# nutrients.cha
| Field | Description | Type | Unit | Default | Range |
| ------------------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------ | :-----: | :---------------------------: | :-----: | :---------: |
| [name](https://swatplus.gitbook.io/io-docs/introduction-1/channels/nutrients.cha/name) | Name of the channel nutrient record | string | n/a | n/a | n/a |
| plt\_n
| Channel organic N concentration | real | ppm | 0.0 | 0.0-100.0 |
| [plt\_p](https://swatplus.gitbook.io/io-docs/introduction-1/channels/nutrients.cha/plt_p) | Channel organic P concentration | real | ppm | 0.0 | 0.0-100.0 |
| [alg\_stl](https://swatplus.gitbook.io/io-docs/introduction-1/channels/nutrients.cha/alg_stl) | Local algal settling rate in the channel at 20ºC | real | m/day or m/hr | 1.0 | 0.15-1.82 |
| [ben\_disp](https://swatplus.gitbook.io/io-docs/introduction-1/channels/nutrients.cha/ben_disp) | 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 |
| [ben\_nh3n](https://swatplus.gitbook.io/io-docs/introduction-1/channels/nutrients.cha/ben_nh3n) | 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 |
| [ptln\_stl](https://swatplus.gitbook.io/io-docs/introduction-1/channels/nutrients.cha/ptln_stl) | Organic N settling rate in the channel at 20ºC | real | 1/day or 1/hr | 0.05 | 0.001-0.1 |
| [ptlp\_stl](https://swatplus.gitbook.io/io-docs/introduction-1/channels/nutrients.cha/ptlp_stl) | Organic P settling rate in the channel at 20ºC | real | 1/day or 1/hr | 0.05 | 0.001-0.10 |
| [cst\_stl](https://swatplus.gitbook.io/io-docs/introduction-1/channels/nutrients.cha/cst_stl) | Arbitrary non-conservative constituent settling rate in the channel at 20ºC | real | 1/day | 2.50 | 0.01-10.0 |
| [ben\_cst](https://swatplus.gitbook.io/io-docs/introduction-1/channels/nutrients.cha/ben_cst) | Benthic source rate for arbitrary non-conservative constituents in the channel at 20ºC | real | mg /m^2\*day | 2.50 | 0.01-10.0 |
| [cbn\_bod\_co](https://swatplus.gitbook.io/io-docs/introduction-1/channels/nutrients.cha/cbn_bod_co) | Carbonaceous biological oxygen demand deoxygenation rate in the channel at 20ºC | real | 1/day or 1/hr | 1.71 | 0.02-3.40 |
| [air\_rt](https://swatplus.gitbook.io/io-docs/introduction-1/channels/nutrients.cha/air_rt) | Reaeration rate in accordance with Fickian diffusion in the channel at 20ºC | real | 1/day or 1/hr | 50.0 | 0.0-100.0 |
| [cbn\_bod*\_*stl](https://swatplus.gitbook.io/io-docs/introduction-1/channels/nutrients.cha/cbn_bod_stl) | 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 |
| [ben\_bod](https://swatplus.gitbook.io/io-docs/introduction-1/channels/nutrients.cha/ben_bod) | 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 |
| [bact\_die](https://swatplus.gitbook.io/io-docs/introduction-1/channels/nutrients.cha/bact_die) | Coliform die-off rate in the channel at 20ºC | real | 1/day | 2.0 | 0.05-4.0 |
| [cst\_decay ](https://swatplus.gitbook.io/io-docs/introduction-1/channels/nutrients.cha/cst_decay) | Decay rate for arbitrary non-conservative constituents in the channel at 20ºC | real | 1/day | 1.71 | 0.0-10.0 |
| [nh3n\_no2n](https://swatplus.gitbook.io/io-docs/introduction-1/channels/nutrients.cha/nh3n_no2n) | 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 |
| [no2n\_no3n](https://swatplus.gitbook.io/io-docs/introduction-1/channels/nutrients.cha/no2n_no3n) | 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 |
| [ptln\_nh3n](https://swatplus.gitbook.io/io-docs/introduction-1/channels/nutrients.cha/ptln_nh3n) | Hydrolysis rate of organic N to ammonia in the channel at 20ºC | real | 1/day or 1/hr | 0.21 | 0.20-0.40 |
