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Local Settling Rate of Algae

The local settling rate of algae represents the net removal of algae due to settling. The user defines the local settling rate of algae at 20 $\degree$ C. The settling rate is adjusted to the local water temperature using the relationship:

$\sigma_1=\sigma_{1,20}*1.024^{(T_{water}-20)}$ 7:3.1.18

where $\sigma_1$ is the local settling rate of algae (m/day or m/hr), $\sigma_{1,20}$ is the local algal settling rate at 20 $\degree$ C (m/day or m/hr), and $T_{water}$ is the average water temperature for the day or hour ( $\degree$ C).

Table 7:3-1: SWAT+ input variables used in algae calculations.

Variable Name

Definition

File Name

Local Settling Rate of Algae

$\sigma_1=\sigma_{1,20}*1.024^{(T_{water}-20)}$ 7:3.1.18

Table 7:3-1: SWAT+ input variables used in algae calculations.

Variable Name

Definition

File Name

LAMBDA0

: Non-algal portion of the light extinction coefficient (m)

.wwq

LAMBDA1

: Linear algal self shading coefficient (m (-chla/L))

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LAMBDA2

: Nonlinear algal self shading coefficient (m(-chla/L))

.wwq

K_N

: Michaelis-Menton half-saturation constant for nitrogen (mg N/L)

.wwq

K_P

: Michaelis-Menton half-saturation constant for phosphorus (mg P/L)

.wwq

RHOQ

: Local algal respiration rate at 20C (day)

.wwq

RS1

: Local algal settling rate at 20C (m/day)

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