Quantifying flood model accuracy under varying surface complexities

This is the final version. Available on open access from Elsevier via the DOI in this recordData availability: Data will be made available on request.Open Access experimental datasets used in this paper are available at https://zenodo.org/communities/floodinteract/Floods in urban areas which feature interactions between piped and surface networks are hydraulically complex. Further, obtaining in situ calibration data, although necessary for robust simulations, can be very challenging. The aim of this research is to evaluate the performance of a commonly used deterministic 1D-2D flood model, calibrated using low resolution data, against a higher resolution dataset containing flows, depths and velocity fields; which are replicated from an experimental scale model water facility. Calibration of the numerical model was conducted using a lower resolution dataset, which consisted of a simple rectangular profile. The model was then evaluated against a dataset that was higher in spatial resolution and more complex in geometry (a street profile containing parking spaces). The findings show that when the model increased in scenario complexity model performance was reduced, though most of the simulation error was < 10% (NRMSE). Similarly, there was more error in the validated model that was higher in spatial resolution than lower. This was due to calibration not being stringent enough when conducted in a lower spatial resolution. However, overall the work shows the potential for the use of low-resolution datasets for model calibration.Engineering and Physical Sciences Research Council (EPSRC

Investigation of uniform and graded sediment wash-off in an urban drainage system: numerical model validation from a rainfall simulator in an experimental facility

[Abstract:] Understanding sediment wash-off in urban environments plays an essential role in sediment transport management; and is critical for accurate pluvial flood control to assist in adaptation and mitigation strategies. Sediment transport models have been researched previously, though challenges still arise due to the complicated nature of graded sediment transport. This study tested the accuracy of the van Rijn model using a sparse distribution of particle sizes using the geometric mean. As such, this study used high-resolution datasets collected in a water laboratory to investigate sediment wash-off and transport on an urban street. This included the interaction of two gully pots receiving sediment loads that were washed off from a hypothetical urban surface by three rainfall intensities. The results showed that the model was able to simulate uniform sediments entering the gully pots accurately when the sediment size was assigned to a median diameter. Using the grain diameter to represent the geometric mean can improve the model performance for simulating a graded sediment.EPSRC Centre for Doctoral Training in Water Informatics Science and Engineering, WISE CDT; EP/L016214/1The work presented in this paper was carried out as part of PhD research and was supported by the EPSRC Centre for Doctoral Training in Water Informatics Science and Engineering (WISE CDT; EP/L016214/1). The experimental part and data collection received funding from the Spanish Ministry of Science, Innovation and Universities under POREDRAIN project RTI2018-094217-B-C33 (MINECO/FEDER-EU). The authors would also like to thank the Danish Hydraulic Institute for supplying the academic license for the MIKE 21 model

General anaesthetic and airway management practice for obstetric surgery in England: a prospective, multi-centre observational study

There are no current descriptions of general anaesthesia characteristics for obstetric surgery, despite recent changes to patient baseline characteristics and airway management guidelines. This analysis of data from the direct reporting of awareness in maternity patients' (DREAMY) study of accidental awareness during obstetric anaesthesia aimed to describe practice for obstetric general anaesthesia in England and compare with earlier surveys and best-practice recommendations. Consenting patients who received general anaesthesia for obstetric surgery in 72 hospitals from May 2017 to August 2018 were included. Baseline characteristics, airway management, anaesthetic techniques and major complications were collected. Descriptive analysis, binary logistic regression modelling and comparisons with earlier data were conducted. Data were collected from 3117 procedures, including 2554 (81.9%) caesarean deliveries. Thiopental was the induction drug in 1649 (52.9%) patients, compared with propofol in 1419 (45.5%). Suxamethonium was the neuromuscular blocking drug for tracheal intubation in 2631 (86.1%), compared with rocuronium in 367 (11.8%). Difficult tracheal intubation was reported in 1 in 19 (95%CI 1 in 16-22) and failed intubation in 1 in 312 (95%CI 1 in 169-667). Obese patients were over-represented compared with national baselines and associated with difficult, but not failed intubation. There was more evidence of change in practice for induction drugs (increased use of propofol) than neuromuscular blocking drugs (suxamethonium remains the most popular). There was evidence of improvement in practice, with increased monitoring and reversal of neuromuscular blockade (although this remains suboptimal). Despite a high risk of difficult intubation in this population, videolaryngoscopy was rarely used (1.9%)