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CONFERENCE B R I S T O L Z O O U N I T E D K I N G D O M

18-19th April 2018

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Welcome to the 2018 UK TUFLOW Conference. We have an exciting line up of presentations, workshops and round table discussions, and plenty of opportunities for networking, catching up and having a beer or two, as long as no one mentions the cricket! Starting off we explore the growing emphasis on Natural Flood Risk Management during our keynote talk, debate and in the presentations after morning tea. Other presentation sessions over the two days focus on national scale and international applications, and the wide range of TUFLOW applications within in the UK varying from broad-scale modelling to IUD surface water investigations.

In parallel with the presentations are a series of TUFLOW modelling workshops and round-table discussions covering: new developments, visualisation software, computer hardware optimisation, and for those on the geekier side, a workshop on python scripting to improve your workflow efficiency may appeal. Finally, but not least, we’ll be presenting what’s new in the 2017-09 and 2018-03 releases, with the major feature being the new HPC 2D Solver that’s redefining what’s possible in fluvial and surface water modelling. It’s an exciting time to be TUFLOW modelling, and myself, Phil Ryan and the London sales and support team look forward to catching up with you. Thank you for attending and enjoy the conference.

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BILL SYMETUFLOW AuthorBMT

MAT ROBERTSDirectorBMT

JOHN YOUNGDirectorEdenvale Young

CONTENTS

Welcome Note

PRESENTATION ABSTRACTS (DAY 1)

• Natural Flood Management – Part of the Nation’s Flood Resilience

• Natural Flood Risk management on the River Aire

• Issues, Challenges and Advantages of Distributed Catchment Modelling using

2D (HPC) Models

• Natural Flood Risk Managment

• Whole Catchment NFM Modelling, interesting NFM examples and

economic costs and benefits

• Visualise Safety for the Public and the TUFLOW Modeller

• Brisbane River Catchment Flood Study - Monte Carlo Analysis:

The Definitive Study

• Canadian National Scale Assessment

• Use of TUFLOW for Catchment and Detailed Rainfall Runoff Modelling

in Sri Lanka

• Dam Breach Assessment using the Reservoir Flood Modelling Guidance

and TUFLOW

• A Collaborative Approach to Modelling and Mapping of 1,865

Reservoirs in England

• TUFLOW FV: The Coolest Middle Child

• Modelling Flood Alleviation Schemes in Hastings using XPSTORM

PRESENTATION ABSTRACTS (DAY 2)

• TUFLOW 2017’s New HPC 2D Solver and FV integration

• Civil Contingency; Making better decisions for emergency flood response with

hydraulic modelling

• TUFLOW HPC and the challenges of IUD modelling

• Assessing River Gauge Rating Curves using 1D-2D hydraulic models

• Modelling of Temporary Defences for Supporting the Community

Offices

Venue Map

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CONFERENCE PROGRAMME

D AY 1 ( 1 8 T H A P R I L , 2 0 1 8 )

10:10

11:50

Lunch

11:10 Refreshments and Networking

Registration and Refreshments

12:10 Whole Catchment NFM modelling Barry Hankin (JBA Consulting)

12:30

11:30 Issues, Challenges and Advantages of Distributed Catchment Modelling using 2D (HPC) Models.Adam Parkes (Jacobs)

Meet the TUFLOW team and Open DiscussionChairperson: Chris Whitlow (Edenvale Young)

Visualise Safety for the Public and the TUFLOW ModellerRob Graham (12D)

Natural Flood Management – Part of the Nation’s Flood Resilience Mark Russell (Environment Agency)

Natural Flood Risk Management on the River Aire Simon Jepps (Thomas Mackay)

Natural Flood Risk ManagementGerald Morgan (Edenvale Young)

10:40Natural Flood Risk Management DebateDavid Balmforth (MWH Global)Mark Russell (Environment Agency)Jack Spees (Ribble Rivers Trust)Simon Jepps (Thomas Mackay) Bill Syme (BMT) Chris Whitlow (Edenvale Young)

08:30

09:30

09:40

Conference Welcome and IntroductionsMat Roberts (BMT)

14:30

16:20

14:50 Refreshments and Networking

16:40

17:00

17:15

Modelling Flood Alleviation Schemes in Hastings using XPSTORM Georgia Athanasia (ARDENT) Julien Lhomme (Innovyze)

