InfoWorks CS to ICM – Culture Shock? Neil McClung Presentation Content 1. Example Study Background 2. Hydraulic Modelling 1. Importing & Enhancing CS Model 2. Sewer / Surface Linkage 3. River Modelling 4. 2D Surface 5. 2D Runoff 6. Simulation & Analysis 3. Software / System Setup 4. Review of Issues / Learning Points Example Study Background • South West Water (SWW) – Strategic Planning • DEFRA Programme ‘Making Space for Water’ • 5 Integrated Urban Drainage Studies • Clarify stakeholders, responsibilities and promote co-operation • Locate drainage issues, impact of urban flooding and causes • Identify cost effective solutions / Integrated funding mechanisms • DEFRA Surface Water Management Planning ‘Wheel’ • Truro, Cornwall Hydraulic Modelling • Enhance & Integrate Existing Models • SWW InfoWorks CS model • EA ISIS/TUFLOW/ESTRY model • Build Detailed Catchment-wide Surface Model • Undertake Detail Risk Assessment • Impact of climate change on urban flooding • SWW sewer network performance & capacity • EA flood zones & Flood Maps for Surface Water • CCC critical & vulnerable infrastructure Hydraulic Modelling • Existing SWW InfoWorks CS Model • Existing EA ISIS/TUFLOW/ESTRY Model • Additional Data • • EA LiDAR Data • SWW MasterMap Data • Other drainage records New InfoWorks ICM Model • Entire urban area & flood plains • Tide gate & river flood protection dams • Detailed 2D surface model • 1D runoff integrated with some 2D direct runoff Importing & Enhancing CS Model • Efficient / No dramas (as you’d expect) • Node ground level interpolation speedy • 3D visualisation useful in identifying survey errors in original CS model Sewer / Surface Linkage • Gully representation important • Usefulness of Google Street View • Inference of other gullies using MasterMap® data River Modelling • Steep (but achievable) learning curve for traditional CS modeller • Consideration for the filtering effects of converting the LiDAR to a DTM where river banks dominated by undergrowth • Interrogation of the ‘realism’ of interpolated bank heights assists simulation calculations • Interpolated river reach cross sections can be spurious when connecting sewer outfalls 2D Surface • Can develop major 2D components efficiently & precisely from OS MasterMap® • However, beware of geometry issues in MasterMap® (e.g. overlaps) • Careful consideration of the creation, directly or indirectly, of elements below the minimum settings which may increase meshing times • Reasonable proficiency in GIS technique helps • Roughness zones not always necessary – heavy on simulation times • Simplicity (where possible) is the Key 1D, 2D & 1D/2D Runoff • Subcatchments should to be spatially defined • Rain gauge boundaries can be used to apply 2D rainfall to selected areas of a 2D zone only • However, will need to consider what to do with your 1D subcatchments • 2D runoff simulation intensive • Alternatively, could create 1D subcatchments from OS MasterMap Model Simulation & Analysis • Time-steps • 2D Simulation Parameters • 2D Runoff Simulation Times • Instability Chasing • More places to uncover problems in ICM • Scenario testing useful • Power of Scenarios • GPU Cards Software / System Setup • Standalone vs. Workgroup database • Local vs. Remote simulations • • • Storage on local machine or server IT department need to be onboard • Permissions and access • Data flow across the network Local Folders Review of Issues / Learning Points • A firm understanding of the provenance of the CS model needed • Creating the 2D surface components from MasterMap® efficient & powerful • Importance of GIS / geometric precision for 2D • Integrating 2D runoff into 1D subcatchments not ideal... but is possible • 2D direct runoff weighs heavy on simulation speeds • Can never have enough gully information (although you knew that already) • Interpolated ground levels can be misleading • But more importantly – ICM is more fun than CS! ☺ Thank you Some Possible Directions for the Future • Multiple Interacting 2D zones? • Automated 2D polygon generation from MasterMap? • Goal seek analysis? • ICM export to CS? • Standard gully headloss defaults? • 2D meshing using multi-threading? For Further Information: [email protected] [email protected]