The Dutch Delta model to support national policy analysis Erik Ruijgh Deltares, the Netherlands 16 maart 2016 Water management in the Netherlands Water management in the Netherlands Water management in the Netherlands Delta programme Historically, measures were implemented AFTER a disaster. The Dutch government started the Delta programme to implement a series of measures to PREVENT new disasters. Focus on consequences of climate change and socio-economic development. Both flood risk, drought management and spatial planning are included. Delta…. • Delta commission • Delta commissoner • Delta act • Delta fund • Delta programme • Delta decisions • Delta model / Delta scenarios Delta programme Generic sub-programs: • Flood protection • Fresh water supply • Reallocation and renovation IJsselmeer region Regional sub-programs: • Coast • Wadden region Rhine-Meuse Rivers • Southwest Delta estuary • Rivers Southwest Delta • Rhine Meuse estuary • Lake IJsselmeer region Planning 2011 2012 2013 2014 2015 Delta programme Possible Promissing Preferred Implementation strategies strategies strategies Delta model - 0.2 1.0 1.1 1.2 Screening Subprograms National Delta decisions DP2013 DP2014 DP2015 DP2016 9 Delta scenarios social economic growth Busy Steam change climate rapid Quiet Warm moderate climate chnage climate moderate chnage social economic squeeze Delta scenarios: urban development 1900 1960 2010 The Delta model: a coherent set of models original situation Deltamodel measure, scenario database model impact assessment Delta model components for Fresh Water terrestrial aquatic drinking cooling agriculture navigation nature nature water water unsaturated surface distribution hydro water zone water model dynamics temp. ground water NHI Delta model components for flood protection damage* costs* hydro dike dike waves dynamics failure strenght* max. water levels return times probabilistic engine Lots of meetings, participants, discussions IAC Requirements to the Delta model • Functionality • Scenarios: climate change, sea level, socio-economic • Measures: new storm surge barriers, operation rules, water use • Useability • Large amount of calculations, transparent and reproducable • Consistency • Flood protection and Water allocation, models, data • Acceptance • Delta commission + Ministry + regional watermanagers + scientists • Accuracy • Compared to available monitoring data Dilemma • These requirements are (partly) contradicting • Acceptance vs. Consistency • Accuracy vs. Functionality • Functionality vs. Useability • It was not possible to implement all requirements Views on the Delta model Policy makers Water managers • Long term effects • Near time effects • Scenario’s • Implementation • Sensitivity • Accuracy Scientists • Knowlegde • Software • Consistency Approach to gain acceptance Scientists 19 Model resolution “Fit for Purpose” Spatial resolution Temporal resolution Droughts Floods Droughts Floods Policy analysis Regions Rivers Years Season Forecasting Districts River stretch Days Hours Management & Field Dike segment Hours Minutes Maintenance Design & hectare Talud Minutes Seconds Construction Conclusions Delta model provides a coherent set of models for flood risk and drought management in the Netherlands. Acceptance was gained by using fairly detailed models of regional watermanagers for national policy analysis. Next steps will be to reduce the complexity of the included models, in order to improve the useability for policy analysis. Erik Ruiijgh: The Dutch Delta model Thank you for your attention! [email protected] .