End of day 1 Wrap up John Young (Edenvale Young)

Day 1 Close

Brisbane River Catchment Flood Study - Monte Carlo Analysis: The Definitive StudyBill Syme (BMT)

Canadian National Scale Assessment Martin Salaj (Aon Benfield) and Mat Roberts (BMT)

15:40 A Collaborative Approach to Modelling and Mapping of 1,865 Reservoirs in England Stephanie Dufour (BMT), Peter Robinson (JBA-Consulting), Marianne Piggott (Mott McDonald)

Distributed hydraulic modelling (DHM) vs FEH & ReFHChris Cameron Hann (Aegaea)

Leaky dams, antecedent conditions catchment wetness. Why can’t hydraulic modellers get it right? Jack Spees (Ribble Rivers Trust)

Why are all 1D Structures including bridges and weirs wrongGerald Morgan (Edenvale Young)

Round Table Session - Visualisation Packages• FloodModeller Bob Potter (Jacobs)• Waterride Mat Roberts (BMT) • Floodintel Mat Roberts (BMT) • SMS Phillip Ryan (BMT)• QGIS Rachel Jensen (BMT), Peter Aylett (Edenvale Young)• 12D Rob Graham (12D)

Configuring Your Hardware and Software (CPU, GPU and the Cloud)Phil Ryan (BMT), Jon Wicks (Jacobs), Dave Tarrant (NRW)

Flood Modeller Pro - TUFLOW HPC LinkingKonrad Adams (Jacobs)

Use of TUFLOW for Catchment and Detailed Rainfall Runoff Modelling in Sri Lanka Chris Whitlow (Edenvale Young)

General Level of Uncertainty Associated with Design Flood Estimation and GenericChallengesThomas Kjeldsen (University of Bath)

TUFLOW FV: The Coolest Middle ChildRohan King (BMT)

15:20 Dam Breach Assessment using the Reservoir Flood Modelling Guidance and TUFLOW Kathryn Fuller (Arcadis)

13:30

13:50

14:10

D AY 2 ( 1 9 T H A P R I L , 2 0 1 8 )

CONFERENCE PROGRAMME

10:40 Refreshments and Networking

14:10 Assessing River Gauge Ratings Curves Using 1D-2D Hydraulic Models(Simon DeSmet Capita)

14:30 TUFLOW HPC and the Challenges of IUD ModellingRachel Jensen (BMT)

Lunch12:30

13:30 Civil Contingency; Making Better Decisions for Emergency Flood Response with Hydraulic ModellingRay Pickering (RAB Consulting)

Python Scripting – Improve Your Workflow EfficiencyPhillip Ryan and Rachel Jensen (BMT)

Increasing Source Data Quality and Reducing Preparation Time for Hydraulic Models with GeoRiver®

Mike Hopkins (Storm Geomatics), Anthony Pritchard (Storm Geomatics), Rohan King (BMT)

11:10 TUFLOW 2017’s New HPC Solver and FV integration Bill Syme and Phillip Ryan (BMT)

13:50 Modelling of Temporary Defences for Supporting the Community Sarah Demetriou (Arcadis)

New Features in TUFLOW 2017 Phillip Ryan (BMT)09:40

09:30 Day 2 WelcomeJohn Young (Edenvale Young)

14:50 Refreshments and Networking

15:50 Final Q&A Session, Survey Results and Prize Draw!Bill Syme and Mat Roberts (BMT)

15:20 Into the future. What we have planned for 2018 and beyondBill Syme and Mat Roberts (BMT)

08:30 Registration and Refreshments

1Environment AgencyNatural flood management is when natural processes are used to reduce risk of flooding and coastal erosion. It is not new, but has a much greater prominence in our thinking after a decade of more and more extreme floods. In January, the Prime Minster launched the Government’s new national 25 year environment plan putting the environment at the heart of flood resilience. This provides us with a once in a generation opportunity to bring together engineering and the environment and to embed climate resilience into the way we all work. We see managing flood resilience as a mosaic ranging from greater awareness of flooding, our flood response and recovery to using a wide range of interventions to reduce flooding from flood walls to re-wilding our catchments. We have our best ever understanding of the evidence of natural flood management and the Environment Agency launched in October 2017 our most comprehensive evidence base including more than 60 case studies across England. Of course, the success of natural flood management interventions is based on more than just the scientific evidence base but also on the involvement of communities, landowners and other water management authorities and the Government announced last year a further £15m for natural flood management schemes across England for community led and catchment scale projects to further test the concepts.

