Calculate ReFH/ReFH2 Parameters Dialog

The Calculate ReFH/ReFh2 model parameters dialog is used to view and edit Subcatchment parameters associated with the either the ReFH or ReFH2 runoff model.

This dialog can be displayed by selecting the button adjacent to the ReFH/ReFH2 Descriptors field on a subcatchment's Property Sheet.

Or alternatively, for calculating ReFH parameters for multiple subcatchments, this dialog can also be displayed by:

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Subcatchment ReFH/ReFH2 parameters can be entered manually or calculated from specified catchment descriptors. Click the OK button to accept the values currently displayed in the dialog. The ReFH/ReFH2 parameter fields for all currently selected subcatchments will be updated with the contents of the parameter Value field in the bottom half of the dialog.

Note

To use ReFH2 in InfoWorks ICM, the ReFH2 software must be installed on the same PC as InfoWorks ICM, and a licence must have been obtained from Wallingford HydroSolutions (WHS). The ReFH2 software must be available when the relevant calculations are performed for subcatchments and rainfall events. However, the ReFH2 software does not have to be installed on the PC that is running the simulation.

Catchment Descriptors

Catchment descriptors can either be entered manually, loaded from the FEH CD, or downloaded from the FEH Web Service.

These descriptors will be used to calculate those ReFH/ReFH2 parameters listed in the bottom half of the dialog that have Method set to Design.

Catchment Descriptors

Fields

Description
PROPWET Proportion of time the catchment soil moisture deficit (SMD) was below 6mm during the period 1961-1990
BFIHOST Baseflow Index
DPLBAR Mean drainage path length
DPSBAR Mean drainage path slope
URBEXT

These options are enbled when Model type field is set to ReFH

  • 1990 - value derived from Land cover data based on satellite imagery taken around 1990
  • 2000 - value derived from CEH Land Cover Map 2000

Extent of urban and suburban land cover:

SAAR Only enabled when Model type field is set to ReFH2

Standard -period average annual rainfall (1961-1990)

Model type

The version of model used for the calculation:

  • ReFH
  • ReFH2
Note

If the ReFH/ReFh2 Parameters dialog was displayed by selecting the Calculate ReFH parameters option from the Model menu (described above), then the Model Type field is automatically set to ReFH.

Scale Only enabled when Model type field is set to ReFH2

The scale can be set to :

  • Catchment
  • Plot
Country Only enabled when Model type field is set to ReFH2

The county can be set to:

  • England, Wales and Northern Ireland
  • Scotland
ReFH2

The version number of the ReFH2 software currently being run on the PC.

A read-only field which is displayed when Model type field is set to ReFH2

Click on:

Calculation of ReFH Parameters

For each parameter with the Method field set to Design, InfoWorks ICM will calculate the parameter value using the Catchment Descriptors specified in the top part of the dialog.

The Value field will be set to the calculated value multiplied by the Factor specified for the parameter.

Parameter

Calculated Value

(R&D Technical Report FD1913/TR)

Cmax 596.7 BFIHOST0.95 PROPWET-0.24
Tp 1.563 PROPWET-1.09 DPLBAR0.60 (1+URBEXT)-3.34 DPSBAR-0.25
Up 0.65
Uk 0.8
BL 25.47 BFIHOST0.47 DPLBAR0.21 PROPWET-0.53 (1+URBEXT)-3.01
BR 3.751 BFIHOST1.08 PROPWET0.36

For each parameter with the Method field set to User, the value of the ReFH parameter is manually entered in the Value field of the parameter.

Subcatchments

Subcatchment Data Fields

Importing Catchment Parameters from the FEH CD or Web Service