Configuration Parameters

This page documents all variables defined in General_Data.xlsx.

Each parameter controls a specific aspect of HydroPol2D, including:

• simulation timing
• numerical stability
• hydrological processes
• hydraulic routing
• input datasets
• output control

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Running Control

Variable	Units	Description
$\mathrm{time\_step\_model}$	$\mathrm{s}$	Initial model time step used in the simulation
$\mathrm{min\_time\_step}$	$\mathrm{s}$	Minimum allowable adaptive time step for numerical stability
$\mathrm{max\_time\_step}$	$\mathrm{s}$	Maximum allowable adaptive time step
$\mathrm{time\_step\_change}$	$\mathrm{s}$	Increment used to adjust the adaptive time step
$\alpha_{\min}$	—	Minimum Courant-like stability coefficient
$\alpha_{\max}$	—	Maximum Courant-like stability coefficient
$\mathrm{date\_begin}$	—	Simulation start date and time
$\mathrm{date\_end}$	—	Simulation end date and time

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Normal Flow Boundary Condition

Variable	Units	Description
$\mathrm{slope\_outlet}$	$\mathrm{m\,m^{-1}}$	Prescribed slope used to estimate normal flow conditions at the outlet boundary

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Maps and Plots Control

Variable	Units	Description
$\mathrm{record\_time\_maps}$	$\mathrm{min}$	Time interval for saving raster outputs
$\mathrm{record\_time\_hydrographs}$	$\mathrm{min}$	Time interval for saving hydrograph outputs
$\mathrm{Pol\_min}$	$\mathrm{mg\,L^{-1}}$	Minimum pollutant concentration threshold for visualization
$\mathrm{depth\_wse}$	$\mathrm{m}$	Threshold depth used to define water surface elevation outputs
$\mathrm{flag\_wse}$	—	Flag to activate water surface elevation outputs instead of depth
$\mathrm{record\_time\_spatial\_rainfall}$	$\mathrm{min}$	Time interval for exporting spatial rainfall maps
$\mathrm{time\_save\_ETP}$	$\mathrm{min}$	Time interval for saving evapotranspiration outputs
$\mathrm{record\_time\_spatial\_ETP}$	$\mathrm{min}$	Time interval for exporting spatial ETP fields

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River Geometry Parameters

If flag_reduce_dem is activated, river cells elevation are reduced to account for river bathymetry. A set of 4 parameters are then required to describe the flow width and depth. These parameters are valid to convert flow accumulation area [$\mathrm{km^2}$] into flow depth [$\mathrm{m}$] and width [$\mathrm{m}$].

Variable	Units	Description
$\alpha_1$	—	Empirical coefficient controlling channel geometry scaling
$\alpha_2$	—	Secondary coefficient for hydraulic geometry relationships
$\beta_1$	—	Exponent controlling width or hydraulic scaling behavior
$\beta_2$	—	Secondary exponent for hydraulic scaling relationships
$n$	$\mathrm{s\,m^{-1/3}}$	Manning’s roughness coefficient for channel and surface flow

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Water Quality Inputs

Variable	Units	Description
$\mathrm{ADD}$	$\mathrm{days}$	Antecedent dry days used in pollutant buildup modeling
$\mathrm{min\_Bt}$	$\mathrm{g\,m^{-2}}$	Minimum pollutant buildup threshold
$\mathrm{Bmin}$	$\mathrm{g\,m^{-2}}$	Minimum allowable pollutant mass
$\mathrm{Bmax}$	$\mathrm{g\,m^{-2}}$	Maximum pollutant buildup capacity

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DEM Processing and Terrain Controls

Variable	Units	Description
$\mathrm{min\_area}$	$\mathrm{km^2}$	Minimum drainage area threshold for channel initiation
$\tau$	—	Smoothing parameter controlling DEM filtering intensity
$\mathrm{K\_value}$	—	Parameter controlling terrain processing or hydraulic scaling
$\mathrm{sl}$	$\mathrm{m\,m^{-1}}$	Minimum slope threshold used in DEM conditioning
$\mathrm{resolution\_resample}$	$\mathrm{m}$	Target resolution for DEM resampling
$\mathrm{slope\_DTM}$	$\%$	Slope threshold used for terrain correction or filtering

