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-rw-r--r--R/PEC_sw_drift.R31
1 files changed, 26 insertions, 5 deletions
diff --git a/R/PEC_sw_drift.R b/R/PEC_sw_drift.R
index eccb5bf..22aa012 100644
--- a/R/PEC_sw_drift.R
+++ b/R/PEC_sw_drift.R
@@ -8,15 +8,19 @@
#' @seealso [drift_parameters_focus], [drift_percentages_rautmann]
#' @param rate Application rate in units specified below
#' @param drift_percentages Percentage drift values for which to calculate PECsw.
-#' 'drift_data' and 'distances' if not NULL.
+#' Overrides 'drift_data' and 'distances' if not NULL.
#' @param drift_data Source of drift percentage data. If 'JKI', the [drift_data_JKI]
-#' included in the package is used. If 'RF', the Rautmann formula is used, if
-#' implemented for the crop type and number of applications
+#' included in the package is used. If 'RF', the Rautmann drift data are calculated
+#' either in the original form or integrated over the width of the water body, depending
+#' on the 'formula' argument.
#' @param crop_group_JKI When using the 'JKI' drift data, one of the German names
#' as used in [drift_parameters_focus].
#' @param water_depth Depth of the water body in cm
#' @param rate_units Defaults to g/ha
#' @param PEC_units Requested units for the calculated PEC. Only µg/L currently supported
+#' @param water_width Width of the water body in cm
+#' @param side_angle The angle of the side of the water relative to the bottom which
+#' is assumed to be horizontal, in degrees. The SYNOPS model assumes 45 degrees here.
#' @return The predicted concentration in surface water
#' @export
#' @author Johannes Ranke
@@ -35,6 +39,14 @@
#'
#' # Using custom drift percentages is also supported
#' PEC_sw_drift(100, drift_percentages = c(2.77, 0.95, 0.57, 0.48, 0.29, 0.15, 0.06, 0.03))
+#'
+#' # The influence of assuming a 45° angle of the sides of the waterbody and the width of the
+#' # waterbody can be illustrated
+#' PEC_sw_drift(100)
+#' PEC_sw_drift(100, drift_data = "RF")
+#' PEC_sw_drift(100, drift_data = "RF", formula = "FOCUS")
+#' PEC_sw_drift(100, drift_data = "RF", formula = "FOCUS", side_angle = 45)
+#' PEC_sw_drift(100, drift_data = "RF", formula = "FOCUS", side_angle = 45, water_width = 200)
PEC_sw_drift <- function(rate,
applications = 1,
water_depth = 30,
@@ -46,6 +58,9 @@ PEC_sw_drift <- function(rate,
crop_group_focus = c("arable", "hops", "vines, late", "vines, early",
"fruit, late", "fruit, early", "aerial"),
distances = c(1, 5, 10, 20),
+ formula = c("Rautmann", "FOCUS"),
+ water_width = 100,
+ side_angle = 90,
rate_units = "g/ha",
PEC_units = "\u00B5g/L")
{
@@ -54,14 +69,20 @@ PEC_sw_drift <- function(rate,
drift_data <- match.arg(drift_data)
crop_group_JKI <- match.arg(crop_group_JKI)
crop_group_focus <- match.arg(crop_group_focus)
- water_volume <- 100 * 100 * (water_depth/100) * 1000 # in L (for 1 ha)
+ formula <- match.arg(formula)
+ if (side_angle < 0 | side_angle > 90) stop("The side anglemust be between 0 and 90 degrees")
+ mean_water_width <- if (side_angle == 90) water_width
+ else water_width - (water_depth / tanpi(side_angle/180))
+ water_volume <- 100 * mean_water_width * (water_depth/100) * 1000 # in L (for 1 ha)
PEC_sw_overspray <- rate * 1e6 / water_volume # in µg/L
dist_index <- as.character(distances)
if (is.null(drift_percentages)) {
drift_percentages <- switch(drift_data,
JKI = pfm::drift_data_JKI[[applications]][dist_index, crop_group_JKI],
- RF = drift_percentages_rautmann(distances, applications, crop_group_focus)
+ RF = drift_percentages_rautmann(distances, applications,
+ formula = formula,
+ crop_group_focus, widths = water_width/100)
)
names(drift_percentages) <- paste(dist_index, "m")
} else {

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