Reservoir Inundation Mapping, Dam Break and Breach Assessments with MIKE FLOOD
INTRODUCTIONMIKE by DHI Software for ReservoirInundation Mapping
Who are DHI?About usDHI is an independent, international consulting and research organisationwith the global objective of advancing technological development andcompetence with respect to water, in all of its environments.Services and technologiesWe offer a wide range of consulting services and leading edge technologies,software tools, environmental laboratories, and physical model test facilitiesas well as field surveys and monitoring programmes.International collaborating centresDHI is designated as Collaborating Centre for the World Health Organisation,WHO, and for the United Nations Environmental Programme, UNEP, andfurthermore as Advisory Centre for the Global Water Partnership. DHI’s first commercially available software tool was MOUSE in 1985.
Who are DHI?Research and developmentDesignated as a not-for-profit organisation DHI is able to invest 25% of itshuman resources in research and development. Today we co-operate withuniversities in Denmark and abroad and are recognised globally for ourinnovation and expertisePlaces and peopleOur headquarters are located in Denmark, but more than half of theemployees work in one of DHI’s 29 offices around the globe. We are morethan 1000 employees worldwide. For the past 20-years, with the assistance of key local representatives, DHI has provided services and support for our UK clients from our head office in Denmark. We feel that the time has come to formalise our presence in the UK and, from 1st January 2012, we are pleased to announce that DHI Water Environments (UK) Ltd has been established as a full UK subsidiary.
MIKE by DHI Software - PerformanceSpeedParallelisation – many MIKE by DHIproducts have been modified to takeadvantage of multicore PCs, including;MIKE 3 FMHD and MIKE 21 FMHD(distributed memory – see graph), MIKE21 SW, MIKE 21 BW, MIKE 21 HD, MIKE21C, MIKE FLOOD and MIKE SHE(shared memory).64-bit architecture – with the shift from32-bit to 64-bit hardware and software, The graph above shows MIKE 21 / MIKE 3 FM speed-up usingthe size of your models is no longer multicore PCs for Release 2011constrained by memory. with distributed memory architecture. MIKE by DHI products are delivered in standard 4-core versions.
MIKE by DHI Software - PerformanceUsability / Efficiency EA2D ‘benchmarking’ – relative runtimes of the five ‘main’ modelling packages. Lower values means faster simulations. Green (and the value 1) indicates the fastest package (taken from the Environment Agency’s Benchmarking of 2D Hydraulic Modelling Packages‘ report)Average user ratings for mostfrequently used 2D hydraulicmodelling packages (five isexcellent, one is poor) from theEnvironment Agency’s ‘DesktopReview of 2D Hydraulic SoftwarePackages’
OVERVIEWUse of MIKE FLOOD for Reservoir InundationModelling as a Result of Dam Failure
Reservoir Inundation ModellingMIKE FLOOD 2D Overland Flow (MIKE 21)An assessment of the potential area ofinundation, resulting from an uncontrolledrelease of water from a reservoir (e.g. as aconsequence of dam failure), may bemodelled directly within MIKE 21 (in either‘Classic’ single grid or flexible mesh versions)utilising: -• Point source inflows representing the likely discharge hydrograph from a dam / embankment failure (if known)• Initial water level conditions within the reservoir permitted to spill through an open (static) breach, or through a standard 1D control structure (e.g. gate structure) MIKE 21 FM; dambreak flow through a sharp bend – Read more…
Reservoir Inundation ModellingNB: There is some evidence to suggest that, where a detailed description ofsupercritical to subcritical flow transition is required (e.g. in urban areas closeto a dam or embankment breach), modelling packages which employ a shockcapturing numerical scheme (MIKE 21 HDFM) perform better overall incapturing the detail of the flow field.The MIKE Animator video above presents surface water elevation resultsfrom MIKE 21 / MIKE FLOOD FM for the critical dam break test case includedin the Environment Agency’s ‘Benchmarking of 2D Hydraulic ModellingPackages’ report. Read more…
Reservoir Inundation ModellingMIKE FLOOD 1D-2D Integrated Inundation Model (MIKE 11 & MIKE 21)There are numerous modules / features within MIKE 21, MIKE 11 and MIKEFLOOD that will augment the above, and enable a more detailed assessmentof breach development and the resulting inundation: -• MIKE 11 Dambreak structures (DB)• MIKE FLOOD side structure links• MIKE FLOOD time varying lateral links• MIKE 21 time varying bathymetryOther useful features: -• MIKE 11 Seamless Mapping (DEM generation with river topography)Results and presentation: -• MIKE Animator• Results Viewer• Plot Composer
Reservoir Inundation ModellingMIKE 11 Dambreak structures (DB)A dambreak structure is a compositestructure composed of a structurerepresenting the flow over the crest(rest flow structure) and anotherstructure representing the breach ofthe dam. The breach can be modelledin two different ways i.e. as a failure Crest failureof the crest (breach structure) or aspiping failure of the dam (pipe failurestructure) followed by breach failure.The flow through a dam breach maybe described in MIKE 11 through theuse of the energy equation oralternatively a the calculation methodas implemented in National Weather Piping failureServices (NWS) DAMBRK program.
