Storm Duration
This describes the duration of the design storm event. The intensity of the storm is higher for lower durations, though the total quantity of water is higher for longer durations. Therefore the designer must decide which duration will present the worst case for the drainage system being considered. Typically a storm duration of 5 minutes is used on sites less than 4,000m2. For larger catchments, durations up to 15 minutes can be critical depending on the time of concentration.
Related Spreadsheets from CivilWeb;
Colebrook White Pipe Design Spreadsheet
This spreadsheet uses the Colebrook-White and Darcy-Weisbach formulas to calculate the flow conditions in a circular pipe acting under gravity.
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Manning Pipe Design Spreadsheet
This spreadsheet uses the Manning formula to calculate the flow conditions in a circular pipe acting under gravity only.
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Manning Open Channel Design Spreadsheet
This spreadsheet uses the Manning formula to calculate the flow conditions in an open channel acting under gravity only.
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Runoff Calculator Spreadsheet
This spreadsheet calculates the design runoff flow for a site in accordance with the Flood Estimation Handbook.
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Linear Drainage Design Spreadsheet
This spreadsheet calculates the maximum flow from a specified linear drainage channel and checks whether the channel is sufficient for the specified site and storm conditions.
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Attenuation Design Spreadsheet
This spreadsheet calculates the requirements for a attenuation system and assists the user to design a suitable system.
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Soakaway Design Spreadsheet
This spreadsheet calculates the requirements for a soakaway system and assists the user to design a suitable system.
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Full Drainage Design Suite
Full drainage design suite (50% Discount) including 7 spreadsheets;
- Colebrook White Pipe Design
- Manning Pipe Design
- Manning Open Channel Design
- Linear Drainage Design
- Runoff Calculator
- Attenuation Design
- Soakaway Design