The modelling community has a vital role in supporting natural flood management to provide the evidence to optimise the blending of engineering and environmental improvements but not just for flood resilience but also for greater environmental outcomes and creating a better place to live. However, this role comes with its technical challenges as well as proportionate costs, a strong voice in advising and communicating and ensuring we understand the value provided by natural flood management.

PRESENTATION ABSTRACTS (DAY 1)

Natural Flood Management – Part of the Nation’s Flood ResilienceMark Russell

Natural Flood Risk management on the River AireSimon Jepps

1Thomas Mackay Ltd, Leeds, UK

Leeds City Council (LCC) and the Environment Agency (EA) are working together to identify a solution to flood risk to Leeds from the River Aire. Construction of Leeds Flood Alleviation Scheme Phase 1 has just completed, providing protection to the city centre. Phase 2 of the Leeds Flood Alleviation Scheme is underway, with a focus on the area from the city railway station extending upstream to the ring road at Rodley is taking a catchment-wide approach to this problem. This means the entire River Aire catchment area will be considered to help reduce flood risk in Leeds. This approach will adopt a combination of Natural Flood Risk Management and engineered measures to help slow the flow and store water upstream of Leeds so that flood peaks are reduced downstream.

In developing a catchment wide approach, LFAS2 aims to identify options for local improvement to flood risk management within neighbouring communities and to generate further social, environmental and economic benefits across the catchment through development of a catchment-wide approach. Underpinning the successful implementation of this scheme are the following questions, addressed in this talk: What? Why? Where? When and How?

1Jacobs, Warrington, UK Recent advances in computing and software, combined with client requirements and changing approaches to flood risk management have resulted in an increased use of 2D models such as TUFLOW in distributed catchment modelling. This presentation will include:

• The “What Percentage Hydrologist Are You?” Quiz.

• Current state of UK hydrology An overview of current UK methods, what are their benefits and disadvantages, data requirements and common issues

• Where are current methods not working? For an increasing number of modelling applications, standard UK Hydrological methods are not ideal. This includes assessment of Natural Flood Management (NFM), fully integrated modelling and assessment of catchment change (e.g. urban expansion). What options are available and how can methods be adapted? Are we always choosing the best approach?

• How can TUFLOW be used as a distributed catchment model? Overview of common ways TUFLOW has been adapted as a fully distributed hydrological model, including treatment of rainfall, infiltration, losses and flow routing. What are the considerations when selecting approach to different hydrological processes (e.g. infiltration) and how do those choices impact upon model complexity and certainty? What are the current shortfalls?

• Examples of recent application Drawing on recent projects, discussing the study objectives, technical approach adopted, challenges encountered and ultimately study outcomes. The main two examples are of appraising Natural Flood Management in Lancashire and very large-scale catchment modelling in Somerset.

• Problems and challenges in application What problems and challenges have we faced in adopting Distributed Catchment Modelling, from computational requirements to study confidence? Are we using the right tools for the right problems? How as a profession can we develop and promote best practice in this developing area?

Issues, Challenges and Advantages of Distributed Catchment Modelling using 2D (HPC) Models Adam Parkes

CONFERENCE PROGRAMME

Whole Catchment NFM Modelling, interesting NFM examples and economic costs and benefitsBarry Hankin

1Edenvale Young, Bristol, UK Edenvale Young’s experiences using TUFLOW as a distributed hydrological model are described including:

• Appropriate sources of infiltration data and how to use them in TUFLOW.

• Calibration of infiltration and depth-varying hydraulic roughness parameters to reproduce historical event data.

• Changing roughness and infiltration parameters to represent natural flood risk management interventions in the upper catchment.

• Effectiveness mapping: how to target interventions within the catchment to the most effective locations.

