Evaporation Losses

Evaporation losses from the reach are calculated:

Ech=coefevEoLchWfrΔtE_{ch}=coef_{ev}*E_o*L_{ch}*W*fr_{\Delta t} 7:1.6.1

where EchE_{ch} is the evaporation from the reach for the day (m3^3 H2_2O), coefevcoef_{ev} is an evaporation coefficient, EoE_o is potential evaporation (mm H2_2O), LchL_{ch} is the channel length (km), WW is the channel width at water level (m), and frΔtfr_{\Delta t} is the fraction of the time step in which water is flowing in the channel.

The evaporation coefficient is a calibration parameter for the user and is allowed to vary between 0.0 and 1.0.

The fraction of the time step in which water is flowing in the channel is calculated by dividing the travel time by the length of the time step.

Table 7:1-6: SWAT+ input variables that pertain to evaporation losses.

Variable NameDefinitionFile Name

EVRCH

coefevcoef_{ev}: Reach evaporation adjustment factor

.bsn

CH_L(2)

LchL_{ch}: Length of main channel (km)

.rte

Last updated