Have applications of continuous rainfall-runoff simulation realized the vision for process-based flood frequency analysis?

Keith Beven was amongst the first to propose and demonstrate a combination of conceptual rainfall–runoff modelling and stochastically generated rainfall data in what is known as the ‘continuous simulation’ approach for flood frequency analysis. The motivations included the potential to establish better links with physical processes and to avoid restrictive assumptions inherent in existing methods applied in design flood studies. Subsequently, attempts have been made to establish continuous simulation as a routine method for flood frequency analysis, particularly in the UK. The approach has not been adopted universally, but numerous studies have benefitted from applications of continuous simulation methods. This paper asks whether industry has yet realized the vision of the pioneering research by Beven and others. It reviews the generic methodology and illustrates applications of the original vision for a more physically realistic approach to flood frequency analysis through a set of practical case studies, highlighting why continuous simulation was useful and appropriate in each case. The case studies illustrate how continuous simulation has helped to offer users of flood frequency analysis more confidence about model results by avoiding (or exposing) bad assumptions relating to catchment heterogeneity, inappropriateness of assumptions made in (UK) industrystandard design event flood estimation methods, and the representation of engineered or natural dynamic controls on flood flows. By implementing the vision for physically realistic analysis of flood frequency through continuous simulation, each of these examples illustrates how more relevant and improved information was provided for flood risk decision-making than would have been possible using standard methods. They further demonstrate that integrating engineered infrastructure into flood frequency analysis and assessment of environmental change are also significant motivations for adopting the continuous simulation approach in practic

FEH Local: improving flood estimates using historical data

The traditional approach to design flood estimation (for example, to derive the 100-year flood) is to apply a statistical model to time series of peak river flow measured by gauging stations. Such records are typically not very long, for example in the UK only about 10% of the stations have records that are more than 50 years in length. Along-explored way to augment the data available from a gauging station is to derive information about historical flood events and paleo-floods, which can be obtained from careful exploration of archives, old newspapers, flood marks or other signs of past flooding that are still discernible in the catchment, and the history of settlements. The inclusion of historical data in flood frequency estimation has been shown to substantially reduce the uncertainty around the estimated design events and is likely to provide insight into the rarest events which might have pre-dated the relatively short systematic records. Among other things, the FEH Local project funded by the Environment Agency aims to develop methods to easily incorporate historical information into the standard method of statistical flood frequency estimation in the UK. Different statistical estimation procedures are explored, namely maximum likelihood and partial probability weighted moments, and the strengths and weaknesses of each method are investigated. The project assesses the usefulness of historical data and aims to provide practitioners with useful guidelines to indicate in what circumstances the inclusion of historical data is likely to be beneficial in terms of reducing both the bias and the variability of the estimated flood frequency curves. The guidelines are based on the results of a large Monte Carlo simulation study, in which different estimation procedures and different data availability scenarios are studied. The study provides some indication of the situations under which different estimation procedures might give a better performance

Planning and partnerships: a model for successful section 319(h) projects

Proceedings of the 2013 Georgia Water Resources Conference, April 10-11, 2013, Athens, Georgia.Restoration of Georgia’s water quality requires many elements and players. From developing a plan, to deciding on the appropriate implementation actions, to finding the right organization to coordinate these efforts, trying to restore water quality in a given stream, lake, or estuary presents many challenges. However, when all of the necessary elements and players do come together, the results are well worth the challenges. One of the most important aspects of restoring waters is partnerships, and the partnerships forged by the Soque River Watershed Association (SRWA) have proven extremely effective. The Soque Partnership (SP) was formed by SRWA and the City of Clarkesville to develop a watershed management plan (WMP) and engage many diverse stakeholders in its many partnerships and implementation actions. The SP has demonstrated what a model Section 319(h) Grant funded project can look like. The SRWA continues to utilize their partnerships in the most effective manner, which has resulted in several rounds of funding under Section 319(h) to implement their WMP. The result of this work will be a segment of the Soque River that has been moved from Not Supporting is designated use to Supporting on the Draft 2012 3035(b)/303(d) List of Waters. The SRWA hopes to continue this model to further their restoration effort and to being teaching others in an attempt to export this successful model of planning and implementation to other in the hopes of seeing more of Georgia’s waters restored.Sponsored by: Georgia Environmental Protection Division; U.S. Department of Agriculture, Natural Resources Conservation Service; Georgia Institute of Technology, Georgia Water Resources Institute; The University of Georgia, Water Resources Faculty.This book was published by Warnell School of Forestry and Natural Resources, The University of Georgia, Athens, Georgia 30602-2152. The views and statements advanced in this publication are solely those of the authors and do not represent official views or policies of The University of Georgia, the Georgia Water Research Institute as authorized by the Water Research Institutes Authorization Act of 1990 (P.L. 101-307) or the other conference sponsors