Natural Flood Risk ManagmentGerald Morgan

1JBA ConsultingHigh resolution modelling of whole catchments can help understand the cumulative impacts of many distributed NFM measures, so long as we can reasonably represent the uncertainty in how these measures influence change in different catchment processes. Numerous studies have also identified the sensitivity of hydrograph response to dynamic utilisation of additional storage or measures to reduce conveyance on the floodplain, and the relative timing of multiple tributaries where peak synchronisation can have a disproportionate impact on upstream or downstream risk. In our winning Defra floods competition entry we explored the sensitivity of the effectiveness of distributed NFM measures in combination with more traditional flood risk management measures to an event-set of spatially realistic extremes for the Eden catchment, Cumbria, generated from spatial joint probability modelling. This built on work undertaken in Cumbria modelling NFM to provide communities with strategic opportunity maps that showed potential changes to baseline timings and peak flows across three large Cumbrian catchments, and which also used a GLUE uncertainty framework. Through Lancaster Environment Centre’s NERC funded Q-NFM science, this approach will be revisited, combining new primary literature reviews of acceptable changes to effective model parameters and supplementary paired plot measurements of hydrological variables to try and further constrain the uncertainties. Part of this work will also explore network performance of NFM measures, building on a recent ‘challenge’ set by the JBA Trust for the Maths Foresees network. We will also be exploring a hybrid combination of Dynamic Topmodel and JFLOW for the best representation hill slope hydrology and floodplain hydraulics.

Visualise Safety for the Public and the TUFLOW ModellerRob Graham1

112d Solutions Pty Ltd, Sydney, AustraliaWorking with water means creating a safe environment for the modeller and the public. GPU processing means larger models, more data and a greater need for certainty.Safety for the modeller includes the confidence that TUFLOW ‘sees’ what you intend it to see. The presentation will show the tools to create a 3d representation of the TUFLOW model. This includes the final grid, the ESTRY 1D pipe systems, evacuation routes and more. This should be part of the modelling process and not an extra task at the end of the modelling process.Seeing is believing when expressing safety for the public. Modellers need the tools to create ‘live’ visualisations even for large TUFLOW models. The presentation will display tools to show the danger of rapidly rising water levels and becoming trapped as your ‘escape route’ becomes submerged.

Brisbane River Catchment Flood Study - Monte Carlo Analysis: The Definitive StudyB Syme1

1BMT, Brisbane, Australia The Brisbane River Catchment Flood Study is the most comprehensive study of its kind undertaken in Australia. The study comprises more than 2,900 pages, leading-edge computer modelling, and thousands of maps and charts. The hydraulic modelling was governed by a Steering Committee, and reviewed by a Technical Working Group of twenty government representatives, and an independent panel of experts.

Roughly half of the 15,000 km2 catchment runoff is significantly influenced by flood gates on two major dams. Dam levels prior to flooding may vary from near empty to 100%. Catchment rainfall is highly variable temporally and spatially, as are antecedent conditions. These highly indeterminate influences ruled out conventional approaches for deriving design floods, necessitating a Monte Carlo statistical approach. Two hydraulic models were developed and calibrated. The Fast Model, with a run time of 5 minutes, was used for the Monte Carlo analysis to simulate 11,340 floods. The Detailed Model, simulated a sub-set of events for flood mapping and is the benchmark for assessing floodplain management options. The calibration of both models to a considerable quantity of recorded data from five historical floods, resulted in some interesting findings on modelling parameter selection, while the Monte Carlo analysis potentially sets a new benchmark for deriving design floods for complex systems. The innovative and thought-provoking findings from the study are presented.

References:Rodgers B, Syme W J, Ryan P A (2017). Brisbane River Catchment Flood Study – Calibration of Hydraulic Models. Conference on Hydraulics in Water Engineering (HIWE), Sydney, 2017Smith M J, Syme W J, Nathan R (2017). Brisbane River Catchment Flood Study Monte Carlo Hydraulic Analysis. Conference on Hydraulics in Water Engineering (HIWE), Sydney, 2017

PRESENTATION ABSTRACTS (DAY 1)

1Aon Benfield, Prague, CZE 2BMT, London, UKCatastrophic models for the insurance market need to cover whole countries, but (mainly for underwriting purposes) in relatively detailed resolution. The Canadian National Scale Assessment was a great challenge in this regard.

