From 527d927371083e784ad583a6b3c7465c49a53cdc Mon Sep 17 00:00:00 2001 From: Johannes Ranke Date: Thu, 10 Mar 2016 05:17:45 +0100 Subject: Add NL specific drift calculations --- pkg/R/PEC_sw_drift_NL.R | 49 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 49 insertions(+) create mode 100644 pkg/R/PEC_sw_drift_NL.R (limited to 'pkg/R') diff --git a/pkg/R/PEC_sw_drift_NL.R b/pkg/R/PEC_sw_drift_NL.R new file mode 100644 index 0000000..cc92185 --- /dev/null +++ b/pkg/R/PEC_sw_drift_NL.R @@ -0,0 +1,49 @@ +# Copyright (C) 2016 Johannes Ranke +# Contact: jranke@uni-bremen.de +# This file is part of the R package pfm + +# This program is free software: you can redistribute it and/or modify it under +# the terms of the GNU General Public License as published by the Free Software +# Foundation, either version 3 of the License, or (at your option) any later +# version. + +# This program is distributed in the hope that it will be useful, but WITHOUT +# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS +# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more +# details. + +# You should have received a copy of the GNU General Public License along with +# this program. If not, see + +#' Calculate predicted environmental concentrations in surface water due to drift +#' +#' This is a basic, vectorised form of a simple calculation of a contaminant +#' concentration in surface water based on complete, instantaneous mixing +#' with input via spray drift. +#' +#' @param rate Application rate in units specified below +#' @param applications Number of applications for selection of drift percentile +#' @param drift_percentages Percentage drift values for which to calculate PECsw +#' @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 +#' @return The predicted concentration in surface water +#' @export +#' @author Johannes Ranke +#' @examples +#' PEC_sw_drift_NL(100) +PEC_sw_drift_NL <- function(rate, + applications = 1, + water_depth = 30, + drift_percentages = c(1), + rate_units = "g/ha", + PEC_units = "\u00B5g/L") +{ + rate_units <- match.arg(rate_units) + PEC_units <- match.arg(PEC_units) + water_volume <- 100 * 100 * (water_depth/100) * 1000 # in L (for 1 ha) + PEC_sw_overspray <- rate * 1e6 / water_volume # in µg/L + PEC_sw_drift <- PEC_sw_overspray * drift_percentages / 100 + names(PEC_sw_drift) <- paste(drift_percentages, "%") + return(PEC_sw_drift) +} -- cgit v1.2.1