RATIONAL METHOD 3
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PROJECT INFORMATION
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Project name: Floods estimation example
Project number: 2026-001
Client: City of Tshwane
Designer: Marco van Dijk
Stream / river: Moretele Spruit
Project folder: C:\GHI HydroSuite\Examples\Flood estimation\Flood_estimation_example_1

CATCHMENT CHARACTERISTICS
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Catchment area: 0.000 km²
Time of concentration: 1.252 h
Combined base runoff coefficient: 43.71 %

RAINFALL INFORMATION
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Extraction method: 3. Area-weighted grid rainfall
Location method: Latitude / longitude
Catchment file: C:/GHI HydroSuite/Examples/Flood estimation/Data_files/Catchment.gpkg
Station: 0513529_W — GARSTFONTEIN
Grid block size: 2
Rainfall values used: Estimate
Area reduction factor method: Small-area interpolation

RATIONAL METHOD 3 PEAK-FLOOD RESULTS
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Return period   TC (h)    Point rainfall (mm)  Point intensity (mm/h)  ARF (%)    Average intensity (mm/h)  Factor Ft    Runoff C (%)    Peak flow (m³/s)  
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1:2             1.25      30.70                24.52                   97.68      23.95                     0.500        21.85           39.15             
1:5             1.25      42.38                33.85                   96.79      32.77                     0.550        24.04           58.91             
1:10            1.25      51.25                40.93                   96.12      39.35                     0.600        26.23           77.17             
1:20            1.25      60.65                48.45                   95.41      46.23                     0.670        29.29           101.24            
1:25            1.25      63.99                51.12                   95.16      48.64                     0.709        30.99           112.73            
1:50            1.25      74.37                59.41                   94.37      56.07                     0.830        36.28           152.11            
1:100           1.25      85.89                68.60                   93.50      64.15                     1.000        43.71           209.68            
1:200           1.25      98.55                78.72                   92.55      72.85                     1.000        43.71           238.14            

Software: GHI HydroSuite Version 1.1
Engineering Reference Library: Version 2.2.0
Method: Rational Method 3
Date analysed: 2026-09-16 13:58:23

DISCLAIMER
This software has been developed as a tool to assist users and is provided for convenience only. While every reasonable
effort has been made to ensure the accuracy and reliability of the calculations and outputs, Green Hippo Innovations
makes no warranties, express or implied, regarding the results produced. Users are responsible for independently
verifying all results and interpretations. Green Hippo Innovations accepts no liability for any loss, damage, or consequences
arising from the use of this software or reliance on its outputs. Use of this software is entirely at the user's own risk.
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