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Decay rate for arbitrary non-conservative constituents in the channel at 20ºC
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Oxygen production rate per unit of algal photosynthesis
Oxygen uptake rate per unit of algae respiration
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Fraction of solar radiation computed in the temperature heat balance that is photosynthetically active
Half-saturation coefficient for light
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Non-algal portion of the light extinction coefficient
Linear algal self-shading coefficient
Nonlinear algal self-shading coefficient
Algal preference factor for ammonia
Channel organic N concentration
Name of the channel nutrient record
The name of the channel nutrient record is a primary key referenced by nut in channel-lte.cha.
Local algal settling rate in the channel at 20ºC
If routing is performed on an hourly time step, the units of alg_stl are converted to m/hr by the model.
Channel organic P concentration
Benthic source rate for dissolved P in the channel at 20ºC
If routing is performed on an hourly time step, the units of ben_disp are converted to mg P/m2*hr by the model.
Benthic source rate for NH3-N in the channel at 20ºC
If routing is performed on an hourly time step, the units of ben_nh3n are converted to mg N/m2*hr by the model.
Carbonaceous biological oxygen demand deoxygenation rate in the channel at 20ºC
If routing is performed on an hourly time step, the units of cbn_bod_co are converted to 1/hr by the model.
Reaeration rate in accordance with Fickian diffusion in the channel at 20ºC
If routing is performed on an hourly time step, the units of air_rt are converted to 1/hr by the model.
Rate of loss of carbonaceous biological oxygen demand due to settling in the reach at 20 ºC
Arbitrary non-conservative constituent settling rate in the channel at 20ºC
Benthic source rate for arbitrary non-conservative constituents in the channel at 20ºC
Organic P settling rate in the channel at 20ºC
If routing is performed on an hourly time step, the units of ptlp_stl are converted to 1/hr by the model.
Organic N settling rate in the channel at 20ºC
If routing is performed on an hourly time step, the units of ptln_stl are converted to 1/hr by the model.
Biological oxidation rate of NO2 to NO3 in the channel at 20ºC in well-aerated conditions
If routing is performed on an hourly time step, the units of no2n_no3n are converted to 1/hr by the model.
Biological oxidation rate of NH3 to NO2 in the channel at 20ºC in well-aerated conditions
If routing is performed on an hourly time step, the units of nh3n_no2n are converted to 1/hr by the model.
Benthic oxygen demand rate in the channel at 20ºC
If routing is performed on an hourly time step, the units of ben_bod are converted to mg/m2*hr by the model.
Qual2E option for calculating the local specific growth rate of algae
Qual2E provides three different options for computing the algal growth rate:
Multiplicative: The multiplicative option multiplies the growth factors for light, nitrogen and phosphorus together to determine their net effect on the local algal growth rate. This option has its biological basis in the multiplicative effects of enzymatic processes involved in photosynthesis.
Limiting nutrient: The limiting nutrient option calculates the local algal growth rate as limited by light and either nitrogen or phosphorus. The nutrient/light effects are multiplicative, but the nutrient/nutrient effects are alternate. The algal growth rate is controlled by the nutrient with the smaller growth limitation factor. This approach mimics Liebig’s law of the minimum.
Harmonic mean: The harmonic mean is mathematically analogous to the total resistance of two resistors in parallel and can be considered a compromise between the multiplicative and limiting nutrient options. The algal growth rate is controlled by a multiplicative relation between light and nutrients, while the nutrient/nutrient interactions are represented by a harmonic mean.
Hydrolysis rate of organic N to ammonia in the channel at 20ºC
If routing is performed on an hourly time step, the units of ptln_nh3n are converted to 1/hr by the model.
Coliform die-off rate in the reach at 20ºC
Mineralization rate of organic P to dissolved P in the channel at 20ºC
If routing is performed on an hourly time step, the units of ptlp_solp are converted to 1/hr by the model.
Fraction of algal biomass that is P
This file controls the channel nutrient properties.
