Unit-specific Calculations

In general, RiverWare does calculations in internal units. Changing the scheme will not affect underlying results. But, there are a few methods that depend on one or more slot units. The methods are described, organized by the category of calculation.

Exponentiation

For the methods in Table 4.3, a change in the units can produce different results due to calculations that use user-units in combination with a user-input exponent with units of NONE.

Object | Category | User Method | Link, in Objects |
---|---|---|---|

Groundwater Storage | Groundwater Outflow | Exponential Flow | |

Groundwater Storage | Deep Percolation | Exponential Percolation | |

Reach | Reach Evaporation | Inflow Exponent Pan Evaporation | |

Reach | Reach Seepage | Seepage and Riparian CU Loss | |

Reservoir | Sediment | CRSS Sediment |

Time Units

If the model timestep is 1 Month, the lag time slots for the methods in Table 4.4 must have TIME units of “month” or an error will occur.

Object | Category | User Method | Link, in Objects |
---|---|---|---|

Reach | Routing | Time Lag | |

Reach | Routing | Variable Time Lag | |

Reach | Drain Elevation | Stage Elevation Interpolation |

Similarly, in one or more table slots for the methods in Table 4.5, the TIME unit must be “day” in the first column or an error will occur.

Object | Category | User Method | Link, in Objects |
---|---|---|---|

Reach | Gain Loss | Interpolated Flow Gain Loss | |

Reach | Routing | Variable Time Lag |

Unit-dependent Calculations

The methods in Table 4.6 convert values to specific units for calculations. These calculations also use user-input parameter values with units of NONE. Changing the unit scheme should not change the results from these methods, but you must know the units used in order to set the parameter values appropriately.

Object | Category | User Method | Link, in Objects |
---|---|---|---|

Reach | Routing | Storage Routing | |

Reach | Routing | Variable Storage Routing | |

Reach | Depth to Flow | Power Function | |

Distribution Canal | Flow Routing | Storage Time | |

Distribution Canal | Flow Routing | Variable Storage Time | |

Reservoir | Sediment Transport | Perm Pool Sed (Pre2000) | |

Reservoir | Sediment Transport | Total Vol Sed (Post2000) |

Revised: 01/05/2024