1 / 31

ISIS in River Modelling A Practical Perspective

ISIS in River Modelling A Practical Perspective. Luke Lovell Senior Hydrologist. Overview. ISIS today ISIS in the market Why model? ISIS 1D – Modelling channels and structures ISIS 1D – Modelling the floodplain ISIS 1D – Hydrological Boundaries Case Study – Lower Thames FRM Strategy

elpida
Télécharger la présentation

ISIS in River Modelling A Practical Perspective

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. ISIS in River Modelling A Practical Perspective Luke Lovell Senior Hydrologist

  2. Overview • ISIS today • ISIS in the market • Why model? • ISIS 1D – Modelling channels and structures • ISIS 1D – Modelling the floodplain • ISIS 1D – Hydrological Boundaries • Case Study – Lower Thames FRM Strategy • 2D Modelling • ISIS2D • Case Studies – Molesey to Teddington Thames Estuary 2100

  3. ISIS – A quick introduction • History • ISIS Suite of Modelling Software comprises • ISIS (free and professional versions) • ISIS Sediment • ISIS WQ (Water Quality) • Network manager • ISIS TUFLOW • TUFLOW Coming Soon… ISIS Fast

  4. ISIS in the Market Place • One of the leading software packages for river modelling • Application worldwide, by consultants and public bodies (e.g. Laos, China etc) • Main competitors: • Infoworks RS • Mike 11 • HECRAS

  5. Why do we model rivers? • Typically to support and inform decisions, for example • Policy & strategic planning – where and when do I invest/retreat? • What would be the most effective FRM intervention? • When do I need to raise a Flood Warning? • Should I insure Joe Blogs at 49 Acacia Avenue? • Is it safe to allow development here? • What will be the effect of climate change? • These are important decisions to make; flooding is a serious economic, social and environmental problem for people and their governments

  6. Some numbers - UK • 2.2M homes and 185,000 businesses lie in flood risk areas • £220 Billion (excluding agricultural land) of assets at risk • £110 Billion of property assets are located In the Thames floodplain • £2.1 billion of damage due to flooding and coastal erosion in 2004 • £564M was spent on “Flood Management” in England and Wales in 2003/04 • 80,000 properties are to benefit from new flood management between April 2003 - March 2006

  7. Boscastle 2004

  8. Boscastle 2004

  9. Boscastle 2004

  10. Carlisle 2005

  11. Ulley Dam - 2007

  12. Brazil 2008

  13. Typical Applications of ISIS in the UK • Flood Risk Mapping – EA Flood Map • Flood Forecasting • Scheme Appraisal • Strategies – e.g. LTS & TE2100 • CFMPs • Flood Incident Management & Emergency Planning (THEMIS) • Surface Water Mapping • Dam Break (2D only) • Sediment & water quality studies

  14. ISIS 1D – Modelling Channels and Structure The ISIS GUI

  15. A typical ISIS river Section • Input data • Survey • Information on roughness (e.g. photos)

  16. Weirs & Spills

  17. Bridges

  18. ISIS 1D – Modelling the Floodplain • Extended cross sections • Quasi-2D reservoir units and spills • Now less popular due to advent of linked 1D-2D models

  19. ISIS 1D – Hydrological Boundaries • Choose from: • QT, QH • HT • Normal/Critical Depth • Tidal • FSSR • FEH • ReFH • US SCS • FRQSIM (not released) • Direct Rainfall • Abstraction/evaporation

  20. 1D Results Dependant on: • Choice of software • Capability of the software • Skill of modeller • Model schematisation • Data quality and extent • Budget (value)

  21. Case Study – Lower Thames FRM Strategy • Old Windsor, Wrasbury, Staines, Chertsey, Sunbury, Molesey, Kingston • 14,500 properties and 36,000 people at risk (0.5% AEP event) • Preferred strategy = £300m scheme – largest since TB built ISIS used for: • Outline design of 3 diversion channels • Downstream impacts & compenstation • Mapping (economics)

  22. 2D Modelling • Solves mass and momentum • Can be quick to set up • Do not have to define flow paths • Obtain depths and velocities • Now more achievable due to • Data sets/coverage • Computing power (speed) • Distributed processing • Need to consider effect of • Buildings • Grid size • Time step

  23. 1D vs 2D some key differences

  24. ISIS -2D • Uses ADI (Alternating Direction Implicit) scheme – equations are solved in each direction once per time step • Links to ISIS 1D • Represents floodplain as grid of square cells, predicting [h, u, v] at each • What you need to set up a model: • Hydrological Data • Topography • Roughness • Floodplain and channel locations • XML control file • And a 1D channel only ISIS model • Continuity Equation • Momentum Equation

  25. Importance of Grid Resolution 20m 10m 5m

  26. 2D Results

  27. Case Study: Teddington to Hammersmith

  28. Case Study – TE2100

  29. Case Study TE2100

  30. The best model? Think first, model later!

  31. Further info… think technology think innovation think Halcrow www.halcrow.com/isis

More Related