What to expect

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Runoff can be calculated using runoff models and rainfall-runoff relationships within NWSRFS.

In general, multiplying runoff times the unit hydrograph determines the forecast hydrograph for an upstream location in question.
Unit hydrograph theory assumes the hydrographs for given locations reflect the characteristics (e.g., shape, size, slope, etcetera) of that unique basin and that similar storms in the basin will produce similar hydrographs.
Downstream hydrographs can then be developed by various routing procedures.

Hydrologic routing

Analysis of a floodwave using procedures to solve the continuity equation (or storage equation) for an extended reach of the river, usually bounded by selected gage points.

Hydraulic routing

Deals directly with the hydraulic characteristics of the channel and may take into account dynamic effects.

Streamflow routing

The general methods used to forecast flow/stage downstream in streams.

The following are not intended to be detailed descriptions of possible routing techniques, but simply to touch on routing techniques currently available within NWSRFS.