Historical, future and design event methods

Model events and EventSets

The model Event class defines fluvial (discharge), pluvial (rainfall), or coastal (water levels) forcings. The class contains one or more hydroflows.methods.events.Forcing objects with references to time series data, the start and end times of the event, and optionally a return period (RP) associated with the event.

The EventSet class is a collection of references to multiple Event files. It is used to group the events which are jointly used to e.g. calculate risk.

All event methods generate one or more Event files and one EventSet file. The Event files serve as inputs for the hazard model (SFINCS) using the SfincsUpdateForcing method.

The EventSet file is used as input to the risk model (FIAT) using the FIATUpdateHazard method and flood adaptation model (FloodAdapt) using the SetupFloodAdapt method.

Event methods

HydroFlows has several methods to generate events for historical, future, and design events.

The historical events can be extracted from time series data using the HistoricalEvents method and contain one or more forcings.

Design events are currently univariate and are derived using extreme value analysis from time series data. The design events can be derived for coastal (storm tide), rainfall, and discharge time series data. For coastal design events, a second method is available to use existing return period CoastRP dataset. For rainfall design events, the global GPEX Intensity-Duration-Frequency (IDF) curve data can be used.

The future climate events are used to scale historical or design events to future climate conditions. For rainfall the multiplicative Clausius-Clapeyron scaling is used, while for sea level rise an additive approach is used. For discharge events, rather than scaling then scaling the events a new set of events is generated from hydrological simulations under future climate conditions by scaling the input meteorological data, see the data method ChangeFactor.

An overview with the current supported event methods in HydroFlows is shown in the table below.

Table overview with the available event methods

Event Type	Historical	Design events	Future climate events
Coastal	HistoricalEvents	CoastalDesignEvents CoastalDesignEventFromRPData	FutureSLR
Rainfall	HistoricalEvents	PluvialDesignEvents PluvialDesignEventsGPEX	FutureClimateRainfall
Discharge	HistoricalEvents	FluvialDesignEvents	N.A.
Combined	HistoricalEvents	N.A.	N.A.