Reservoir Inundation ModellingMIKE 11 Dambreak structures can be applied as: -• A regular structure in a MIKE 11 river branch as part of a MIKE FLOOD 1D-2D integrated inundation model• A side structure that can be linked directly to a 2D domain in MIKE FLOOD (encompassing, for example, rivers and floodplains)
Reservoir Inundation ModellingMIKE FLOOD side structure linksMIKE FLOOD side structure links aredesigned to model interaction between theriver model and the overland flow modelthrough Side Structures as defined in MIKE11. Side structure links are explicit links, andwork in the same way as standard link.Side structure links are used specifically fordam break, embankment failure, pumping orlocal spilling. Local breaches
Reservoir Inundation ModellingMIKE FLOOD time varying lateral linksThe Levee Breach Generation is a tool for the creation of time varying levees.By supplying a number of parameters defining the geometry of the leveebreach a time varying line series is created which may be used as input to theMIKE FLOOD model. Dynamic, spatially varying breaches
Reservoir Inundation ModellingMIKE 21 time varying bathymetry – Landslide option (SG)By including the landslide option in MIKE 21 ‘Classic’ grid, the user is able tomodel the hydraulic effects of a time varying bathymetry. The effect of thelandslide is modelled by forcing terms representing the temporal dynamicvertical deformation of the bathymetry. The landslide may be of submarine orsubaerial (e.g. for use in dam or levee breach) type. Also the effects of aseismic seafloor deformation can be modelled using a time varyingbathymetry rather than a spatial varying initial surface elevation.
Reservoir Inundation ModellingMIKE 21 time varying bathymetry – Dynamic Bathymetry Update (FM) Initial condition Final cross section Allows users to apply time varying bathymetries to represent land slides, levee failures or dune breaks
Reservoir Inundation Modelling Example; dune break during 40-hour storm – water level variations
Reservoir Inundation ModellingMIKE 11 Seamless Mapping• Use the MIKE 11 mapping feature in coupled simulation• Combines seamlessly 2D Bathymetry and 1D Cross sections (one operation – no additional map-editing required) Seamless map output – Combined MIKE 21 bathymetry and MIKE 11 topography (Release 2012)
Reservoir Inundation ModellingMIKE 11 GIS GIS based pre-processing; e.g. generation of cross section from LIDAR
Reservoir Inundation ModellingFurther ConsiderationsUtilising the benefits of the full MIKE 21 FMHD model (inc. HD and NHD) andextra add-on modules, the scope of any reservoir inundation modelling workcan be extended (particularly if the initial focus is on hydrodynamics only) toaccount for other important consequences of a dam failure, including: -• Sediment movement (morphological change); identification of downstream areas at risk of scour, bank instability, deposition of eroded material, secondary levee failure and their effects on river and floodplain hydrodynamics• Environmental impacts; assessment of habitat changes (both short and long term), water quality issues and the assessment of potential remediation measures• Design of mitigation measures for the impacts of morphological and environmental change FYI: A special module of MIKE 21 is available that is based on a curvilinear grid (MIKE 21C), which makes it suitable for detailed simulation of rivers and channels, where an accurate description of bank lines is required. As such, MIKE21C is particular suited for river morphological studies.