| [ptlp\_solp](https://swatplus.gitbook.io/io-docs/introduction-1/channels/nutrients.cha/ptlp_solp) | 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 |
| [q2e\_lt](https://swatplus.gitbook.io/io-docs/introduction-1/channels/nutrients.cha/q2e_lt) | Qual2E light averaging option | integer | n/a | 2 | 1-4 |
| [q2e\_alg](https://swatplus.gitbook.io/io-docs/introduction-1/channels/nutrients.cha/q2e_alg) | Qual2E option for calculating the local specific growth rate of algae | integer | n/a | 2 | 1-3 |
| [chla\_alg](https://swatplus.gitbook.io/io-docs/introduction-1/channels/nutrients.cha/chla_alg) | Ratio of chlorophyll-a to algal biomass | real | μg chla/mg alg | 50.0 | 10.0-100.0 |
| [alg\_n](https://swatplus.gitbook.io/io-docs/introduction-1/channels/nutrients.cha/alg_n) | Fraction of algal biomass that is N | real | mg N/mg alg | 0.08 | 0.07-0.09 |
| [alg\_p](https://swatplus.gitbook.io/io-docs/introduction-1/channels/nutrients.cha/alg_p) | Fraction of algal biomass that is P | real | mg P/mg alg | 0.02 | 0.01-0.02 |
| [alg\_o2\_prod](https://swatplus.gitbook.io/io-docs/introduction-1/channels/nutrients.cha/alg_o2_prod) | Oxygen production rate per unit of algal photosynthesis | real | mg O2/mg alg | 1.60 | 1.40-1.80 |
| [alg\_o2\_resp](https://swatplus.gitbook.io/io-docs/introduction-1/channels/nutrients.cha/alg_o2_resp) | Oxygen uptake rate per unit of algae respiration | real | mg O2/mg alg | 2.0 | 1.60-2.30 |
| [o2\_nh3n](https://swatplus.gitbook.io/io-docs/introduction-1/channels/nutrients.cha/o2_nh3n) | Oxygen uptake rate per unit of NH3-N oxidation | real | mg O2/mg N | 3.50 | 3.00-4.00 |
| [o2\_no2n](https://swatplus.gitbook.io/io-docs/introduction-1/channels/nutrients.cha/o2_no2n) | Oxygen uptake rate per unit of NO2-N oxidation | real | mg O2/mg N | 1.07 | 1.00-1.40 |
| [alg\_grow](https://swatplus.gitbook.io/io-docs/introduction-1/channels/nutrients.cha/alg_grow) | Maximum specific algal growth rate at 20ºC | real | 1/day | 2.0 | 1.00-3.00 |
| [alg\_resp](https://swatplus.gitbook.io/io-docs/introduction-1/channels/nutrients.cha/alg_resp) | Algal respiration rate at 20ºC | real | 1/day or 1/hr | 2.50 | 0.05-5.0 |
| [slr\_act](https://swatplus.gitbook.io/io-docs/introduction-1/channels/nutrients.cha/slr_act) | Fraction of solar radiation computed in the temperature heat balance that is photosynthetically active | real | fraction | 0.30 | 0.0-1.0 |
| [lt\_co](https://swatplus.gitbook.io/io-docs/introduction-1/channels/nutrients.cha/lt_co) | Half-saturation coefficient for light | real | MJ/(m^2\*hr) | 0.75 | 0.223-1.135 |
| [const\_n](https://swatplus.gitbook.io/io-docs/introduction-1/channels/nutrients.cha/const_n) | Michaelis-Menton half-saturation constant for N | real | mg N/L | 0.02 | 0.01-0.30 |
| [const\_p](https://swatplus.gitbook.io/io-docs/introduction-1/channels/nutrients.cha/const_p) | Michaelis-Menton half saturation constant for P | real | mg P/L | 0.03 | 0.001-0.05 |
| [lt\_nonalg](https://swatplus.gitbook.io/io-docs/introduction-1/channels/nutrients.cha/lt_nonalg) | Non-algal portion of the light extinction coefficient | real | 1/m | 1.0 | 0.0-10.0 |
| [alg\_shd\_l](https://swatplus.gitbook.io/io-docs/introduction-1/channels/nutrients.cha/alg_shd_l) | Linear algal self-shading coefficient | real | 1/(m\*ug chla/L) | 0.03 | 0.006-0.065 |
| [alg\_shd\_nl](https://swatplus.gitbook.io/io-docs/introduction-1/channels/nutrients.cha/alg_shd_nl) | Nonlinear algal self-shading coefficient | real | (1/m)(ug chla/L)^(-2/3) | 0.05 | 0.0-1.0 |
| [nh3\_pref](https://swatplus.gitbook.io/io-docs/introduction-1/channels/nutrients.cha/nh3_pref) | Algal preference factor for ammonia | real | none | 0.50 | 0.0-1.0 |