HGDM: Applies HGDM to forcings

In HGDMr: Hysteretic and Gatekeeping Depressions Model

Applies HGDM to forcings

Description

Applies the Hysteretic and Gatekeeping Depressions Model to basin-scale fluxes determined by hydrological modelling to calculate the outflows during a given time interval. Note than no routing is performed.

Usage

HGDM(
  upland_area = NULL,
  small_depression_area = NULL,
  large_depression_area = NULL,
  area_units = "km2",
  max_small_depression_storage = 0,
  max_large_depression_storage = 0,
  initial_small_depression_storage = 0,
  initial_large_depression_storage = 0,
  storage_units = "mm",
  small_depressions_initial_connected_fraction = 0,
  upland_fraction_to_small = 0,
  upland_fraction_to_large = 0,
  upland_fraction_to_outlet = 0,
  small_fraction_to_large = 0,
  forcings = NULL,
  small_p = NULL,
  large_rating = 0,
  sub_intervals = 1
)

Arguments

upland_area	Required. Area of uplands, which drain to the outlet, small depressions or the large depression.
small_depression_area	Required. Area of small depressions.
large_depression_area	Optional. If 0 or NULL large depression is not \ modelled.
area_units	Units of all areas. Must be one of km2 (default), ha or m2.
max_small_depression_storage	Maximum depth of storage in small depressions.
max_large_depression_storage	Maximum depth of storage in large depressions.
initial_small_depression_storage	Initial depth of storage in small depressions.
initial_large_depression_storage	Initial depth of storage in large depressions.
storage_units	Units of all storage depths. Must be one of mm (default) m, or m3. If a depth is specified then it will be converted to a volume by multiplying by the appropriate area.
small_depressions_initial_connected_fraction	Initial connected fraction (0-1).
upland_fraction_to_small	Fraction of uplands draining to small depressions. If 0 then the small depressions are unlikely to fill.
upland_fraction_to_large	Fraction of uplands draining to large depression. This is the basin of the large depression.
upland_fraction_to_outlet	Fraction of uplands draining directly to outlet. Analogous to the effective fraction.
small_fraction_to_large	Fraction of small depression area draining into large depression. Governed by location of large depression in the basin.
forcings	Required. A data frame of time series of rainfall, snowmelt, evap, and runoff. The first variable must be either date (an R date) or datetime (a POSIXct date-time).
small_p	Parameter for small depression water volume-area relationship.
large_rating	Rating curve parameters for large depression.
sub_intervals	Number of sub-intervals for solution of each time step.

Value

Returns a data frame. Depending on whether or not a large depression was specified, the data frame will have differing variables. Note that regardless of the units specified for areas and volumes, all of the variables returned are in SI dimensions, i.e. 'm' and 'm^3/s' values

If no large depression is specified, the returned variables are:

date or datetime

R date or POSIXct datetime.

total_contrib_frac

The connected/contributing fraction of the basin. Includes both the meta depression and the upland fraction connected to the outlet.

total_outflow_volume

The volume of outflow (m ^3) in the interval.

small_depression_contrib_frac

The connected/contributing fraction of the meta depression.

small_depression_water_volume

The volume of water (m ^3) retained in the meta depression.

small_depression_water_depth

The depth of water (m) retained in the meta depression.

small_depression_water_area

The area of water (m ^2) retained in the meta depression.

If there is a large depression, then 'total_contrib_frac' includes the effect of the large depression and the additional variables are also returned:

date or datetime

R date or POSIXct datetime.

large_depression_contrib_frac

The connected/contributing fraction of the large depression.

large_depression_water_volume

The volume of water (m ^3) retained in the large depression.

large_depression_water_area

The area of water (m ^2) retained in the large depression.

Examples

{ 
daily_fluxes <- daily_7120951600  
basin_area <- 100
small_depression_frac <- 0.24
small_depression_area <- small_depression_frac * basin_area
large_depression_area <- 0
upland_area <- basin_area - (small_depression_area + large_depression_area)
area_units <- "km2"
max_small_depression_storage <- 300
max_large_depression_storage <- 0
initial_small_depression_storage <- max_small_depression_storage / 2
initial_large_depression_storage <- max_large_depression_storage / 2
storage_units <- "mm"
small_depressions_initial_connected_fraction <- 0
upland_fraction_to_small <- 0.98
upland_fraction_to_large <- 0
upland_fraction_to_outlet <- 0.02
small_fraction_to_large <- 0
small_p <- 1.2
large_rating <- 1.4
sub_intervals <- 1

results <- HGDM(upland_area, 
small_depression_area, 
large_depression_area = 0, 
area_units = "km2", max_small_depression_storage, 
max_large_depression_storage,
initial_small_depression_storage, 
initial_large_depression_storage,
storage_units,
small_depressions_initial_connected_fraction,
upland_fraction_to_small,
upland_fraction_to_large,
upland_fraction_to_outlet,
small_fraction_to_large,
forcings = daily_fluxes[1:100,],
small_p = small_p,
large_rating = large_rating,
sub_intervals = sub_intervals)
}

HGDMr documentation built on Dec. 9, 2025, 1:06 a.m.