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Load flood factor scenarios

Source: R/fl_scenarios.R
fl_scenarios.Rd

Returns a tibble of pre-defined flood factor scenarios for fl_valley_confine(). Each row is a complete parameter set that can be passed to the function. The bundled CSV includes three scenarios spanning active channel margin (ff=2) to full valley bottom (ff=6).

Usage

fl_scenarios(path = NULL)

Arguments

path

Character. Path to a custom scenarios CSV. When NULL (default), loads the bundled inst/extdata/flood_scenarios.csv. Users can copy the default CSV, add rows for site-level work (e.g., smaller thresholds for 1m lidar), and pass the custom path.

Value

A tibble with columns: scenario_id, flood_factor, slope_threshold, max_width, cost_threshold, size_threshold, hole_threshold, run, description, ecological_process, citation_keys.

Details

The flood_factor is a DEM compensation parameter, not an ecological threshold — no paper maps specific ff values to ecological processes. The scenario descriptions are an interpretive overlay based on where different ff values fall relative to field-validated studies:

  • ff=2: Rosgen flood-prone width, ~50-yr flood stage

  • ff=3-4: Historical floodplain (Hall et al. 2007 validated ff=3 on 10m DEM against 213 field sites; ff=4 compensates for 25m DEM smoothing)

  • ff=5-7: Valley bottom including terraces (Nagel et al. 2014)

DEM resolution matters: coarser DEMs need larger ff to compensate for smoothed valley floors. At 1m lidar, ff=2-3 may suffice.

The run column allows consuming projects to document all scenarios but only execute selected ones (e.g., dplyr::filter(scenarios, run)).

Examples

scenarios <- fl_scenarios()
scenarios[, c("scenario_id", "flood_factor", "description")]
#> # A tibble: 3 × 3
#>   scenario_id flood_factor description                              
#>   <chr>              <int> <chr>                                    
#> 1 ff02                   2 Flood-prone width / active channel margin
#> 2 ff04                   4 Functional floodplain                    
#> 3 ff06                   6 Valley bottom extent                     

# Filter to scenarios marked for execution
to_run <- scenarios[scenarios$run, ]