PEC_sw_exposit_runoff: Calculate PEC surface water due to runoff and erosion as in...

In jranke/pfm: Utilities for Pesticide Fate Modelling

Calculate PEC surface water due to runoff and erosion as in Exposit 3

Description

This is a reimplementation of the calculation described in the Exposit 3.02 spreadsheet file, in the worksheet "Konzept Runoff".

Usage

PEC_sw_exposit_runoff(
  rate,
  interception = 0,
  Koc,
  DT50 = set_units(Inf, "d"),
  t_runoff = set_units(3, "days"),
  exposit_reduction_version = c("3.02", "3.01a", "3.01a2", "2.0"),
  V_ditch = set_units(30, "m3"),
  V_event = set_units(100, "m3"),
  dilution = 2
)

Arguments

rate	The application rate in g/ha
interception	The fraction intercepted by the crop
Koc	The sorption coefficient to soil organic carbon
DT50	The soil half-life in days
t_runoff	The time between application and the runoff event, where degradation occurs, in days
exposit_reduction_version	The version of the reduction factors to be used. "3.02" is the current version used in Germany, "3.01a" is the version with additional percentages for 3 m and 6 m buffer zones used in Switzerland. "3.01a2" is a version introduced for consistency with previous calculations performed for a 3 m buffer zone in Switzerland, with the same reduction being applied to the dissolved and the bound fraction.
V_ditch	The volume of the ditch is assumed to be 1 m * 100 m * 30 cm = 30 m3
V_event	The unreduced runoff volume, equivalent to 10 mm precipitation on 1 ha
dilution	The dilution factor

Details

It is recommened to specify the arguments rate, Koc, DT50, t_runoff, V_ditch and V_event using units::units from the units package.

Value

A list containing the following components

perc_runoff

The runoff percentages for dissolved and bound substance

runoff

A matrix containing dissolved and bound input for the different distances

PEC_sw_runoff

A matrix containing PEC values for dissolved and bound substance for the different distances. If the rate was given in g/ha, the PECsw are in microg/L.

Source

Excel 3.02 spreadsheet available from https://www.bvl.bund.de/SharedDocs/Downloads/04_Pflanzenschutzmittel/zul_umwelt_exposit.html

See Also

perc_runoff_exposit for runoff loss percentages and perc_runoff_reduction_exposit for runoff reduction percentages used

Examples

  PEC_sw_exposit_runoff(500, Koc = 150)
  PEC_sw_exposit_runoff(600, Koc = 10000, DT50 = 195, exposit = "3.01a")

jranke/pfm documentation built on Nov. 17, 2024, 6:42 a.m.