Aon Benfield’s Impact Forecasting team has been developing a Canadian flood model since 2014. The Hazard component contains >100,000km of river channel for fluvial flood modelling (2014-2015) and 2,300,000 km2 for pluvial flood modelling (2016-2018). TUFLOW 2D simulations were used to model both types of flooding. Available DTM data allowed a 5x5m grid in big cities and a 30x30m grid elsewhere. Although the model is relatively simple from a hydraulic point of view, the capabilities of TUFLOW enabled us to simulate the effect of key features on the flood extents e.g. levees and channels (ZSH), narrow streams (CWF, FLC), infiltration (by soil) and sewage systems (virtual pipes). In addition, risk maps for cars and people were generated based on velocityXdepth output of TUFLOW.

Due to the size of Canada, the preparation of inputs and setup of all partial models was a big challenge. Hardware capacity, to simulate many different scenarios for each part of model, was also an important consideration. 8 scenarios for fluvial and 36 for pluvial were necessary for a final probabilistic model for loss estimation. TUFLOW HPC with GPU module was primarily used to deliver the modelling.

The BMT London office developed a Cloud solution using Microsoft Azure to support the project and increase our hardware capacity. Several thousand simulations were successfully run on the Cloud, split across multiple GPUs, to dramatically increase the computational throughput. Approximately 404 GPU days of simulation were necessary to deliver the complete pluvial flood modelling.

Canadian National Scale Assessment M Salaj1, M Roberts2

Use of TUFLOW for Catchment and Detailed Rainfall Runoff Modelling in Sri LankaC Whitlow1

1Edenvale Young, Bristol, UK

CONFERENCE PROGRAMME

1Arcadis, Bristol, UKReservoir breach modelling and the resulting flood maps are used to inform the public of the areas at risk of flooding in the event of a dam or reservoir failure. The Reservoir Inundation Mapping Specification (RIMS) guidance document was originally published in 2009 by the Environment Agency (EA), detailing the process of carrying out modelling of reservoir breaches using two-dimensional (2D) hydrodynamic flood models. The specification was updated in 2016, following an improved understanding of flood risk to create the Reservoir Flood Mapping (RFM) Specification (EA, 2016). Changes to the guidance document included a revision to the recommended cell size and the addition of a ‘dry day’ model run, to understand the impacts of a reservoir failure on a dry day with no associated fluvial flooding.

This presentation will examine the process of carrying out breach modelling using TUFLOW for a reservoir in England following the RFM guidance. Areas focused on include discussion of the differences between the RIMS document and the RFM document, the calculation of reservoir breach hydrographs, building the model using TUFLOW and the issues and challenges related to this modelling. These challenges include defining the orientation of the model grid and active area, setting the location of the reservoir breach and determining which features downstream of the breach would impact flow routes and therefore need to be included within the model. The results of the modelling and sensitivity tests are discussed and presented.

Edenvale Young were appointed by Atkins Accuity to develop and implement a modelling strategy to inform decisions for medium and long term investment in both climate resilient flood and drought mitigation measures for around half of the island of Sri Lanka. This project is funded by both the World Bank and the government of Sri Lanka.

The purpose of this paper is to present both the modelling strategy and results obtained to date which includes calibration of both the basin scale models and detailed models to rated flow hydrographs and measured level hydrographs together with recorded flood extents at various locations throughout the island.

A key requirement of the rainfall runoff modelling using TUFLOW has been the availability of a suitable digital terrain model for each basin. It is shown for the most populous basins, a relatively accurate dtm was available as funded by the Japan International Co-operation Agency (JICA) but others lacked such high quality data with some impact on model results.

Another key feature has been the use of the Green Ampt infiltration model in TUFLOW, spatial rainfall variation and local land use maps. The presentation also discusses the link between TUFLOW and the University of Texas SWAT model for long term simulations and the use of TUFDAMAGES software.

Modelling in locations such as Sri Lanka is subject to considerable uncertainty in data and the presentation discusses how these challenges have been addressed.

Dam Breach Assessment using the Reservoir Flood Modelling Guidance and TUFLOWK Fuller1

References:Environment Agency (2016). Reservoir Flood Mapping Specification Report – ENVFCPMM00277B00 Version 1.0.1. Environment Agency, Bristol.

