set_evaporation.wateres: Evaporation setting or calculation

In tgmwri/wateres: Characteristics and Simulations for Water Reservoirs

Evaporation setting or calculation

Description

For monthly or daily data, sets or calculates time series of evaporation from the reservoir.

Usage

set_evaporation(reser, values, altitude, plant_cover)

## S3 method for class 'wateres'
set_evaporation(reser, values = NULL,
  altitude = NULL, plant_cover = NULL)

Arguments

reser	A wateres object.
values	A vector of evaporation values in mm, either monthly or daily values of length of reservoir time series, or 12 monthly values starting by January.
altitude	Reservoir altitude (m.a.s.l.) used for calculation of monthly evaporation values according to the Czech Technical Standard ČSN 75 2405, where evaporation is a function of altitude for range from 100 to 1200 m.
plant_cover	Part of flooded area covered with plants, optional number between 0 and 0.75.

Details

Evaporation is applied when calculating reservoir water balance. If no elevation-area-storage relationship is provided for the reservoir, evaporation only for flooded area related to the potential storage is assumed. Otherwise, evaporation is calculated for the area interpolated linearly by using the area-storage relationship (or area equal to the one of the limit value if storage fall out of the relationship limits).

If the plant_cover argument is given, evaporation will be increased by plant transpiration as given by Vrána and Beran (1998). When the reservoir is getting empty, it is assumed that the plant cover area corresponds with the shallowest parts of the reservoir and therefore the coefficient increasing evaporation is adjusted accordingly.

An error occurs if data in reser are not in monthly or daily time step of length one or if no dates are associated with daily data.

Value

A modified wateres object with evaporation time series added (denoted as E).

References

ČSN 72 2405; Vrána, Karel, and Beran, Jan: Rybníky a účelové nádrže, ČVUT, Praha, 1998 (in Czech)

Examples

reser = data.frame(
    Q = c(0.078, 0.065, 0.168, 0.711, 0.154, 0.107, 0.068, 0.057, 0.07, 0.485, 0.252, 0.236,
          0.498, 0.248, 0.547, 0.197, 0.283, 0.191, 0.104, 0.067, 0.046, 0.161, 0.16, 0.094),
    DTM = seq(as.Date("2000-01-01"), by = "months", length.out = 24))
reser = as.wateres(reser, storage = 14.4e6, area = 754e3)
sry(reser, storage = 21e3, yield = 0.14)
reser = set_evaporation(reser, c(7, 14, 40, 62, 82, 96, 109, 102, 75, 48, 34, 13))
reser = set_evaporation(reser, altitude = 529)
resul = calc_series(reser, storage = 21e3, yield = 0.14)

tgmwri/wateres documentation built on Feb. 13, 2024, 10:25 p.m.