R&D highlights edition 2019

PROJECTS Ecosystems and environmental quality 22 ‘D-EMISSIONS’: A TRULY GENERIC AND FLEXIBLE EMISSION MODEL ‘D-Emissions’ is a new emission modelling tool that can be used to simulate the quantity and spatial distribution of emitted substances in catchments. Its generic nature andflexibilitymake it unique in its kind. M any issues with water quality are caused by harmful substances (nutrients, chemical/organic/biological pollutants, heavy metals, plastics) that have been discharged into the water. Instead of studying the water (pool, lake or bay) where these substances accumulate, it would be better to look at where they are emitted in the first place and how they have ended up in the surface water. An emissionmodel could be useful here by providing a quantitative and systematic overview of the sources, fate and transport of the emitted substances. There is already a range of emission models available (both at Deltares and elsewhere). However, they are typically designed for a specific substance and/or a specific area. In practice, thismeans that newmodels are designed for individual projects or problems, making assessments inefficient and error prone. We therefore decided to take up the challenge to design an emission modelling tool that is truly generic and flexible. The state-of-the- art emissionmodel set up in the EU project SOLUTIONS provided a good starting point. Further developments focused on maximum flexibility with respect to compartments, hydrological processes & models, substances, pathways and sources. The resulting tool was named ‘D-Emission’. In combination with rainfall runoff and a hydrological model, it can be used to create an integral catchment model that allows for the simulation of the quantity and spatial distribution of the emitted substances in the catchment. Because the model is ‘source-oriented’ and simulates the true cause-effect chain, it provides predictive power and allows for ‘what-if’ scenarios driven by policy projections and implemented measures. ‘D-Emissions’ could facilitate assessments of water quality and health throughout the world. It has already been applied successfully on a range of projects focusing on different substances and areas. Currently, we are planning to use ‘D-Emissions’ for global-scale assessments. In summary, ‘D-Emissions’ is… • …based on a ‘source-oriented approach’, providing it with predictive power • …based on a mass balance approach that prevents double- counts and omissions • …responsive to inter-annual hydrology variations such as peak discharges during heavy rainfall • …flexible with respect to compartments, hydrological processes & models, substances, pathways and sources • …embedded in the Delft3D-Suite, which guarantees software maintenance. Contact: Tineke Troost, Tineke.Troost@deltares.nl , t +31 (0)88 335 8281 Jos van Gils, Jos.vanGils@deltares.nl , t +31 (0)88 335 8380 Further reading : https://www.deltares.nl/en/software/d-emissions/ Generic overview of an integral catchment modelling framework including D-Emissions Spatial distribution of simulated tyre and road wear particles caused by wash-off of roads and particle erosion aggregated over the Scheldt Basin for hydrological year 2008 (Unice et al., 2018) schematization rainfall schematization in- & outflows control rules inflow outflow inflow schematization meteo forcing water level salinity water flow & level dispersion T-stratification 3D Hydrodynamic model 3DWater quality model 1D Hydraulic model Rainfall-Runoff model 1D Transport model Emission model water flow loads source types capacities flows concentrations loads representative year simulations