Get septic well array

This function prepares an array of septic systems or private wells for the groundwater model function get_intersection_probability().

get_septic_well_array(hh_array, hh_array_type, ...)

Arguments

hh_array	array of septic or well systems with coordinates [x, y] as units objects and (optionally) z1, z2, rs
hh_array_type	either "septic" or "well" describing the hh_array. See Details below.
...	See details for optional inputs

Details

This function takes as input an array of septic systems or wells with (x,y) coordinates where (0,0) is the location of the domestic well.

Option 1:

If the goal is to calculate the probability that a single septic system at (0,0) contaminates any well within a set of wells at (x, y), then hh_array should represent a set of wells and hh_array_type should be set to "wells". In this case, the x-y locations in hh_array are kept and each well is parameterized with with a well_rect.

Option 2:

Alternatively, if the goal is to calculate the probability that a single well at (0,0) is contaminated by any of a set of septic systems at (x, y), then hh_array represents septic systems and hh_array_type should be set to "septic". In this case, the function translates a set of point-source septic fields that might contaminate the well into a set of virtual wells to use with get_intersection_probability(). Furthermore, each virtual well is parameterized with with a well_rect. In order to calculate the probability of a septic system contaminating a well, the septic system is treated as a virtual well identical to the actual well and located directly opposite original septic system at (-xi, -yi). In other words, the septic array is translated to a well array rotated 180 degrees around the domestic well. The problem of determining contamination can then be treated by considering the probability that a particle introduced at (0,0) will intersect the virtual wells at (-xi, -yi).

Optial input in ... can include:

• z_range: units vector of length 2 representing depth from the water table surface to the top and bottom of the well

• rs: units object representing the radius of the well source area

Examples

# Generate household array
library(units)

# Option 1: Prepare array of wells -- see Details
wells <- get_septic_well_array(hh_grid_example, "well")

# plot the array of wells
library(ggplot2)
library(ggforce) # needed to plot axes using units objects
ggplot(mapping = aes(x, y, color = id)) +
  geom_point(data = hh_grid_example, aes(shape = "wells from\nhh_grid_example"),
      size = 4, stroke = 1) +
  geom_point(data = wells, aes(shape = "wells"), size = 2) +
  scale_shape_manual(values = c(16, 1)) +
  scale_color_viridis_c(option = "B") + coord_equal()

# Option 2: Prepare array of virtual wells -- see Details
virtual_well_array <- get_septic_well_array(hh_grid_example, "septic")

# plot the flipped array of virtual wells
library(ggplot2)
library(ggforce) # needed to plot axes using units objects
ggplot(mapping = aes(x, y, color = id)) +
  geom_point(data = hh_grid_example, aes(shape = "septic systems\nfrom hh_grid_example"),
      size = 4, stroke = 1) +
  geom_point(data = virtual_well_array, aes(shape = "virtual wells"), size = 2) +
  scale_shape_manual(values = c(1, 16)) +
  scale_color_viridis_c(option = "B") + coord_equal()