Using ReFH2 to Generate TUFLOW Boundary Inputs

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In 2016, the Centre of Ecology and Hydrology (CEH) and Wallingford Hydro Solutions (http://www.hydrosolutions.co.uk) released another version of the revitalised rainfall-runoff model (ReFH2) which allows users to generate design flows and hydrographs from given rainfall events for both catchment and development sites. ReFH2 is the 2nd version of the “Revitalised Flood Handbook”, created and developed by Wallingford Hydro Solutions. It’s a rainfall-runoff model specifically applicable to England, Wales and parts of Scotland. It takes inputs from the FEH 2013 website and generates design rainfall events and provides a method for calculating design runoff from subcatchments. For a full description of the approaches, the reader is referred to their document which can be freely accessed at:- http://files.hydrosolutions.co.uk/refh2/ReFH2_Technical_Report.pdf
To use the ReFH2, the software must be installed locally and a licence must be obtained from Wallingford HydroSolutions. The ReFH2 software can be installed from (http://files.hydrosolutions.co.uk/refh2/latest).

FEH 2013 Rainfall

FEH2013 is a new method for generating design rainfall hyetographs, superseding the FEH1999 method. In order to generate the design rainfall, the user obtains design rainfall depths from the FEH2013 web service at https://fehweb.ceh.ac.uk for pre-defined return periods/duration combinations. This requires a log on and user credits to purchase the data for the desired location. Data is available at a river catchment scale and as a point value. Both of these provide XML containing the rainfall depths. This is then imported into the ReFH2 software to generate hyetographs based on Flood Studies Reports (FSR) approaches (which have been published).

ReFH2 Runoff

ReFH2 is the new method for the calculation of runoff. It hasn’t changed significantly from the original ReFH approach for which equations are publicly available, although there has been a mass balance closure improvement to the runoff model. There has however, been a change to the initial conditions, BF0 and Cini (initial baseflow and initial soil moisture, C) and there is an additional parameter, alpha. The data contained in the XML from the FEH2013 website also provides the catchment descriptors to calculate the necessary model parameters within ReFH 2 from which the runoff hydrograph is developed.

Creating Design Rainfall and Runoff within ReFH2 for use with TUFLOW

To generate rainfall or runoff using ReFH2, firstly open the ReFH2 software and create a new ReFH project.