PRESENTATION ABSTRACTS (DAY 1)

A Collaborative Approach to Modelling and Mapping of 1,865 Reservoirs in England S Dufour1, P Robinson2, M Piggott3

1 BMT, London UK2 JBA Consulting, Warrington, UK3 Mott MacDonald, Cambridge, UK

In 2009/2010 the Environment Agency produced National Reservoir Inundation Maps (NRIM) for large raised reservoirs defined by Reservoirs Act 1975. Maps from this programme were originally intended to assist with emergency planning. Over time their uses have expanded to also include; indication of risk for risk designation, spatial planning and public awareness about the risk of dam failure.

In 2015, the Environment Agency started the Reservoir Flood Mapping (RFM) project which is delivering improvements to the existing maps. The updates respond to the expanded range of applications for the reservoir flood maps, technical advances in dam break analysis, hydrology, computational hydraulic flood modelling and digital terrain models and changes in the legislative requirements.

This presentation will discuss the collaborative approach taken to deliver hydraulic modelling and mapping for up to 1,865 reservoirs in England, with a focus on the key challenges faced on this national-scale project:

• Advances in the methodology and the need to efficiently deliver a ‘Dry’ and ‘Wet’ Day scenario approach for all of England.

• The use of TUFLOW HPC to deliver high resolution hydraulic models using bespoke software to meet the requirements of the Specification.

• The derivation of a modelling and mapping workflow supported by custom-developed tools ensuring consistency across three modelling teams around the globe delivering efficiency in both project cost and programme.

1BMT, London, UK TUFLOW FV is known for applications in the hydraulics of coastal and marine environments. TUFLOW FV lends itself well to coupling with water quality modules due to the use of both triangles and quadrilaterals for modelling fine scale detail in areas of interest. Aquatic EcoDynamics (AED2), from the University of Western Australia, is an open-source research driven library of modules allowing the modeller to customise aquatic ecosystems. The ability to pick and choose from various modules, ranging from dissolved oxygen through to phytoplankton and beyond, allows for a specific project or management requirements and a bespoke model structure.

The Catchment and Receiving Environment (CARE) team within BMT has comprehensive experience in the development and application of water quality modelling internationally. This presentation will highlight a number of modelling capabilities available in TUFLOW FV and FV-AED2 that are not well known within the UK market, namely; multiple estuary modelling in South-East Queensland, ice sheet formation in Canada, marine fauna movement, and microbial modelling in Lake Samsonvale.

TUFLOW FV: The Coolest Middle Child R King1

CONFERENCE PROGRAMME

1Ardent, London2Innovyze, Newbury

Flood risk in Hastings is characterised by a complex set of interactions involving multiple RMAs within a densely developed town (amongst the highest densities outside London). The Hastings SWMP (2011) identified the town centre as a flooding hotspot with significant risk present to both residential and business properties.

In order to better understand the problem and determine the most appropriate and sustainable mitigation measures, East Sussex County Council, (with support from key partners; Southern Water and Hastings Borough Council), commissioned a 1D/2D integrated model to be built using XPSTORM. The Hasting’s sewer and river network have been incorporated in the model.

This presentation will show the methodology behind identifying flood risk mitigation options which will give a high cost benefit ratio and therefore high chance of gaining funding through the FDGiA scheme so they can be taken forward to detail design and implementation. XPSTORM and TUFLOW visualisation tools will be used.

The presentation will also focus on the practicality of the Dynamic Section tools when checking 1D networks and visualising results in XPSTORM as well as the interaction between the 1D and 2D domain between the two softwares.

Modelling Flood Alleviation Schemes in Hastings using XPSTORMG Anthanasia1, M Reeves2

PRESENTATION ABSTRACTS (DAY 2)

1BMT, Brisbane, Australia

TUFLOW HPC (Heavily Parallelised Compute) is a powerful new 2D solver. As its name implies it utilises the substantial power of parallel computing. TUFLOW HPC can be simulated on CPU or NVidia GPU hardware (if paired with the GPU Hardware Module).

The 2D solver is an explicit, finite volume, TVD solution of the full 2D Shallow Water Equations, including shock capturing and sub-grid scale turbulence representation (eddy viscosity). The scheme is volume and momentum conserving, is 2nd order spatial and 4th order in time, and is extremely stable. It is dynamically linked with TUFLOW’s own 1D solver and external 1D schemes providing full access to 1D pit, pipe, hydraulic structure and open channel functionality.

