1642 research outputs found
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UK sustainable drainage systems: past, present and future
No full textUrban drainage has developed from an engineering discipline, concerned principally with public health and safety outcomes, into a multifaceted vision linking drainage with environmental and wider social and economic imperatives to deliver multifunctional outcomes. UK attention is too often focused on surface water as ‘a problem’, despite international progress and initiatives showing that an ‘opportunity-centred’ approach needs to be taken. Sustainable drainage systems, or ‘Suds’, can, when they are part of an integrated approach to water management, cost-effectively provide many benefits beyond management of water quality and quantity. New tools are available that can design Suds for maximum value to society but this requires greater collaboration across disciplines to seize all of the opportunities available. This paper introduces those tools and a roadmap for their use, including guidance, design objectives and criteria for maximising benefits. These new supporting tools and guidance can help to provide a business case for greater use of Suds in future
Risk analyses for large dams
No full textThis paper describes the United Kingdom method for conducting risk analyses for large dams. The importance of checking results against published statistics is emphasised. Whilst the method was developed primarily for use in the United Kingdom it has been successfully used in other countries where natural hazards are greater than in UK.
The paper gives examples of how the method has been used in Japan and offers comments on the results obtained particularly with respect to risks from earthquakes and typhoons. For the rockfill dams considered it is found that indirect seismic risks (eg. From seiches and landslides) overshadow the direct risks associated with settlement and consequential overtopping. Other risks such as typhoon rainfall, internal erosion and non-operation of spillway gates are significant
Particle-In-Cell numerical solver for free surface flows with fluid-solid interactions
No full textThis paper presents a novel numerical approach based on the Particle-In-Cell (PIC) technique for the solution of the incompressible Navier-Stokes equations with emphasis on free surface deformation and two-way fluid-solid interactions. As a hybrid Eulerian-Lagrangian approach, this method has the exibility of the Smoothed Particle Hydrodynamic (SPH) method as well as the efficiency of an
Eulerian method.
Two-way fluid solid-interaction simulation has been integrated inside the numerical model by adopting the Distributed Lagrangian Multiplier (DLM) technique proposed in Patankar [7]
US North Atlantic Coast comprehensive study: resilient adaptation to increasing risk
No full textHurricane Sandy originated as a late season hurricane in the south-western Caribbean Sea on October 22, 2012. On October 29, 2012, the remnants of Hurricane Sandy in the form of a post-tropical cyclone made landfall near Brigantine, NJ. Because of its tremendous size, the storm drove a catastrophic storm surge into the densely developed New Jersey and New York coastlines, accentuating the vulnerability of the North Atlantic Coast to coastal flood hazard.
On January 29, 2013, the Disaster Relief Appropriations Act, 2013 (Public Law 113-2), was enacted to assist in the recovery in the aftermath of Hurricane Sandy. Public Law 113-2, Chapter 4,
authorized U.S. Army Corps of Engineers (USACE) to conduct a US$ 15-20 million comprehensive study to address the flood risks of vulnerable coastal populations and infrastructure at risk throughout more than 31,000 miles of the North Atlantic coastal region in areas that were affected by Hurricane Sandy. The goals of the NACCS were to:
(i) Provide a risk reduction framework, consistent with the NOAA-USACE Infrastructure Systems Rebuilding Principles; and
(ii) Support resilient coastal communities and robust, sustainable coastal landscape systems, considering future sea level rise and climate change scenarios, to reduce risk to vulnerable populations, property, ecosystems, and infrastructure.
Managing short-term and long-term risk among Federal, State, regional, tribal, and local agencies, and nongovernmental organizations (NGOs) required collaboration, data sharing, overcoming barriers, closing data gaps, and developing new partnerships and incentives for a renewed era of coastal planning and action
Distinguishing resuspension and advection signals in a hypertidal estuary
Get PDFThe Dee Estuary is a hypertidal coastal plain estuary, formed by the flooding of the river valley cut by the River Dee during the last major glaciation. One of three major estuaries emptying into Liverpool Bay along with the Ribble and Mersey it is located at the junction of north-east Wales and north-west England, on the eastern side of the Irish Sea.
