# 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     |
| <p><a href="nutrients.cha/plt_n">plt\_n</a></p><p></p>                                                             | 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\_bo&#x64;*\_*&#x73;tl](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   |
