S Ahilan

The Influence of Floodplain Restoration on Flow and Sediment Dynamics in an Urban River

This article is freely available via Open Access. Follow the DOI to read the whole article on the publishers website.

Physical complexity to model morphological changes at a natural channel bend

This study developed a two-dimensional (2-D) depth-averaged model for morphological changes at natural bends by including a secondary flow correction. The model was tested in two laboratory-scale events. A field study was further adopted to demonstrate the capability of the model in predicting bed deformation at natural bends. Further, a series of scenarios with different setups of sediment-related parameters were tested to explore the possibility of a 2-D model to simulate morphological changes at a natural bend, and to investigate how much physical complexity is needed for reliable modeling. The results suggest that a 2-D depth-averaged model can reconstruct the hydrodynamic and morphological features at a bend reasonably provided that the model addresses a secondary flow correction, and reasonably parameterize grain-sizes within a channel in a pragmatic way. The factors, such as sediment transport formula and roughness height, have relatively less significance on the bed change pattern at a bend. The study reveals that the secondary flow effect and grain-size parameterization should be given a first priority among other parameters when modeling bed deformation at a natural bend using a 2-D model.

Agent-based modelling and inundation prediction to enable the identification of businesses affected by flooding.

Flooding continues to cause significant disruption to individuals, organisations and communities in many parts of the world. In terms of the impact on businesses in the United Kingdom (UK), flooding is responsible for the loss of millions of pounds to the economy. As part of a UK Engineering and Physical Sciences Research Council funded project on flood risk management, SESAME, research is being carried out with the aim of improving business response to and preparedness for flood events. To achieve this aim, one strand of the research is focused on establishing how agent-based modelling and simulation can be used to evaluate and improve business continuity. This paper reports on the development of the virtual geographic environment (VGE) component of an agent-based model and how this has been combined with inundation predictionto enable the identification of businesses affected by flooding in any urban area of the UK. The VGE has been developed to use layers from Ordnance Survey’s MasterMap, namely the Topography Layer, Integrated Transport Network Layer and Address Layer 2. Coupling the VGE with inundation prediction provides credibility in modelling flood events in any area of the UK. An initial case study is presented focusing on the Lower Don Valley region of Sheffield leading to the identification of businesses impacted by flooding based on a predicted inundation. Further work will focus on the development of agents to model and simulate businesses during and in the aftermath of flood events such that changes in their behaviours can be investigated leading to improved operational response and business continuity.

Delivering and evaluating the multiple flood risk benefits in Blue-Green Cities: an interdisciplinary approach

A Blue-Green City aims to recreate a naturally-oriented water cycle while contributing to the amenity of the city by bringing water management and green infrastructure together. The Blue-Green approach is more than a stormwater management strategy aimed at improving water quality and providing flood risk benefits. It can also provide important ecosystem services and socio-cultural benefits when the urban system is in a non-flood condition. However, quantitative evaluation of benefits and the appraisal of the relative significance of each benefit in a given location are not well understood. The Blue-Green Cities Research Project aims to develop procedures for the robust evaluation of the multiple

Investigating the flood responsiveness of Small and Medium Enterprises using agent-based modelling and simulation

In recent years, flooding has caused major damage and disruption to businesses in the United Kingdom (UK) resulting in significant losses to the economy. The effect of flooding on Small and Medium Enterprises (SMEs) is of particular importance given this size of business represents a major component of the UK’s economy. More specifically, according to the UK’s Department for Business Innovation and Skills, SMEs account for 99.9% of all private sector businesses and approximately 47% of annual turnover. In contrast to large businesses, SMEs often have limited resources and in most cases lack business continuity plans, which diminishes the effectiveness and efficiency of their response to flooding. This paper presents an overview of an approach taken to agent-based modelling and simulation of manufacturing SMEs experiencing a flood event, and related organisations. In this overview, the sources used to develop the attributes and behaviour of SMEs are highlighted. In addition, the paper presents preliminary results of simulations of the behaviours and actions of manufacturing SMEs in response to the 2007 flood event in the Lower Don Valley region of Sheffield in the UK. Results include key performance metrics of SMEs which provide an indication of the effectiveness and efficiency of the response of the businesses modelled.

The Influence of Household Rainwater Harvesting System Design on Water Supply and Stormwater Management Efficiency

Rainwater harvesting is increasingly being recognised as a sustainable option for both urban water and stormwater management. This study explores the potential impact of household rainwater harvesting on water supply augmentation and stormwater management in a typical three-bedroom house in Newcastle-upon Tyne, NE England. The continuous simulation of historical rainfall events at 15-min resolution over a 30-year period (1984–2013) is carried out to evaluate the system’s water saving and stormwater control efficiencies. Current and future rainfall projections are also incorporated in the analysis. The British Code of practice (BS 8515) is adopted to design the rainwater harvesting system. Results indicate that a rainwater harvesting system which is primarily designed for water supply augmentation with the size of 2.4 m3 contributes 64% of non-potable water demand (toilet flushing) and an 86% reduction of stormwater runoff volume into the sewer system. A larger system (6.5 m3) which is sized for both water supply augmentation and flood management provides 70% non-potable water supply and 96% reduction of stormwater runoff volume, indicating that a system which is designed for water supply only may be sufficient to achieve dual benefits. The relationship between storage and system efficiencies are explored for commercially available tanks for historical and future rainfall events. The influence of storage volume on flood peak attenuation is also explored for the historical flood events.