Run the full flood model — fl_flood

Convenience wrapper that calls fl_flood_surface() and fl_flood_depth() in sequence, returning a multi-layer SpatRaster with the flood surface elevation, flood depth, and a binary flooded mask.

Usage

fl_flood_model(dem, streams, flood_factor = 6, precip = 1, max_width = 2000)

Arguments

dem: A SpatRaster of elevation.
streams: A SpatRaster of rasterized streams (output of fl_stream_rasterize()). Cell values are upstream contributing area in hectares (or another proxy for channel size).
flood_factor: Numeric. Multiplier on bankfull depth to estimate flood depth. Default 6 (VCA convention).
precip: A SpatRaster of mean annual precipitation (mm), or a single numeric value applied uniformly. Default 1 (omits precipitation term).
max_width: Numeric. Maximum corridor width in map units (metres) within which to interpolate. Default 2000 (1000m each side).

Value

A SpatRaster with three layers:

flood_surface: Water surface elevation at stream cells (NA elsewhere).
flood_depth: Depth above terrain (metres). 0 at streams, NA where not flooded.
flooded: Binary mask: 1 where flood_depth > 0, 0 at streams, NA elsewhere.

Examples

dem <- terra::rast(system.file("testdata/dem.tif", package = "flooded"))
streams <- sf::st_read(
  system.file("testdata/streams.gpkg", package = "flooded"),
  quiet = TRUE
)
stream_r <- fl_stream_rasterize(streams, dem, field = "upstream_area_ha")
precip_r <- fl_stream_rasterize(streams, dem, field = "map_upstream")
flood <- fl_flood_model(dem, stream_r, flood_factor = 6, precip = precip_r)

# Three layers: flood_surface, flood_depth, flooded
names(flood)
#> [1] "flood_surface" "flood_depth"   "flooded"      
terra::plot(flood[["flood_depth"]], main = "Flood depth (m)")