Outflow

Pesticide is removed from the reach segment in outflow. The amount of dissolved and particulate pesticide removed from the reach segment in outflow is:

$pst_{sol,o}=Q*\frac{F_d*pst_{rchwtr}}{V}$ 7:4.1.13

$pst_{sorb,o}=Q*\frac{F_p*pst_{rchwtr}}{V}$ 7:4.1.14

where $pst_{sol,o}$ is the amount of dissolved pesticide removed via outflow (mg pst), $pst_{sorb,o}$ is the amount of particulate pesticide removed via outflow (mg pst), $Q$ is the rate of outflow from the reach segment (m$^3$ H$_2$O/day), $F_d$ is the fraction of total pesticide in the dissolved phase, $F_p$ is the fraction of total pesticide in the particulate phase, $pst_{rchwtr}$ is the amount of pesticide in the water (mg pst), and $V$ is the volume of water in the reach segment (m$^3$ H$_2$O).

Table 7:4-1: SWAT+ input variables that pesticide partitioning.

Variable Name	Definition	Input File
CHPST_KOC	$K_d$: Pesticide partition coefficient (m$^3$/g)	.swq
CHPST_REA	$k_{p,aq}$: Rate constant for degradation or removal of pesticide in the water (1/day)	.swq
CHPST_VOL	$v_v$: Volatilization mass-transfer coefficient (m/day)	.swq
CHPST_STL	$v_s$: Pesticide settling velocity (m/day)	.swq