Reservoir Inundation ModellingDynamic Flood Hazard Mapping Tool* Further ConsiderationsDynamic Flood Hazard Mapping withECO Lab (*included in MIKE FLOOD) ECO Lab A numerical laboratory for ecological modelling • Open Equation solver for coupled ordinary differential equations • Designed for point descriptions of processes of chemistry, ecology, etc • All equations, parameters contained in flexible, portable ECO Lab templates (use DHI supported templates or‘Most Appropriate way of calculating create your own) • Templates include necessary spatialFlood Hazard Rating in UK’ (RPS Group) information for 2D + 3D applications • Integrated with DHI’s hydrodynamic models: MIKE 11, MIKE 21 (henceImage courtesy of RPS Group, UK MIKE FLOOD), MIKE 3 & MIKE SHE
The MIKE Community / Recent ApplicationsThe 2012 MIKE by DHI UK User Group MeetingKeynote Presentation• Urban Flood Flows: The suburb of Merewether in Newcastle is providing engineers with critical data that will inform emergency personnel on how to plan better for the floods which have wreaked havoc across Australia in the past few years. A model of the suburb has been created in Sydneys Water Research Lab (Grantley Smith, University of Newcastle, NSW)Client Presentations: MIKE BASIN – MIKE 21• River Don - Integrated Catchment Management for Yorkshire Water: Integrated Catchment Management using MIKE BASIN (Sally Bielby, JBA)• Reservoir Discontinuance and River Restoration using MIKE 21 FMST: Design Background to a Reservoir Project – The Hydraulic Model and lessons learnt (Mark Bailes, MWH)• Maritime Archaeological Modelling using MIKE 21 - Later Prehistoric Seafaring in Scilly: Modelling of changing ocean/sea conditions for the Holocene around North West Europe, with more detailed focus on the Isles of Scilly (Rodrigo Pacheco- Ruiz, Southampton University)Client Presentations: RENEWABLES - MIKE 21 – MIKE FLOOD – MIKE 11• Wave resource assessment for Oyster farms using MIKE21: Ocean Power – Energy Field Characterisation (Ian Harris, Aquamarine Power)• Modelling the Severn Barrage: A Review of Modelling Strategies for a major UK Renewables Project (John Osment, Halcrow)• Tellisford Mill – Green Electricity from Run of River Hydro in an Historic Setting: A Low-head Hydro Scheme 7 years on from the initial Flood-risk Assessment (Anthony Battersby, FBA / Mendip Power Group)• Validation of a MIKE 21FM Spectral Wave model: For the purpose of an Offshore Wind Farm Coastal Processes Assessment (Emma Holland, METOC)
The MIKE Community / Recent ApplicationsClient Presentations: MIKE 21 BW – MIKE 21 SW – MIKE 21 AD• Wave Modelling with MIKE 21 BW & SW, and Cliff Recession Review: The ‘Baroque on Lamma’ Marina Project in Hong Kong - A MIKE 21 SW & BW Model, and a Review of Empirical Techniques for Analysing Cliff Recession (Vicky Tonks, Mott MacDonald)• Long term coastal water quality predictions using convolutions: A MIKE 21/3 AD Water Quality Study (James Tomlinson, ATKINS)• Recent Experiences in Regional Scale FMHD Modelling: A Case Study of The Pentland Firth (Jack Shipton, ABPMER)Client Presentations: FEFLOW – HABITATS – MIKE FLOOD 1-2-3D• Aquifer Storage and Recovery in a Confined UK aquifer: FEFLOW - Artificial recharge modelling (Mike Streetly, ESI International)• Compliance with The Habitats Directive and Wetlands Ecology at a SSSI: Review of a Wetland Creation Project - 5 Years On (Michael Limbrey, Montgomery Waterway Restoration Trust)• 1-2-3D ‘Dee’ - River Dee Project: An Update and snapshot of a multi-dimensional MIKE Model at a single site ...plus Other Random Musings (Simon Matthews & the UK DSP Team, DHI) Free event!