Boundaries
Within each boundary category, Flood Modeller offers an extensive range of options enabling you to tailor your model to your precise requirements and available data. Rainfall data can be converted directly to inflow (optionally with loss through evaporation and/or infiltration), or flow data (e.g. a discharge hydrograph, having performed your own hydrological analysis), or hydrological boundaries providing full rainfall-runoff methodologies.
You can account for how water enters and leaves your model using flow or water level boundaries. Flow boundaries define the variation of flow with time – most commonly utilised to provide inflows, for example, at the upstream ends of a model. Water level boundaries define the variation of water level with time – most commonly utilised to describe how water leaves the model network.
Boundary options, which represent flows entering and leaving your model, include:
Rainfall/Evaporation Boundary
A rainfall and/or evaporation boundary inflow. Rainfall data, evaporation data and infiltration data can all be specified separately and included as part of the inflow.
Flow Time Boundary
Model a discharge hydrograph (specifying flow versus time) as a boundary condition. This unit is ideal for entering flow data after having used your own analysis methods.
Abstraction Unit
Specify flow entering your system based on specified logical rules. It represents a discharge hydrograph without the time aspect needing to be specified.
FEH Boundary
A rainfall-runoff model based on procedures described in the Flood Estimation Handbook (1999).
FRQSIM Boundary
Derive an inflow hydrograph using FRQSIM (an abbreviation of 'flood FReQuency SIMulation'), a bespoke, fully distributed rainfall-runoff method.
FSSR
A rainfall-runoff model based on the Flood Studies Report (1975) and includes revisions contained in subsequent supplementary reports.
ReFH Boundary
A rainfall-runoff model using procedures developed by CEH to update the FSR/FEH Rainfall Runoff Method. This unit also provides ReFH Urban.
ReFH2 Boundary
Utilise the Revitalised Flood Hydrograph 2 software to derive an inflow hydrograph for a catchment or sub-catchment and includes the updates within ReFH2.3.
FSU
Access extreme rainfall and flood estimation data at both gauged and ungauged locations throughout Ireland. Take outputs from the FSU hydrological portal to use directly in Flood Modeller.
Generic Rainfall-Runoff
A range of globally applicable hydrological model components. Loss through infiltration can be applied using the Green-Ampt or SCS curve number methods.
Boundary options, which describe the variation of water levels in your model include:
Flow Head Boundary
Represent a flow against stage rating relationship. This boundary condition is also often referred to as a rating curve.
Normal/Critical Depth Boundary
A downstream boundary which automatically generates a flow-head relationship based on section data. Apply normal depth (from Manning's equation), or critical depth.
Head Time Boundary
Input a stage hydrograph (specifying water level versus time) as a boundary condition.
Tidal Harmonics Boundary
Generate water level data utilising numerical methods based upon Admiralty Tide Tables and the constituent harmonics of the tide for a given location and date.
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