Description Usage Arguments Value Note References Examples
prec_eros
computes erosivity values using an hyetograph.
1 | hyet_erosivity(hyet, time_step, en_equation = "brown_foster")
|
hyet |
an hyetograph from |
time_step |
hyetograph's time-step in minutes. Must have one of the
values: |
en_equation |
a character string specifying the equation to be used
for calculating kinetic energy of rainfall. Must have one of the values:
The rainfall's kinetic energy equations are:
In the above equations i is rainfall intensity (mm/hr) and e is the kinetic energy per unit of rainfall (MJ/ha/mm). |
a tibble with values.
hyet
must not contain missing dates. Please use the
hyet_fill
function before using prec_eros
.
Brown, L. C., & Foster, G. R. (1987). Storm erosivity using idealized intensity distributions. Transactions of the ASAE, 30(2), 379-0386.
McGregor, K. C., Bingner, R. L., Bowie, A. J., & Foster, G. R. (1995). Erosivity index values for northern Mississippi. Transactions of the ASAE, 38(4), 1039-1047.
Wischmeier, W. H., & Smith, D. D. (1958). Rainfall energy and its relationship to soil loss. Eos, Transactions American Geophysical Union, 39(2), 285-291.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 | # load libraries
library(dplyr)
library(tibble)
# load data
data(prec5min)
# remove near zero values
prec5min$prec <- round(prec5min$prec , 1)
# compute EI
time_step <- 5
ei_values <- prec5min %>%
hyet_fill(time_step) %>%
hyet_erosivity(time_step)
# filter erosivity events based on total rainfall height
ei_values %>%
filter(cum_prec >= 12.7)
|
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