on a 1V:2H sloped impermeable structure with a permeable shingle foreshore of slope 1V:20H. Measurements of the permeable shingle foreshore were benchmarked against those from an identical experimental set-up with a smooth impermeable foreshore (1V:20H) of the same geometry. Results from both experimental set-ups were compared to commonly used empirical formulations, underpinned by the assumption that an impermeable foreshore exists in front of the sea structure. The effect on the shape factor in the Weibull distribution of incident wave steepness, relative crest freeboard, probability of overtopping waves and discharge are examined to determine the variation of individual overtopping volumes with respect to these key parameters. A key finding from the study is that no major differences in Weibull distribution shape parameter were observed for the tested impermeable and permeable sloped foreshores. Existing empirical formulae were also shown to predict reasonably well the Weibull distribution shape parameter, b, at sloping structures with both impermeable and permeable slopes.
  • Publication
    Modelling Quantified Microbial Source Specific Pollution from Domestic Wastewater Treatment Systems during High Flows
    The ability to model the transport of source specific faecal bacteria contamination in river networks can equip water resource managers with information of the different pathogens that are present. Such information can be particularly useful in catchment management plans for rivers from which potable water is extracted or where these rivers discharge to coastal zones where bathing or aquaculture is prominent and where the evaluation of human health risks is of primary importance. This paper presents an application and performance assessment of the commercially available MIKE11 Hydrodynamic model for evaluating the fate of faecal bacteria of human origin, Human Gene Marker HF183f, from Domestic Wastewater Treatment Systems within the Dargle catchment. The Dargle is a spate river and the upper catchment is characterised by steep slopes that incorporates peat bogs and land used for forestry and agricultural purposes. Residential dwellings within the area are predominantly single detached units that rely on septic tanks for wastewater treatment. In the context of faecal bacteria of human origin, malfunctioning systems are of concern, particularly in terms of surface ponding, leakage to groundwater and direct discharge to surface waters. The MIKE11 model was calibrated in a two stages process. Firstly, the model was calibrated for prediction of discharge and microbial water quality parameters, namely E. coli and Intestinal Enterococci (IE), using data from a real-time sensor network within the catchment that comprised rain gauges, weather stations and water level recorders, data from which was used to determine flow records from stage-discharge ratings. E. coli and IE concentrations were determined from high resolution sampling during storm events. Following this, water quality samples taken during storm event sampling were used to identify and quantify the human gene marker HF183f using quantitative polymer chain reaction (qPCR) techniques. Results from the qPCR analysis were used to further calibrate the model at sub-catchment level for the transport of microbial bacteria derived from human origins. Using non-compliance statistics from the EPA National Inspection Plan, domestic sources have been calculated based on the percentage number of malfunctioning septic tank units and average daily faecal gene marker concentrations per household. The study highlights issues with how the fate of the human gene marker is modelled using MIKE11, particularly in terms of advection-dispersion inputs and the requirement to associate microbial concentrations with total runoff when modelling surface and groundwater pathways.
  • Publication
    Effectiveness of Eco-retrofits in Reducing Wave Overtopping on Seawalls
    (Coastal Engineering Research Council, 2020-12-28) ; ; ;
    Terms such as 'nature-based', 'living shoreline', 'green infrastructure' and 'ecological engineering' are increasingly being used to reflect biomimicry-based engineering measures in coastal defences. Innovative interventions for nature-based sea defences have included the retrofitting of man-made water filled depressions or 'vertipools' to existing seawalls (Hall et al., 2019; Naylor et al., 2017) and the addition of artificial drill-cored rock pools to intertidal breakwaters (Evans et al., 2016). Through their capacity to retain water, such measures serve to enhance biodiversity in the built environment (Browne and Chapman, 2014). Evans et al. (2016) for example, experimentally demonstrated that the introduction of artificial rock pools to an intertidal granite breakwater enhanced the levels of species richness compared to those observed on plain surfaces of the breakwater. Notwithstanding these biological benefits, the impetus for incorporation of ecologically friendly measures to existing defences remains low (Salauddin et al., 2020a). This situation could potentially change should it be shown that the addition of 'green' measures to sea defences could enhance wave attenuation and reduce wave overtopping as well as wave pressures on the coastal defence structures. This paper describes small-scale physical modelling investigations of seawalls and explores reductions in wave overtopping that could be realised by retrofitting sea defences with 'green' features (such as 'vertipools'). Surface protrusions of varying scale and density are used in the physical modelling to mimic 'green' features and the results from measurements of overtopping are benchmarked to reference conditions determined from tests on a plain seawall.
  • Publication
    Flow resistance of emergent vegetation
    Conventional resistance equations (such as those of Manning, Chézy and Darcy-Weisbach) are inappropriate for flow through emergent vegetation, where resistance is exerted primarily by stem drag throughout the flow depth rather than by shear stress at the bed. An alternative equation form is suggested, in which the resistance coefficient is related to measurable vegetation characteristics and can incorporate bed roughness when this is significant. Equation performance is confirmed by comparison of predicted and measured stage-discharge relationships for flow through artificial cylindrical stems, and by comparison of calibrated and measured drag coefficient values for natural vegetation.
  • Publication
    The CRITHINKEDU European Course on critical thinking education for university teachers : from conception to delivery
    Within the scope of the CRITHINKEDU project1, this intellectual output (Output 3) reports the experience of conceiving and delivering a European training course on Critical Thinking (CT) education for university teachers. It draws on the proposal of the “European inventory of critical thinking skills and dispositions for the 21st century” and the “Preliminary guidelines for quality in critical thinking education” - both presented in the two previous intellectual outputs of the project (Dominguez, 2018a, 2018b). This report is targeted to each leading partner institution or to any Higher Education (HE) institution which desire to later replicate this training course at the local level, to faculty staff interested in the implementation of CT teaching practices and learning activities in their classroom. Deployments within the CRITHINKEDU project will be carried-out as part of the fourth and following intellectual output (Output 4).
  • Publication
    TRUSS Training in Reducing Uncertainty in Structural Safety: D2.5 Final Report: WP2 - Dissemination and Outreach
    This report describes the outputs of work package WP2 (Dissemination and Outreach) from 1 st January 2015 to 31st December 2018. Dissemination by TRUSS is keenly aware of the importance of not only producing and presenting research outputs for the scientific community and key stakeholders (i.e., via conferences, workshops, publications and reports), but also engaging the general public in line with the Innovation Union objectives. TRUSS mainly deals with the challenges faced at the design, assessment and management stages of large scale structures. Outreach activities, blogs and social media and other communications by TRUSS, bring awareness to the public on the importance of this research on infrastructure to support a community, region or country, and also motivate School and University students to pursue a research career. These activities make citizens aware of: • Infrastructure aging and failing, with funding that has been insufficient to repair and replace it; • The important role of the Marie Skłodowksa-Curie Actions in forming 21st century engineers that will have the skills to face the formidable challenge of modernizing the fundamental infrastructure that support civilization.