Flood Discharge By Fuller's Formula Calculator

Fuller's Formula:

\[ Q_{FL} = C_{FL} \times (A_{km})^{0.8} \times (1 + 0.8 \times \log(T_m, e)) \times (1 + 2.67 \times (A_{km})^{-0.3}) \]

Flood Discharge (Q_FL):

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1. What is Fuller's Formula?

Fuller's Formula is an empirical equation used to estimate peak flood discharge based on catchment area characteristics and time period. It provides a reliable method for flood discharge estimation in hydrological studies and engineering applications.

2. How Does the Calculator Work?

The calculator uses Fuller's Formula:

\[ Q_{FL} = C_{FL} \times (A_{km})^{0.8} \times (1 + 0.8 \times \log(T_m, e)) \times (1 + 2.67 \times (A_{km})^{-0.3}) \]

Where:

\( Q_{FL} \) — Flood discharge (m³/s)
\( C_{FL} \) — Fuller's constant (empirical coefficient)
\( A_{km} \) — Catchment area (km²)
\( T_m \) — Time period for flood discharge (years)
\( e \) — Napier's constant (≈2.71828)

Explanation: The formula accounts for catchment area size, time period, and regional characteristics through the empirical constant to estimate peak flood discharge.

3. Importance of Flood Discharge Calculation

Details: Accurate flood discharge estimation is crucial for hydraulic structure design, flood risk assessment, urban planning, and water resource management. It helps in designing adequate drainage systems and flood protection measures.

4. Using the Calculator

Tips: Enter Fuller's constant (typically ranges from 0.1 to 0.3 depending on regional characteristics), catchment area in km², and time period in years. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is the typical range for Fuller's constant?
A: Fuller's constant typically ranges from 0.1 to 0.3, with specific values determined through regional hydrological studies and empirical data analysis.

Q2: How accurate is Fuller's formula compared to other methods?
A: Fuller's formula provides reasonable estimates for medium to large catchments and is widely used in engineering practice, though site-specific calibration may improve accuracy.

Q3: What are the limitations of Fuller's formula?
A: The formula may be less accurate for very small or very large catchments, and regional variations in hydrological characteristics should be considered when applying the constant values.

Q4: How is the time period determined for flood discharge calculation?
A: The time period refers to the return period or recurrence interval of the flood event being analyzed, typically based on historical flood records and statistical analysis.

Q5: Can this formula be used for all types of catchments?
A: While widely applicable, the formula works best for catchments with relatively homogeneous characteristics. Complex terrain or unusual hydrological conditions may require additional considerations.