# Danube Model ### Description The Danube Model contains a coupling between the spatially distributed eco-hydrological model SWIM and the hydrodynamic CaMa-Flood model. Within DIRECTED, the Danube Model was used to produce monthly Climate projections spanning across the EU (located in the Danube RWL, under ISIMIP Climate Projections), as well as fluvial flooding for the entire Danube Basin at a 10-year flood depth (also located within the operational layers of the Danube RWL). ### Model Specifications | Model Specifications | Description | | ----------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | Model Type | A physically-based, deterministic model. The standard time step is 24 hours, but hydrodynamic calculations within CaMa-Flood require adaptive time steps of approximately two minutes. | | Associated Probability Method | Flood probability distributions can be estimated in the postprocessing of the daily results. Climate change effects have been determined from blocks of 300 simulation years (30-year time slices times 10 realizations per scenario). | | Spatial Resolution | Principal simulation units are so-called unit-catchments. These are derived from a regular 3-arc minute grid, hence they cover approximately 22 km² each in the Danube basin. Their river mainstreams are used for visualisation of the results. | | Intensity Parameters | Daily river runoff, maximum flood height, and water velocity as primary model outputs. Characteristics of average return intervals and their dynamics as derived in the postprocessing. | | Other Inputs | Many. The eco-hydrological modelling part for runoff generation requires at least an elevation model, a land use map, and a soil map with soil profile information for each mapping unit. Crop management (typical crops, planting and harvesting dates) should be reasonably specified. Gridded daily weather or climate scenario data are needed to drive the model (required variables: daily average, minimum and maximum air temperature, precipitation, air humidity, and solar radiation). River gauge time series are needed for calibration and validation. | | Calibration and Validation | The SWIM part was left unchanged from a former calibration on 0.25-degree E-OBS data by Michel Wortmann (cf. Hattermann et al. 2018, ). It seemed to perform even better given the availability of E-OBS data in 0.10 degree resolution. In CaMa-Flood, levees had to be parameterized. Levee heights were determined from empirical flood height functions; after consulting several contradictory sources, an average overtopping return period of 50 years in the north-west andof 25 years in the south-east of the Danube basin had been assumed. Further calibration was made in CaMa-Flood through variation of Manning's roughness parameters for river beds and floodplains. | | Effects of Climate Change | Estimating the effects of climate change on flood hazards was the principal motivation for this Danube Model application. For the time being, we drove the model with ISIMIP bias-adjusted SSP 370 and 585 climate scenarios and produced maps of future return intervals for current 100-year flood events. | --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://directed-eu.gitbook.io/data-fabric-manual/model-documentation/danube-model.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.