Raven

Hello,

I generated a HBV-EC model structure from the template provided in the manual. In the autogenerated .rvp file I get a parameter called TOC_MULTIPLIER under the GLOBAL PARAMETERS. There's no mention of this parameter in the manual. Any pointers on what it is?

Many thanks,

Jason

Hi Jason

The TOC_MULTIPLIER stands for time of concentration multiplier, you have this parameter in your model because of the catchment routing method set to the triangular unit hydrograph (see page 64 of the manual for the calculation of the routing and tc parameter) from the HBV-EC model template.

The value should be at a default value of 1.0, meaning all of the times of concentration for each subbasin are autocalculated and those values are used directly. You can adjust the overall routing with the TOC_MULTIPLIER parameter, which will adjust all the times of concentration by the factor you provide with this parameter. For example, a value of 2.0 for TOC_MULTIPLIER for double the time of concentration for each subbasin, and will effectively route water more quickly within the catchment.

You can also specify times of concentration for each subbasin as separate parameters if you wish. It may be more useful to use the TOC_MULTIPLIER parameter in calibration unless you have specific information for tuning individual catchments, but the synatx would be somehting like this in the rvh file.



Hope that helps, feel free to repost if you have any more questions.

Cheers,
Rob

Hi Rob,

Thanks - that clears things up! I had changed the routing method to 'DUMP' (I'm working with small headwater catchments), but I must have made that change after I created the template parameter file. Therefore, TOC standing for 'time of concentration' wasn't on my radar at all and I wasn't seeing any impact on my simulations by adjusting the value.

Again, thanks for clearing that up.

Kind regards,

Jason