The power of modern, affordable, GPUs combined with HPC allows very large models (>>10 million cells) with fine grids to be simulated within a practical timeframe. The adaptive time-stepping guarantees the model remains stable. The solver can simulate a simulation across multiple GPU cards.HPC sits alongside TUFLOW’s Classic 2D solver to access the powerful pre- and post-processing functionality that make TUFLOW hydraulic modelling highly work flow efficient. To switch between Classic and HPC solvers is simply a single instruction.

TUFLOW HPC is designed for high accuracy, high-speed solutions of complex 1D and 2D hydraulics, across a wide range of applications:

• High resolution 2D solutions from flume to national scale.

• Integrated urban drainage applications, including 1D underground stormwater pipe network and 2D above ground features.

• Direct rainfall applications, as an alternative to using hydrologic models

• Real-time flood inundation forecasting.

The research, development, benchmarking, application and limitations of HPC, including tips and tricks the modeller needs to be mindful of, and simulating a TUFLOW Classic model using HPC along with a comparison of results are presented.

TUFLOW 2017’s New HPC 2D Solver and FV integration B Syme1

References:Collecutt, G, Syme, W J (2017a). Experimental Benchmarking of Mesh Size and Time Step Convergence for a 1st and 2nd Order SWE Finite Volume Scheme. Proceedings of the 37th IAHR World Congress August 13-18, 2017, Kuala Lumpur, Malaysia.Collecutt, G, Syme W J (2017b). Convergence of the 2D Free-Surface Flow Equations (or SWE) using a Parallelised Finite Volume Solution. Conference on Hydraulics in Water Engineering (HIWE), Sydney, 2017

CONFERENCE PROGRAMME

1RAB Consultants Ltd, UK

In 1953 a tidal surge made its way down the East coast of the UK devastating communities and claiming over 300 lives. Without flood forecasts there was no warning and no chance of an effective response. The 1953 floods demonstrated the need for flood forecasts to support timely response decisions and accurate warnings to protect lives and property.

Flood managers increasingly rely on flood forecasts to make timely and accurate decisions in a new era of “forecast led decision making”, rather than responses triggered by observed flood levels. At the same time, temporary defences and property flood resilience measures have changed the nature of the response to floods and changed public expectations.

The presentation will use case studies to explore the nature and type of decisions that modern strategic, tactical and operational flood managers make, led by flood forecasts. We will also explore the challenges for flood forecasters who must interpret and communicate flood forecasting results to support the decision makers.

1BMT, London, UK

A key challenge in urban modelling is that fine scale features and urban complexity often competes with the increasing need to model at a broader catchment scale. To date, computational and input data constraints have limited the increasing detail and spatial extent demanded of 1D-2D linked stormwater models or urban areas.

This presentation showcases new developments in modelling urban drainage systems and case studies of dynamically linked 2D overland flow and 1D stormwater modelling using the latest TUFLOW HPC solver. As urban stormwater data is so variable, from sparse to incredibly detailed, a range of methodology options are explored. These different methods; including fully integrated urban drainage networks, TUFLOW virtual pipes and broad scale drainage losses have been assessed based on suitability to the case study catchment, quality of input data demanded and impact on the final results.

The case study highlights the benefits and lessons learnt when modelling rainfall runoff in complex urban catchments using direct rainfall and a variety of urban drainage methods.

Civil Contingency; Making better decisions for emergency flood response with hydraulic modelling R Burton1, R Pickering1, B Nelson1, M Cranston1, D Matthews1

TUFLOW HPC and the challenges of IUD modelling R Jensen1

PRESENTATION ABSTRACTS (DAY 2)

1Capita Real Estate and Infrastructure, Sheffield, UK

Calibration to historical gauge data is an important tool for validating hydraulic models, providing an evidence basis for confirming model results. Equally the importance of the stage flow relationship (rating curve) at river gauges has been driven by the need for accurate flood forecasting models, historic flood flows, and for flood flow estimation. Often the stage flow ratings at gauges are only supported by spot flow measurements at lower flows and the theoretical equations of the weir or control structure. Consequently hydraulic models are used to assess the reliability of rating curves and extend them to higher flows, and these may be used to investigate the gauge station structure, drowning of the structure, and floodplain modelling and bypassing flows.

