RAINFALL ANALYSIS – AFTER RAINFALL GAUGE MEASUREMENT

Hydrology Engineering Design – Kitchener City Rainfall Analysis

Hydrology Engineering Design: Rainfall Analysis

Kitchener City Watershed – Rainfall Data Processing & Analysis

This tool implements standard hydrological methods for rainfall analysis including Thiessen Polygon, Arithmetic Mean, and Normal Ratio methods.

Input Data for Kitchener City Rainfall Stations

Enter rainfall data (in mm) and station coverage area (in km²) for 6 rainfall stations in Kitchener City region.

Station Rainfall Data (mm)

Enter the precipitation recorded at each station during the storm event:

Station Coverage Area (km²)

Enter the area represented by each station for Thiessen Polygon method:

Additional Parameters

Required for Normal Ratio Method
Select method based on normal rainfall comparison

Arithmetic Mean Method

This method is used when gauges are uniformly distributed and individual gauge catches do not vary greatly about the mean.

Pav = (1/n) Σ Pi

Thiessen Polygon Method

This method gives weightage to all gauges based on their area coverage, assuming rainfall at any point within a polygon is the same as at the nearest gauge.

Pav = Σ (Ai/A) × Pi

Thiessen Polygon Weight Distribution

Normal Ratio Method

This method is used when normal annual rainfall of index stations differs by more than 10% from that of the missing station.

Px = (Nx/n) × Σ (Pi/Ni)

Results Summary & Comparison

Comparison of different methods for computing average rainfall over Kitchener City watershed.

Method Comparison

Engineering Recommendation: The Thiessen Polygon method is generally preferred for watershed analysis as it accounts for spatial distribution of rainfall gauges. However, for preliminary estimates or when station areas are not available, the Arithmetic Mean method provides a quick approximation.

Hydrology Engineering Design Tool for Kitchener City • Based on Standard Hydrology Methods

Note: This tool is for educational and preliminary design purposes. Always verify with field data.