The estuary section of the Dee is 20 km long, and 8.5 km wide at the mouth. The sea bed is covered by a thick (up to 18 m) sediment layer, deposited after the last Ice Age, consisting of fine-grained sands, silt muds, and some gravel beds. Infilling has led to the gradual accretion of the sand and mudbanks, and an increase in saltmarsh area
Use of agent-based modelling to validate hurricane evacuation planning
Get PDFJustification for evacuation and evacuation planning is sometimes questioned and there is a need develop approaches which justify the planning and associated expenditure. To this end, it was decided to carry out a pilot evaluation of the impact of a Hurricane Storm surge flooding on Brunswick, GA using a dynamic Agent Based Model that represents people's interaction with a flood and provides estimates of the number of people that are likely to be killed as a result of a flood event, as well as the time that is required for them to evacuate the area at risk. Climate change increase of 3ft in mean sea level would increase the population at risk in Brunswick by 20% for a category 4 hurricane. The modelling shows that for a category 4 hurricane managed evacuation can significantly reduce the number of fatalities
Seasonal variations in SPM and floc characteristics in a hypertidal estuary
Get PDFThe Dee Estuary is a hypertidal coastal plain estuary, formed by the flooding of the river valley cut by the River Dee during the last major glaciation. One of three major estuaries emptying into Liverpool Bay along with the Ribble and Mersey it is located at the junction of north-east Wales and north-west England, on the eastern side of the Irish Sea.
The physical characteristics of the Dee make it
an ideal location for studying turbulence-sediment
interactions and flocculation: It has a large tidal prism,
high tidal range, and abundant cohesive sediment
Oil spill model assessment procedures for coastal and offshore developments
No full textOil spills can be disastrous in terms of their ecological, social and economic effects. Recent global marine pollution events have demonstrated the potential scale of such incidents. Oil has the potential for accidental release into the marine environment across a range of operations, including coastal developments (ports, terminals, etc.), as well as offshore activities (oil and gas exploration, shipping, etc.). Accurate predictions of the fate and behaviour of spilled oil are therefore important to support environmental studies, clean-up operations, and to inform risk assessments. This usually requires the use of computational models. Simulations rely on a range of model predictions – including detailed hydrodynamic and meteorological fields – as well as adequate representation of the properties and physics of the spilled oil.
This paper presents the results of recent research carried out by HR Wallingford to establish best practice procedures for the assessment of the fate of spilled oil and its impact in coastal and offshore regions. An integrated framework for oil spill assessment is presented, using both established modelling tools and the newly-enhanced Lagrangian model OIL RW. The study brings together expertise in coastal processes, metocean studies, the maritime industry and marine ecology. The model is demonstrated and validated using data for a real spill incident in coastal waters
Representing and Modelling Coastal Systems over a Regional Scale for Coastal Management
No full textCoastal and estuarine landforms, such as beaches, dunes, saltmarshes and mudflats, mediate flood and coastal erosion risk, but are part of an evolving coastal system with dynamic properties. Present and future risk simulations generally use static bathymetry/topography and this may give a misleading view of future risk as the coastal system evolves in time and erosion is widespread. Hence, there is a fundamental need to improve and formalize predictions of coastal change at the temporal and spatial scales that are most relevant to coastal management. Such predictions should account for the key geomorphic feedbacks between climate forcing, sediment supply and morphology, including the geomorphic influence of present and future adaptation options
Modelling the impact of anthropogenic noise on fish
Get PDFAnthropogenic noise is recognized as a global polluter and there is growing concern about its impact on aquatic organisms. Offshore pile driving (e.g. during wind farm construction) creates high intensity impulsive noise which differs from natural noise sources, although its frequency range overlaps with hearing ranges of many marine organisms. Several predictive models have been developed that predict the propagation of noise in aquatic environments, however models combining underwater noise propogation, hydrodynamics and likely animal behavioural responses have been lacking. HAMMER (Hydro-Acoustical Model for Mitigation of Ecological Response) is a tool that predicts underwater noise propagation while taking hydrodynamics into account and it subsequently predicts behavioural responses of animals using individual based modelling (IBM).
As the quality of any predictive model is largely defined by its parameters, we decided to obtain crucial behavioural data for commercially important North Sea fish species exposed to a realistic noise source. To allow realistic behavioural responses, a field experiment using impact piling was conducted in a former dry-dock (size: 85 x 18 x 3 m). Behavioural and physiological data of Atlantic cod (Gadus morhua), plaice (Pleuronectes platessa) and black sea bream (Spondyliosoma cantharus) were obtained and incorporated into the HAMMER model.
Here, we will discuss the results of the field experiment and the value of the tool for predicting animal behaviour in realistic marine environments