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File Paths and Input Data

Variable	Units	Description
$\mathrm{topo\_path}$	—	Path to TopoToolbox directory
$\mathrm{DEM\_path}$	—	Path to Digital Elevation Model
$\mathrm{LULC\_path}$	—	Path to Land Use / Land Cover raster
$\mathrm{SOIL\_path}$	—	Path to soil classification raster
$\mathrm{Warmup\_Depth\_path}$	—	Path to initial warm-up water depth condition
$\mathrm{Initial\_Buildup\_path}$	—	Path to initial pollutant buildup map
$\mathrm{Initial\_Soil\_Moisture\_path}$	—	Path to initial soil moisture condition
$\mathrm{Albedo\_path}$	—	Path to albedo raster
$\mathrm{LAI\_path}$	—	Path to leaf area index raster
$\mathrm{RiverWidths\_path}$	—	Path to river width raster
$\mathrm{RiverDepths\_path}$	—	Path to river depth raster
$\mathrm{DTB\_path}$	—	Path to depth-to-bedrock raster
$\mathrm{B1\_path}$	—	Path to pollutant-related parameter raster
$\mathrm{B2\_path}$	—	Path to pollutant-related parameter raster
$\mathrm{W1\_path}$	—	Path to pollutant wash-off parameter raster
$\mathrm{W2\_path}$	—	Path to pollutant wash-off parameter raster
$\mathrm{Subgrid\_DEM\_path}$	—	Path to high-resolution DEM for subgrid computations
$\mathrm{hydropol2d\_tools}$	—	Path to HydroPol2D function library

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Human Instability Parameters

Variable	Units	Description
$\mu$	—	Friction coefficient between human body and ground
$C_d$	—	Drag coefficient for human body in flow
$\rho_{\mathrm{person}}$	$\mathrm{kg\,m^{-3}}$	Density of human body
$\mathrm{weight\_person}$	$\mathrm{kg}$	Average human weight
$\mathrm{height\_person}$	$\mathrm{m}$	Average human height
$\mathrm{width1\_person}$	$\mathrm{m}$	Characteristic frontal width
$\mathrm{width2\_person}$	$\mathrm{m}$	Secondary width parameter
$\rho_{\mathrm{water}}$	$\mathrm{kg\,m^{-3}}$	Density of water
$g$	$\mathrm{m\,s^{-2}}$	Gravitational acceleration

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Observation Points

Variable	Units	Description
$\mathrm{Gauge}$	—	Gauge identifier
$\mathrm{Easting}$	$\mathrm{m}$	Easting coordinate
$\mathrm{Northing}$	$\mathrm{m}$	Northing coordinate
$\mathrm{Label\ Name}$	—	Output label for time series

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Design Storm Parameters

Variable	Units	Description
$\mathrm{RP}$	$\mathrm{years}$	Return period of design storm
$\mathrm{Rainfall\ Duration}$	$\mathrm{min}$	Total storm duration
$K$	—	Intensity–duration–frequency coefficient
$a$	—	IDF curve parameter
$b$	—	IDF curve parameter
$c$	—	IDF curve parameter
$\mathrm{dt\_design}$	$\mathrm{min}$	Time resolution of synthetic storm

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Satellite or Radar Rainfall

Variable	Units	Description
$\mathrm{Time}$	$\mathrm{min}$	Time step of rainfall raster
$\mathrm{Raster\ Directory}$	—	Path to rainfall raster files

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Satellite Transpiration

Variable	Units	Description
$\mathrm{Time}$	$\mathrm{day}$	Time index for transpiration data
$\mathrm{Raster\ Directory}$	—	Path to transpiration rasters

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Satellite Evaporation

Variable	Units	Description
$\mathrm{Time}$	$\mathrm{day}$	Time index for evaporation data
$\mathrm{Raster\ Directory}$	—	Path to evaporation rasters

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Notes

The descriptions provided here represent the functional role of each parameter within HydroPol2D.

Final definitions should be refined based on:

• spreadsheet comments
• calibration strategy
• application context

This table serves as the central reference for model configuration.