This presentation examines the methods, advantages and limitations encountered when using 1D-2D hydraulic models to either assess the reliability of gauge rating curves, to improve model calibration and to extend ratings at gauges. To explore this topic the presentation will draw from multiple UK based modelling projects that used ESTRY – TUFLOW and Flood Modeller – TUFLOW. When calibrating a model to an existing rating a thorough review and challenge of the data should be undertaken, and a model sensitivity testing approach adopted. Important considerations when assessing modelled gauge ratings include: conservation of flow between gauges down a water course (catchment wide checks), identification and accurate representation of key flow pathways (bypassing), gauge structure schematisation (structure losses, backwater and drowning of gauge station structures), hysteresis, and seasons.

Assessing River Gauge Rating Curves using 1D-2D hydraulic models S DeSmet1, J.Dudley1

1Arcadis, Bristol, UK

Supporting the Communities Remaining at Risk is an Environment Agency (EA) Water and Environmental Management (WEM) project, where the scope is to identify areas across England where the deployment of temporary barriers will reduce the impact of flooding on residential properties. Once key areas that could benefit from temporary defences are identified, suggested barrier alignments are put forward.

These barriers are then added into existing EA approved hydraulic models (typically ISIS-TUFLOW or Flood Modeller Pro-TUFLOW models) to assess both the positive and detrimental impacts of the temporary barriers and the proposed alignment. If the hydraulic modelling indicates that barriers will be successful, Temporary Defence Deployment Plans are created. These plans are to be used when a flood warning is issued by the EA in the area at risk.

This presentation will talk through the hydraulic modelling aspects of the project, step-by-step, identifying key issues encountered and the approaches taken to address these issues at each stage of the project. The particular focus will be on evaluating the limitations and successes of repurposing existing hydraulic models. Some of the limitations include the representation of walls within the model which are not classified as EA defences, an inappropriate grid size to evaluate the success of the temporary barriers and discrepancies between the source of flooding modelled (e.g. fluvial) and the cause of flooding witnessed (e.g. surface water).

Modelling of Temporary Defences for Supporting the Community S Demetriou1

CONFERENCE PROGRAMME

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8200 S. Akron Street, #B120Centennial, Denver Colorado 80112 USATel +1 303 792 9814 Fax +1 303 792 9742Email denver@bmtglobal.comWeb www.bmt.org

Level 4, 20 Parkland Road, Osborne, WA 6017PO Box 2305, Churchlands, WA 6918Tel +61 8 6163 4900Email perth@bmtglobal.comWeb www.bmt.org

Level 8, 200 Creek Street, Brisbane QLD 4000PO Box 203, Spring Hill QLD 4004Tel +61 7 3831 6744 Fax +61 7 3832 3627Email brisbane@bmtglobal.comWeb www.bmt.org

Suite G2, 13-15 Smail Street, Ultimo, Sydney, NSW, 2007PO Box 1181, Broadway NSW 2007Tel +61 2 8987 2900 Fax +61 2 8987 2999Email sydney@bmtglobal.comWeb www.bmt.org

Level 5, 99 King Street, Melbourne 3000Tel +61 3 8620 6100 Fax +61 3 8620 6105Email melbourne@bmtglobal.comWeb www.bmt.org

Suite 401, 611 Alexander StreetVancouver, British Columbia V6A 1E1 CanadaTel +1 604 683 5777 Fax +1 604 608 3232Email vancouver@bmtglobal.comWeb www.bmt.org

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QC30, Suite 2.0430 Queen Charlotte Street,Bristol BS1 4HJUnited Kingdom

GETTING HERE:

The Conference will take place at:The Clifton Pavillion, Bristol Zoo Gardens, College Road, BS8 3HH

The First Bus number 8 runs between Temple Meads Station, the city centre and the Zoo. Alight at the main entrance and walk around the corner to College Road.

If you do decide to travel by car - we have a small number of spaces allocated for delegates, please email Colette.linehan@edenvaleyoung.com to book your space. Parking is provided in the West Car Park opposite the entrance to the venue.

If you prefer to avoid the morning rush hour then The Wessex Bristol 505 Park & Ride service runs from Long Ashton Park and Ride. Opening times and more information available here. For further travel information visit TravelWest journey planner.

BRISTOL ZOO

CLIFTON CATHEDRAL

River A

von

Portway

Pembroke Road

College Road

A4

A4176

BRISTOL ZOO GARDENS CliftonBristol BS8 3HA