Modelling non-stationary flood frequency in England and Wales using physical covariates

Non-stationary methods of flood frequency analysis are widespread in research but rarely implemented by practitioners. One reason may be that research papers on non-stationary statistical models tend to focus on model fitting rather than extracting the sort of results needed by designers and decision makers. It can be difficult to extract useful results from non-stationary models that include stochastic covariates for which the value in any future year is unknown. We explore the motivation for including such covariates, whether on their own or in addition to a covariate based on time. We set out a method for expressing the results of non-stationary models as an integrated flow estimate, which removes the dependence on the covariates. This can be defined either for a particular year or over a longer period of time. The methods are illustrated by application to a set of 375 river gauges across England and Wales. We find annual rainfall to be a useful covariate at many gauges, sometimes in conjunction with a time-based covariate. For estimating flood frequency in future conditions, we advocate exploring hybrid approaches that combine the best attributes of non-stationary statistical models and simulation models that can represent changes in climate and river catchments

Incorporating sedimentological data in UK flood frequency estimation

This study presents a new analytical framework for combining historical flood data derived from sedimentological records with instrumental river flow data to increase the reliability of flood risk assessments. Historical flood records were established for two catchments through re-analysis of sedimentological records; the Nant Cwm-du, a small, steep upland catchment in the Cambrian Mountains of Wales, and a piedmont reach of the River Severn in mid Wales. The proposed framework is based on maximum likelihood and least-square estimation methods in combination with a Generalised Logistic distribution; this enables the sedimentological data to be combined effectively with existing instrumental river flow data. The results from this study are compared to results obtained using existing industry standard methods based solely on instrumental data. The comparison shows that inclusion of sedimentological data can have an important impact on flood risk estimates, and that the methods are sensitive to assumptions made in the conversion of the sedimentological records into flood flow data. As current industry standard methods for flood risk analysis are known to be highly uncertain, the ability to include additional evidence of past flood events derived from sedimentological records as demonstrated in this study can have a significant impact on flood risk assessments

The Very Young Radio Pulsar J1357-6429

We report the discovery of a radio pulsar with a characteristic age of 7300 years, making it one of the 10 apparently youngest Galactic pulsars known. PSR J1357-6429, with a spin period of P = 166 ms and spin-down luminosity of 3.1e36 ergs/s, was detected during the Parkes multibeam survey of the Galactic plane. We have measured a large rotational glitch in this pulsar, with Delta P/P = -2.4e-6, similar in magnitude to those experienced occasionally by the Vela pulsar. At a nominal distance of only ~ 2.5 kpc, based on the measured free electron column density of 127 pc/cc and the electron distribution model of Cordes & Lazio, this may be, after the Crab, the nearest very young pulsar known. The pulsar is located near the radio supernova remnant candidate G309.8-2.6

Migrant networks, language learning and tourism employment

This paper examines the relationship between migrants’ social networks, the processes of language acquisition and tourism employment. Data collected using netnography and interviews are used to identify the strategies that Polish workers in the UK use to develop their language skills. The paper highlights the roles played by co-workers, co-nationals and customers in migrants’ language learning, both in the physical spaces of work and the virtual spaces of internet forums. It also shows how migrant workers exchange knowledge about the use of English during different stages of their migration careers: prior to leaving their country of origin and getting a job, during their employment and after leaving their job. Implications for academic inquiry and human resource management practice are outlined

Maxwell-Chern-Simons Vortices and Holographic Superconductors

We investigate probe limit vortex solutions of a charged scalar field in Einstein-Maxwell theory in 3+1 dimensions, for an asymptotically AdS Schwarzschild black hole metric with the addition of an axionic coupling to the Maxwell field. We show that the inclusion of such a term, together with a suitable potential for the axion field, can induce an effective Chern-Simons term on the 2+1 dimensional boundary. We obtain numerical solutions of the equations of motion and find Maxwell-Chern-Simons like magnetic vortex configurations, where the magnetic field profile varies with the size of the effective Chern-Simons coupling. The axion field has a non-trivial profile inside the AdS bulk but does not condense at spatial infinity.Comment: 17 pages, 5 figures, version accepted for publication in JHE

Values associated with public involvement in health and social care research: a narrative review

addresses: Mood Disorders Centre, Psychology, University of Exeter, Exeter, UK.OnlineOpen articleMuch has been written about public involvement (PI) in health and social care research, but underpinning values are rarely made explicit despite the potential for these to have significant influence on the practice and assessment of PI.Medical Research Council’s Methodology Research Programm