| Field | Description | Type | Unit | Default | Range |
|---|---|---|---|---|---|
Name of the channel nutrient record
string
n/a
n/a
n/a
Channel organic N concentration
real
ppm
0.0
0.0-100.0
Channel organic P concentration
real
ppm
0.0
0.0-100.0
Local algal settling rate in the channel at 20ºC
real
m/day or m/hr
1.0
0.15-1.82
Benthic source rate for dissolved P in the channel at 20ºC
real
mg P/m2*day or mg P/m2*hr
0.05
0.001-0.10
Benthic source rate for NH3-N in the channel at 20ºC
real
mg N/m2*day or mg N/m2*hr
0.50
0.0-1.0
Organic N settling rate in the channel at 20ºC
real
1/day or 1/hr
0.05
0.001-0.1
Organic P settling rate in the channel at 20ºC
real
1/day or 1/hr
0.05
0.001-0.10
Arbitrary non-conservative constituent settling rate in the channel at 20ºC
real
1/day
2.50
0.01-10.0
Benthic source rate for arbitrary non-conservative constituents in the channel at 20ºC
real
mg /m^2*day
2.50
0.01-10.0
Carbonaceous biological oxygen demand deoxygenation rate in the channel at 20ºC
real
1/day or 1/hr
1.71
0.02-3.40
Reaeration rate in accordance with Fickian diffusion in the channel at 20ºC
real
1/day or 1/hr
50.0
0.0-100.0
Rate of loss of CBOD due to settling in the channel at 20ºC
real
1/day or 1/hr
0.36
-0.36-0.36
Sediment oxygen demand rate in the channel at 20ºC
real
mg O2/m2*day or mg O2/m2*hr
2.0
0.0-100.0
Coliform die-off rate in the channel at 20ºC
real
1/day
2.0
0.05-4.0
Decay rate for arbitrary non-conservative constituents in the channel at 20ºC
real
1/day
1.71
0.0-10.0
Biological oxidation rate of NH3 to NO2 in the channel at 20ºC in well-aerated conditions
real
1/day or 1/hr
0.55
0.10-1.0
Biological oxidation rate of NO2 to NO3 in the channel at 20ºC in well-aerated conditions
real
1/day or 1/hr
1.10
0.20-2.0
Hydrolysis rate of organic N to ammonia in the channel at 20ºC
real
1/day or 1/hr
0.21
0.20-0.40
Mineralization rate of organic P to dissolved P in the channel at 20ºC
real
1/day or 1/hr
0.35
0.01-0.70
Qual2E light averaging option
integer
n/a
2
1-4
Qual2E option for calculating the local specific growth rate of algae
integer
n/a
2
1-3
Ratio of chlorophyll-a to algal biomass
real
μg chla/mg alg
50.0
10.0-100.0
Fraction of algal biomass that is N
real
mg N/mg alg
0.08
0.07-0.09
Fraction of algal biomass that is P
real
mg P/mg alg
0.02
0.01-0.02
Oxygen production rate per unit of algal photosynthesis
real
mg O2/mg alg
1.60
1.40-1.80
Oxygen uptake rate per unit of algae respiration
real
mg O2/mg alg
2.0
1.60-2.30
Oxygen uptake rate per unit of NH3-N oxidation
real
mg O2/mg N
3.50
3.00-4.00
Oxygen uptake rate per unit of NO2-N oxidation
real
mg O2/mg N
1.07
1.00-1.40
Maximum specific algal growth rate at 20ºC
real
1/day
2.0
1.00-3.00
Algal respiration rate at 20ºC
real
1/day or 1/hr
2.50
0.05-5.0
Fraction of solar radiation computed in the temperature heat balance that is photosynthetically active
real
fraction
0.30
0.0-1.0
Half-saturation coefficient for light
real
MJ/(m^2*hr)
0.75
0.223-1.135
Michaelis-Menton half-saturation constant for N
real
mg N/L
0.02
0.01-0.30
Michaelis-Menton half saturation constant for P
real
mg P/L
0.03
0.001-0.05
Non-algal portion of the light extinction coefficient
real
1/m
1.0
0.0-10.0
Linear algal self-shading coefficient
real
1/(m*ug chla/L)
0.03
0.006-0.065
Nonlinear algal self-shading coefficient
real
(1/m)(ug chla/L)^(-2/3)
0.05
0.0-1.0
Algal preference factor for ammonia
real
none
0.50
0.0-1.0
Oxygen uptake rate per unit of NO2-N oxidation
Fraction of algal biomass that is N
Maximum specific algal growth rate at 20ºC
If routing is performed on an hourly time step, alg_grow is converted to 1/hr by the model.
Michaelis-Menton half-saturation constant for N
The Michaelis-Menton half-saturation constant for N defines the concentration of nitrogen, at which algal growth is limited to 50% of the maximum growth rate.
Algal respiration rate at 20ºC
If routing is performed on an hourly time step, alg_resp is converted to 1/hr by the model.
Qual2E light averaging option
Qual2E defines four light averaging options:
Depth-averaged algal growth attenuation factor for light (FL) is computed from one daylight average solar radiation value calculated in the steady state temperature heat balance.
FL is computed from one daylight average solar radiation value supplied by the user.
FL is obtained by averaging the hourly daylight values of FL computed from the hourly daylight values of solar radiation calculated in the steady state temperature heat balance.
FL is obtained by averaging the hourly daylight values of FL computed from the hourly daylight values of solar radiation calculated from a single value of total daily, photosynthetically active, solar radiation and an assumed cosine function.
The only option currently active in SWAT+ is 2.
Ratio of chlorophyll-a to algal biomass
Michaelis-Menton half-saturation constant for P
The Michaelis-Menton half-saturation constant for P defines the concentration of phosphorus, at which algal growth is limited to 50% of the maximum growth rate.
Oxygen uptake rate per unit of NH3-N oxidation